Annealing of steel parts
To facilitate mechanical or plastic processing of a steel part, its hardness is reduced by annealing. The so-called full annealing consists in the fact that the part or workpiece is heated to a temperature of 900 ° C, maintained at this temperature for some time necessary to warm it throughout its entire volume, and then slowly (usually together with the furnace) cooled to room temperature.
Internal stresses that arise in the part during machining are removed by low-temperature annealing, in which the part is heated to a temperature of 500-600°C and then cooled along with the furnace. To relieve internal stresses and slightly reduce the hardness of steel, incomplete annealing is used - heating to 750-760 ° C and subsequent slow (also together with the furnace) cooling.
Annealing is also used when hardening is unsuccessful or when it is necessary to overheat a tool for processing another metal (for example, if a copper drill needs to be overheated to drill cast iron). During annealing, the part is heated to a temperature slightly below the temperature required for hardening, and then gradually cooled in air. As a result, the hardened part again becomes soft and amenable to machining.
Copper is also subjected to heat treatment. In this case, copper can be made either softer or harder. However, unlike steel, copper is hardened by slow cooling in air, and copper becomes soft by rapid cooling in water. If a copper wire or tube is heated red hot (600° C) over a fire and then quickly immersed in water, the copper will become very soft. After giving the desired shape, the product can again be heated over a fire to 400 ° C and allowed to cool in air. The wire or tube will then become solid. If it is necessary to bend the tube, it is tightly filled with sand to avoid flattening and cracking.
Annealing brass increases its ductility. After annealing, brass becomes soft, easily bends, knocks out and stretches well. For annealing, it is heated to 600 ° C and allowed to cool in air at room temperature.
Annealing and hardening of duralumin
Annealing of duralumin is carried out to reduce its hardness. The part or workpiece is heated to approximately 360°C, as during hardening, held for some time, and then cooled in air. The hardness of annealed duralumin is almost half that of hardened duralumin.
Approximately the heating temperature of a duralumin part can be determined as follows: At a temperature of 350-360°C, a wooden splinter, which is passed along the hot surface of the part, becomes charred and leaves a dark mark. The temperature of the part can be determined quite accurately using a small (about the size of a match head) piece of copper foil, which is placed on its surface. At a temperature of 400°C, a small greenish flame appears above the foil.
Annealed duralumin has low hardness; it can be stamped and bent twice without fear of cracks.
Hardening. Duralumin can be hardened. When hardening, parts made of this metal are heated to 360-400°C, held for some time, then immersed in water at room temperature and left there until completely cooled. Immediately after this, duralumin becomes soft and flexible, easily bent and forged. It acquires increased hardness after three to four days. Its hardness (and at the same time fragility) increases so much that it cannot withstand bending at a small angle.
Duralumin acquires its highest strength after aging. Aging at room temperatures is called natural, and at elevated temperatures it is called artificial. The strength and hardness of freshly hardened duralumin, left at room temperature, increases over time, reaching its highest level after five to seven days. This process is called duralumin aging.
<<<Назад
Soldering or welding aluminum? What's the difference and which is better?
First, let's look at the definitions. Welding is the process of producing all-in-one joints by establishing interatomic bonds. Soldering is the process of joining metals in a heated state by melting an alloy, melting solder, such as the metals being joined.
In other words, when welding, the edges of the welded parts are melted and then frozen. In soldering, ordinary metal is heated only to a certain temperature, and the joint is produced by surface diffusion and chemical reaction of the solder and fused metals.
So, which is better, soldering or aluminum welding?
To answer this question, consider the main methods of soldering and welding aluminum alloys, their advantages and disadvantages.
Aluminum welding.
Four types of welding are most commonly used when welding aluminum:
1. Electrode or TIG welding. As an electrode that does not consume, tungsten is used with special alloying additives (lanthanum, cerium, etc.).
An electric arc occurs through this electrode, which melts the metal. The welding wire is manually fed by the welding pool. The whole process is very similar to conventional gas welding, only the metal is heated not by burning a torch, but by an electric arc in a protective environment. Such welding is carried out exclusively in argon or helium atmosphere or mixtures thereof.
Is there a difference between argon and helium welding? Eat. The bottom line is that helium provides a more compact combustion arc and therefore deeper and more efficient penetration of the base metals. Helium is more expensive and its consumption is much higher than that of argon. In addition, helium is very liquid, which creates additional problems during production, transportation and storage.
Therefore, it is recommended to use it as a shielding gas only when welding large parts where deep and effective fusion of the weld edges is required. In practice, helium is rarely used as an inert gas, since almost the same penetration effect can be achieved in argon, which only increases the welding current. TIG welding of aluminum generally results in alternating current.
Why with alternating current? It's all about aluminum oxide, a small amount of which is inevitably present in all types of welding. The fact is that the melting point of aluminum is about 660 degrees. The melting point of aluminum oxide is 2060. Therefore, aluminum oxide cannot melt in a weld - the temperature is not enough.
And there will be no manual for high quality welding oxide. What to do? The income comes from the feedback polarity, which has a very interesting feature for cleaning the seam from unnecessary impurities. This property is called "cathode dispersion". However, reverse polarity welding current has very low melting power. Therefore, the arc also contains straight-polarity current components, which are designed to be insensitive but melt metals.
And the exchange of forward and reverse polar currents is an alternating current, which combines both cleaning and melting properties.
2. Consumable electrode welding or semi-automatic welding (MIG welding). All this applies to this type of welding with the only difference that, as a rule, the only permanent "cleaning" is the replacement of the poles of the arc flows and does not pass through the tungsten electrode and directly through the welding wire melted during welding.
A regular semi-automatic machine is used for welding, but with higher wire feeding requirements. This type of welding is characterized by high productivity.
Manual arc welding with coated electrodes (MMA welding). It is used for welding hard parts with a thickness of 4 mm or more. It is applied to reverse polarity flow and has a poor quality seam.
4. Gas welding of aluminum. It can only be used on a limited number of aluminum alloys, which have poor weld quality. This is very difficult and not accessible to every mortal.
In practice this is almost never used.
Leaving exotic welding alone (friction welding, explosion welding and plasma), the quality of the welded joint and its prevalence are far ahead of the form, AC argon arc welding.
It allows welding of pure aluminum, duralumin, silane, etc., alloys from a few millimeters to several centimeters. In addition, it is the most economical and the only one possible for nuclear welding and some other aluminum alloys.
Soldering aluminum
Usually separates low temperature (soft-joint soldering) and high temperature (soldering) type of soldering.
Soldering of aluminum soft solder is usually done with a regular soldering iron and can be used as a special solder for high-zinc aluminum and regular lead-tin solder. The main problem with this type of soldering is the fight against light aluminum oxide. To neutralize it, it is necessary to use various types of fluxes, soldering fats and special types of soldering. In some cases, the surface of the aluminum is plated with a thin layer of copper, which is already soldered with traditional soldering.
However, the use of galvanic coatings is far from technologically feasible and economically feasible. In any case, soldering aluminum alloys at low temperatures is quite difficult, and the quality of solder joints is usually more than average. In addition, due to the heterogeneity of metals, the bonded joint is susceptible to corrosion and must always be coated with varnish or paint. Soft joint soldering cannot be used on loaded systems.
In particular, it should not be used to repair air conditioner radiators, but can be used to repair radiator motors.
High temperature soldering of aluminum. When soldering aluminum radiators in factories, soldering is used. Its characteristic is that the melting point of the solder is only 20-40 degrees below the melting point of the metal itself. This soldering typically involves a special high temperature paste (such as nylon) used for soldering and then sintered in special ovens under a protective gas environment.
This soldering process is characterized by high strength and low corrosion resistance of the resulting joints, since the solder is used as a composition close to the base metal. This type of solder is ideal for thin-walled products, but its technology is quite complex and completely useless for repairs.
The second type of high-temperature aluminum brazing is gas flame brazing. 
Special self-tapping rods are used as solder (for example, HTS 2000, Castolin 21 F, etc.).
Acetylene, propane and, preferably, a hydrogen flame (hydrolysis) are used for heating. The technology here is as follows. First, the torch flame heats the metal, and then the soldering iron is carefully filled into the soldering area. When the rod melts, the flame is removed. The melting point of the rod is not much lower than the temperature of the base plate, so it must be heated thoroughly to prevent it from being removed.
It should be noted that this type of solder is very, very expensive and can cost up to $300. for 1 kilogram. Typically it is used for local repairs.
So which is better?
Baker melts at home: step by step, video
Soldering or welding aluminum? Now we can answer this question. If the thickness of the metals is more than 0.2-0.3 mm, then use argon arc welding. In particular, argon welding of simple honeycomb balm emitters, trays, fenders, brackets, alloy wheels, steering gear, engine head, etc. The resulting weld. It is a monolithic, chemically resistant and strong bond.
If the thickness of the metals is less than 0.2-0.3 mm, it is better to use high-temperature soldering of aluminum. Firstly, it is used for soldering thin honeycomb wall radiators from the engine, which is very difficult to drink with argon. Lower temperature soft soldering is better, if not used at all, as these joints are much weaker and less chemically resistant.
In addition, the acidic fluxes used in low-temperature soldering can destroy both ordinary metals and solder joints in a relatively short time.
Most common metals cannot be strengthened by heat treatment. However, almost all metals are strengthened—to some degree—by forging, rolling, or bending. This is called cold hardening or hardening of metal.
Annealing is a type of heat treatment to soften metal that has become hardened so that it can continue to be cold worked.
Cold working: copper, lead and aluminum
Ordinary metals vary greatly in their degree and rate of strain hardening - cold hardening or cold hardening.
Copper is hardened quite quickly as a result of cold forging, and, therefore, quickly reduces its malleability and ductility. Therefore, copper requires frequent annealing so that it can be processed further without the risk of destruction.
On the other hand, lead can be hammered into almost any shape without annealing or risk of breaking it.
Lead has such a reserve of ductility that allows it to obtain large plastic deformations with a very low degree of strain hardening. However, although copper is harder than lead, it is generally more malleable.
Aluminum can withstand quite a large amount of plastic deformation through hammer forming or cold rolling before it needs to be annealed to restore its ductile properties.
Pure aluminum hardens much more slowly than copper, and some sheet aluminum alloys are too hard or brittle to allow much hardening.
Cold working of iron and steel
Industrial pure iron can be cold worked to large degrees of deformation before it becomes too hard for further processing.
Impurities in iron or steel impair the cold workability of the metal to such an extent that most steels cannot be cold worked, except of course special low carbon steels for the automotive industry. At the same time, almost all steel can be successfully processed plastically in a red-hot state.
Why is metal annealing necessary?
The exact nature of the annealing process to which the metal is subjected depends largely on the purpose of the annealed metal.
There is a significant difference in the method of annealing between annealing in factories where huge quantities of sheet steel are produced, and annealing in a small auto repair shop, where only one part requires such processing.
In short, cold working is plastic deformation by destruction or distortion of the grain structure of the metal.
During annealing, a metal or alloy is heated to a temperature at which recrystallization occurs - the formation of new grains - not deformed and round - instead of old - deformed and elongated - grains. Then the metal is cooled at a given speed. In other words, crystals or grains within the metal that have been displaced or deformed during cold plastic working are given the opportunity to realign and recover to their natural state, but at an elevated annealing temperature.
Annealing of iron and steel
Iron and mild steels must be heated to temperatures of around 900 degrees Celsius and then allowed to cool slowly to ensure they are as "soft" as possible.
At the same time, measures are taken to prevent contact of the metal with air in order to avoid oxidation of its surface. When this is done in a small auto repair shop, warm sand is used for this.
High carbon steels require similar processing except that the annealing temperature for them is lower and is about 800 degrees Celsius.
Annealing of copper
Copper is annealed at about 550 degrees Celsius, when the copper is heated to a deep red color.
Once heated, the copper is cooled in water or allowed to cool slowly in air. The cooling rate of copper after heating at the annealing temperature does not affect the degree of “softness” of this metal obtained. The advantage of rapid cooling is that it cleans the metal of scale and dirt.
Annealing aluminum
Aluminum is annealed at a temperature of 350 degrees Celsius.
Heat treatment of non-ferrous alloys
In factories this is done in suitable ovens or salt baths. In the workshop, aluminum is annealed with a gas torch. They say that in this case a wooden splinter is rubbed over the surface of heated metal.
When the wood begins to leave black marks, it means that the aluminum has received its annealing. Sometimes a bar of soap is used instead of wood: when the soap begins to leave brown marks, the heating should be stopped. The aluminum is then cooled in water or left to cool in air.
Annealing of zinc
Zinc becomes malleable again at temperatures between 100 and 150 degrees Celsius.
This means that it can be annealed in boiling water. Zinc must be processed while it is hot: when it cools, it loses much of its malleability.
Copper is widely used in the manufacture of products for various purposes: vessels, pipelines, electrical distribution devices, chemical equipment, etc. The variety of uses of copper is associated with its special physical properties.
Copper has high electrical and thermal conductivity and is resistant to corrosion. The density of copper is 8.93 N/cm3, the melting point is 1083°C, the boiling point is 2360°C.
The difficulties in welding copper are due to its physical and chemical properties4. Copper is prone to oxidation with the formation of refractory oxides, absorption of gases by the molten metal, has high thermal conductivity, and a significant coefficient of linear expansion when heated.
The tendency to oxidation necessitates the use of special fluxes during welding that protect the molten metal from oxidation and dissolve the resulting oxides, converting them into slag.
High thermal conductivity requires the use of a more powerful flame than when welding steel. The weldability of Cu depends on its purity; the weldability of Cu is especially impaired by the presence of B1, Pb, 3 and Oz in it. The content of rg, depending on the grade of Cu, ranges from 0.02 to 0.15%, III and Pb give copper brittleness and red brittleness. The presence of oxygen in Cu in the form of copper oxide Cu20 causes the formation of brittle layers of metal and cracks that appear in the thermal zone influence.
Copper oxide forms a low-melting eutectic with copper, which has a lower melting point. The eutectic settles around the copper grains and thus weakens the bond between the grains.
The copper welding process is influenced not only by oxygen dissolved in copper, but also by oxygen absorbed from the atmosphere. In this case, along with copper oxide CuO, copper oxide CuO is formed. When welding, both of these oxides make gas welding difficult and must be removed using flux.
Hydrogen and carbon monoxide also negatively affect the Cu welding process.
As a result of their interaction with copper oxide CuO, water vapor and carbon dioxide are formed, which form pores in the weld metal. To avoid this phenomenon, copper welding must be performed with a strictly normal flame. The purer the Si and the less 0-2 it contains, the better it welds.
According to GOST 859-78, the industry produces copper grades M1r, M2r MZr, which has a reduced content of Oa- (up to 0.01%), for the manufacture of welded structures.
In C gas welding, butt and corner joints are used; T-joints and lap joints do not give good results.
Before welding, the welded edges must be cleaned of dirt, oil, oxides and other contaminants in an area of at least 30 mm from the welding site. Welding areas are cleaned manually or mechanically with steel brushes. Welding of copper up to 8 mm thick is carried out without cutting edges, and for thicknesses over 3 mm, X-shaped cutting of edges at an angle of 45° is required on each side of the joint. The bluntness makes it equal to 0.2 of the thickness of the metal being welded. Due to the increased fluidity of copper in the molten state, thin sheets are butt welded without a gap, and sheets over 6 mm are welded on graphite and carbon backings.
The power of the welding flame when welding copper up to 4 mm thick is selected based on the acetylene consumption of 150-175 dm3/h per 1 mm thickness of the metal being welded; for a thickness of up to 8-10 mm, the power is increased to 175-225 dm8/h.
For large thicknesses, it is recommended to weld with two torches - one for heating and the other for welding. To reduce heat dissipation, welding is performed on an asbestos backing. To compensate for large heat losses due to removal to the heat-affected zone, preliminary and concomitant heating of the welded edges is used.
The edges are heated with one or more burners.
The flame for welding C is chosen strictly normal, since the oxidizing flame causes strong oxidation, and with a carburizing flame, pores and cracks appear. The flame should be soft and should be directed at a greater angle than when welding steel. Welding is carried out in a recovery zone, the distance from the end of the core to the metal being welded is 3-6 mm.
During the welding process, the heated metal must be protected by flame at all times. Welding is performed using both the left and right methods, however, the right method is most preferable when welding copper. Welding is carried out at maximum speed without interruptions.
Welding is carried out upward. The angle of inclination of the torch mouthpiece to the product being welded is 40-50°, and the filler wire is 30-40°. When making vertical seams, the angle of inclination of the torch mouthpiece is 30° and welding is carried out from the bottom up. When welding copper, it is not recommended to fasten parts with tacks. Long seams are welded in a free state using a reverse-step method.
Gas welding of copper is performed in only one pass.
The composition of the filler wire has a great influence on the gas welding process. For welding, rods and wire in accordance with GOST 16130-72 of the following grades are used as an additive: M1, MSr1, MNZH5-1, MNZHKT5-1-0.2-0.2.
Error 503 Service Unavailable
Welding wire MSr1 contains 0.8-1.2% silver. The diameter of the filler wire is selected depending on the thickness of the metal being welded and is taken equal to 0.5-0.75 8, where 5 is the thickness of the metal, mm, but not more than 8 mm.
The welding wire should melt smoothly, without spattering. It is desirable that the melting temperature of the filler wire be lower than the melting temperature of the base metal. To protect Cu from oxidation, as well as to deoxidize and remove the resulting oxides into the slag, welding is carried out with flux. Fluxes are made from oxides and salts of boron and sodium. Fluxes for welding Cu are used in the form of powder, paste and in gaseous form. Fluxes No. 5 and 6, containing salts of phosphoric acid, must be used when welding with wire that does not contain phosphorus and silicon deoxidizers.
Si welding can also be performed using BM-1 gaseous flux; in this case, the torch tip must be increased by one number in order to reduce the heating rate and increase the power of the welding flame. When using gaseous flux, the KGF-2-66 installation is used. Powdered flux is sprinkled onto the welding site 40-50 mm on both sides of the weld axis. Flux in the form of a paste is applied to the edges of the metal being welded and to the filler rod. Remains of flux are removed by washing the seam with a 2% solution of nitric or sulfuric acid.
To improve the mechanical properties of the deposited metal and increase the density and.
To ensure the plasticity of the weld, it is recommended to forge the weld metal after welding. Parts up to 4 mm thick are forged in a cold state, and with greater thickness - when heated to a temperature of 550-600°C.
Additional improvement of the seam after forging is provided by heat treatment - heating to 550-600°C and cooling in water. The products to be welded are heated with a welding torch or in a furnace. After annealing, the weld metal becomes tough.
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Home>>Welding of non-ferrous metals>>Welding of copper and steel
Welding copper and its alloys with steel. How to weld copper and steel?
In practice, welding of copper and steel is most often carried out in butt joints. Depending on the nature of the structure, the seams in such a connection can be external or internal.
For welding brass to steel, gas welding is best suited, and for welding red copper to steel, electric arc welding with metal electrodes.
Good results are also obtained when welding with carbon electrodes under a layer of flux and gas welding under a submerged arc BM-1. Often in practice, gas welding of brass to steel is performed using copper as a filler material.
The preparation of welded edges with the same thickness of non-ferrous metal and steel is carried out in the same way as when welding ferrous metals.
Welding of sheets less than 3 mm thick is performed without cutting, and sheets starting from 3 mm are welded with beveled edges.
If the edges are insufficiently beveled, or if there is contamination at the ends of the parts being welded, good penetration cannot be achieved. Based on this, when welding parts of large thicknesses in which an X-shaped groove is made, blunting should not be done.
Welding copper with steel is a complex task, but quite feasible for surfacing and welding, for example, parts of chemical equipment, copper wire with a steel block.
The quality of welding of such joints meets the requirements for them. The strength of copper can be increased by introducing up to 2% iron into its composition. With more iron, strength begins to decrease.
When welding with a carbon electrode, it is necessary to use direct current of straight polarity.
The voltage of the electric arc is 40-55V, and its length is approximately 14-20mm. The welding current is selected in accordance with the diameter and quality of the electrode (carbon or graphite) and is in the range of 300-550A. The flux used is the same as for welding copper; the composition of these fluxes is given on this page.
Flux is introduced into the welding zone, pouring it into the groove.
The welding method is used "left".
The best results when welding copper busbars to steel are obtained when welding “in a boat”. The diagram of such welding is shown in the figure. First, the copper edges are heated with a carbon electrode, and then welded with a certain position of the electrode and filler rod (see figure). The welding speed is 0.25m/h. Welding copper with cast iron is carried out using the same technological techniques.
Welding of low-alloy bronze of small thickness (up to 1.5 mm) to steel with a thickness of up to 2.5 mm can be done overlapping with a non-consumable tungsten electrode in an argon environment on an automatic machine with a filler wire with a diameter of 1.8 mm supplied from the side.
In this case, it is very important to direct the arc towards the overlap from the copper side. Modes of such welding: current 190A, arc voltage 11.5V, welding speed 28.5m/h, wire feed speed 70m/h.
Copper and brass can be welded well to steel using flash butt welding.
With this welding method, steel edges melt quite strongly, and non-ferrous metal edges melt slightly. Taking into account this circumstance, and taking into account the difference in the resistivity of these metals, the overhang for steel is taken to be 3.5d, for brass 1.5d, for copper 1.0d, where d are the diameters of the rods being welded.
For butt welding of such rods using the resistance method, an overhang of 2.5d for steel, 1.0d for brass and 1.5d for copper is recommended. The specific resistance of the settlement is assumed to be in the range of 1.0-1.5 kg/mm2.
In practice, it often becomes necessary to weld studs with a diameter of 8-12 mm made of copper and its alloys to steel, or steel studs to copper products.
Such welding is carried out using direct current of reverse polarity under fine flux of the OSTS-45 brand without preheating.
Copper studs with a diameter of up to 12 mm or brass studs of grade L62, with a diameter of up to 10 mm, with a current strength of 400 A are well welded to steel or cast iron.
And studs made of brass grade LS 59-1 are not used for welding.
Steel studs are poorly welded to copper and brass products.
How to weld copper at home?
If you put a copper ring 4 mm high on the end of a pin with a diameter of up to 8 mm, then the process of welding metals proceeds satisfactorily. The same studs with a diameter of 12 mm for broze brand Br. OF 10-1 are welded well. For arc welding of copper and steel, the best results are provided by K-100 electrodes.
WikiHow carefully monitors the work of its editors to ensure that every article meets our high quality standards.
Thanks to annealing, copper becomes softer and more ductile, after which it bends easily. This allows the metal to be forged and shaped into the desired shape without breaking it. You can anneal copper of any grade and thickness if you have a powerful enough torch. The easiest way to anneal copper is to heat it with an oxy-acetylene torch and then quickly cool it in water.
Steps
Part 1
Preparing for annealing- Safety glasses used for annealing, arc cutting and welding are rated on a scale of 2 to 14, with 2 being the least tinted and 14 being the darkest. An acetylene torch produces a much less bright flame than a welding torch, so slightly tinted glass is sufficient to protect your eyes.
- If you don't have safety glasses, purchase some from a hardware or welding supply store.
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Connect one hose to each cylinder to prepare the acetylene torch. The burner itself, which produces the flame, has two hoses coming out of it. Connect the red torch hose to the acetylene cylinder and the black hose to the oxygen cylinder. The acetylene will ignite the flame, after which oxygen will continue to feed it. By changing the amount of oxygen supplied from the cylinder, you can control the intensity of the flame.
Turn the acetylene valve a quarter turn clockwise. By doing this, you will open the acetylene cylinder and gas will begin to flow into the reducer. Turn the valve only a quarter turn - this will be enough for the acetylene to maintain the flame, but the flow of gas will not be too strong and you can control it. Watch the pressure gauge and adjust the valve so that the pressure is 0.5 atmospheres.
- The pressure gauge is located on top of the acetylene cylinder. It has a round scale with the inscriptions “pressure” and “atm”.
- Once the flame is established, you can adjust its intensity using the valve on the acetylene cylinder. The valve is located at the top of the cylinder. Typically, it is located next to the pressure gauge (or even connected to it).
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Turn the valve on the oxygen cylinder fully counterclockwise. Then adjust the pressure using the screw on the reducer (turn it clockwise). At the same time, keep an eye on the pressure gauge on the oxygen cylinder - make sure it shows 2.7 atmospheres.
- The oxygen valve is located at the top of the oxygen cylinder. There may be an arrow on it that indicates which direction the valve should be unscrewed.
- It is necessary to achieve the correct ratio of oxygen and acetylene to obtain a controlled hot flame.
-
Light the acetylene torch using a silicon lighter. To light the flame, hold the torch in one hand and turn the valve at the top of the acetylene bottle half a turn clockwise with the other hand. As a result, gas will begin to flow into the burner. Bring the silicon lighter closer to the burner nozzle about 1.5 centimeters. Click it until an orange-red flame appears.
- Light the flame no later than 2-3 seconds after turning off the valve on the acetylene cylinder, as this gas is highly flammable.
-
Adjust the valve on the burner until the flame turns blue. Once the burner begins to produce a light orange flame, turn the oxygen valve on the side of the burner clockwise to introduce oxygen into the burning acetylene. Continue turning the valve until the flame turns blue. The blue color of the flame indicates that its temperature is ideal for annealing copper.
- Turn the oxygen valve slowly to avoid a sudden flash of flame.
- A flame that is too hot will burn the metal, and a flame that is too cold will not heat the copper enough and its durability and ductility will not be affected.
Part 2
Heating copper-
When annealing, keep the flame at a distance of 7.5–10 centimeters from the surface of the copper. Point the flame directly at the copper plate or pipe. Don't get the torch too close to the metal or you will burn the surface. Hold the torch at least 10-13 centimeters from the surface of the copper and wait until the metal heats up.
Move the torch flame quickly across the metal surface. Move the torch along the entire surface to heat the copper evenly. It is necessary to distribute the heat evenly throughout the volume of the metal so that certain areas do not anneal faster than others. In this case, you will notice that in places where it is heated, the surface of the copper turns red or orange.
- When working with open flames, keep a dry chemical fire extinguisher handy. If anything catches fire, use a fire extinguisher immediately.
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Thicker and more massive pieces of copper should take longer to heat up. Annealing softens any piece of copper, regardless of its thickness or size. However, the thicker the metal, the longer it should be heated.
- For example, it is enough to heat a thin piece of jewelry copper for 20 seconds to anneal it. At the same time, a massive copper pipe or copper sheet 1.5 centimeters thick must be heated for at least 2–3 minutes.
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Keep the flame in one place until the copper turns red. When heated with an acetylene torch, the surface of the copper will first turn black. Don't worry, it will turn red after this. Continue moving the flame across the surface of the metal until the black color changes to a glowing bright red. This color indicates that the copper has been annealed.
Wear safety glasses before working with the burner. When handling open flames, safety glasses must be worn. Wear safety glasses with a shade rating of at least 4 to properly protect your eyes from the glare of an acetylene flame. Looking into an acetylene torch flame without safety glasses can cause serious eye damage.
Parshev 01-09-2005 02:01
“The temperature can be determined quite accurately using a small (about the size of a match head) piece of copper foil, which is placed on the surface of the heated part. At a temperature of 400? C, a greenish flame appears above the foil.
Hardening of a preheated copper part occurs by slow cooling in air. For annealing, the heated part is quickly cooled in water. When annealing, copper is heated to red heat (600? C), when hardening - up to 400? C, determining the temperature also using a piece of copper foil.
In order for brass to become soft, bend easily, forge and stretch well, it is annealed by heating to 500°C and slowly cooling in air at room temperature.”
It is interesting that annealing of copper and brass occurs in the opposite way - there with rapid cooling, there with slow cooling.
When molding sleeves, it is recommended to anneal after 2 operations.
Remus 02-09-2005 01:49
After what 2 operations?
Parshev 02-09-2005 02:11
Case molding operations. For example, re-crimping to a different size is done by running it through the dies.
ABAZ 05-09-2005 08:12
sorry, translit zaklinilo.
Anyman 06-09-2005 08:27
capercaillie 11-09-2005 15:13
Take a gas-foam brick, drill holes in it for your caliber, one-third of the product deep, insert the workpiece into the holes bottom up, and use a gas burner or hairdryer to heat the product until it glows lightly and drop the product into water or cool to room temperature in a jig (brick).
TSV 11-09-2005 22:29
What if you just stuff the cartridges into the holder, place the holder in a bath of water, which should be poured below the slope, and heat the protruding barrels with a burner?
The cartridges are naturally without primers so that water can flow inside.
The dulce will be annealed, and the rest will remain untouched
And there is no need to drill bricks
Machete 12-09-2005 12:54
The couple will be like in a bathhouse.
capercaillie 12-09-2005 13:18
Try. Tell us.
TSV 12-09-2005 20:34
Nothing. No burner. Can't heat it up with a hairdryer.
I tried it on a regular gas burner. I wrapped it in a wet rag and into the fire. Seems to be OK. Only the fire is weak.
TSV 12-09-2005 23:34
The couple will be like in a bathhouse.
There shouldn't be a couple. Now, if I heated it up and lowered it, then yes, I would get a steam room.
But in this case, everything would heat up, and not just the barrel.
Machete 13-09-2005 12:23
When you say “should”, knock on wood (Mayan folk saying).
TSV 13-09-2005 12:29
quote: Originally posted by Machete:
When you say “should”, knock on wood (Mayan folk saying).
Then let's say this - it didn't happen when I kept it on the gas in a wet rag.
If you anneal it properly, then you need the sleeve to rotate around its axis. Otherwise, the side heats up, but the rest remains unheated. Visible by the trace of tarnish.
Machete 13-09-2005 02:02
I somehow like Gennady Mikhailych’s version better. Although our interest is purely gastronomic - for now.
TSV 13-09-2005 21:10
Do you like drilling holes in bricks?
I don’t know what that brick is, but the metal needs to be cooled, except at the heating point.
capercaillie 13-09-2005 21:56
Sergey, regarding the technology, write to the bullet manufacturer.
And the brick is cut with a knife.
Machete 13-09-2005 22:05
You can't cool the sleeve with water while simultaneously heating the barrel - it's brass, the thermal conductivity is bad.
TSV 13-09-2005 22:45
quote: Originally posted by Machete:
You can't cool the sleeve with water while simultaneously heating the barrel - it's brass, the thermal conductivity is bad.
I won’t be able to try it for a while (I’m running errands), then I’ll test the brass in water.
Although metal is thermally conductive, it cannot heat up below the water level. We are only interested in the annealed butt.
Machete 14-09-2005 01:13
quote: Originally posted by TSV:Although metal is thermally conductive, it cannot heat up below the water level.
Not completely screwed. What is meant?
TSV 14-09-2005 01:28
If the sleeve is stuffed into something porous, there will be poor heat dissipation. And heating the barrel will heat up the rest at the same time. The sleeve should definitely warm up until halfway and turn black, or even warm up more.
The water takes away heat, and the part further from the water will warm up more.
Last time I wrapped the cartridge case in a rag and wet it so that the water would drain. Then he put it in the fire. A wet rag prevented the body of the cartridge case from heating up. The muzzle and slope have warmed up.
Next time I'll try heating the cartridge case sticking out of the water. I'll write about the result. I don't have a gas burner at hand right now.
Machete 14-09-2005 01:39
So running water is needed, similar to the cooling of a coil in a moonshine still, otherwise there will be no kick.
TSV 15-09-2005 20:22
Actually, I checked the version.
Basically it works. But the power of a gas soldering iron is not enough to heat it up, since the water takes away the heat. But the sleeve does not anneal below water. There is no hissing or bubbling. Not the right temperature to instantly warm up all the water.
I tried it without water, empty. It warmed up quickly, but due to heat transfer, half of the sleeve had time to warm up.
If the view doesn’t bother you that it’s below the slope, then it will do without water. But you still need to turn it. Otherwise, on one side the stain burns out, and on the other the heating is weaker
Parshev 16-09-2005 17:05
2 ParshevWhere did the information come from? The writing style is not similar to technical literature, closer to housewifery
Do you want checkers or go?
Anyman 20-09-2005 08:27
quote: Originally posted by Parshev:Do you want checkers or go?
Technical literature describes how to do it in factory or laboratory conditions, do you have them?
Anyman 20-09-2005 08:54
quote: Originally posted by wood grouse:
Bullet manufacturers recommend:
Take a gas-foam brick, drill holes in it for your caliber, one-third of the product deep, insert the workpiece into the holes bottom up, and use a gas burner or hairdryer to heat the product until it glows lightly and drop the product into water or cool to room temperature in a jig (brick).
2 capercaillie
Do you mean regular building bricks or something special like fireclay?
capercaillie 20-09-2005 10:12
Yes, they sell it at every construction fair.
Gas-foam-brick bought a block and sawed myself any bricks I wanted.
I use a gas torch for annealing.
They also sell it, refilled from lighter cans.
RAY 27-09-2005 15:20
quote: Originally posted by Anyman:On the one hand, you are right. But remembering from the time of training that heat treatment is not the easiest thing, I would certainly consult with a thermist or look in the appropriate reference book. After all, if with copper everything can be more or less unambiguous, then brass can be very different in chemical composition and, accordingly, suitability for heat treatment.
For example, annealing temperature for brass:Brass L96: 540 - 600 degrees;
Brass L90 - L62: 600 - 700 degrees;Since people have gathered here to count every grain of powder, then everything must be accurate.
-----------
Yeah... they brought me so many shell casings for analysis - there were more and more L63...
L96 and L90 - even in color - COPPER... more and more L63 and L65 seemed to always be used for cartridges...
Anyman 27-09-2005 20:00
So, in L96 there is 95-97% copper, which is why the color is copper. In L63 62-65%
tov_Mauser 14-10-2005 11:04
ingredients: Naganov revolver cartridges
tools: pliers, rag, gas burner on the stove
We wet the rag and wring it out, wrap the handles of the pliers, take the sleeve by the pliers and heat it in the flame at an angle of 45 (preferably in the twilight - so that the glow of the metal can be seen), heat the neck until dull red, then put the sleeve aside to cool. When heated, massive pliers remove heat from the base of the sleeve - which is clearly visible by the way the metal warms up
The output is high-quality cartridges that do not crack during repeated reloading and rolling/flaring of the gun
The need for heat treatment.
Heat treatment of steel parts is carried out in cases where it is necessary either to increase the strength, hardness, wear resistance or elasticity of a part or tool, or, conversely, to make the metal softer and easier to machine.
Depending on the heating temperatures and the method of subsequent cooling, the following types of heat treatment are distinguished: hardening, tempering and annealing. In amateur practice, you can use the table below to determine the temperature of a hot part by color.
Heat color: steel |
Heating temperature "C |
Dark brown (visible in the dark) |
530-580 |
Brown-red |
580-650 |
Dark red |
650-730 |
Dark cherry red |
730-770 |
Cherry red |
770-800 |
Light cherry red |
800-830 |
Light red |
830-900 |
Orange |
900-1050 |
Dark yellow |
1050-1150 |
Light yellow |
1150-1250 |
Bright white |
1250-1350 |
Hardening gives the steel part greater hardness and wear resistance. To do this, the part is heated to a certain temperature, held for some time so that the entire volume of the material warms up, and then quickly cooled in oil (structural and tool steels) or water (carbon steels). Typically, parts made from structural steels are heated to 880-900° C (light red incandescent color), those from instrumental steels are heated to 750-760° C (dark cherry red color), and those from stainless steel are heated to 1050-1100° C ( color dark yellow). The parts are heated slowly at first (to about 500°C), and then quickly. This is necessary to ensure that internal stresses do not arise in the part, which can lead to cracks and deformation of the material.
In repair practice, they mainly use cooling in one medium (oil or water), leaving the part in it until it cools completely. However, this cooling method is unsuitable for parts with complex shapes, in which large internal stresses arise during such cooling. Parts of complex shape are first cooled in water to 300-400 ° C, and then quickly transferred to oil, where they are left until completely cooled. The residence time of the part in water is determined at the rate of 1 s for every 5-6 mm of the part’s cross-section. In each individual case, this time is selected empirically depending on the shape and mass of the part.
The quality of hardening largely depends on the amount of coolant. It is important that during the cooling process of the part, the temperature of the coolant remains almost unchanged, and for this its mass must be 30-50 times greater than the mass of the part being hardened. In addition, before immersing a hot part, the liquid must be thoroughly mixed to equalize its temperature throughout the entire volume.
During the cooling process, a layer of gases forms around the part, which impedes heat exchange between the part and the coolant. For more intense cooling, the part must be constantly moved in the liquid in all directions.
Small parts made of low-carbon steel (grades “3O”, “35”, “40”) are slightly heated, sprinkled with potassium iron sulfide (yellow blood salt) and again placed on the fire. As soon as the coating melts, the part is lowered into the cooling medium. Potassium iron sulfide melts at a temperature of about 850° C, which corresponds to the quenching temperature of these steel grades.
Tempering of hardened parts.
Tempering of hardened parts reduces their fragility, increases toughness and relieves internal stress. Depending on the heating temperature, low, medium and high tempering are distinguished.
Low Vacation used mainly in the processing of measuring and cutting tools. The hardened part is heated to a temperature of 150-250 ° C (temperature color is light yellow), maintained at this temperature, and then cooled in air. As a result of this treatment, the material, while losing its brittleness, retains high hardness and, in addition, the internal stresses that arise during hardening are significantly reduced.
Average holiday used in cases where they want to give the part spring properties and sufficiently high strength with medium hardness. To do this, the part is heated to 300-500 ° C and then slowly cooled.
And finally, high holiday subjected to parts in which it is necessary to completely remove all internal stresses. In this case, the heating temperature is even higher - 500-600 ° C.
Heat treatment (hardening and tempering) of simple shaped parts (rollers, axles, chisels, punches) is often done at one time. The part heated to a high temperature is dipped into the coolant for some time, then removed. Tempering occurs due to the heat retained inside the part.
A small area of the part is quickly cleaned with an abrasive block and the color of the tarnish on it is monitored. When the color corresponding to the required tempering temperature appears (220° C - light yellow, 240° C - dark yellow, 314° C - light blue, 330° C - gray), the part is again immersed in the liquid, now until completely cooling. When tempering small parts (as during hardening), some blank is heated and the part to be tempered is placed on it. In this case, the color of the tarnish is observed on the part itself.
Annealing of steel parts.
To facilitate mechanical or plastic processing of a steel part, its hardness is reduced by annealing. The so-called complete annealing consists in the fact that the part or workpiece is heated to a temperature of 900 ° C, maintained at this temperature for some time necessary to heat it throughout its entire volume, and then slowly (usually together with the furnace) cooled to room temperature.
Internal stresses that arise in the part during machining are removed by low-temperature annealing, in which the part is heated to a temperature of 500-600 ° C and then cooled along with the furnace. To relieve internal stresses and slightly reduce the hardness of steel, incomplete annealing is used - heating to 750-760 ° C and subsequent slow (also together with the furnace) cooling.
Annealing is also used when hardening is unsuccessful or when it is necessary to overheat a tool for processing another metal (for example, if a copper drill needs to be overheated to drill cast iron). During annealing, the part is heated to a temperature slightly below the temperature required for hardening, and then gradually cooled in air. As a result, the hardened part again becomes soft and amenable to machining.
Annealing and hardening of duralumin.
Annealing of duralumin is carried out to reduce its hardness. The part or workpiece is heated to approximately 360° C, as during hardening, held for some time, and then cooled in air.
The hardness of annealed duralumin is almost half that of hardened duralumin.
The approximate heating temperature of a duralumin part can be determined as follows. At a temperature of 350-360° C, a wooden splinter, which is passed along the hot surface of the part, becomes charred and leaves a dark mark. The temperature of the part can be determined quite accurately using a small (about the size of a match head) piece of copper foil, which is placed on its surface. At a temperature of 400° C, a small greenish flame appears above the foil.
Annealed duralumin has low hardness; it can be stamped and bent twice without fear of cracks.
Hardening. Duralumin can be hardened. When hardening, parts made of this metal are heated to 360-400 ° C, held for some time, then immersed in water at room temperature and left there until completely cooled. Immediately after this, duralumin becomes soft and flexible, easily bent and forged. It acquires increased hardness after three to four days. Its hardness (and at the same time fragility) increases so much that it cannot withstand bending at a small angle.
Duralumin acquires its highest strength after aging. Aging at room temperatures is called natural, and at elevated temperatures it is called artificial. The strength and hardness of freshly hardened duralumin, left at room temperature, increases over time, reaching its highest level after five to seven days. This process is called duralumin aging
Annealing of honey and brass.Annealing of copper. Copper is also subjected to heat treatment. In this case, copper can be made either softer or harder. However, unlike steel, copper is hardened by slow cooling in air, and copper becomes soft by rapid cooling in water. If a copper wire or tube is heated red hot (600°) over a fire and then quickly immersed in water, the copper will become very soft. After giving the desired shape, the product can again be heated over a fire to 400 ° C and allowed to cool in air. The wire or tube will then become solid.
If it is necessary to bend the tube, it is tightly filled with sand to avoid flattening and cracking.
Annealing brass increases its ductility. After annealing, brass becomes soft, easily bends, knocks out and stretches well. For annealing, it is heated to 500 ° C and allowed to cool in air at room temperature.
Blueing and "blueing" of steel.
Blueing. After bluing, steel parts acquire a black or dark blue color of various shades, they retain a metallic luster, and a persistent oxide film forms on their surface; protecting parts from corrosion. Before bluing, the product is carefully ground and polished. Its surface is degreased by washing in alkalis, after which the product is heated to 60-70° C. Then it is placed in an oven and heated to 320-325° C. An even coloring of the surface of the product is obtained only when it is heated evenly. The product treated in this way is quickly wiped with a cloth soaked in hemp oil. After lubrication, the product is slightly warmed up again and wiped dry.
"Blueing" of steel. Steel parts can be given a beautiful blue color. For this, two solutions are made: 140 g of hyposulfite per 1 liter of water and 35 g of lead acetate (“lead sugar”) also per 1 liter of water. Before use, the solutions are mixed and heated to a boil. The products are pre-cleaned, polished to a shine, then immersed in boiling liquid and kept until the desired color is obtained. Then the part is washed in hot water and dried, after which it is lightly wiped with a rag moistened with castor or clean machine oil. Parts treated in this way are less susceptible to corrosion.
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Technology selection
The types of heat treatment of brass are determined by the percentage of zinc in the alloy, as well as the type of phase diagram, what type of brass the alloy belongs to - single-phase or two-phase. The supplier Evek GmbH offers to buy rolled brass products of domestic and foreign production at an affordable price in a wide range. We will ensure delivery of products to any point on the continent. The price is optimal.
Heat treatment of single-phase (simple) brasses
For such varieties, recrystallization or conventional annealing is used. The goal is to relieve internal stresses that may appear during plastic deformation of the material. The annealing mode depends on the zinc concentration in the alloy: with an increase in this parameter, the required heat treatment temperature decreases, but not more than 300 °C. The efficiency of annealing depends on the final grain size in the microstructure. They are installed according to the readings of a metal-instrumental microscope, or according to reference structures, which are given in GOST 5362.
Annealing atmosphere
It is not recommended to perform heat treatment in a normal atmosphere containing significant amounts of oxygen. This leads to an uneven decrease in grain size, and oxide spots are clearly visible on the surface of the alloy, which have to be removed by etching the alloy in a solution of orthophosphoric acid or potassium dichromate. A more effective heat treatment method is vacuum annealing or the use of a protective atmosphere of inert gases. At the same time, zinc burnout is reduced.
Heat treatment of two-phase brasses
Multiphase brasses are obtained by adding alloying elements other than zinc - iron, aluminum, lead, etc. Each of the brass grades has its own recrystallization annealing temperature. The most commonly used modes are:
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