Aluminum alloy- JCG Industrial Co., Ltd. Manufacturing Factory

Smelt
Plastic processing provides aluminum ingots. The smelting furnace uses a gas-fired reactor or an oil-fired reactor with a general capacity of 40 tons; an electric heating reactor is also used, with a general capacity of 10 tons. In order to shorten the furnace loading time, improve the melting efficiency, reduce the absorption of gas and the involvement of oxide film, the industry has adopted the tilting top-loading round furnace. Use rapid analysis instrument to analyze alloy composition during smelting and adjust in time. In order to ensure the purity of the melt, prevent the pollution of harmful gases and control the chemical composition, in addition to shortening the smelting time as much as possible, it can be covered with a powdered flux based on potassium chloride and sodium chloride, and the general dosage is 0.4 to 2 of the weight of the charge. %. The melting temperature is usually controlled at 700 to 750°C.
The molten metal needs to be refined and filtered to remove the harmful hydrogen gas and non-metallic impurities in the metal and improve the purity of the metal. Refining usually uses solid refining agents or gas refining agents. The solid refining agent is generally based on chloride salt, and hexachloroethane is also used as a refining agent to replace chlorine salt. Early use of highly reactive chlorine gas as a gas refining agent, although the purification effect is good, but serious environmental pollution, so the development of nitrogen-chlorine mixed gas, inert gas and three gases (N2, Cl2, CO) refining agent, the effect is better. In order to ensure the refining effect, the oxygen and moisture content in the refined gas should generally be less than 0.03% (volume) and 0.3 g/m3, respectively. The dynamic vacuum degassing method also has better degassing and sodium removal effects.
Filtration is to let the molten metal pass through a filter made of neutral or active materials to remove suspended inclusions in the melt. Commonly used glass wire mesh, microporous ceramic tubes and plates, and alumina particles are used as filter beds for filtration, and electric flux refining and flux layer filtration can also be used.
Casting
The casting generally adopts vertical or horizontal water-cooled semi-continuous casting method. In order to improve the structure and surface quality of the billet in vertical casting, electromagnetic crystallization tanks, crystallization tanks and hot top casting methods have been developed. The water-cooled semi-continuous casting method is to introduce the liquid metal into a water-cooled crystallizer through a launder, so that the liquid metal is cooled to form a solidified shell, which is pulled by the base of the casting machine or dropped out of the crystallizer by its own weight to form an ingot. The process parameters vary greatly due to the alloy composition and the size of the billet. Generally, the casting speed and cooling rate should be increased as much as possible, and the height of the crystallization tank should be reduced. The casting temperature is usually 50 to 110°C higher than the liquidus line of the alloy. In addition, the continuous casting and rolling process of aluminum strip has been developed.
Plate and strip production adopts flat roll rolling, and the basic processes are hot rolling, cold rolling, heat treatment and finishing. For hard aluminum alloys such as LY12 and LC4 with complex chemical composition, homogenization treatment should be carried out before hot rolling. The treatment temperature is generally lower than the eutectic temperature of the low-melting phase in the alloy by 10-15°C, and the temperature is kept for 12-24 hours. The clad aluminum of hard aluminum alloy is to place the clad aluminum plate on both sides of the milled billet, and weld it by means of hot rolling. The thickness of the aluminum-clad layer is generally 4% of the thickness of the sheet. Hot rolling is generally performed above the recrystallization temperature. Hot rolling can be carried out on a single-stand reversing mill or continuous rolling on multiple stands. In order to improve the yield and production efficiency, develop large ingot rolling, with ingots weighing more than 10-15 tons. For factories with an annual output of less than 100,000 tons, four-roll reversible hot rolling and hot coiling are generally used, and the thickness of the hot-rolled strip is about 6 to 8 mm. In factories with an output of more than 100,000 tons, most of the four-high reversible hot rolling mills adopt single-stand, two-stand, three-stand, and five-stand continuous rolling after the billet is opened. The hot finish rolling is implemented, and the strip thickness can reach 2.5-3.5. Mm. The hot-rolled strip is used as a cold-rolled billet after being coiled. In order to ensure the best plasticity of the metal, hot rolling should be carried out in a single-phase structure. The hot-rolled billet temperature of LY11, LY12 and other alloys is 400-455°C. The deformation rate of the first few passes is generally within 10%, and it will gradually increase in the future. The pass deformation rate of pure aluminum and soft aluminum alloy can reach 50%, and that of hard aluminum alloy is about 40%. The total deformation rate of hot rolling can reach more than 90%.
Cold rolling is often carried out at room temperature. Through cold rolling, thinner plates and strips with precise dimensions, smooth and smooth surfaces can be obtained, and work-hardened plates and strips with specific mechanical properties can be obtained. Cold rolling mainly adopts a belt-type production process, using a four-high reversible rolling mill or a four-high irreversible rolling mill for cold rolling, and currently developing an irreversible rolling mill for cold rolling. The rolling mill is equipped with hydraulic pressure, hydraulic roll bending, automatic thickness control system or automatic thickness control system for measuring roll gap and shape control instrument. Various parameters are controlled, recorded and stored by a microcomputer to obtain accurate size and flat shape. The tolerance of the strip, such as 0.18 mm strip, can reach ±5 microns. Small factories also have the block method to produce plates. The cold deformation rate of aluminum after annealing can reach more than 90%. Multiphase hard aluminum alloy has obvious cold work hardening and requires intermediate annealing. The cold deformation rate after intermediate annealing is 60 to 70%. Hot rolling uses emulsion lubrication, and cold rolling has developed from emulsion to full oil lubrication. A multi-stage cooling system with individually controlled nozzles is used to reduce the friction between the aluminum plate and the roll, cool the roll, control the roll shape, and wash away aluminum powder and other impurities to obtain a good surface quality and plate shape.
The cold-rolled and heat-treated coils are often finished on a roll straightener or a continuous stretch-bending straightener train. The flattening and quenching of the plate should be carried out during the aging incubation period, which is generally completed within 30 to 40 minutes after quenching. The total deformation of the quenched plate should not exceed 2%.
The continuous casting and rolling of aluminum strip, which was successfully tested in 1955, can produce thin plates and aluminum foil blanks.

According to the deformation method of the workpiece, aluminum alloy processing is divided into rolling, extrusion, drawing, forging, spinning, forming processing (such as stamping, cold deformation, deep drawing) and deep processing.
Rolling-
The ingot is drawn into the rotating rolls by friction, and with the pressure applied by the rolls, its cross section is reduced, the shape changes, the thickness becomes thinner, and the length increases. According to the different rotation directions of the rolls, rolling can be divided into longitudinal rolling, cross rolling and cross rolling. During longitudinal rolling, the direction of rotation of the work roll is opposite, and the longitudinal axis of the rolled piece is perpendicular to the axis of the roll. It is the most commonly used method in flat roll rolling of aluminum alloy plates, strips, and foils; The direction of rotation is the same, and the longitudinal axis of the rolling piece is parallel to the axis of the roll, which is rarely used in the rolling of aluminum alloy plate and strip; during cross rolling, the rotation direction of the work roll is the same, and the longitudinal axis of the rolling piece is in a certain line with the axis of the roll. slope. In the production of aluminum alloy pipes and some special-shaped products, two-roll or multi-roll cross-rolling is often used. According to different roll systems, aluminum alloy rolling can be divided into two-roll (pair) rolling, multi-roll rolling and special roll rolling (such as planetary rolling, V-shaped rolling, etc.) rolling: according to the roll shape Different, aluminum alloy rolling can be divided into flat roll rolling and grooved roll rolling. According to different product varieties, aluminum alloy rolling can be divided into plate, strip, foil rolling, bar, flat bar and special-shaped section rolling, pipe and hollow section rolling, etc.
Extrusion-
A processing method in which the billet is loaded into an extrusion cylinder, and the metal is pressurized through an extrusion shaft to extrude it from a die hole of a given shape and size, and produce plastic deformation to obtain the required extruded product. According to the different direction of metal flow during extrusion. Extrusion can be divided into forward extrusion, reverse extrusion and joint extrusion. During forward extrusion, the movement direction of the extrusion shaft is consistent with the flow direction of the extruded metal, while during reverse extrusion, the movement direction of the extrusion shaft is opposite to the flow direction of the extruded metal. According to the heating temperature of the billet, extrusion can be divided into hot extrusion and cold extrusion. In hot extrusion, the ingot is heated to a temperature above the recrystallization temperature for extrusion, and cold extrusion is extrusion at room temperature.
Drawing-
The stretching machine pulls the aluminum alloy billet or tube blank from the die hole L of a given shape and size through the clamp, and causes it to be plastically deformed to obtain the required processing method of the tube, rod, shape, and wire. According to different types and shapes of the products produced, stretching can be divided into wire stretching, pipe stretching, bar stretching and profile stretching. Pipe stretching can be divided into air-drawing, core-head stretching and floating core-head stretching. The main elements of drawing processing are drawing machine, drawing die and drawing reel. According to the stretching mold, stretching can be divided into single-mode stretching and multi-mode stretching.
Forging-
A forging hammer or press applies pressure to aluminum alloy ingots or forging billets through the indenter to produce plastic deformation of the metal. There are two basic methods for aluminum alloy forging: free forging and die forging. Free forging is to place the workpiece in a flat anvil for forging; die forging is to place the workpiece in a die of a given size and shape, and then apply pressure to the workpiece to forge deformation to obtain the required die forging.

Among the aluminum and aluminum alloy processed materials, rolled materials-plates, strips, strips, foils and extruded materials-tubes, rods, shapes, and wires, are the most widely used.