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Optimization and improvement of extrusion quality and output of aluminum profiles

Optimization and improvement of extrusion quality and output of aluminum profiles

2020-11-17

Because of the variety and specification of aluminum profiles, the flow of data in the process of extrusion is complicated, the extrusion die is subjected to bad load, so the development of aluminum profile extrusion products and the design of the die has become a difficult task.

Aluminum alloy profile industry is the most widely used non-ferrous metal structural materials in aviation, aerospace, automotive, machinery manufacturing, shipping, construction, decoration.

The traditional production mode of attachment lesson design and mould test and repair can not satisfy the needs of ancient economic development.

In the effectiveness of life, quality is the key to the market economy environment, aluminum extrusion production enterprises more important is the improvement of mold design and processing of the yield and yield of extrusion rate.

In the production of aluminum and aluminum alloy semi-finished products, extrusion is one of the important forming processes. The quality of the extrusion die and the speed of extrusion directly affect the product quality and output of aluminum and aluminum alloy extrusion enterprises.


In this case, how to improve the productivity of the extruder has become a matter of no delay.

There are many ways to improve productivity. Improving the level of installed machinery, improving the quality of workers and improving water management are all practical and effective ways.


One, the important factor that affects product output and quality


1. The importance of aluminum bar quality


For aluminum profiles with high quality requirements, the quality of the bar directly affects the quality and yield of the product. Alloying, grain, refining and homogenizing high-quality ingot may reduce the loss of the mold, improve the effective production time, and thus improve the extrusion speed to achieve a larger yield.

Aluminum alloy profile industry is the most widely used non-ferrous metal structural materials in aviation, aerospace, automotive, machinery manufacturing, shipping, construction, decoration.


2. Advanced equipment and high-quality workers are the premise of improved output


To the output of product of progressive extrusion, progressive equipment, worker of high quality, ancient change scientific management is having crucial effect.


3. Importance of molds


Reasonable mold design, timely nitriding to improve the hardness and smoothness of the mold working belt, the number of die changing, reduce the non-work time, improve the yield of product quality drop is very important to achieve greater output.


4, temperature control and progress in the production of important correlation


In general, if there is no unscheduled downtime, then the larger volume is significantly determined by the extrusion speed, while the latter is subject to four factors, three of which are fixed.

The latter factor is that the temperature and its controlled level are variable.


The first factor is the extrusion pressure of the extruder. The extruder with large extrusion pressure can be successfully extruded when the billet temperature is low.

The second factor is the mold design. During extrusion, the friction between the metal and the mold wall usually causes the temperature of the aluminum alloy passing through to rise 35 ~ 62℃.

The third factor is the characteristics of the extruded alloy, is the limit of extrusion speed can not control the factor, the profile outlet temperature can not exceed 540℃, otherwise, the nominal quality of the data will fall, die marks significantly increased, and even show aluminum, gravure, micro crack, tear and so on.

The latter factor is temperature and its controlled level.


If the extrusion pressure of the extruder is not large enough, it is difficult to successfully extrude or even presents the picture of the die and cannot be squeezed, the billet temperature can be improved, but the extrusion speed should be lower, in case the data outlet temperature is too high.

Each alloy has its own particular optimum extrusion (billet) temperature.


The production practice proves that the billet temperature is better at 430℃ or so (when the extrusion speed is ≥16mm/s).

The die temperature of 6063 alloy profile shall not exceed 500℃, and the die temperature of 6061 alloy profile shall not be greater than 525℃.

Little change of mold temperature will also affect the output and quality of the product.


The temperature of the extrusion drum is also very important, especially the temperature of the preheating stage should be careful to increase, should avoid excessive thermal stress between the layers, it is better to make the extrusion drum and bushing rise to the working temperature at the same time.

The preheating heating rate shall not be greater than 38℃/h.

The better preheating standard is: rise to 235℃, heat preservation for 8 hours, continuous temperature rise to 430℃, heat preservation for 4 hours, before putting into work.

Not only does this guarantee uniform internal and external temperatures, but there is enough time to eliminate all internal thermal stresses.

Of course, the better preheating method is to heat the extruder in the furnace.


In the process of extrusion, the temperature of the extrusion drum should be 15 ~ 40℃ lower than that of the billet.

If the speed of extrusion is so high that the temperature of the cylinder rises above the billet temperature, it is necessary to make the temperature of the cylinder drop, which is not a troublesome task and the yield will drop.

In the process of production speed recovery, sometimes by the electric couple control of the heating element will be cut off, but the temperature of the extrusion drum is still rising.

If the temperature of the extrusion container is higher than 470℃, the finished product will rise.

The imaginary cylinder temperature should be determined according to different alloys.


Production of high quality nominal profile, extrusion pad temperature should be strictly controlled, in order to reduce the nominal tone inconsistent volume of finished products.

The quality of the fixed extrusion pad is much better than that of the active extrusion pad, which can accumulate more heat, thus lowering the billet end temperature, reducing the entry of impurities into the profile, and contributing to the improvement of output.


Mold temperature plays an important role in obtaining a high yield, individual must not be lower than 430℃;

On the other hand also must not be too high, otherwise, but the hardness may fall, at the same time will produce oxidation, important in the working belt.

During the mold heating process, the molds should not be close to each other, obstructing the air flow.

It is better to use box-type heating furnace with grid, each mold is put in a separate box.


The temperature rise of the billet in the extrusion process can be up to 40℃ or higher, and the amount of rise depends on the mold design.

In order to obtain the larger output, the temperature can never be ignored, should record each temperature and strictly control, in order to find out the larger output of the machine and each temperature correlation.


Later, the extrusion factory staff should bear in mind: temperature exquisite control, is crucial to the improvement of output.


2. Important ways to improve product output and quality


Because the output and quality of products depend on the original data, equipment and mold, suitable process parameter setting, the quality of workers.

The specific ways to improve product output, quality and volume of finished products are as follows:


Choice of alloying, grain, refined, homogenized high quality ingot;


Optimize the mold design, improve the hardness and finish of the mold working belt timely by nitriding, drop the number of mold changes, reduce the non-work time;


Lengthen the billet, reduce the pressure surplus quantity;


The solid yield of metal was improved by using hot shear.


Sawing at the welding part of the profile to choose the appropriate length of ingot and extrusion;


Drop ingot temperature, improve extrusion speed to ensure outlet temperature.

Aluminum alloy profile industry is the most widely used non-ferrous metal structural materials in aviation, aerospace, automotive, machinery manufacturing, shipping, construction, decoration.


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