Manufacturing process of expansion alloy 4J36 round bar.
1. Overview. Expansion alloy 4J36 is an alloy material with excellent thermal expansion properties, which is widely used in aerospace, electronics, precision instruments and other fields. Its round steel products have the characteristics of high precision, high strength and high corrosion resistance, so special process technology is required in the manufacturing process. This article will focus on the manufacturing process, technical points and quality control measures of 4J36 round bar.
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Second, the manufacturing process.
1.Smelting and ingots.
First, the various raw materials are precisely metered and added to the electric arc furnace for melting, depending on the required composition. During the smelting process, the melting temperature, time and atmosphere in the furnace should be strictly controlled to ensure the accuracy of the alloy composition. After the smelting is completed, the molten alloy is poured into the casting mold, and the ingot is obtained after cooling and solidifying.
2.Hot rolling.
The ingots are heated and hot rolled after the temperature reaches a suitable hot rolling temperature. In the process of hot rolling, it is necessary to control the rolling temperature, the amount of depression and the rolling speed to ensure the dimensional accuracy and surface quality of the round bar. After several passes of rolling, the thickness of the round bar is gradually reduced until the required specifications are reached.
3.Cold rolling and annealing.
Hot-rolled round bars need to be cold-rolled to further improve their dimensional accuracy and mechanical properties. In the cold rolling process, the rolling force, the amount of depression and the rolling speed should be strictly controlled to ensure the geometric shape and dimensional accuracy of the round steel. After each pass of cold rolling, intermediate annealing is required to eliminate work hardening and restore the plasticity of the material. The annealing temperature is controlled below the phase change point, and the temperature is kept for a period of time and then air cooled or slowly cooled.
4.Straightening and shearing.
Cold-rolled round bars may have deformations such as bending or twisting and need to be straightened. The straightening method can be selected according to the actual situation, such as tensile straightening, pressure straightening, etc. Finally, according to the customer's requirements, the round steel is sheared to obtain the desired length or shape of the product.
5.Surface treatment and inspection.
Sheared round bars need to be surface treated to improve their corrosion resistance and aesthetics. The surface treatment method can be selected according to the actual needs, such as shot peening, chemical plating, etc. After the treatment is completed, the round steel needs to be strictly inspected, including dimensional inspection, surface quality inspection, performance testing, etc., to ensure that the product quality meets the requirements.
3. Technical points and quality control.
1.Smelting and ingots.
During the smelting process, the alloy composition should be strictly controlled to ensure that the content of each element meets the standard requirements. At the same time, it is necessary to maintain the stability of the melting temperature to prevent overheating or undermelting. When casting ingots, it is necessary to ensure that the temperature of the casting mold is appropriate to prevent defects such as cracks or porosity.
2.Hot and cold rolled.
In the process of hot rolling, the temperature and amount of pressure should be controlled to avoid overheating, overburning or cracking. During cold rolling, it is necessary to ensure the stability of the rolling force and avoid surface defects such as wave lines. At the same time, the annealing temperature and time should be strictly controlled to ensure the plasticity and dimensional accuracy of the material.