The Hazards of Residual Stress Annealing

Generally, mechanical products always have residual stress on the processing surface. If the product is not subjected to appropriate stress annealing treatment and is improperly exposed to heat sources such as sunlight, heat engines, etc., it may deform.
In addition, residual stress is often highly concentrated in a certain local area, welding area, etc., which can locally reduce the mechanical strength of the product. To avoid these problems, we must use residual stress tube electric furnace annealing treatment.
Due to the fact that stress annealing utilizes the phenomenon of small latent changes in atoms at high temperatures to recombine atomic positions and eliminate the presence of stress. Therefore, the stress annealing temperature of the material varies with the high temperature creep ability of the material.
The annealing temperature commonly used for tube furnaces with creep resistant materials, such as low alloy steel, is 595-675 ℃, while for high chromium alloy steel, it is 900-1065 ℃. We can use lower temperatures and longer durations as needed to achieve the same effect of stress relief as the treatment at high temperatures in a short time electric furnace.
This treatment involves slowly and uniformly heating the product to a temperature lower than the point of change in the direction of the box furnace, and then gradually cooling down at this temperature for a period of time. The most important thing for the box furnace in this process is to maintain the same cooling rate in each area of the product. Otherwise, due to the differences in cooling rates in each area after cooling, residual stress will occur again. This is particularly serious for products with complex shapes.

The above content is organized by Superb heater Company, super heater. Mainly professional production: industrial heating elements, temperature measuring elements, production equipment, accessories, and raw materials such as tubular heaters, tubular heaters, belt heaters, ceramic heaters, silicone rubber heaters, thermocouples, etc.

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