Stainless steels are generally heat-treated based on the stainless steel type and reasons for carrying out the treatment. Heat treatment methods, such as stress relieving, hardening and annealing, strengthen the ductility and corrosion resistance properties of the metal that is modified during fabrication, or generate hard structures capable of tolerating abrasion and high mechanical stresses.

Commonly used gear materials are various grades of high-quality carbon structural steel, alloy structural steel, cast steel, cast iron, and non-metallic materials. Generally use forging or rolled steel. When the size of the gear structure is large and the wheel blank is not easy to forge, cast steel can be used; for open low-speed transmission, gray cast iron or ductile iron can be used. Steels with better comprehensive performance should be selected; high-speed gears are prone to pitting on the tooth surface, and materials with high tooth surface hardness should be selected; gears subject to impact load should be selected from materials with good toughness. For high-speed, light-load and low-noise gear transmissions, non-metallic materials, such as cloth bakelite, nylon, etc. can also be used. Commonly used gear materials and their mechanical properties are listed in the table below.

Various heat treatment methods for carburizing and carbonitriding gears

​Bearing steel ingots are generally subjected to long-term diffusion annealing at a high temperature of 1200 ~ 1250 ℃ to improve carbide segregation. The atmosphere in the furnace should be controlled during hot working, the heating temperature of the billet should not be too high, and the holding time should not be too long to avoid serious decarburization. The final rolling (forging) temperature is usually between 800 and 900 ℃. If it is too high, it is easy to appear coarse network carbides, and if it is too low, it is easy to form rolling (forging) cracks. The finished rolled (forged) material should be quickly cooled to 650°C to prevent cementite from precipitating in a network on the grain boundary. If conditions permit, a controlled rolling process can be used.

The stainless steel bright annealing production line (BAL) of a steel mill is a large-scale production line designed and manufactured by a foreign company for bright annealing stainless steel strips. Its total height is 55m, and it can handle stainless steel plates with a width of 600 to 1250 mm and a thickness of 0.1 to 3.0 mm. belt.

what are the differences among 2E, 2D, 2B and BA?