Gear heat treatment
Classification： Blog
Release time：2024-06-20
The tooth body of the gear should have high resistance to breaking, and the tooth surface should have strong resistance to pitting corrosion, wear resistance and high resistance to gluing, that is, the tooth surface is hard and the heart is tough. Therefore, different heat treatments will be carried out for gears under different working conditions. Generally speaking, for example, due to the small load of 3C and lithium battery automation equipment, S45C or SUS304 is often used for surface treatment after direct processing, without redundant heat treatment. However, when gear transmission is needed in the design of non-standard equipment with large load, the following heat treatment process is often used for gear treatment.
Overall quenching, overall quenching and then low temperature tempering. Commonly used materials are medium carbon steel or medium carbon alloy steel, such as 45, 40Cr, etc. The surface hardness can reach 45HRC ~ 55HRC. This heat treatment process is relatively simple, but the gear deformation is large, the heart toughness is low. The quality is not easy to guarantee, not suitable to bear the impact load. After heat treatment, tooth grinding, tooth grinding and other finishing shall be carried out.
Surface quenching, surface quenching and then low temperature tempering. Commonly used materials are medium carbon steel or medium carbon alloy steel, and the surface hardness can reach 48HRC ~ 54HRC. Due to the high toughness of the heart, it can be used to withstand medium impact loads. Medium and small size gears can be heated by medium frequency or high frequency induction, and large size gears can be heated by flame. Flame heating is relatively simple, but it is difficult to obtain uniform hardness on the tooth surface, and the quality is not easy to guarantee. Should only be heated on the surface of the thin layer, the gear deformation is not big, not grinding teeth, but if the hardening layer is deeper, the deformation is larger, should be finished.
When normalizing and quenching and tempering, small batch size, single-piece production, and no strict restrictions on transmission size, normalizing or quenching and tempering are often used. The material is medium carbon steel or medium carbon alloy steel. The surface hardness can reach 40HRC ~ 55HRC. After the heat treatment of gear finishing, in order to reduce the risk of gluing and make the service life of large and small gears similar, the tooth surface hardness of small gear should be tens of HB units higher than that of large gear.
Carburizing quenching, impact load larger gear, should be used carburizing quenching. Commonly used materials are low carbon steel or low carbon alloy steel, such as 15, 20, 15Cr, 20Cr, 20CrMnTi and so on. After carburizing and quenching of low carbon steel, due to the low strength of the heart, and it is not easy to combine with the carburized layer, the possibility of peeling when the load is large, the bending strength of the gear is also low, and the important field should be low carbon alloy steel, Its tooth surface hardness can reach 58HRC ~ 63HRC. After the gear is carburized and quenched, the gear deformation is large and the gear should be ground.
Carbon-nitrogen co-osmosis, carbon-nitrogen co-osmosis process time is short, and has the advantages of nitrogen seepage, can replace carburizing quenching, its material is the same as carburizing quenching.
Nitriding and nitriding gears have high hardness and small deformation, and are suitable for internal gears and gears that are difficult to grind. Often used materials are 42CrMo, 38 CrMoA1 and so on. Because the hardened layer is very thin, it is easy to break under impact load, and when the wear is serious, the hardened layer will be worn away and scrapped, so it is suitable for transmission with stable load and good lubrication.
keyword： Gear,Shaft