With the development of science, gears have gradually changed from metal gears to plastic gears. Because plastic gears are more lubricious and wear resistant. It can reduce noise, reduce costs and reduce friction.
China's medium and heavy-duty trucks use more steel grades for gears, mainly to meet the requirements of introducing advanced foreign automotive technology at that time. In the 1950s, China introduced the production technology of the Soviet medium-sized truck (the “liberation” brand) from the former Soviet Union’s Rikhov Automobile Factory. At the same time, it also introduced the 20CrMnTi steel produced by the former Soviet Union.
Chromium manganese titanium steel and boron steel
For a long time, the most common steel used in China's truck gears is 20CrMnTi. This is a medium-sized automobile gear 18XTr steel (ie 20CrMnTi steel) imported from the former Soviet Union in the 1950s. The steel grain is fine, the grain growth tends to be small when carburizing, and has good carburizing and quenching performance, and can be directly quenched after carburizing. According to the literature, before 1980, China's carburized alloy structural steel (including 20CrbinTi steel) only guaranteed the chemical composition of steel and the mechanical properties measured by samples when it was shipped from the factory, but it often showed chemical composition and mechanical properties in automobile production. Qualified steel, due to excessive fluctuation range of hardenability, affects product quality. For example, if the hardenability of 20CrMnTi carburized steel is too low, the hardness of the core after the carburized and quenched is lower than the value specified in the technical conditions. When the fatigue test, the fatigue life of the gear is reduced by half; if the hardenability is over If the gear is high, the shrinkage of the inner hole after the carburizing and quenching is too large, which affects the gear assembly.
Hangzhou Donghua Power Transmission Imp. & Exp. Co.,Ltd
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