More medium-duty truck gear with steel grades more in our country, mainly in order to adapt to the introduction of foreign advanced automotive technology at the time.
In the 50 s in our country from the former Soviet union, geoff medium-sized truck plant the introduction of the Soviet union (
The 'liberation' brand original models)
Production technology at the same time, also introduced the former Soviet union in the production of automobile gear 20 crmnti steel grade.
After the reform and opening up, with the rapid development of China's economic construction, in order to meet the requirements of the rapid development of transportation in our country, starting in the 80 s, our country in a planned way to introduce all kinds of advanced industrial developed countries, all kinds of foreign advanced medium-duty truck is introduced.
At the same time, large car factory in China with foreign famous automobile companies to cooperate, the introduction of foreign advanced automobile manufacturing technology, including automobile gear production technology.
At the same time, China's iron and steel smelting technology level has been improved, based on ladle and secondary smelting composition adjustment and continuous casting and rolling and other advanced smelting technology, makes the steel mill to produce high purity and hardenability band narrow gear steel, so as to realize the localization of the introduction of automobile gear steel, gear steel in our country's production level on a new step.
Suitable for China's national conditions of domestic heavy automobile gear can use nickel high hardenability steel has been applied, has obtained the good effect.
Automobile gear heat treatment technology is also from the original 50 -
Well type gas carburizing and applied in the '60 s development to the current widely used by the computer control of continuous gas carburizing automatic line and box-type multi-purpose furnace and automatic production line,
Including low voltage (
, the gear carburizing oxidation processing technology, gear quenching controlled cooling technology (
Due to the use of special oil quenching and quenching cooling technology)
, gear forging stock isothermal normalizing technology, etc.
These technologies, not only make the gear carburizing and quenching distortion has been effectively controlled, the gear machining accuracy was improved, prolong the service life, but also can meet the needs of the modernization of the gear with the mass production of the heat treatment.
Literatures, points out that the service life of automobile gear is mainly composed of two major index evaluation, one is the gear contact fatigue strength and bending fatigue strength of gear.
The former is mainly decided by carburizing and quenching quality, which is mainly determined by the gear material.
Therefore, it is necessary for automobile gear with the requirement of carburizing steel, properties and heat treatment characteristics a more comprehensive understanding.