Tempering is one of the main processes in heat treatment. The hardness (H) of general mechanical parts when treated with H=f(T) depends on tempering temperature (t) and tempering time (t), and there is a certain functional relationship between them: h = f (t, t). When the tempering time is constant, the functional relationship between tempering hardness and tempering temperature of steel can be divided into four types (H and T are inverse functions):
① line type;
② Parabolic type;
③ Power function type;
④ Combination of straight line and power function.
Because the two types are very inconvenient to calculate and draw in use, they can be simplified to straight lines or parabolas in most cases and expressed by empirical equations (formulas), namely: h = a1+r1t; H=a2+R2T
Where: h-tempering hardness value (HRC, HV, HB or HRA)
T—— Tempering temperature (℃)
A 1, a2, R 1, R2 coefficient to be determined.
The tempering equation of heat treatment is mainly calculated and corrected by using mathematical statistics method according to the actual process test and the data of relevant references. The tempering equation is practical and can be used as a reference for the process design of mechanical parts and the formulation of heat treatment process specifications.
Extended data
Yang Jingfeng, CEO of Baiyi Technology, believes that the transformation and upgrading of the manufacturing industry will take some time. For the enterprises involved, heat treatment is a technology to seize the commanding heights. "Based on the grand strategy of transformation and upgrading of China's manufacturing industry, what we are doing now is to seize the high point of heat treatment, a basic technology," said Yang Jingfeng.
He introduced that at present, Baiyi Technology has applied heat treatment database, online measurement and control system and computer simulation technology to heat treatment equipment to complete intelligent, high-quality, low-cost and environmentally friendly heat treatment. This technology can realize zero pollution and zero emission in the production process, reduce the production cost by 75%, reduce the energy consumption by 80%, improve the production yield by 90%, and prolong the service life of equipment by 10 times.
Yang Jingfeng introduced that digital energy control system, AI process control system and industrial Internet of Things system can ensure the quality of heat treatment. "Our patented CO2 supercritical cooling technology uses the energy in the manufacturing process to accurately copy the cooling curve required by the process and maintain the best thermal state;
The self-developed online measurement and control system can simulate the process according to the product requirements, measure and control the production process with all factors, and automatically correct the process according to the product detection data; Online control software can complete the intelligent management of each production subsystem in the factory, help digital operation and create reliable, efficient and interconnected commercial value. "
People's Network-Domestic Heat Treatment Breakthrough Helps Transformation and Upgrading of Manufacturing Industry