On 2018-08-08 14:48:54
Heat treatment theory of steel
Metal heat treatment, for the heat treatment industry, its direct downstream industries are various parts sub industries of the metal machinery manufacturing industry, mainly including automobile parts industry, mechanical basic parts industry (including bearings, molds, fasteners, etc.), aerospace parts industry, engineering machinery parts industry, new energy parts industry, machine tool parts industry, etc.
Among them, due to the large market scale, the automotive parts and mechanical basic parts industry has a great impact on the demand of heat treatment industry; due to the large market scale, the automotive parts and mechanical basic parts industry has a significant impact on the demand of heat treatment industry; while the aerospace parts, engineering machinery parts, new energy parts and machine tool parts industry have developed rapidly in recent years It has become a new increasing point in the heat treatment industry. The development of various fields in the downstream of heat treatment industry has brought a strong pull to the demand market of heat treatment.
The purpose of double heat treatment with high temperature tempering is to make the workpiece have good comprehensive mechanical properties. High temperature tempering refers to tempering between 500-650 ℃. Heat treatment refers to a kind of metal hot working process in which materials are heated, insulated and cooled in solid state to obtain the expected structure and properties. In the process from the stone age to the bronze age and iron age, the role of heat treatment is gradually recognized.
The theoretical basis of heat treatment of steel is the isomerization of iron. The isomeric transformation of iron results in the change of internal structure of steel during heating and cooling. Solution strengthening: because the solute atoms enter the gap or node of the solvent lattice, the lattice will be distorted and the hardness and strength of the solution will be increased. This phenomenon is called solution strengthening phenomenon.
Heating temperature is one of the important process parameters of heat treatment process. The selection and control of heating temperature is the main problem to ensure the quality of heat treatment. Zhuhai metal heat treatment also cools in different medium at different speed. Heat treatment generally does not change the shape and overall chemical composition of the workpiece, and the cooling speed of quenching is fast. However, by changing the microstructure of the workpiece or the chemical composition of the workpiece surface, the performance of the workpiece can be given or changed.