Heat treatment and quenching process

Operation method: heat the steel piece to the transformation temperature above AC3 or AC1, keep it warm for a period of time, and then cool it quickly in water, nitrate, oil or air.


Intention: the purpose of quenching is usually to obtain martensitic arrangement with high hardness. Sometimes when quenching some high alloy steels (such as stainless steel and wear-resistant steel), it is to obtain single and uniform austenite arrangement to improve wear resistance and corrosion resistance.


The key points of application: (1) generally used for carbon steel and alloy steel with carbon content more than 0.3%; (2) quenching can give full play to the strength and wear resistance potential of the steel, but together it will form a great internal stress, reducing the plasticity and impact toughness of the steel, so it is necessary to conduct tempering to get better inductive mechanical function.


Operation method: after heating the steel parts to AC3 + 30 ~ 50c or AC1 + 30 ~ 50c or below AC1 (relevant materials can be consulted), they usually cool down slowly with the furnace temperature.


Intention:


Reduce hardness, improve plasticity, improve machining and pressure machining functions;


Refine the grain, improve the mechanical function, and prepare for the next process;


Eliminate the internal stress caused by cold and hot working.


The key points of application: (1) suitable for forgings, weldments and raw materials with unqualified supply conditions of alloy layout steel, carbon East West steel, alloy East West steel and high-speed steel; (2) usually annealed in the blank condition.