Thermal treatment method of martensitic stainless steel liner plate

Abstract

The invention provides a thermal treatment method of a martensitic stainless steel liner plate. The thermal treatment method comprises the following steps: quenching for the first time, namely increasing the temperature from the room temperature to 700 DEG C at a temperature increasing rate of less than or equal to 50 DEG C per hour, equalizing the temperature at 700 DEG C for 3 hours, increasing the temperature from 700 DEG C to 980 DEG C at a temperature increasing rate of less than or equal to 40 DEG C per hour, preserving heat at 980 DEG C for more than 5 hours, and then cooling to 60 DEG C; quenching for the second time, namely increasing the temperature from the room temperature to 700 DEG C at the temperature increasing rate of less than or equal to 50 DEG C per hour, equalizing the temperature of the liner plate at 700 DEG C for 4 hours, increasing the temperature from 700 DEG C to 980 DEG C by the temperature increasing rate of less than or equal to 40 DEG C per hour, preserving heat at 980 DEG C for more than 6 hours, and then cooling to 60 DEG C and carrying out medium-temperature tempering; medium-temperature tempering, namely increasing the temperature from the room temperature to 350 DEG C at a rate of less than or equal to 50 DEG C per hour, preserving heat at 350 DEG C for 1 hour, increasing the temperature from 350 DEG C to 500 DEG C at the temperature increasing rate of less than or equal to 50 DEG C per hour, preserving heat at 500 DEG C for more than 8 hours, and then taking out the liner plate out of an oil tank after the oil is cooled below 100 DEG C. The thermal treatment method has the advantages that the thermal treatment process of double continuous quenching is adopted and the twice quenching is carried out continuously without time interval, and therefore, the cracking of the liner plate during quenching is reduced, the grain size is refined to the utmost extent and the comprehensive mechanical properties of the liner plate are improved.

Description

technical field [0001] The invention relates to a stainless steel treatment technology, in particular to a heat treatment method for a martensitic stainless steel liner. Background technique [0002] Martensitic stainless steel can adjust its mechanical properties through heat treatment. In layman's terms, it is a type of hardenable stainless steel. Typical grades are ZGCr13, such as ZG2Cr13, ZG3Cr13, ZG4Cr13, etc. After quenching, the hardness is higher, and different tempering temperatures have different combinations of strength and toughness. Due to its good oxidation resistance, some companies in the world have used this material in the lining wet raw material mill. [0003] At present, the heat treatment process adopted by martensitic stainless steel is mainly quenching and high temperature tempering. After quenching and high-temperature tempering, martensitic stainless steel has a hardness of 170HB to 250HB. Although it has good impact toughness, due to its low hard...

AI Technical Summary

Problems solved by technology

After martensitic stainless steel is quenched and tempered at high temperature, the hardness is not high at 170HB-250HB. Although it has good impact toughness, due to its low hardness, when used as a lining, it has poor wear resistance and is easily deformed by impact.

When quenching and tempering at low temperature are adopted, although the hardness increases, the impact resistance is extremely poor. When used as a liner, it is easy to break and the service life is also short.

And due to the existence of temper brittleness, it is not easy to obtain high hardness and impact toughness at the same time