What are the types of roll heat treatment commonly used by roll manufacturers?

The commonly used heat treatment types of rolls include stress relief annealing, isothermal spheroidizing annealing, dispersion annealing, normalizing, tempering, quenching and cryogenic treatment. Today, let the roll manufacturer Wuxi Taihu roll editor explain the common heat treatment types of rolls and answer a few questions. I hope it can help you know more about roll.

Why should metallurgical cast steel rolls be treated by high temperature dispersion?

The roll manufacturer said that during the condensation of cast steel roll, due to the existence of dendritic crystallization, the intragranular segregation of alloy composition will be formed. This segregation is formed because the upper and lower layers, inner and outer layers of roll body cannot realize sequential condensation in the process of roll condensation. The larger the diameter of the roll body, the longer the length of the roll body, the greater the condensation temperature gradient, and the more severe the alloy condensation segregation. With the increase of alloy content of alloy cast steel roll, the segregation index during condensation increases, and the degree of composition heterogeneity is also greater. Therefore, in order to fully disperse the atoms of alloy elements and obtain the austenite arrangement with uniform composition, it is necessary to heat the high alloy cast steel roll to 150-250 ℃ above AC3 for a certain time. This heat treatment method is called high temperature dispersion treatment.

Why do alloy cast steel rolls need spheroidizing annealing heat treatment?

The spheroidizing annealing heat treatment of alloy cast steel roll is mainly to improve the cutting performance of the roll, improve the cutting power and make corresponding arrangements for the subsequent quenching treatment. Spheroidizing annealing treatment makes the carbides in the arrangement change from flake to spherical, that is, spherical or granular carbides are evenly distributed on the ferrite matrix to form a spherical pearlite arrangement. The spheroidizing temperature selected in production is generally slightly higher than the AC1 critical point. If the temperature is too low, the spheroidization time is too long, and if the temperature is too high, granular pearlite with different particle sizes will appear.

Why do alloy cast steel rolls need quenching heat treatment?

Quenching of alloy cast steel roll is to heat it above the critical temperature (ACM or AC1), keep it warm for a certain time to make it fully austenitized, and then rapidly cool it to the bainite transformation zone at a cooling rate greater than the critical cooling rate, so as to make the working layer of roll body obtain the thermal treatment process of bainite arrangement.

The purpose of quenching heat treatment of alloy cast steel roll is to make the roll operation layer obtain good applicable arrangement, give full play to the effect of alloy elements in the roll, and improve the hardness and wear resistance of the roll body operation layer.

OK, the above is a brief introduction of the common heat treatment types of rolls by the roll manufacturer. If you want to know more about roll products and roll manufacturers, please pay attention to the roll manufacturer Wuxi Taihu roll Xiaobian.