Thermal treatment process for X12CrMoWVNbN10-1-1 grain refinement

Abstract

The invention provides a thermal treatment process for X12CrMoWVNbN10-1-1 grain refinement. According to the thermal treatment process, the amount of acicular austenite is decreased as much as possible by increasing the heating speed, and the amount of spherical austenite is increased, so that grain refinement is achieved, the grain size can meet the technical requirement, and the using range of X12CrMoWVNbN10-1-1 is enlarged. Fed materials are forged into workpieces, the workpieces are sequentially subjected to high-temperature normalizing, high-temperature tempering, conventional normalizingand high-temperature tempering, and then the workpiece subjected to high-temperature tempering are subjected to subsequent processing treatment. In the high-temperature normalizing process, the temperature increasing speed of the workpieces in an alpha and gamma two-stage region is increased, the workpieces can pass through the two-stage region rapidly, and the spherical austenite can be obtainedas much as possible. On one hand, the orientation relationship of crystallography is broken through to a greater extent, namely, the K--S relationship; and on the other hand, the nucleation rate of the austenite can be increased by increasing the heating speed. The high-temperature tempering process particularly comprises the steps that heat preservation is conducted for 15-20 h at the environmental temperature of 700 DEG C to enable carbides to be dissolved as many as possible to further destroy the orientation relationship of metallography, and then air cooling is conducted.

Description

technical field [0001] The invention relates to the technical field of material heat treatment, in particular to a heat treatment process for X12CrMoWVNbN10-1-1 grain refinement. Background technique [0002] The forging manufacturing industry is the basic industry of the national equipment manufacturing industry. It is also an indispensable strategic industry related to national security and the lifeline of the national economy. It is also an important component of national capabilities. The development level of large forgings is a measure of a country's comprehensive capabilities important sign. [0003] With the rapid development of electric power, petrochemical and other industries at home and abroad, some new technologies and equipment have appeared, and some new materials have been used; at the same time, new requirements have been put forward for the forging industry, which not only promotes the continuous upgrading of forging equipment , and accelerated the generati...

AI Technical Summary

Problems solved by technology

However, due to the high content of alloying elements and a variety of strong carbide-forming elements, this material has very good hardenability and very stubborn structure inheritance. Therefore, after the grain is coarse, the grain size is difficult to refine, and the grain The difficulty of grain refinement is obviously more than that of martensitic heat-resistant steel such as SA336F91 and SA336F92

[0008] The existing heat treatment process for grain refinement of X12CrMoWVNbN10-1-1 steel is normalizing + high temperature tempering, high temperature normalizing + high temperature tempering, and then conventional normalizing + high temperature tempering, complete annealing, the effect is very poor , the grain size can only be increased by 0.5 grades, and the grain size is coarse, the grain boundary area is reduced, and the concentration of carbides and nitrides is relatively increased, thereby increasing the sensitivity to temper brittleness; The path is relatively straight and simple, which reduces the energy absorption and has a significant impact on the impact absorption energy. At present, there is no effective solution. Therefore, to solve the problem of grain size coarsening of X12CrMoWVNbN10-1-1 steel forgings becomes an imminent subject