A post-forging heat treatment process for 12cr2mo1v hydrogenation reactor forgings

Abstract

The invention provides a heat treatment process after forging of a 12Cr2Mo1V hydrogenation reactor forged piece. The heat treatment process includes the following steps that one-time high temperaturenormalizing is performed, wherein segmented heating is adopted, the heating temperature of the first segment is 650-720 DEG C, heat preserving is performed for 0.5-2 h / 100 mm, the heating temperatureof the second segment is 250-350 DEG C, heat preserving is performed for 1-2 h / 100 mm, the heating temperature of the third segment is 1010-1030 DEG C, heat preserving is performed for 1.5-4 h / 100 mm,and then cooling is performed till temperature is 250-350 DEG C; and one-time isothermal annealing is performed, wherein temperature rises to 650-720 DEG C, heat preserving is performed for 0.5-1 h / 100 mm, temperature rises to 940-960 DEG C, heat preserving is performed for 1.5-4 h / 100 mm, cooling is performed till temperature is 650-720 DEG C, heat preserving is performed for 2-4 h / 100 mm, and cooling is performed till temperature is 250 DEG C or below. The heat treatment process after forging of the 12Cr2Mo1V hydrogenation reactor forged piece effectively eliminates structural inheritance,the coarse crystal and mixed crystal condition of the forged pieces is obviously improved, and the comprehensive performance of the forged piece is improved; and meanwhile, the normalizing frequency after forging is reduced, and the production cost is saved.

Description

technical field [0001] The invention relates to the technical field of large forgings, in particular to a post-forging heat treatment process for forgings of a 12Cr2Mo1V hydrogenation reactor. Background technique [0002] In the petrochemical industry, with the improvement of processes such as hydrocracking and hydrodesulfurization, the increase in demand for light oil products, the cracking and refining of heavy crude oil, and the need to prevent air pollution, hydrofining units and hydroprocessing units have been promoted. The development and prosperity of the core equipment in the hydrogen cracking unit, and the cylinder forging is an important part of the pressure vessel. It is a forging that works for a long time under certain pressure, temperature and medium conditions, so it has high requirements for materials. In addition to the mechanical properties at room temperature, according to the different use environments and importance of the container, it is also required...

AI Technical Summary

Problems solved by technology

However, compared with the conventional 12Cr2Mo1 material, due to the addition of element V, the structure inheritance phenomenon is more obvious, and the problems of mixed crystals and coarse structure of the forging after heat treatment after forging are more prominent, resulting in poor impact toughness after quenching and tempering, which brings hidden dangers to use.

At present, the post-forging heat treatment process generally adopts normalizing at a temperature of 920-980°C. Due to the low normalizing temperature, it is impossible to eliminate the pinning effect of VC and other carbides on the grain boundaries, and it is difficult to eliminate the phenomenon of coarse grains and mixed crystals. Coarse bainite Tissue produces tissue heredity, which affects the final performance of the product. It must be normalized many times to refine the grain size, resulting in energy waste and delaying the production cycle.

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