1Mn18Cr18N steel guard ring forgeable piece forging technique for electric generating set

Abstract

The invention discloses a process for forging 1Mn18Cr18N retaining ring steel used in a generator set. In the method, blank materials that are pre-processed are forged in a die with a 5000t hydraulic press, and water-cooling thermo-mechanical treatment is performed after forging. The method includes the following steps: (1) closed-type punching deformation of the electroslag blank materials; (2) extrusion deformation in die; (3) forward extrusion shrinkage deformation; and (4) water-cooling thermo-mechanical treatment after forging. The inventive process has the advantages of high production efficiency, good and stable product quality, and high operability without utilizing large equipment such as ten thousand ton-level hydraulic press.

Description

technical field [0001] The invention relates to the forging technology of the steel retaining ring forging used in the steam turbine generator set or the nuclear power plant, and mainly relates to the forging process of the 1Mn18Cr18N steel retaining ring forging used in the generator set. Background technique [0002] At present, the manufacturing method of the retaining ring in the forging manufacturing industry of steam turbine generator sets at home and abroad is mainly as follows: adopt ordinary 10,000-ton free forging hydraulic press with small deformation and multiple fires for free forging, stop forging at any time for the cracks generated during forging, and use them after cooling. Flame or arc gouging is used to remove, water-cooled deformation heat treatment after forging, and solid solution treatment at high temperature for a long time after rough machining. Ordinary 10,000-ton free forging hydraulic press does not need special tooling for small deformation and m...

AI Technical Summary

Problems solved by technology

Ordinary 10,000-ton free forging hydraulic press does not need special tooling for small deformation and multi-fire free forging, but because of its slow movement, narrow forgeable temperature range, and easy to crack 1Mn18Cr18N steel, it is easy to cause forging cracks, so it may be at any time due to Insufficient forging ratio per fire caused by stopping forging to clear cracks, metal defects are difficult to forge, uneven deformation, coarse grains and other internal quality problems and production efficiency problems of forgings; flame or arc gouging to remove forging cracks results in stress concentration 1. Overheating and overburning defects in the heat-affected zone make repeated cracking during the forging process after the cracks are removed, exacerbating the above-mentioned internal quality problems and production efficiency problems, and the pollution is also relatively large; The hydraulic press moves slowly and may stop forging to clear the crack at any time, so the two conditions of a certain amount of deformation and a certain deformation temperature necessary for the deformation heat treatment cannot be guaranteed, and the deformation heat treatment cannot be realized stably, so the subsequent solution treatment must be kept at high temperature for a long time resulting in coarser grains