Nuclear island evaporator reducing cylinder integral forge piece and forging forming method thereof

Abstract

The invention discloses a nuclear island evaporator reducing cylinder integral forge piece. The forge piece body is composed of a conical cylinder and a cylinder, wherein the cylinder is arranged at the lower end of the conical cylinder; the conical cylinder comprises a conical pipe upper opening section, a conical pipe section and a conical pipe lower opening section which are sequentially arranged from top to bottom; the cylinder comprises a main cylinder pipe section, and the ratio h1 / h2 of the height h1 of the conical cylinder to the height h2 of the cylinder is equal to 0.60-0.70. The forming method for forging a nuclear island evaporator reducing cylinder integral forge piece comprises the following steps of: (1) selecting a steel ingot, (2) segmented heating, (3) blanking the blank,(4) forging blank upsetting and drawing, (5), forging blank forming, (6) punching a bobbin hole, (7) heat treatment after forging. In the upsetting, drawing and punching processes, the initial forging temperature is 1210-1250 DEG C, the final forging temperature is 830-870 DEG C and the normalizing temperature is 1030-1060 DEG C. The forge piece and the method disclosed in the invention have theadvantages of uniform metal microstructure and mechanical property, reliable forging safety and good economy.

Description

technical field [0001] The invention relates to a large-scale structural part for a nuclear island steam generator, in particular to an integral forging of a different-diameter cylinder composed of a conical cylinder and a cylindrical cylinder of the steam generator. The invention also relates to a forging forming method of the integral forging of the cylinder with different diameters. Background technique [0002] The pressurized water reactor nuclear power plant is mainly composed of a nuclear island and a conventional island. The four major components of the nuclear island of the pressurized water reactor nuclear power plant are the steam generator, the pressurizer, the main pump and the core. Among them, the nuclear island steam generator is the most critical main equipment of the nuclear power plant. Its function is to transfer the heat of the heat carrier in the reactor and convert it into steam with a certain pressure for the steam turbine to work. The steam generato...

AI Technical Summary

Problems solved by technology

This method of splicing and manufacturing multi-unit cylinders by welding obviously has many shortcomings: firstly, the structure spliced ​​by welding cannot always form a complete metal flow line, because the nuclear power steam generator has been in the harsh operating environment of high temperature and high pressure for a long time , and bear the sudden change of pressure formed by alternating loads and pipeline eddy currents, it is easy to cause uneven stress distribution and stress concentration, and it is easy to cause fatigue, creep and damage. Moreover, the welding manufacturing method is complicated, the welding cycle is long, and the welding process is complicated. Poor quality stability in the stress area directly results in low yield and high manufacturing cost

Due to the extremely high performance requirements of the forging material of the cone shell forging, and the material has the characteristics of high quality and high price, during the machining process of the finished cone shell forging, too much cutting allowance will cause a lot of cutting metal waste, so unreasonable sample The reserved amount and finishing cutting allowance not only cause waste of high-performance and high-cost metals, but also increase the cost of processing and manufacturing

[0004] The existing forging production process adopts welding, casting or hot extrusion forming process, obviously these traditional processes are difficult to meet the performance requirements of nuclear grade forgings

Since the nuclear island evaporator different-diameter cylinder forging is a large block-shaped component, there is a low utilization of materials. Most of the materials are machined and become waste and are difficult to reuse. big waste

Second, the technological process is complicated and the production efficiency is low. During the forging process, it is difficult for this kind of thick cake solid forging to be heated and compacted. There are differences in the thermodynamic and dynamic conditions of the inner layer, outer layer, core and upper part of the steel ingot. , so that there are defects such as segregation, porosity and shrinkage cavity inside the steel ingot. These defects often lead to quality problems such as cracks and coarse grains in the forging during the subsequent forging process, and in severe cases, the forging will be scrapped.

Third, the material of the nuclear island evaporator different-diameter cylinder forging is heat-resistant steel, which has poor thermal processing performance, and it is difficult for the core material of this large forging to obtain sufficient forging pressure due to the "bridge arch" effect of the outer material , a small deformation area is formed in the center, which cannot effectively forge the porosity defects such as shrinkage porosity and shrinkage cavity inside the billet, and cannot crush the as-cast dendrites inside it, resulting in anisotropy of the forging and the mechanical properties of the cylinder forging inconsistencies

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