Electric-smelting formation method for barrel of pressure vessel of nuclear power station

Abstract

The invention provides an electric-smelting formation method for a barrel of a pressure vessel of a nuclear power station. According to the method, electric arc heat, resistance heat and electro-slag heat are combined to form a high-energy heat source for smelting continuously-conveyed metal wires so that the metal wires are solidified and stacked layer by layer on a base material to form a metal component; a computer is used for controlling relative movement between an electric smelting head and the base material so as to realize rapid cooling and layer-by-layer solidification and stacking on the base material in a smelting bath, and finally the barrel of the pressure vessel of the nuclear power station is formed. The electric-smelting formation method provided by the invention has the advantages of high efficiency, low cost, good mechanical properties and the like.

Description

technical field [0001] The invention relates to an electric fusion forming method for a nuclear power plant pressure vessel cylinder body. Background technique [0002] As the heart equipment in the nuclear island of a nuclear power plant, the reactor pressure vessel is mainly used to hold the reactor core, keep the high temperature and high pressure coolant in a sealed shell, and at the same time play a role of radiation shielding. The strong neutron irradiation makes the material performance continuously been exacerbated. Therefore, the harsh working environment, the ever-increasing extreme requirements for nuclear power safety, and the container itself as a non-replaceable part of the nuclear island will become larger and larger as the power generation increases. The requirements for nuclear power pressure vessel materials are very strict and are becoming more and more higher. [0003] At present, the pressure vessel material is Mn-Mo-Ni low-alloy high-strength steel (A...

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Problems solved by technology

[0004] Although this method is widely used in industrial production, it is still very difficult to manufacture special material parts due to the actual manufacturing level of forging enterprises in my country. Taking a typical third-generation nuclear power AP1000 pressure vessel as an example, the production of integrated roof and head materials Scrapping abounds, and the success rate is extremely low. And because of the technical limitations of steel ingot smelting and forging, the container cylinder and special parts are forged in sections and then assembled and welded together. Obviously, the increase in welds splits the mechanical fibers. The continuity greatly affects the mechanical properties of the material. And the forming efficiency is low, the manufacturing cycle is long, and the cost is increased.

[0005] Moreover, due to the thick cross-sectional size of the pressure vessel, during heat treatment, the core and the surface undergo different heat treatment speeds during the heating and cooling process, which is prone to stress cracking, and the macroscopic material phase structure is not uniform, so it is difficult to obtain good full-section properties. .In addition, judging from the final grain measurement results of this process, the pressure vessel material is generally only about 5-7 grades. For the purpose of improving the mechanical properties, especially the comprehensive performance of strength and toughness, through refining grains in the current research and development and production , the process has a large bottleneck.

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