Nickel chromium alloy for sealing face of nuclear power valve

Abstract

The invention discloses a nickel chromium alloy for a sealing face of a nuclear power valve. The nickel chromium alloy comprises the following components in percentage by weight: 26.0-28.0 percent of chrome, 2.0-2.5 percent of silicon, 1.1-1.3 percent of boron, 4.5-5.5 percent of molybdenum, 3.0-4.0 percent of tungsten, 0.9-1.1 percent of carbon and the balance of nickel. Meanwhile, a coating layer is prepared by a laser cladding technology so as to obtain a sealing face coating layer of a nickel-based alloy nuclear power valve, which has the following relevant parameters: the rigidity is HRC 42-46 which is slightly higher than HRC39-43 of a Stellite-6 cobalt-based alloy coating layer; the tissue grain fineness number of the coating layer is 11-12 grades which is superior to 9-10 grades of a general plasma jet welding layer and 8-9 grades of a flame resurfacing welding layer; and the width of a combination band of the coating layer and a basal body is 10-30 micrometers which is superior to 80-120 micrometers of a plasma jet welding combination band and 200-300 micrometers of a flame resurfacing welding combination band.

Description

technical field [0001] The invention relates to a nickel-chromium alloy, in particular to a cobalt-free nickel-chromium alloy used as a strengthening material for the sealing surface of nuclear power valves. Background technique [0002] The service conditions of nuclear power valve sealing surfaces are quite harsh, requiring high wear resistance, corrosion resistance, and high temperature resistance. At present, the surfacing welding materials for the sealing surface of nuclear valves are generally cobalt-based alloys, such as Stellite 6 or Stellite 21. Cobalt-based alloys have good high temperature performance, excellent low friction and anti-wear properties, excellent hot corrosion resistance and thermal fatigue resistance, especially in the hot state with excellent scratch resistance, so they are often used for surfacing welding The service conditions are relatively harsh, and the valve sealing surface with high anti-wear and anti-corrosion performance requirements. Ho...

AI Technical Summary

Problems solved by technology

However, due to the high price of cobalt-based alloys and the lack of cobalt resources in my country, the search for substitutes for cobalt-based alloys has always been a concern of Chinese scientists.

Especially for valves working in a nuclear environment, cobalt-based alloys present a major defect: Co59 in the wear and corrosion debris of cobalt-based alloys will be excited to form Co60 isotopes

This will prolong the half-life of nuclear radiation, cause an increase in maintenance time and threats to maintenance personnel during shutdown maintenance, and will also greatly increase the difficulty and cost of nuclear fuel shielding