Heat-resistant sintered material excellent in oxidation resistance, high-temperature wear resistance, and salt corrosion resistance, and production method thereof

Abstract

In this heat-resistant sintered material and its manufacturing method, it is an object to obtain a heat-resistant sintered material excellent in oxidation resistance, high-temperature wear resistance, and salt erosion resistance. The heat-resistant sintered material is characterized in that it has a composition containing Cr: 25-50%, Ni: 2-25%, P: 0.2-1.2% in mass%, and the balance is composed of Fe and unavoidable impurities; and Has a structure with a Fe-Cr parent phase and a hard phase composed of Cr-Fe alloy grains dispersed in the Fe-Cr parent phase; the amount of Cr in the Fe-Cr parent phase is expressed in mass % 24-41%, the amount of Cr in the hard phase is 30-61% by mass %; and the effective porosity is 2% or less.

Description

technical field [0001] The present invention relates to a heat-resistant sintered material excellent in oxidation resistance, high-temperature wear resistance, and salt corrosion resistance, and a method for producing the same. [0002] This application claims priority based on Japanese Patent Application No. 2015-066748 for which it applied in Japan on March 27, 2015, and uses the content here. Background technique [0003] Among internal combustion engines, there is known a turbocharger that utilizes the energy of exhaust gas to rotate a turbine at a high speed, drives a centrifugal compressor with the rotational force, and sends compressed air into the engine to improve the performance of the internal combustion engine. Thermal efficiency. [0004] A turbocharger attached to an internal combustion engine is provided with a nozzle mechanism and a valve mechanism that divide a part of the exhaust gas to adjust the inflow amount of the exhaust gas to the turbine. [0005] ...

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Problems solved by technology

[0016] However, if the precipitation of high-Cr carbide particles is given priority, the amount of Cr in the parent phase will decrease, so there will be problems in oxidation resistance and salt corrosion resistance. If the number of high-Cr carbide particles is reduced, there will be wear resistance Deterioration problem

[0017] In addition, if the amount of Cr in the entire alloy is increased in the sintered material, the compressibility of the powder will deteriorate, and there is a problem that it cannot be molded into the desired shape.

[0018] In addition, in the structure in which high-Cr carbide particles are precipitated in the parent phase, if the amount of high-Cr carbide particles precipitated is increased, the wear resistance of the sintered material itself is good, but the loss of the counterpart material due to sliding increases. The problem

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