Austenitic stainless steel sheet which is not susceptible to diffusion bonding

Abstract

An austenitic stainless steel sheet which is provided with a coating film on at least a part of the surface thereof, and which has a chemical composition containing, in mass%, from 0.01% to 0.10% (inclusive) of C, from 0.2% to 2.0% (inclusive) of Si, 1.5% or less of Mn, 1.0% or less of Mo, from 15.0% to 22.0% (inclusive) of Cr, from 4.5% to 10.0% (inclusive) of Ni, 1.0% or less of Cu, 0.30% or less of Nb and from 0.01% to 0.15% (inclusive) of N, with the balance made up of Fe and unavoidable impurities. The coating film is provided with a Si-increased layer in a region from the surface to the depth of 10 nm, said Si-increased layer having a maximum Si amount of 10.0% or more and a maximum Fe amount of 8.5% or less. The Si-increased layer has a thickness of 5 nm or more. This austenitic stainless steel sheet is not susceptible to diffusion bonding even at high temperatures.

Description

technical field [0001] The present invention relates to an austenitic stainless steel sheet that is difficult to diffusion join. Background technique [0002] Austenitic stainless steel is used for heat-resistant parts such as exhaust system gaskets of automobiles and two-wheeled vehicles that require high heat resistance. From the viewpoint of increasing fuel consumption, the exhaust gas temperature is increasing year by year, and these heat-resistant components may be exposed to high temperatures of 700°C or higher. At such a high temperature, in addition to the softening of the raw material, there is also a problem of bonding with surrounding workpieces (parts). This is a phenomenon called diffusion bonding in which atoms in the contacted parts diffuse with each other. [0003] For example, Patent Document 1 proposes that by adding 3 to 10% of Al, Al 2 o 3 Ferritic stainless steel that is coated and difficult to diffusion join. [0004] prior art literature [0005]...

AI Technical Summary

Problems solved by technology

At this high temperature, in addition to the softening of the raw material, there is also the problem of bonding with the surrounding workpieces (parts)

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