17-4PH 和 455不銹鋼銲接性分析

Abstract

The main 17-4PH and 455 stainless steel alloy. Analysis of heat treatment in different conditions of temperature mechanical properties. To explore the Dissimilar welding with post weld heat affected zone microstructure. And the creation of appropriate conditions of heat treatment. To improve the performance of welded components. The results of their research are as follows： 455 stainless steel at different temperature 830-1200℃/1 hour. Its grain size D=0.25T-283.By the tensile test showed that the grain is greater than 0.72μm alloy showed the phenomenon of embrittlement. During this period the relationship between strength and grain size as: σ = σ0 +55 D-½, grain size increases as the temperature changes and decreased strength. 455 stainless steel by Solution heat treatment(SHT) 830℃/1 hours aging in 480-600℃/4-16 hours, during which the tensile strength, yield strength and elongation, respectively 165-309.9 ksi ,157.8-300.8 ksi and 6.84 - 20%.SHT on 980℃/1 hours, at 480-600℃/4-16 hours, during which the tensile strength, yield strength and elongation, respectively 168-246.4 ksi ,158-239.1 ksi and 4.6-19.38%.17-4PH stainless steel SHT on 1040℃/1 hours of 480℃-600℃ tensile strength, yield strength and elongation, respectively 162-208.3 ksi ,160-203ksi and 11.68-18.8%. When 455 and 17-4PH stainless steel materials of their respective two SHT after welding, at 525℃/4H aging, the occurrence of brittle fracture. From TEM analysis that the 455 stainless steel in the heat affected zone and the weld between the addition to α-phase precipitates, but also the structure of ω-phase precipitates, which have a fragile structure. When the two materials after welding to 980℃/1H SHT + 525℃/4H aging,in addition to improved strength 17-4PH problem, also to improve the problem of weld cracks.