On aging of high-strength stainless steel 08Cr15Ni5Cu2Ti

Tat’Yana Makhneva,Vyacheslav Dement’Yev,Sergei Makarov,S Bratan,S Leonov,S Roshchupkin,S Gorbatyuk

doi:10.1051/matecconf/201712902012

Tat’Yana Makhneva, Vyacheslav Dement’Yev + Show 5 more

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https://doi.org/10.1051/matecconf/201712902012

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Abstract

Based on our results and the results of the experimental studies previously conducted by other researchers, the analysis has been made of the influence of remelting methods on the character of the formation of the level of the impact strength KCU and its component KCV at aging of steel 08Cr15Ni5Cu2Ti prepared by two methods of remelting. The results of studying the influence of the remelting methods, heat treatment modes and impurity cleanness of steels on the level of KCU and the degree of its decrease at the temperatures of age hardening are presented. The factors causing the difference in the structure and phase composition in the steel formed by different remelting methods are established. The temperature range in which a significant decrease in KCU takes place has been determined. The hypothesis is offered about the role of interstitial impurities in the KCU decrease at aging.

Highlights

IntroductionThe desired set of properties of steels of this grade (highstrength Stainless) is attained by the selection of optimal conditions at quenching and aging in the temperature range of (400÷600)° C
The desired set of properties of steels of this grade is attained by the selection of optimal conditions at quenching and aging in the temperature range of (400÷600)° C
The investigation of the impact strength of the ESR- and VAR-steel quenched from 1000° C after aging in the studied temperature range shows that in the quenched condition both melts have high values of KCU, 2.6 and 1.6 MJ/m2, respectively (Fig. 1, a)

Summary

Introduction

The desired set of properties of steels of this grade (highstrength Stainless) is attained by the selection of optimal conditions at quenching and aging in the temperature range of (400÷600)° C. It is believed that the possible reasons for decreasing KCU at aging of chromium-nickel steels with the martensitic-austenitic structure are a small amount or absence of retained austenite, γ retain, in the structure; coarse grain; the presence of embrittling phases on grain boundaries; the formation of segregations of harmful impurities and alloying elements, chromium, as the result of the separation process in the iron-chromium matrix [10], and their interaction with interstitial impurities [1114]. The comparative study of the mechanical properties of steel 08Cr15Ni5Cu2Ti prepared by vacuum-arc and electroslag remelting (VAR and ESR) after quenching and aging shows that though the VAR-steel structure differs from that of ESR-steel in the grain size, larger tendency toward the grain growth at heating and small amount of γ retain, the character of the formation of the mechanical properties is the same in both VAR- and ESR-steel [8]. After aging for maximum strength, the impact strength appears to be the most unstable characteristics (inadequacy is 40% of the required level)

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