Duplex Heat Treatment of a Precipitation Hardening Carburising Steel

IF 0.3 Q4 THERMODYNAMICS

HTM-Journal of Heat Treatment and Materials Pub Date : 2022-06-01 DOI:10.1515/htm-2022-1006

S. I. Böhle, V. Strobl, J. Lechleitner, R. Schnitzer

{"title":"Duplex Heat Treatment of a Precipitation Hardening Carburising Steel","authors":"S. I. Böhle, V. Strobl, J. Lechleitner, R. Schnitzer","doi":"10.1515/htm-2022-1006","DOIUrl":null,"url":null,"abstract":"Abstract This article reports the microstructural development of a molybdenum and copper alloyed steel by different thermochemical heat treatments for gears and shafts in automotive applications. The case hardening is compared to a duplex heat treatment consisting of carburising, ageing and plasma nitriding. This study evaluates the microstructure, the surface hardness and hardness profiles. For all applied heat treatment routes, the ageing conditions have a minor influence on the case and core hardness compared to the influence of the carbon concentration. Retained austenite fractions decreased to < 5 % in all duplex heat-treated samples without cryogenic treatment. Material characterisation with optical light microscopy and scanning electron microscopy indicate unwanted phases of nitrogen and carbon-rich precipitates at the grain boundaries after duplex heat treatment. Therefore, the sequence of duplex heat treatment is changed to carburising followed by solely plasma nitriding where the unwanted precipitates are detected only up to a depth of 15‒20 μm from the compound layer.","PeriodicalId":44294,"journal":{"name":"HTM-Journal of Heat Treatment and Materials","volume":"11 1","pages":"197 - 213"},"PeriodicalIF":0.3000,"publicationDate":"2022-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"HTM-Journal of Heat Treatment and Materials","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1515/htm-2022-1006","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"THERMODYNAMICS","Score":null,"Total":0}

引用次数: 0

Abstract

Abstract This article reports the microstructural development of a molybdenum and copper alloyed steel by different thermochemical heat treatments for gears and shafts in automotive applications. The case hardening is compared to a duplex heat treatment consisting of carburising, ageing and plasma nitriding. This study evaluates the microstructure, the surface hardness and hardness profiles. For all applied heat treatment routes, the ageing conditions have a minor influence on the case and core hardness compared to the influence of the carbon concentration. Retained austenite fractions decreased to < 5 % in all duplex heat-treated samples without cryogenic treatment. Material characterisation with optical light microscopy and scanning electron microscopy indicate unwanted phases of nitrogen and carbon-rich precipitates at the grain boundaries after duplex heat treatment. Therefore, the sequence of duplex heat treatment is changed to carburising followed by solely plasma nitriding where the unwanted precipitates are detected only up to a depth of 15‒20 μm from the compound layer.

查看原文本刊更多论文

沉淀硬化渗碳钢的双相热处理

摘要:本文报道了一种钼铜合金钢在不同热化学热处理条件下的显微组织发展。将其与由渗碳、时效和等离子体渗氮组成的双相热处理相比较。本研究评估了显微组织、表面硬度和硬度分布图。对于所有应用的热处理路线，与碳浓度的影响相比，时效条件对外壳和芯硬度的影响较小。在所有双相热处理样品中，未进行低温处理的奥氏体残留分数降低到< 5%。通过光学显微镜和扫描电镜对材料进行表征，发现双相热处理后晶界处存在富氮和富碳相。因此，双相热处理的顺序改为渗碳，然后再进行等离子体渗氮，其中仅在距复合层15-20 μm深度处检测到不需要的沉淀。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

求助全文

约1分钟内获得全文求助全文

来源期刊

HTM-Journal of Heat Treatment and Materials THERMODYNAMICS-

CiteScore

1.50

自引率

33.30%

发文量