{"title":"Effect of Cooling Process on Microstructure and Properties of Low Carbon Bainite Steel","authors":"Zhifeng CAO, JiMan WANG, Shenggang ZHOU, Hu YAN","doi":"10.5755/j02.ms.34199","DOIUrl":null,"url":null,"abstract":"This article used Mn-Mo-Cr-B low-carbon bainitic steel as the experimental material. The continuous cooling transformation curve of the steel during continuous cooling was determined using a Gleeble-1500D thermal simulation test machine, and a corresponding phase transformation model for bainitic steel during continuous cooling was established. The influence of different cooling rates and final cooling temperatures on the microstructure and mechanical properties of the steel was investigated. Employing metallography, SEM, and EBSD techniques, the microstructure, crystallographic orientation, and grain boundary angle distribution of the low-carbon bainitic steel were explored, and their relationship with the steel's strength and toughness was studied. The research findings reveal that varying cooling rates and final cooling temperatures impact the phase transformation process and microstructure of the steel, consequently affecting its mechanical properties indirectly. With increasing cooling rate, the diffusion and fineness of martensite increase, and the quantity of lath bainite grows while the laths become finer. Elevated final cooling temperatures lead to larger martensitic-austenitic (MA) islands and reduced lath bainite quantity, causing the laths to become wider. Through analysis of the substructure of bainitic steel, it was determined that the bainite organization in the tested steel comprises primary austenite grains, lath packet, and lath block in succession. Lath packets are composed of lath blocks with different orientations, where lath size predominantly controls strength. Finer lath size corresponds to higher strength, and the influence of substructure on toughness is comparatively minor.","PeriodicalId":18298,"journal":{"name":"Materials Science-medziagotyra","volume":"25 1","pages":"0"},"PeriodicalIF":0.8000,"publicationDate":"2023-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Materials Science-medziagotyra","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.5755/j02.ms.34199","RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"MATERIALS SCIENCE, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0
Abstract
This article used Mn-Mo-Cr-B low-carbon bainitic steel as the experimental material. The continuous cooling transformation curve of the steel during continuous cooling was determined using a Gleeble-1500D thermal simulation test machine, and a corresponding phase transformation model for bainitic steel during continuous cooling was established. The influence of different cooling rates and final cooling temperatures on the microstructure and mechanical properties of the steel was investigated. Employing metallography, SEM, and EBSD techniques, the microstructure, crystallographic orientation, and grain boundary angle distribution of the low-carbon bainitic steel were explored, and their relationship with the steel's strength and toughness was studied. The research findings reveal that varying cooling rates and final cooling temperatures impact the phase transformation process and microstructure of the steel, consequently affecting its mechanical properties indirectly. With increasing cooling rate, the diffusion and fineness of martensite increase, and the quantity of lath bainite grows while the laths become finer. Elevated final cooling temperatures lead to larger martensitic-austenitic (MA) islands and reduced lath bainite quantity, causing the laths to become wider. Through analysis of the substructure of bainitic steel, it was determined that the bainite organization in the tested steel comprises primary austenite grains, lath packet, and lath block in succession. Lath packets are composed of lath blocks with different orientations, where lath size predominantly controls strength. Finer lath size corresponds to higher strength, and the influence of substructure on toughness is comparatively minor.
期刊介绍:
It covers the fields of materials science concerning with the traditional engineering materials as well as advanced materials and technologies aiming at the implementation and industry applications. The variety of materials under consideration, contributes to the cooperation of scientists working in applied physics, chemistry, materials science and different fields of engineering.