Gao-jun Mao , Rui Cao , Jian-hong Chen , Xi-li Guo , Yong Jiang
{"title":"不同镍含量低碳贝氏体再加热焊缝金属显微组织演变的原位观察","authors":"Gao-jun Mao , Rui Cao , Jian-hong Chen , Xi-li Guo , Yong Jiang","doi":"10.1016/S1006-706X(18)30019-0","DOIUrl":null,"url":null,"abstract":"<div><p>Microstructural evolution in weld metals was in-situ observed through utilizing a laser scanning confocal microscope at two cooling rates. The specimens with various nickel contents were adopted for the observation. In the specimen with low fraction of Ni (≤2 wt. %), granular bainite microstructure (i. e. broad surface relief) transformation from intragranular nucleation site was in-situ observed, while, lath bainite microstructure originating from grain boundary of austenite was in-situ observed for specimens with high mass percentage of Ni (≥ 4 wt. %). With increasing nickel content, the transformation temperature dropped. The prior austenite grain size was initially depressed and subsequently coarsened dramatically with the addition of Ni. The microstructure difference was ascribed to various nucleation sites and growth direction in the matrix. On account of those observations, not only the chemical component, cooling rate and microstructure were systematically correlated, but also the microstructural evolution was definite.</p></div>","PeriodicalId":64470,"journal":{"name":"Journal of Iron and Steel Research(International)","volume":null,"pages":null},"PeriodicalIF":3.1000,"publicationDate":"2017-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1006-706X(18)30019-0","citationCount":"2","resultStr":"{\"title\":\"In-situ observation of microstructural evolution in reheated low carbon bainite weld metals with various Ni contents\",\"authors\":\"Gao-jun Mao , Rui Cao , Jian-hong Chen , Xi-li Guo , Yong Jiang\",\"doi\":\"10.1016/S1006-706X(18)30019-0\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>Microstructural evolution in weld metals was in-situ observed through utilizing a laser scanning confocal microscope at two cooling rates. The specimens with various nickel contents were adopted for the observation. In the specimen with low fraction of Ni (≤2 wt. %), granular bainite microstructure (i. e. broad surface relief) transformation from intragranular nucleation site was in-situ observed, while, lath bainite microstructure originating from grain boundary of austenite was in-situ observed for specimens with high mass percentage of Ni (≥ 4 wt. %). With increasing nickel content, the transformation temperature dropped. The prior austenite grain size was initially depressed and subsequently coarsened dramatically with the addition of Ni. The microstructure difference was ascribed to various nucleation sites and growth direction in the matrix. On account of those observations, not only the chemical component, cooling rate and microstructure were systematically correlated, but also the microstructural evolution was definite.</p></div>\",\"PeriodicalId\":64470,\"journal\":{\"name\":\"Journal of Iron and Steel Research(International)\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":3.1000,\"publicationDate\":\"2017-12-01\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"https://sci-hub-pdf.com/10.1016/S1006-706X(18)30019-0\",\"citationCount\":\"2\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of Iron and Steel Research(International)\",\"FirstCategoryId\":\"1087\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S1006706X18300190\",\"RegionNum\":2,\"RegionCategory\":\"材料科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"METALLURGY & METALLURGICAL ENGINEERING\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Iron and Steel Research(International)","FirstCategoryId":"1087","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S1006706X18300190","RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"METALLURGY & METALLURGICAL ENGINEERING","Score":null,"Total":0}
In-situ observation of microstructural evolution in reheated low carbon bainite weld metals with various Ni contents
Microstructural evolution in weld metals was in-situ observed through utilizing a laser scanning confocal microscope at two cooling rates. The specimens with various nickel contents were adopted for the observation. In the specimen with low fraction of Ni (≤2 wt. %), granular bainite microstructure (i. e. broad surface relief) transformation from intragranular nucleation site was in-situ observed, while, lath bainite microstructure originating from grain boundary of austenite was in-situ observed for specimens with high mass percentage of Ni (≥ 4 wt. %). With increasing nickel content, the transformation temperature dropped. The prior austenite grain size was initially depressed and subsequently coarsened dramatically with the addition of Ni. The microstructure difference was ascribed to various nucleation sites and growth direction in the matrix. On account of those observations, not only the chemical component, cooling rate and microstructure were systematically correlated, but also the microstructural evolution was definite.