摘要
Effect of boron on microstructure and toughness of simulated CGHAZ of 790 MPa grade HSLA steel was studied.In the CGHAZ,boron improved the toughness of granular bainite(Bg),but deteriorated that of martensite.The major reason of boron improving toughness of Bg was to reduce the.quantity of M-A constituents.The reasons of martensitic brittleness in microstructure were discussed in detail.The experimental results proved that the order state of dislocations was an important factor of martensitic brittleness caused by boron, and the higher the order degree of dislocations was, the more brittle the martensite was.
Effect of boron on microstructure and toughness of simulated CGHAZ of 790 MPa grade HSLA steel was studied.In the CGHAZ,boron improved the toughness of granular bainite(Bg),but deteriorated that of martensite.The major reason of boron improving toughness of Bg was to reduce the.quantity of M-A constituents.The reasons of martensitic brittleness in microstructure were discussed in detail.The experimental results proved that the order state of dislocations was an important factor of martensitic brittleness caused by boron, and the higher the order degree of dislocations was, the more brittle the martensite was.
