Q960高强钢焊丝熔敷金属组织及性能研究
Analysis on microstructure and mechanical properties of 960 MPa deposited metal
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摘要: 采用真空冶炼技术研制开发了Q960高强钢气体保护焊丝，利用金相显微镜(OM)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线衍射(XRD)并通过常温拉伸和低温冲击等试验研究了焊丝及熔敷金属化学成分、组织及力学性能之间的关系。结果表明，采用Mn-Ni-Cr-Mo-Ti合金体系，研制的最佳强韧性焊丝焊态熔敷金属抗拉强度为920 MPa，-60 ℃冲击吸收能量为66.7 J；合金元素含量提高，组织由贝氏体相向贝氏体+马氏体混合相转变，但合金元素含量过高，会导致马氏体相增多，对韧性不利；熔敷金属中存在一定量的残余奥氏体，可提高韧性。Abstract: The solid wire of high strength and toughness was successfully developed by vacuum melting technique. The microstructure and mechanical properties of deposited metal were analyzed in detail by means of optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), instrumented impact tests. Results showed that the highest tensile strength and toughness of deposited metal can reached to 920 MPa and 66.7 J (-60 ℃), respectively, for the alloying systems of Mn-Ni-Cr-Mo-Ti. With the content of alloying elements being increased, the microstructure transformed from bainite to the mixture of granular bainite and low carbon martensite. However, the higher content of alloying elements in deposited metal can promote the formation of martensite, and its appearance is adverse to toughness. The existence of the film-like residual austenite which can improve the impact toughness was found between the lath-like bainite ferrites.
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Keywords:
- high strength steel /
- solid wire /
- microstructure /
- mechanical properties
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