1200MPa高强耐磨钢热影响区显微组织及显微硬度的研究

Research on HAZ microstructure and microhardness of 1200 MPa high-strength wear-resistant steel

为了研究1 200 MPa高强耐磨钢的焊接性,采用GMAW法对钢板进行斜Y形坡口铁研试验。对所得试样进行金相试验和显微硬度测试,并且分析不同的焊接热输入对此高强耐磨钢焊接热影响区(HAZ)显微组织变化及其显微硬度的影响。试验结果表明:在焊接热输入增大至24.9 k J/cm时,热影响区淬火粗晶区会出现网状铁素体组织及部分魏氏组织。回火区由回火马氏体组成,并会出现明显的回火软化现象,这些现象使得焊接接头的显微组织连续性遭到破坏,焊接接头综合性能下降。

Microstructure was studied and microhardness was measured on the samples of 1 200 MPa highstrength wear-resistant steel GMAW joint of y-slit type cracking test. Based on the results, analysis was made on changes of HAZ mierostructure and microhardness of this high-strength wear-resistant steel. The test results indi- cated that when the heat input reached 24.9 kJ/cm, mesh ferrite appeared in coarse grain heat affected zone （CGHAZ）. Temper softening occurred in tempering zone. All of these phenomena contributed to adverse effects of welding joint＇ s mechanical properties.