超超临界HR6W钢平板钨极氩弧焊接焊缝的微观组织和性能

Microstructure and Properties for Welding Seam of Ultra-supercritical HR6W Steel Plant with Argon Tungsten Arc Welding

为检验超超临界钢焊接工艺及焊缝接头的可靠性,通过万能拉伸实验研究了超超临界锅炉用钢HR6W平板钨极氩弧对接焊缝的焊接工艺及焊接接头性能,利用光学显微镜、扫描电子显微镜分析了其微观组织。结果表明:对于10 mm厚新型超超临界HR6W钢,采用小电流I=50 A打底焊,焊接速度为10~12 mm/min,再将焊接电流增大至70 A,进行单面焊双面成型,焊接速度为15 mm/min,最后在焊缝背面采用小电流I=40 A,焊接速度为12 mm/min,增焊一道焊缝进行焊接变形矫正,可以得到焊缝成形美观,微观组织均匀,变形小,焊缝无裂纹,拉伸性能、冲击韧性和弯曲性能优良的焊接接头。

In order to test the reliability of the ultra-supercritical steel welding process and weld joints,the welding process and weld joint performance of the HR6W flat tungsten arc butt weld of ultra-supercritical boiler steel HR6W were studied through universal tensile experiments and its microstructure was analyzed by using optical microscope and scanning electron microscope.The results showed that for the 10 mm thick new ultra-supercritical HR6W steel,the low current I=50 A was used for bottom welding,and the welding speed was 10~12 mm/min,then when the welding current increased to 70 A and single-sided welding and double-sided forming were performed,the welding speed was 15 mm/min,and finally I=40 A small current was used on the back of the weld,and the welding speed was 12 mm/min,the welding deformation was corrected by adding a weld to obtain a beautiful and microscopic weld.Thus a welded joint with beautiful weld shape,uniform microstructure,small deformation,no cracks in the weld seam,and excellent tensile properties,impact toughness and bending properties can be obtained.