0Cr19Ni9 1Cr18Ni9不锈钢薄壁焊管缺陷及对策

Weld Defect on the Surface of Thin Wall Welded Tube of OCr19Ni9 and 1Cr18Ni9 Stainless Steel and the Appropriate Countermeasure

南京某厂从日本引进焊管机组,用带式法生产薄壁不锈钢管。其工艺流程如下: 钢带分剪→轧辊成型→钨极氩弧焊(TIG)焊成管坯→冷拔→矫直→成品。采用某厂一批0.3mm厚的1Cr18Ni9和0Cr19Ni9奥氏体不锈钢带试焊,发现有焊渣间隔分布于焊缝的内外壁上。间隔距离从5mm至100mm不等,大部分在20～30mm之间,见图1.焊渣多呈灰褐色,其形如纺锤状,尺寸(长×宽)约在(10～20)mm×(4～6)mm。

The weld slag spot on the surface of thin wall welded tube of 0Crl9Ni9 and 1Cr18Ni9 anstenitic stainless steel is analysed by scanning electron microscope and electron probe X-ray micro-analyser. Results show that the slag consists of oxides of Fe, Ti, Cr, Al, Si, etc. Excessive inclusions in base metal and the air drawn into the arc and puddle are the reasons for the occurrence of slag spot. The defect can be effectively prevented if some hydrogen is introduced into the welding arc region.