一、前言焊接过程中可能出现一些意想不到的某些参数的变化,使焊敷金属产生缺陷。这些缺陷包括气孔、夹渣、未熔合、未焊透和下陷等。气孔是夹在凝固着的焊缝金属中的气泡或孔洞。随着温度的降低,气体在金属中的溶解度下降,迫使气体从熔融金属中析出。这些气体不是由于原来保护不好,由空气卷入的,就 I. INTRODUCTION Some unexpected changes in the parameters may occur during the welding process to make the weld metal defective. These defects include porosity, slag inclusions, unfused, incomplete penetration and sag. The air hole is a bubble or hole in the solidified weld metal. As the temperature decreases, the solubility of the gas in the metal decreases, forcing the gas to precipitate out of the molten metal. These gases are not due to the original protection is not good, from the air involved, it