水下局部干法药皮焊条焊接的研究

本文介绍要用压缩空气排水，水下局部干法药皮焊条手弧焊的方法。应用流体力学理论对排水罩进行计算和试验，确定了合理的排水罩结构和尺寸，且进行了局部干法焊接试验。结果表明：该法的焊接冷却速度、焊接接头中的扩散氢含量和焊接ＨＡＺ最高硬度值均比湿法的要低，得到的焊缝无气孔、裂纹和夹渣等缺陷；Ｖ型坡口焊接接头的机械性能能满足ＡＰＩ１１０４和ＡＳＭＥＩＸ等标准规定的要求。本研究为水下焊接施工提供了一种操作容易、

INVESTIGATION OF THE LOCALLY DRYING UNDERWATER WELDING BY COVERING ELECTRODE

The locally drying underwater MMA welding by covering electrode withthe compressed air to drain away water in the weld region is introduced. After calculated with the hydromechanics theory and tested for the internal diameter of thedrain hood,the gas--entering mode and there sealing mode,the reasonable structureand size of the drain hood are determined. Then,the experiments of locally dryingunderwater welding at the depth of 150mm in a water tank have been done. The results indicate: the welding cooling rate, diffusible hydrogen content of depositedmetal and they maximum hardness in welding HAZ gained by this method are lowerthan that gained by wet welding and there are free from the defects,such as porosities,crackings and inclusions in the welded metal obtained by this method. The mechanical properties of welding joint'of V-grove meet the standard of API 1104 andASME IX. An underwater welding method being easy in operation,simple in equipment,cheap in cost and satisfied in welded joint is provided for the construction ofunderwater welding.