The molten observation hole needle (3) is arranged on the pipe fitting body so that a weldingprogress can be conveniently detected, and the welding quality can be controlled.
焊接熔观察孔针(3)设置在管件本体上，方便检测焊接进程，控制焊接质量。
2
The local branch of Ivy tech, a community college, agreed to create a three-week welding course to teach the specialised techniques Progress Rail USES.
The welding technology in our country has made a great progress, and our country becomes the largest welding material consumption country in the world.