What is the maximum length of tack welds used for joining a 150 mm pipe?

Study for the Gas Metal Arc Welding Exam, including GMAW, FCAW, and MCAW methods. Use flashcards and multiple choice questions with hints and explanations for effective learning. Get ready for your welding certification!

Tack welds are short, temporary welds used to hold the pipe pieces in alignment before the full weld is applied. Keeping each tack weld to a small length minimizes heat input in one spot, reducing the risk of distortion or misalignment as the joint is welded around the circumference. For a pipe around 150 mm in diameter, the standard practice is to limit a single tack weld to three-quarters of an inch. This length is long enough to be effective for positioning but short enough to keep heat concentration and distortion under control, ensuring the pipe sections stay aligned as you complete the final weld around the joint. Longer tacks can cause excessive local heating, warping, or cracking, which is why the three-quarters of an inch limit is used.