If you are looking for one welding jobs, you must know how to check the welding defects
1. What is a welding defect?
A: Defects that do not meet the standard requirements during the welding process.
2. Why do welds cause defects?
A: Because of the influence of factors such as people, machine, material, law, and ring, welds will be produced inside and outside the weld.
The defects are: weld size does not meet the requirements, craters, burn through, undercut, welding tumor, strictHeavy splashes, inclusions, pores, cracks, etc.
3. What is a blowhole?
A: In the welding process, the gas in the bath metal cannot come before the metal cooling
And escaping, and holes formed in the weld metal (inside or surface).
4. What is crack?
Answer: In the joint effect of welding stress and other brittle factors, produced in the weld metal
And the gap formed by the heat-affected zone (internal or surface) is called a crack.
a) Hot cracks - cracks that occur immediately after welding at high temperatures.
b) Cold cracks - Cracks that occur when the metal is cooled to room temperature after welding; or a few hours after welding Cracks that occur after a few days are called delayed cracks.
5. What is undercut?
Answer: Due to improper welding parameter selection or incorrect operation method along the weld toe (The groove or indentation generated in the base material part of the fusion line, called undercut, will cause local Stress concentration.
6. What is incomplete fusion?
Answer: When welding, joint roots are not fully penetrated.
7. What is not fused?
A: When welding, the weld bead is not completely melted with the base metal or between the weld bead and the weld bead.The combined part.
8. Why control the amount of hydrogen in the weld?
A: The three harmful gases of hydrogen, oxygen and nitrogen can cause great harm to welded joints; especiallyIs "hydrogen", it will produce hydrogen hole, hydrogen white point, hydrogen embrittlement, hydrogen induced crack (delayed crack) Other hazards.
9. What is welding spatter?
A: During the welding process, molten metal particles and slag are scattered around.
10. What is a welding microscope?
A: During the welding process, the molten metal flows to the unmelted parent metal outside the weld seam.The formation of metal tumors.
11. What is slag inclusion?
Answer: The phenomenon of residual welding residue in the weld.
12. What is arc pit? How to prevent?
Answer: When the arc is received, the tail of the weld bead forms a pit below the height of the weld.