Low weld strength can be caused by anything which retards weld nugget growth or formation. It can also be caused by the condition of the materials being welded.
Expulsion of molten particles from between the two sheets of metal being welded can be caused by several items. All are related to causing excessive heat between the two work pieces or not containing the weld nugget during welding.
Do you have a question that is not covered in our knowledgebase? Do you have questions regarding the above article? Click here to ask the professor.