Manual Metal Arc Welding

Question 1

describe the principles of MMA welding

Answer 1

electrode consists of steel core wire and a covering flux containing alloying elements

arc melts parent metal and electrode

flux melts with core wire and flows over surface of pool to form slag.

Question 2

what are the functions of slag

Answer 2

minimizing impurities in the weld

form coating which protects weld from oxidization

prevent cracking and brittleness

Question 3

describe multi run welds

Answer 3

produces a finished weld in structure better than single run welds

each run of welds has a post heating effect on the previous weld