Pipe Welding Questions For Student

by Dewald
(South Africa)

I'm a student studying drafting and at he the moment I'm specializing in piping, which involves welding, and was wondering if you could please help with theses questions regarding welding?

1.) What is slag, how is it produced, why is it necessary and what duty does it perform in the manual arc welding process?

2.) What is preheating?

3.) When would hard-facing be used?

4.)If an inspection of a weld on a 10mm cast iron pipe that will transport non-flammable liquid at low temperature, reveals a crack in the weld, what must be done:

a) What changes to the welding technique can be made to prevent cracking?

b)What changes to the electrode can be made to prevent cracking?

c)Must the weld be removed, how will it be removed and how much of the weld must be removed?

d)How is the repair and re-weld carried out, if required?

e)What preparations are required to the joint area?

f)What testing can be done after welding has been completed?

5.) What is the difference between semi and fully automatic welding equipment?

6.) Can dissimilar metals be welded?

7.) Can flux improve the mechanical properties of the welded join?

8.) Does flux improve penetration?

9.) What is the differences between globular and spay feed patterns?

If you can please help me with some of these questions I would be very grateful!

Best Regards,

Dewald