tube welding

[660Z]

I`m finising up my cage, working on it off and on due to my nightshift job. Anyway, while looking at the welds, i`m wondering if my welding pernatration was enough.

I`m going to do a strengh test and check penatration on a scrap piece when I get home.

If I find that there wasn`t enough. Can I grind the welds flat and go back over the them with a hotter range?

 

My thinking when starting this was I wanted the weld to dig in but not be so hot that it had burn thru or become brittle. Now I`m wandering if I should have set it so it had potenal to burn thru due to the thickness of the tube.

 

Thanks,

Mark

[roger.svoboda]

generally when welding pipe/tubing you use a chill ring which fits inside the pieces to be welded. Thus you can get full penetration of the tube because the chill ring prevents burning through. If you are going to reweld because you are unsure of the weld penetration you should V out the weld before rewelding. I would probably V out half the circumference reweld that and then do the other half with a bit of overlap.

[roger.svoboda]

You want to use a U shaped motion when welding otherwise you get too much heat and blow out joint. By welding in a U you take heat to the unwelded section thus preheating it and allowing the hot spot at the joint to cool slightly before you come down and then make the other side of the U.

[johnc]

The majority of welding mistakes are caused by three things:

 

Poor fitup - that parts are not fitted close together and the weldor is welding air.

Poor preparation - the parts are not thoroughly cleaned.

Poor penetration - not enoughheat is used to weld the parts together. Look at the recommendations in your welding manual or go buy: "Guide for Welding Mild Steel Pipe" AWS D10.12M/D10.12:2000 from AWS (http://www.aws.org).