stainless to mild steel weld

By Dipesh Date 08-19-2005 13:28

We weld a stainless steel part on huge mild steel box (Made of sheet metal). After welding that big stainless steel part (Which requires a lot welding) mild steel box gets bowed. We figured it that it is happening due to access heat generated during the process. Are there any ways to avoid it?

By jon20013 (*****)

Date 08-19-2005 13:33

There are more ways to avoid the bowing on this fabrication than could probably be adequately addressed in this particular forum, but to begin with, sequencing would certainly help as would backstepping techniques. Bracing may help, fit-ups could be pre-stressed, etc., etc.,

By Dipesh Date 08-19-2005 13:43

We already have a sequence in place for it. When we have a smaller part (less welding) we do not see a bowing problem with it. As the part size increases bowing tends to increase. Will taking out excess heat help me to avoid it? If yes, what are the possible alternativesthat I have?

By - Date 08-19-2005 13:51

If you already know you are using excess heat, then naturally it will help to lower the heat to a more reasonable range.

By jon20013 (*****)

Date 08-19-2005 13:57

Without seeing a photo or drawing of the part configuration it's difficult to give anything other than generalized advice; perhaps you can install copper chill bars somehow?

By MDG Custom Weld (***)

Date 08-19-2005 17:08

We have seen similar problems on large "I" beam structures and other thick plate fabrications. The best way to avoid it is to predict it and over-bend or pre-stress the parts in the other direction so that they pull flat (or very close) when welded. It's very easy on a square box type of fabrication. It gets a little more difficult when working in 2 planes or compound angles. Calculate the amount of joules going into the part and over what time span. From that you can predict the amount of warp you will see.