By -
Date 08-05-2005 15:37
I have no environmental documentation to back this up, but GMAW will expose you to more welding fumes, if thats what you're talking about. As you probably know, there is litigation going on right now concerning manganese and chromium residing in the welding fumes. I assume the dry ice is used to counteract the distortion, as you stated. What is going to happen is the weld and HAZ is going to cool down very rapidly. If you're asking if this is going to cause any metallurgical disadvantages, the answer is probably "no". I said "probably" not. If you do have any problems, it will most likely be a rapid solidification of the weld bead that can possibly lead to a center-line crack due to the inability of the molten weld pool to completely solidify before cooling.
Chuck
If you are concerned with chromium drifting about the welding arena, you do not want to TIG or TGAW the joint. The CO2 ice packed around the weld will only reduce the weld's corrosion-resistant properties. MIG or GMAW produces the least floating chromium but has a tendancy to make you over-weld in order to make the desired product.