American Welding Society Forum
We are about to start welding Aluminized Steel. Should we grind or sand down the areas to be welded prior to welding? Are there any special safety precautions? Any info would be helpful
I think it would be a good idea to remove the aluminzed coating before welding. This coating may have impurities that could lead to contamination of the weld pool and subsequent hot cracking. Ensure that whoever is doing the grinding and welding have more than adequate air quality through fans , venting and that they wear the correct filter masks.
Unlike galvanized steel, aluminized steel can be sucessfully welded over. If aluminum caused the same problems as zinc, there would be no such thing as self-shielded FCAW as these electrodes use large amounts of aluminum to tie up the oxygen and nitrogen that the molten weld pool absorbs. Colins does bring up the point about cracking, but this can be dealt with by choosing an electrode that is resitant to hot cracking, or using techniques to minimize it. (i.e. proper depth to width ratio and using convex beads) If you have access to an AWS handbook, the 8th edition volume 4 has about 8 pages covering welding aluminized steel. It even mentions the fact that sometimes you can ge accptable properties using a FCAW electrode designed for use with shilding gas by welding on aluminized steel without shielding gas.
There are other items that could be addressed if you post more details about your application. What process are you planning on using? What thicknesses of steel, and thickness/type of aluminum coating?
In response to your comment concerning aluminum, you are correct, however, the aluminizing treatment may have high copper, sulphur and other elements that may cause cracking. I was wondering if you know a little more of the chemistry of this surface treatment ? I spoke with a company not to long ago about their chemistry and they would not reveal it . I do not have a copy of that particular AWS book, would you mind faxing a copy of the pages for my own reference, if it is not to much trouble ?
my fax # is (604) 683-9164
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