Weld slag removal

By mountspire (*)

Date 01-16-2009 14:23

Yes a needle gun is the best

By welderbrent (*****)

Date 01-18-2009 00:34

Welcome to the Forum,

The main reference would include needle scalers as the main tool that fits the definition. You will find many CWI's who do not care for them because too often a welder will let the gun rattle on in one spot trying to 'cover up' porosity or other inconsistencies. I like to see a needle scaler used very sparingly and moving rather quickly across a weld. This indicates the slag is coming off easily which tells me he had all welding perameters set properly and was manipulating the rod or gun correctly within the joint being welded. If there is a problem with slag removal there are usually other problems I need to be checking out.

Have a Great Day, Brent

By hogan

Date 01-19-2009 15:45

I have told my welders that when using a needle gun, they can use it a max of 1 second per inch of weld. When I see excessive needle gunning the first thing I think is they were trying to hide something. I usually refer them to AWS D1.1 (08) 5.28 (caulking).

By jwright650 (*****)

Date 01-19-2009 15:52

Me too...when I see excessive hammering, I know something is up. I have had some of the newer guys try to shape the weld into something less ugly with the chipping hammer. The guys who love the look of their welds, won't even hit it with the hammer because they don't want to mess up that pretty weld before I can see it(...and I try to brag on those guys every chance I get). Get the welding machine setup correctly and the slag will almost fall off all by itself, no need for the heavy hitting hammers and all that extra noise.

By hogan

Date 01-19-2009 16:24

JW,
I totally agree. When I started at my current fab shop this was a big issue. We frequently weld 3/4" plate 20' to 40' long. these welds are made with SAW. They were spending 20 minutes making a root pass and 45 minutes grinding out the slag. I asked why it took so long. The foreman explained that the slag would get locked in due to the 25-30 degree angle (B-2a-S). I explained that if the amp/volts were set correctly then it would be easier to remove. He thought I had no idea what I was talking about. I made some slight adjustments and the next pass took less than 5 minutes to remove the slag. Same is true with FCAW. When operating correctly the slag will come off easily.