View Full Version : crack in bead
I am welding a frame on a semi trl. local welding shop recomended 7018 rod explaining a higher nickle ct.for more strengh in this area. problem-i keep getting a crack in the weld bead as it cools.am welding about 75 amp dc+ .can anyone help? thanks.
01-17-2003, 08:47 AM
Are you outside in the cold (below 32 F) welding an open root with E7018, possibly with a root opening that is kind of wide? Just guessing here. Give me the exact conditions you are working under and I believe we can solve your problem.
01-17-2003, 11:13 AM
Get a new pack of rods, sealed from factory. Even two hours opened, and the rods will suck enough water from the air to give you hydrogen embrittlement(which is what I believe you are getting here).
I have used 12018 on truck frames with good results, even the frames that have a notice printed on them that reads" HEAT TREATED ALLOY, DO NOT WELD"
Also, if possible, use a backer strip and do a full penetration weld, using an 1/8" root gap and a 45 degree bevel on the frame edges.
Weld this in three passes, a root and two stringers, using verticle-up technique.
If after three passes the joint is not filled flush with the surface. a cap pass may be needed, do this in a modified 'U' weave, (A really wide, shallow U, bringing the ends up enough for the pool to cool a bit ) making sure there is no under cut at the sides of the weld.
Wire wheel the bead to clean between passes, make sure the weld is CLEAN, as no slag inclusions can be had on a frame , a crack may develop from this.
thanks ed, changed rod and followed your instruction & it worked perfectly.Thank You Again. Darryll
01-25-2003, 11:19 AM
Darryl, I'm glad that you were able to get around the cracking problem.
If you need any more help, advise, or problem questions answered, usually somebody on this board has the knowledge, and/or the firsthand experience needed to help you.
There are no'stupid' questions, as we all had to crawl before we walked.