Anyone have experience welding 4150 steel. I am working on a machine part. It is about 7" long, 4" in diameter, with a 1.5" bore. A .750 thick sleeved it pressed midway into the bore to a shoulder and then welded on both sides. I am using a filler wire that I have used successfully on 4130 and 4140 but seem to be having a problem with the 4150. The filler is a Linde 65 wire. What happens is that the weld bead will show a crack right through the middle. My next option was to pre-heat to 550 defrees and slow cool after welding, but was wondering if there may be a metalurgic conflict with the filler wire. Any help is appreciated. Thanks...Mike