Maybe someone with some materials knowledge can enlighten me or send me to a link with info...
I'm interested in welding a tube on the end of a 1-3/4" x 6" bolt so that the tube is @ a 4* angle. To do this, I'm going to turn the head of the bolt round and then mill the 4* angle into the end of the bolt head so that the tube will actually be sunk into the head of the bolt. I've got this all figured out... My question though is on the properties of welding on a grade 5 bolt vs. a grade 8 bolt? If I remember right the bead with a Mig didn't look to penatrate as much or deep as welding onto a grade 5 bolt. Is this true? Could the grade 8 bolt actually become brittle in the welded area? Any worries of doing this?
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I dont see how the grade of the bolt would affect the penetration. But keep in mind when you weld something you are heat treating it in a way, in other words if you weld on a grade 8 bolt, dont expect it to still be grade 8 afterwards.
Kris, I have seen people weld bolts for years. I would use a grade 8 bolt and TIG if you could. MIG would be ok, But make sure you dial in the welder...Duh... I made a tool for the PT Balljoints. I used 4 grade 8 7\16 bolts. Put a Radius on the Hex\Head of the bolt and welded away. The PT Ball joints are a PITA and bent the grade 8 bolts, Put them in a vise and bent the right back to the PT balljoint pattern. Point being, They where NOT brittle, From the weld or from the bend. In your case, I would do as you suggested... The only thing I would do is make a cap the would slip over the OD of the bolt and weld to the OD of the tubing. Use 4130 .125 N plate. So now the bolt is welded from the inside and has a cap the picks up the OD of the bolt and now has to rip the tubing and bolt out to fail. This is where I would use a TIG welding process to control heat and make sure you don't make your tube brittle>>>>>>>>>>> ;>>SLR
Cool, thanks for the info... If I'm understanding what you're thinking about on the method I think it'll interfere with the end use of the part. Your example of bending the bolts and then bending them back summed up my worry about the brittleness for sure though. Tig is possible and I guess I'll probably have it done with that...
If you weld on a grade 8 bolt and put enough heat into it you'll pull the heat treat right out of it and it will no longer have the strength of grade 8.
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