Plug welding holes in plate

[PSweeney]

My dragster has a solid mounted rear axle. It has 3mm plates bolting each side of the axle to another 3mm plate, secured with 4 high tensile bolts each side. This is a normal arrangement for a hardtail dragster, however the bolt holes on one side have been drilled way too close to the edge of the plate and I'm not happy with it. I want to redrill the holes in the middle of the plate and intend to plug weld up the old holes. Given this is a high strength and critical safety application, I'm wondering if theres any ill effect to the tensile strength of the material by doing this ?

 

[BrokenBiker]

depends on what material it is. if its just mild steel then there wont be, but if its a material that's been heat treated then welding could locally destroy the heat treatment causing problems

 

[PSweeney]

no just mild steel. What about stress risers etc at the weld ?

What's the best way to do this ? I usually use an ally or copper block behind and plug it up, but the backside normally looks a little porus with MIG. Would it be better use TIG for this ?

 

[Lawnmowerboy]

No. Should be fine. Weld material is often higher tensile than the parent material itself

 

[BrokenBiker]

if its just mild then it will be ok. just put backing on it, weld it up and grind/machine it flat

 

[aametalmaster]

How about some dragster pics. Speed demon here too...Bob

 

[PSweeney]

thanks guys, will get some pics up soon not much to look at right now all in bits