Welding Lugs to Stainless Steel Barrels

[McLernon]

Does anyone know how NEF welds the lug to 400 series barrels.?? I wonder about the weldability of the barrel material. Anyone else share this concern?

McLernon

[Fred M]

What are you trying to weld on a SS barrel? I don't think it is a good idea to weld on any rifle barrel in front of the underlug. JB45 would know he is a welder.

The fore arm nut is a fusion weld, 4 spots about 1/16", the under lug looks like a  TIG weld. I am guessing on that.

The weld penetration on the barrel nut sure played heck with the milling cutter, I ground the penetration out on the second barrel so I did not have to regrind the milling cutter.

[jbtazgrabber]

when i had my 357 built 10 years ago the gunsmiyh silver soldered the lug and forearm nut to my ss barrel... hope this helps jb..

[McLernon]

What I was trying to get at is that 410 SS air hardens when welded so it cracks on cooling. NEF must have some special procedure to weld the lug on to avoid this. I have my doubts about silver soldering being strong enough to take the loads. I am a mechanical engineer and we avoid designs requiring welding this type of SS. Fred M. any thoughts on this.

Thanks

McLernon

[Fred M]

McLernon

Yes silver solder to attach the underlug raised a flag for me too. I am a structural engineer and never had many dealings in SS. Except for SS equipment we installed on occasion. I would think if you welded to a SS barrel you would have to stress relieve it after.

 At the thick end where the underlug is, the induced stress may not be too detrimental? But I think that is wishful thinking. Nothing ever gets welded to a regular SS barrel except the Handi and a few others.

Mind you the underlug is just mild steel and it could be welded with a special rod or fusion welded?

My friend who owns the machine shop is about as good a welder I have seen. I will talk to him and find out? He is also a mechanical engineer and extremely knowledgeable in metallurgy.

When I made the new forearm studs, I ask him if we could weld them on the octagon barrel he said no way. I used two 10x40 screws and J-B weld instead.

[Smokin Joe]

410 can be welded sucessfully as long as you use a preheat and postheat process.
In general, pre-heat at 200-320°C and then air cool from about 650. You can weld it
with 308L, 309, 310 or 410 electrodes without pre-heat if the steel is above 15°C but post heat
process is still required.

[neptoon]

The welding process used when welding on crack sensitive material is also important.I would have tigged or gas welded as these two processes tend to normilize the weld heat affected zone.Neptoon.

[jbtazgrabber]

yes siver solder is not very strong.......but you did not say a cal.....but the last p.b.barrel i had tig welded  looks as good as factory..but it is not s.s.........jb

[McLernon]

Thanks for the responses. I guess my pressure vessel back-ground had me on the wrong track. Pressure vessel welds and heat affected zones must have an equal or greater strength than the parent materials welded. We do this to avoid strain concentration. 308/4 would certainly not develop the full strength of 4xx but might be as strong as the lug itself --ie no strain concentation mechanism under high load. Problem solved. Maybe this is why they use 'soft' steel lugs??

Thanks

McLernon