Chromoly frame. How do you weld ? Mig,Gas, or Tig
Basi
Hiya Guys,
I need to do some welding on a dirtbike frame with chromoly steel.
I have access to a Gas and Mig welder. I don't have a tig, but I
understand that Tig is the way to go. Any ideas how I can weld with
the Gas or Mig and if so what Gas rod, and /or what Mig Wire ??
Thanks
-Basi
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Simmonsmc
heliarc it, but it is possible to do it either way depending on the aplication
check with your local welding shop on the proper filler rod, but I can tell you
just about any mild steel rod will work, it's very hard to control the heat
with a torch but it could be done. it will also cost you some money to by a
whole roll of mig wire for just a small crack, I would think you could use
NR-211 wire and it would be just fine(I've done it)but since i have a heli-arc
i use it for everything!
Mike Simmons
99 KTM 300 MXC
AMA Dist.36
Hoyt McKagen
>
> Hiya Guys,
>
> I need to do some welding on a dirtbike frame with chromoly steel.
> I have access to a Gas and Mig welder. I don't have a tig, but I
> understand that Tig is the way to go.
Don't use electric on chrome-mo;y, the intense localized heat will often
cause brittlement next to weld. I would use gas every time.
This isn't a guess, BTW, I've built frames and repaired frames both, of
chrome-moly, have had excellent results with gas and never a failure. And
on top of that welding manuals agree with me. HTH!!
--
Best wishes,
Hoyt McKagen
Belfab CNC - http://www.freeyellow.com/members/belfab/belfab.html
Best MC Repair - http://www.freeyellow.com/members/batwings/best.html
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What happens when you let out the smoke?
Mike DeLoach
Basi <bangulo...@aol.com.invalid> wrote:
>
>
>Hiya Guys,
>
> I need to do some welding on a dirtbike frame with chromoly steel.
>I have access to a Gas and Mig welder. I don't have a tig, but I
>understand that Tig is the way to go. Any ideas how I can weld with
>the Gas or Mig and if so what Gas rod, and /or what Mig Wire ??
>
>Thanks
>-Basi
It's always best to use Chrome-Moly when your welding Chrome-moly. Find out
what type you have e.g. type 501 would be 5 percent Chromium and .5 percent
Molybdenum. Then get electrodes with the same properties. Always preheat
Chrom-Moly and you may want to temper it for strenth. You can also use
Austenitic electrodes if you can't find the Chrome-Moly ones.
Good Luck
Mike D.
Jay C
news:hAq54.21$be4...@cletus.bright.net...
> Most of the jap dirt bike frames are made of mild steel and are assembled
at
> the plant with mig welders. They can also be welded with gas or tig.
>
> The aftermarket frame builders who use 4130 Chromoly (a steel alloy) use
> both tig and mig. But the best chassis builders in race cars and bikes use
> tig for everything
I always thought that all of the super-performance race car frames were
brazed.
J
Louis Tweed
used for dissimilar metals.
Louis
Wesley Grass
--
The English were big on brazing frames. I think it had something to do with
the materials they had not working well with welding. There are still a few
bicycle frame builders that fillet braze their frames. Supposedly, the fillet
reduces stress concentrations at the joints.
FWIW, 4130 was alloyed for gas welding. Using TIG or MIG usually requires
post weld stress relieving for highly stressed structures.
Wes
Hoyt McKagen
>
> No brazing for strength applications (roll cages, frames.) Brazing is a process
> used for dissimilar metals.
You don't weld/braze, do you? You can join any combo of similar ferrous
metals with brazing. I do MC frames and SA and have for decades brazed
critical joints. I use all chrome-moly for frames and have never had a
brazed joint fail though I once lost a welded joint on a foot peg.
Recently I switched to braze for mild steel SA because there is less
distortion and less effect of heat on the materials and the process is
much faster to boot. My customers and my self both bet our asses on this
and I would never do it if I didn't have the utmost confidence.
'Braze' as a word refers to using brass for filler. That is not specific
enough these days as high-strength fillers based on nickel and silver are
available; the process is still referred to as brazing though the rod is
often stronger than the steel.
Louis Tweed
stronger a frame that is brazed vs. a frame that is welded and then heat treated as a
weldment? Which metals are you brazing and what filler are you using, with what
fuel? Everything is a factor.
Louis
Carl Pole
whole message in my reply.
4130 is an alloy of steel containing chromium and molybdenum. what's important
is the 30 on the end of the alloy type (4130). that tells you the carbon
content. for the life of me, and i used to know this but my reference books are
at work right now and i don't remember if the 30 means .3% or 3.0% or 30% carbon
but what you need to know is this metal is capable of accepting a heat
treatment. what that means is if you wanted to harden this material, you can.
generally, you heat treat a material (steel) by heating it and cooling it either
in air, oil or water. the deal with gas welding is that it heats and cools it
slowly. oh yea, to anneal, or soften a steel material, you heat it to some
temperature and cool it slowly. what you get when you arc weld (stick) or mig
something is that the material is heated and cooled quickly. if you are welding
on a heat treatable material, this can lead to the material being accidentally
heat treated in the area of the weld. generally, when you gain hardness from a
heat treatment, the material becomes somewhat brittle. that's why knife blades
will snap off on you. you heat treated it so it will hold an edge, but you also
gained brittleness from the process. it's a tradeoff. i'm not sure but i think
4130 wants an oil quench to cool it.
if it was me and i had the money, from my point of view, to get the best weld
would be to take it to a professional and have them pre-heat the weld area with
a gas torch to 400-500 degrees, then tig the piece and then put the torch to it
and let it cool slowly. if you want, you can bring the weld area to a real dull
red after welding, to a dull red, and then take a minute or so heating the area
while you move the torch farther and farther away while the temperature drops.
the nature of the problem might not allow for this, but this will keep you from
having a brittle weld.
i'm not a professional welder (machinist/electronics tech) but i was pointed
this method years ago as a way to fix my old '82 cr250 that i crushed a frame
member on. i never had a problem again with it. i did the tig work myself.
the metallurgy ( what i remember of it) comes from junior college and many years
in the machinist trade.
carl pole
L Sommers wrote:
> Most of the jap dirt bike frames are made of mild steel and are assembled at
> the plant with mig welders. They can also be welded with gas or tig.
>
> The aftermarket frame builders who use 4130 Chromoly (a steel alloy) use
> both tig and mig. But the best chassis builders in race cars and bikes use
> tig for everything. Most of the chassis builders simply weld and go which is
> not the correct way to work with this alloy. This alloy was designed with
> aircraft frames in mind. When the aircraft builders join this alloy with a
> weld they have special procedure to heat an area around the weld and misc.
> to normalize the stresses in the joint. I have seen a lot of nice welds
> break through he center of the weld due to improper techniques of working
> with this alloy.
>
> LS
>
> Hoyt McKagen <batw...@i-plus.net> wrote in message
> news:38716B...@i-plus.net...
> > Basi wrote:
> > >
> > > Hiya Guys,
> > >
> > > I need to do some welding on a dirtbike frame with chromoly steel.
> > > I have access to a Gas and Mig welder. I don't have a tig, but I
> > > understand that Tig is the way to go.
> >
> > Don't use electric on chrome-mo;y, the intense localized heat will often
> > cause brittlement next to weld. I would use gas every time.
> >
> > This isn't a guess, BTW, I've built frames and repaired frames both, of
> > chrome-moly, have had excellent results with gas and never a failure. And
> > on top of that welding manuals agree with me. HTH!!
> >
Peter Patton
ahead a year. I suppose you have a bomb shelter built 10 stories below your
basement and food and water for the next 5 years. Too bad cable TV won't be
around. It's gonna get pretty boring down there. Hye, sis you see the movie
Blast form the Past? I'm just kidding around with ya. Hope you didn't mind :)
Peter
L Sommers wrote:
--
http://www.minnesotamotocross.com
Pe...@minnesotamotocross.com
Motocross Rules!!
Peter 3 # 524
Peter # 739
ICQ#59437543
Peter Patton
Peter Patton
time back to the present. See, now wasn't that a big hassle for nothing :)
Peter