[TheForge] Welding 5160
David E. Smucker
[email protected]
Mon Aug 25 08:50:01 2003
Grant and (Ralph)
I basically agree with all you are saying below except I would like to point
out one item in your heat treating of 5160.
"Heat treating 5160 is simple. Critical temps are 1550F to 1600F, hold
for one hour per inch of thickness."
For most Blacksmithing applications the "hold for one hour per inch of
thickness" doesn't make sense. I misunderstood this for years until I got
into a conversation with Jim Batson at LaCrosse last summer. The heat for 1
hour per inch of thickness is standard industrial practice and I always
would write that into the spec going to a custom industrial heat treat shop.
The reason it is required is that to control the temperature in a industrial
heat treat furnace the operator adjusts the set point of the furnace to the
desired critical temperature -- and then expects the work piece to come up
to that temperature over time. To be sure that the piece fully gets to the
temperature we use that 1 hour per inch of thickness rule of thumb. "We let
it soak" to be sure that the whole piece reaches critical temperature.
In our Blacksmith shops on the other hand most of us don't have a industrial
heat treat furnace with a temperature control system. We just heat the item
in the coal or gas forge and use color or temp sticks to judge when we have
reach critical temperature. Since in the forge we have a "furnace" with its
set point temperature much higher than the desired critical temperature we
have lots of driving force to heat the work piece. In other words we don't
have to let it "soak" to get up to critical temperature. We still want to
wait long enough that we feel good about the whole piece being at
critical -- but not near a hour per inch. (Having the item soak at critical
temperature doesn't hurt it -- having it above critical temperature on the
other had leads to grain size growth that we would like to avoid.)
As I said I didn't understand this point for years and have watch lots of
stuff get heat treated. (In heat treating of hard aluminum alloys heating
above the solution heat treat point is really bad, you get local melting in
the piece and airplanes fall out of the sky.)
This is a really good discussion Ralph, In welding of small powerhammer
tools and such using 5160, 4140, H13, and S7, I have had good luck just TIG
welding them with common carbon steel TIG rod. I always used a preheat, and
then let them air cool. For the H13 and S7 I then did a heat treat -- took
to critical temperature and let them air quench, followed by a reheating to
temper. Note that for both of these critical is higher than for plain
carbon steels (1850 F for H13 and 1725 F for S7) and the magnet test is
not a good one. My tempering temperature tended to be a good "guess" for
the H13 at around 1000 F. I don't think I have had any handles break off,
except for spring swage dies where the spring was welded to the working end.
Dave Smucker
----- Original Message -----
From: "gblacksmith" <[email protected]>
To: <[email protected]>
Sent: Sunday, August 24, 2003 9:49 PM
Subject: Re: [TheForge] Welding 5160
> Ralph: Sounds like you reflected plenty on the QA issues here. The 700F
> temp will soften a hardened/tempered piece of 5160.
>
> This alloy is medium carbon (60 pt.) steel that is very tough and well
> suited for the application you have. It is also not high in chromium
(0.70
> to 0.90%) , which would prompt me to use a regular carbon (for hard
service)
> vs. stainless filler. The chromium at this level produces even hardening
in
> thicker sections, vs. the 12-13% required to make steels truly stain
> resistant. This alloy is used for swords, axes and BIG bowies, etc. The
> 4140 type alloys are 40 pt. nickel /chromium alloys that are still
> considered "carbon steels" and are used in firearms because of their
> excellent shock resistance. I would still use fillers recommended for
> carbon steels vs. stainless. Preheating and subsequent stress relieving
> are always a good idea with any tool steel. You have thought of this
> already.
>
> Heat treating 5160 is simple. Critical temps are 1550F to 1600F, hold for
> one hour per inch of thickness. However, it is HIGHLY advisable to
> construct an igloo if using a gas forge, to keep LPG flame off of piece.
I
> routinely do this when forging blades from air-hardening steels such as A2
> or ATS-34
>
> Use pure hardwood charcoal thrown into furnace to reduce oxygen and quench
> in oil. Tempering can be done in home oven at 450-500F..brighten area of
> steel to reveal color and soak until blue color is present. Quench whole
> piece again in room temp water to arrest tempering process.
>
> I hope this helps
>
>
> Grant
>
>
>
>
> ----- Original Message -----
> From: "Ralph Sproul" <[email protected]>
> To: <[email protected]>
> Sent: Sunday, August 24, 2003 6:09 PM
> Subject: Re: [TheForge] Welding 5160
>
>
> > Grant and Dan, Thanks for the responses.
> >
> > I had figured the best option would be to buy or make another
arm,
> > the second was to repair this one.
> > We were told it was 5160 and the fellow who owned the hammer had
> > some cheap drills that were pretty dull. When I got the arms here, I
> found
> > that a drill would "sliver" cut the arm, and a file would affect it and
> not
> > skate. So I assumed I had an "as forged" piece of 5160. I figured it
> > would have a certain hardness to it being it was a medium carbon steel
> with
> > .60 points of carbon.
> >
> > If it had been hardened I would have considered two options:
> > 1) use stainless or a rod such as Dan mentioned with alloys to allow
> for
> > deflection. If it broke you would be dealing with no other option but
> > stainless at this point if you were trying to keep the rods equal
length.
> > 2) Anneal, grind bevel equal from both sides, weld with a strong
> tensile
> > strength rod 8018 or 10018. Oil harden, temper(which I felt would be
> > difficult with the gear at my shop.
> >
> > It wasn't hardened from my estimation of drilling and file
> testing,
> > and it was definitely a medium carbon steel so I'm assuming the 5160 (we
> > were told) was in the ball park from the spark test I did comparing it
to
> > another piece of known 5160 I had.
> > So I approached it like this: Cut bevels with plasma cutter to
> keep
> > heat down and remove crystalized metal at break, Jiged broken parts with
> > good fit at break for alignment of pin 90 degrees to arm, and keeping
arm
> > straight with clamps. The arms were arced, so I used shims to keep it
in
> > the identical arc using the first arm as my pattern. I set up some
> > firebricks with the broken smaller 4 1/2" end and the arm resting on a
> piece
> > of 1 x 4 flat bar as a heat sink..........or I should say a heat holder.
> > The small part was on the heated flat bar and out over the brick
allowing
> me
> > to align, clamp, and wedge the parts to exactly the arc I needed. I
> > preheated to 450 degrees, then welded the two sides, tacked the center
> with
> > a 3/4" stitch, flipped the arm and welded the back side, then came back
> and
> > completed the top side. I kept staggering my stringer beads and
checking
> > with a tempil marker not letting the project get above 700 degrees
> anywhere.
> > (the ears that held the rollers tended to get hot the fastest). I
> > completed the welding, let it cool slowly, then ground everything like a
> > gradual stress riser into the ears so there were no undercuts either,
and
> > all welds were above original surface and brought back to that surface
> again
> > after grinding.
> > When the part was cool it still cut the same as before with a
> drill
> > and file. So I'm assuming I have a 5160 as forged arm, with a repair
done
> > between 450 and 700 so I should have done the least damage as possible
to
> it
> > for grain change.
> >
> > Not being really familiar with 5160 and not having done this
alloy
> > repair before, could you comment on the rods I used (low hydrogen high
> > tensile strength, with elongation qualities) .......as I used a dual
> shield
> > wire I have used in the past for fastening mild and medium carbon steels
> to
> > HY80, HY100, and T1 - in heavy equipment repair. It was not however the
> > wire I also have for connecting those HY80, HY100, and T1 to themselves.
> > Would you have chosen that wire? or a different wire or rod?
> > Would you have annealed and heat treated the 5160 no matter
what?
> > even with the drill slivers and file test showing what I would call half
> > hard or as forged conditions..........or is that how a "tough spring
steel
> > would react when properly heat treated?
> > Not knowing if this is how heat treated 5160 would react, I
opted
> > out of using stainless alloys and staying away from the heat treated
> > question and solution of "use stainless when in doubt".
> > I'm new to this material and just looking for some pointers.
I've
> > made lots of power hammer tools out of the 4140HT which is also called
> 4142
> > or "half hard" heat treated to a 35-40 rockwell and they hold up fairly
> well
> > to the task as welded to a handle (with regular wire and not stainless).
> >
> > If you don't mind answering a couple more questions:
> >
> > When welding a handle to a forged air hardened, or forged spring
> > steel .......it is obviously hard then from heated, forged, and air
> cooled.
> > I have always made practice of welding with stainless rod at this
> juncture.
> > Would you recomend continuing this? or do you have other suggestions on
> > fastening handles to hardened or forged tool and spring steels?
> >
> > Thanks for any input you may have to offer, as all my results have been
by
> > trail and error.
> >
> > Ralph
> >
> > ----- Original Message -----
> > From: "gblacksmith" <[email protected]>
> > To: <[email protected]>
> > Sent: Sunday, August 24, 2003 12:03 AM
> > Subject: Re: [TheForge] Welding 5160
> >
> >
> > > Ralph: I misread your post.....if it is 5160, it is medium carbon and
> was
> > > likely heat treated. If so, you may have a soft spot at the joint.
You
> > can
> > > always heat treat the whole piece, if need be....just quench in oil
vs.
> > > water.
> > > ----- Original Message -----
> > > From: "gblacksmith" <[email protected]>
> > > To: <[email protected]>
> > > Sent: Saturday, August 23, 2003 8:56 PM
> > > Subject: Re: [TheForge] Welding 5160
> > >
> > >
> > > > Ralph: There are a number of welding rods that would work well for
> that
> > > > application. I have made similar repairs on shock-loaded members
and
> > > > usually what I did was to verify the needed LOA of the piece and
> bevel
> > > each
> > > > side of the joint steeply, with ridge (or gap) left in the middle
that
> > > > guaranteed the LOA. Then preheat the surfaces to be joined.
> > > >
> > > > If you need to clamp the pieces firmly, clamp them in the "V" of a
> piece
> > > of
> > > > angle-iron at the needed LOA. This acts as a splint that holds the
> > pieces
> > > > at a predetermined position.
> > > >
> > > > Weld by first tacking the piece and then filling the bevels so the
> > beads
> > > > are just above the original surfaces. Make sure that the filling
> beads
> > > are
> > > > run in a connecting line to the joined ends of the original piece.
I
> > > would
> > > > suspect the tension arms are of carbon steel, probably in the 40 pt.
> > > range,
> > > > like axles.
> > > >
> > > > I don't know if these arms are heat-treated, so the welding will
undo
> > the
> > > > heat treat near the joint. Before welding, check with the edge of a
> > file.
> > > > If a good file barely bites and makes a high-pitched scraping sound,
> the
> > > > metal is likely heat treated. If the file bites easily with a lower
> > > pitched
> > > > sound, the piece is likely not heat treated. just my cents
> > > >
> > > > Grant
> > > > ----- Original Message -----
> > > > From: "Ralph Sproul" <[email protected]>
> > > > To: <[email protected]>
> > > > Sent: Saturday, August 23, 2003 6:33 PM
> > > > Subject: [TheForge] Welding 5160
> > > >
> > > >
> > > > > Here's a question I should have asked earlier.......... Any
> > > comments
> > > > on
> > > > > welding 5160?
> > > > >
> > > > > Today I welded up a broken tension arm from a #4 Beaudry
> Power
> > > > > hammer. We'll see if it holds together when the hammer goes back
> into
> > > use
> > > > > on Monday(then I'll really know if my plan was a good one or not).
> > :-)
> > > > >
> > > > > I used a particular method I thought might work, and I
> wonder
> > > what
> > > > > others would say on how to do it..........
> > > > >
> > > > > Ralph
> > > > >
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