[TheForge] Welding 5160
Chuck Robinson
[email protected]
Tue Aug 26 13:10:01 2003
Hey Grant, The reason I proposed using a pipe and a Magnet, Is because I was
assuming that Ralph didn't have any fancy heat treating equipment available.
I use salt baths and so can control the temperature to a few degrees.
The salt bath also allows you to bring the billet to temperature much faster
and hold precise temperatures while preventing scaling.
When a billet is placed in the salt, the color difference between the
billet and the salt shows how close it is to temp. If you see dark shadows
in the billet the core is still not ready.
Of all the steels used by bladesmiths the 5160 is one of the easiest and
most forgiving of alloy steels to heat treat.
I can see a big advantage in normalizing to reduce stresses and grain size,
but I still have a problem with why the arm needs to be hardened.
The weak area, will be the weld zone, and that's where the arm will likely
fail again due to the high shock loading of the hammer in operation.
Chuck
----- Original Message -----
From: "gblacksmith" <[email protected]>
To: <[email protected]>
Sent: Monday, August 25, 2003 5:07 PM
Subject: Re: [TheForge] Welding 5160
> Ralph, Chuck: I would absolutely agree with the need to normalize/anneal
> prior to hardening....I neglected to mention that step. I routinely do
this
> after forging. I normally use a pyrometer when heat treating, for greater
> uniformity of temperature control and I anneal in preheated vermiculite.
>
> The most important aspect of hardening is the efficient transformation of
> pearlite and ferrite to austenite, which requires proper through-heating
of
> the metal at critical temp. The one hour per inch of thickness rule
refers
> to the time spent at critical temp, rather than the total time spent under
> heat. Yes, it really takes that much time for austenitic transformation
for
> thick sections. One of the greatest challenges for metallurgists was to
> figure out how to get thick sections of tool steel to harden throughout,
> hence the addition of certain refractory elements.
>
> Industrial heat also treaters have the option of using electric or baffled
> furnaces to avoid having higher temperature flames
> strike the pieces in differing areas. These produce a still heat of
uniform
> temperature. You can mimic industrial processes to some degree by heating
> the pieces inside of pipes or using an igloo of kiln shelf for even
heating.
> Regardless of the heat treating operation; normalizing, annealing,
hardening
> or tempering; the closer you can come to an even, still heat, the more
> uniform and complete your heat treating ops will be. because you have
> avoided hot spots that prevent uniform heating..
>
> In normalizing, a still air cooling allows the austenite to revert to
> pearlite and ferrite again. Also, the stresses induced by forging are
> reduced in the piece. A non-air-hardening steel such as 5160 will not
> harden appreciably, as little or no austenite is being transformed into
> martensite because the temperature is not decreasing quickly enough.
Such
> treatment will likely render the piece cuttable with a file.
>
> I have never found magnets a reliable method of predicting critical
temps.
> The magnet will fail to hold due to the weaker electrochemical bonds
between
> atoms at the surface, but they do not reveal the completeness of
austenitic
> transformation, especially in thicker sections.
>
> One of the most complete texts on this subject is "Alloying Elements in
> Steel" by Edgar C. Bain. Originally printed in 1939, it is still a
standard
> reference text in graduate materials science courses.
>
> I wouldn't shy away from oil quenching a welded section that needed to be
> hardened, provided the weld was properly done and the piece properly
heated.
> Oil is far gentler than water or brine.
>
>
> Grant
>
> ----- Original Message -----
> From: "Chuck Robinson" <[email protected]>
> To: <[email protected]>
> Sent: Monday, August 25, 2003 7:02 AM
> Subject: Re: [TheForge] Welding 5160
>
>
> > Another thing that Jim Batson stresses is "normalizing" 3 times to
> thermally
> > refine the grain structure.
> > 5160 is an alloy steel that benefits from normalizing.
> > I would recommend that you heat a section of 3" id heavy wall pipe in
your
> > forge to red heat then place the arm in it.
> > When the arm reaches non magnetic remove and let it cool to black heat
in
> > still air.
> > Repeat the process 2 X.
> > Then heat the arm to nonmagnetic, remove it and let it harden in still
air
> > to room temperature.
> > This will allow it to air harden some, but not subject the weld area to
> the
> > high stress of a full oil hardening.
> > Chuck
> > ----- Original Message -----
> > From: "David E. Smucker" <[email protected]>
> > To: <[email protected]>
> > Sent: Monday, August 25, 2003 7:43 AM
> > Subject: Re: [TheForge] Welding 5160
> >
> >
> > > 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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