2 Strokes Down Under

I read somewhere that after frame welding etc, you should temper the frame in an oven at 600 degrees and then cool slowly.
Does anyone know how true this is ?

yeah... look up some articles on the tulda (dr tullies first bike before the tularis)

its a custom chromoly framed cr500.

he had to go to a univerisity to find an oven large enough to fit a whole frame in...

that was back in the early 90's so maybe the industry has caught up and you can find a cheaper alternative


Im no welding expert but from what Iv learnt about metal crystal formation at uni is this

if you cool it fast you get tiny crystals (same theory behind snap freezing peas and beans haha, tiny ice crystals wont ruin the vegies!)
cool it slow and you get larger crystals in the metal

joins in the crystals are weak points

the bigger the crystals in your metal the lest joins, the less weak points
this is especially true for fatigue

this has been taken to the extreme in the aeronauticl engineering field where they have found a process that creates a 'single crystal' piece of metal that is almost free of impuritees and i guess 'perfect'

it is used in modern jet turbines in commercial and military jets

sorry I went off on a tangent...

but anyhow, heating it up for 600 hits the 'reset button' on the crystal structure.
then you cool it down slowly for optimum performance
or you cool if down fast for hardness (quenching) but your material will be brittle and prone to fatique



whether you need to do it for your particular aplication... well thats another question to ask

what is the aplication exactly?

CrMo needs post weld heat treatment, mild steel you can get away with it, provided it was welded correctly to begin with. I have several flood lights I put on ANY frame before welding, that gets them hot enough, so you can get burnt if you touch it to long, then weld, then on with a old fire blanket and keep the lights on it for 4-5 hours after.
What Jeram said is correct the slower the heat up and cool down process the more ductile the weld(large crystals).
Aluminium frames can be 'artificialy aged' but most times the welding process does this.
What is the single crystal process?

ductile... thats the word I was looking!

thats a good home precess youve got there lozza!
if you want another Idea for for hollow pipes, try getting a 30 dollar ozito heat gun and shooting the hot air down the pipes, i got my pipes hot enough to ignite WD40 the otherday.... Iv just been inventing used for it ever since I bought it haha

the other nite I was sick of waiting for my coal barbie to heat up so out come the heat gun... I had blue 200mm flames coming out of the fire lighter!
the missus' stake was a bit on the rare side, so out came the heat gun... char grilled the stake in 20 seconds haha
cant help myself!!!


Ill see if I cant find some info on the single crystal tech, but Im guessing it will all be hush hush secret buisness... but the blades on high performance turbines are now a single crystal blade

seems like there are a couple ways to make it...
simply cool the metal down incredibly slowly so you get crystals so large that they take up the entire item...
otherwise you can do it with chemical processes, nano techniques, or syntheticly create the crystal

single crystals are particularly great when you are already starting with a great material such as superalloys

Man Id love to get my hands on some super alloy engine parts


"Crystalline structures occur in all classes of materials, with all types of chemical bonds. Almost all metal exists in a polycrystalline state; amorphous or single-crystal metals must be produced synthetically, often with great difficulty. "


"In the case of silicon and metal single crystal fabrication the techniques used involve highly controlled and therefore relatively slow crystallization.
Specific techniques to produce large single crystals (aka boules) include the Czochralski process and the Bridgman technique. Other less exotic methods of crystallization may be used, depending on the physical properties of the substance, including hydrothermal synthesis, sublimation, or simply solvent based crystallization.
A different technology to create single crystalline materials is called epitaxy. As of 2009, this process is used to deposit very thin (micrometre to nanometer scale) layers of the same or different materials on the surface of an existing single crystal. Applications of this technique lie in the areas of semiconductor production, with potential uses in other nanotechnological fields and catalysis."


"Growing a single xstal of pure metal is fairly straight forward, directional solidification, done at the proper solidification rate (slowly) will produce long crystals all grown in one direction. The trick is weeding out all but one dendrite (one single xstal). This is typically done by forcing the directional growth through a small tube that makes the correct corners. Once it exits the small tube, there is only one dendrite and then it fills the remaining mold with one single crystal. With alloys, such as with superalloys used for turbine blades, it is more difficult because the solidification conditions are much more critical.

For equipment, you need a furnace that allows you to slowly lower the mold (containing the liquid metal) out of the heat zone. The solidification starts at the bottom and proceeds upward as the bottom of the mold cools.

Another method is the method used to grow large single xstals of Si for semiconductors. The process is call the Czochralski crystal puller. This produces large boules (round ingots pointed on both ends).
"

Thanks for the replies, thats makes it a bit clearer.
Application is for the RZ frame that has been modded as per Eddahenrys post rz/rgv/r6 hybrid and a bit of extra subsequent bracing by Laurie Alderton at Smithfield who didnt seem to worried about it and said the welds and frame all looked pretty solid.
I read on another forum that eddahenry was going to temper the frame and get an engineering report for it, but I was wondering if I really needed to ?

probably not just for bracing...

it wouldnt hurt...

but if the original welder knew what they were doing and therefore the welds are of a high quality you should be right

So this is the main area I was concerned about - the shock mount eddahenry put in for the rgv shock and the extra bracing I put in to make sure the shock mount wouldnt push it forward.
Whaddayathink ??

Hmmm, Jeram thats pretty cool, but a bit over my ability and current tooling... Think ill have to go with sticking it in an oven. think ive got a mate at Uni of Wollongong who have a pretty good engineering dept- he he
Any other ideas where i could get her baked ???

oh dont worry bout that single crystal thing... It wouldnt help for your aplication anyway.

ummm you could always heat treat it yourself with an oxy torch (guess)

heat that localised section up to 600 degrees slowly (use an infrared temp sensor off ebay), keep it at 600deg for a length of time (look it up, maybe 10mins) then slowly cool the flame or increase the distance from flame and slowly cool it down over a period of 10-20mins (again look that up)


Im sure someone on here can help you more

The only concern would be that it was not done on a jig of some sort, but of Laurie said it was OK I'd be happy with that. BTW if you want wheels straightened (spoked/cast) Laurie and his son are the go. They Did Jerams RS wheel for $120 or so including shipping. Might be worth starting alist of suppliers Jeff????

Well Laurie certainly wasnt too concerned about it and it certainly looked like he was doing similar work for a hell of a lot of people / racers.
Might still check out the oven situation though, like siad, cant hurt...

Looking again I would be inclined to add a few curved gussets to that boxy top mount(ride height adjuster would be ideal to) both at the base and top in the verticle plane to the horizontal cross members and one to the curved cross member in the horizontal plane. To quote Masao Furusawa frames should 'bend like a tree in the wind'.
Curved gussets transfer the forces in a gradual manner.

Found a great Ol bloke who works for a company LSW Group, who will do the tempering of the frame for $1.10kg which I think is pretty good and worth getting done to be sure. SO its off there this arvo !