What Type Of Steel Are Maico Frames

[Ji Gantor]

Why do aerospace engineers suggest using ER70 s-2 filler rod on 4130 when it is not going to be post heat treated?
The reason is that tests show that the low carbon content filler absorbs some of the carbon from the parent tubes that are being fused. This draws the carbon away from the area near the toe of the bead. This section is the most likely to be come brittle after welding and the removal of carbon makes it ductile or less brittle. I will ask Laurie and Geoff if they ever saw the frames being heat treated after welding in the Maico factory.

Ji 

[Lozza]

The amount of carbon is steel has an enormous influence on the decision to use that steel or not. There is a simple formula to determine the steels weldabilty, called Carbon Equivalent. The higher the number from the CE formula the more consideration has to be given to pre/post weld heat treatment. Generaly steels with less than 0.2% carbon give little trouble.

ER-70S-2 makes the most ductile weld the ER70S-6 stronger but less ductile and the 80S-B/D2 the strongest least ductile welds. All these filler wires have 0.12% carbon (the 80S-B2 has 0.14%).

[All Things 414]

They're still at it?
Ji. You didn't have a Canadian relative who was into jumping cars a few years ago did you?

[Ji Gantor]

What happened to The Flux Capacitor

Ji

[vmx42]

If we are going to stress out [and make unsubstantiated claims] about a variation of 2% in the carbon content of our frames and how/why it varied then we need to get out more. Take a look at the above chart and you can see that the standard spec for 4130 allows for a 5% variation in carbon content - so the 2 or 3% variation found in the samples means absolutely nothing. Not significant - normal production variations - end of story. Not enough evidence to make these extrapolations.

Actually it’s more like 0.05 %  and it does mean a lot

The actual variation in the Carbon content of the Maico frame test to 4130 is around 0.04 to 0.08 %
2% is a huge change when talking of percentage of carbon in steel.
Mild steels have under 0.2 % carbon and tool steels have 1.5 – 2 % so a small amount can make a big difference.

Ah, the power of the decimal point and the flurry of a hot keyboard. Sorry about that!

Now that God is a member of this forum I will seek his penance for my mistake [and try harder next time]. 
VMX42

[AjayVMX]

                                                           

[vmx42]

OK Ajay,

How about this then…

WHAT TYPE OF STEEL ARE GUITAR STRINGS?

Does that help? 

[AjayVMX]

OK Ajay,

How about this then…

WHAT TYPE OF STEEL ARE GUITAR STRINGS?

Does that help? 

Oh, I dunno...  I just play 'em. 

When they break, you replace 'em, not weld them up. 

[vmx42]

…when they break, you replace 'em, not weld them up. 

But just imagine if you could? 

[vmx42]

Ohh god 

See now you are talking to him as well! Who said nothing good came from a love of old motorbikes.

Good thing he is everywhere!! 

[AjayVMX]

…when they break, you replace 'em, not weld them up. 

But just imagine if you could? 

Now THERE'S an idea... 

[Ji Gantor]

That is a brilliant idea Walter.
That could keep this thread going for another ten pages.
I will get right on it

Ji

[vmx42]

Back to work Jigantor , I want a fully documented string weld operation , backed up with test results by the afternoon. .

you will also need to ensure that the pitch of the original string is maintained after reprocessing!!

[Ji Gantor]

My first impressions would be to take a Kawasaki frame and band saw the tubes really thin.
Then place the strips into the lathe and turn them down to 0.8mm diam filler rods.
And finally TIG weld the string back together.

Ji

[vmx42]

My first impressions would be to take a Kawasaki frame and band saw the tubes really thin.
Then place the strips into the lathe and turn them down to 0.8mm diam filler rods.
And finally TIG weld the string back together.

Ji

What could go wrong?