Steel Chassis Stress Concentration Points Caused By Uncontrolled Fire 3

[jaysaynay]

Greetings all.
I would like your opinion on an issue I am having. Would you consider a steel frame, such as a motorcycle chassis, that has been in a fire to be dangerous to re-use? My concern is that the fire has caused annealling in the steel and the curves and shapes of the steel frame may have cooled at different rates casuing stress concentration points.
I know that metal can be heated without causing any detrimental effects by controlling the cooling rate in an oven, but not sure if this is feasible in this situation, and would like some advice on what to do with this chassis.
Thanks ahead of time for the advice.

 

[CoryPad]

Metallic structures exposed to fire can have numerous problems with reuse. Caution is warranted.

 

[TVP]

Agreed.

 

[Screwman1]

make that 3.
What was the max temp, the atmosphere, how even was the heating, how long was it heated, what is the material, what was the original heat treatment.....you need to know all those to really answer the question with any reliability. I would make it into yard art.

 

[metengr]

Would you consider a steel frame, such as a motorcycle chassis, that has been in a fire to be dangerous to re-use?

I would consider it unsafe to use because of unknowns that can't be quantified unless you were to destroy the frame to test the material.

 

[redpicker]

It really depends on what you want to re-use it for.

If you want to re-use it as a lawn ornament, then it would be suitable.

If you want to re-use it as a motorcycle frame, the best thing to do would be send it to the scrap dealer and have them melt it down and make new steel out of it.

I ride, and have heard more than enough "donor-cycle" jokes, but this really isn't anything to joke around with.

rp

 

[jaysaynay]

Thanks for the replies. Follow-up question:
If I had the frame powder-coated and cured at say, 400 degrees F, do you think that would help in stress-relief?

 

[metengr]

Not for this frame material, the temperature is too low for stress relief. Please re-review the posts above for hints on what to do with this damaged frame.

 

[Screwman1]

It's not the stress relief that we are all worried about. It's things like overheating and decarburization or quench cracking from fire hose water, or any one of a dozen other uncontrolled things that a fire does to fabricated structures. If the forging for the head was exposed to say 1,800 degrees for a period of time and decarburized (or maybe carburized, because we don't know what was in the fire), do you want to risk your life on it being structurally sound?

 

[EdStainless]

There is an entire discipline dedicated to assessing fire damage in chemical plants and refineries.
For as little value as this frame has it isn't worth the work required to determine if it is safe to used.

If:
1. You knew the original heat treat condition (normalize and temper maybe?)
2. you could prove that it was not reheated above the critical temperature
3. you could prove that there was not decarb, cracking, or other heat related damage

Then maybe you could re-temper the frame and have a usable item.
But compared to the risk of death I sure wouldn't do it.

= = = = = = = = = = = = = = = = = = = =
Plymouth Tube

 

[arunmrao]

Agree with Ed. Why are you pursuing with a material that is questionable?

_____________________________________
"It's better to die standing than live your whole life on the knees" by Peter Mayle in his book A Good Year

 

[Metaljon]

I would recommend you get a hardness test to confirm the condition of the chassis. It is important to test the steel in the area of the fire concentration and away on steel not affected by the fire. The best hardness method is Proceq Equostat hardness tester. This is designed for testing thin steel. Check for distortion on the frame as well.

 

[racookpe1978]

Why do you think this is a "plain steel" motorcycle frame?

Most that I know of are high-carbon, or high-alloy or non-steel ... High value item, highly stressed and with a low-weight desireable? Why do you think any modern frame would use simple (cheap but heavy and relatively low strength) carbon steel?

 

[jaysaynay]

Thanks for all your responses. I plan on searching for a new frame to use in this application, it's not worth risking my life.
racookpe, see here:
Link

 

[Metaljon]

Q. Why do you think this is a "plain steel" motorcycle frame?

Well for a start the guy says it is a steel frame.... Duh I doubt they would use high carbon steel for this application as it would need to be stress relived after welding. It is quite common to use MS and Cr-Mo steels for frames. I doubt it would be titanium or super exotic steel either unless we are talking about NASA super bike. Still think it is possible to test the frame with the correct equipment.