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[Closed] "Any metallurgists/framebuilders in?" II (al's not giving up)

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Cheers...no one (as far as I know) has done this before, which may mean its not do-able, but not necessarily.

Headingsouth I have already said (at least once) the frame would go from room temp, into the kiln, 2mins, then out again to room temp to cool, so please don't flame my question when you've not even read it properly.

I don't doubt it would be easier for you all if I just gave up! I guess I'll need to do the research and try and work it out, or ask tubing manufacturers.


 
Posted : 23/12/2014 10:19 am
 dpfr
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But as described there are far too many unknowns. I suspect tubing manufacturers would be similarly vague, if not more so since they probably wouldn't want to risk something bad happening and the finger being pointed at them for giving advice.

If you can't define the problem more precisely then there's probably no alternative to doing an experiment as others have suggested.


 
Posted : 23/12/2014 10:25 am
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I am asking about-will it lose its strength?

See I'm not convinced that's the right question, after all steel has plenty of 'strength' for you to play with. I'd be more concerned about making it brittle or some other effect.

Is the frame even going to see 800 degC? Frame goes in cold, then what happens how is the coating applied?

Surely the company doing the coating can provide some advice?


 
Posted : 23/12/2014 10:26 am
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Simples - you want to be a pioneer: do it, ride it, post it


 
Posted : 23/12/2014 10:53 am
 TimP
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Just wondering if the coating will act as an insulator to stop the steel itself from getting as hot? And it will also presumably increase the time taken to cool down? If this is the case no-one will be able to offer too much insight as you are venturing into the unknown in terms of the actual heating and cooling curves


 
Posted : 23/12/2014 11:22 am
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[i]room temp, into the kiln, 2mins, then out again to room temp to cool[/i]

room temp of an office or a workshop where the frame's been sat at near zero overnight and then slung straight in the kiln?


 
Posted : 23/12/2014 11:28 am
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Based on steels thermal conductivity, and the relatively low mass in relation to surface area, it's likely that the majority of the frame will reach 1100k when in the kiln.

Since it's 853, and cooling will likely be as mentioned in my earlier post, it's probable that you'll maintain the Baininte crystal structure of the material.

The problem you may have is that by raising the temperature of the frame to such a high degree (beyond most heat treatment levels) and because you're doing so in an oxygen environment, there's a chance that you'll force the material into the Austinitic phase. If this happens the frame will not create a self protecting oxide layer on the surface, but will form slag, effectively removing/reducing the carbon content from the material, thereby leaving you with a type of exotic iron...

If the heat treatment could be kept below 1000k, this should eliminate the problem.


 
Posted : 23/12/2014 11:50 am
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I've said twice I think:

IT IS NOT 853

I had presumed heat treated tubes are more likely to lose strength.


 
Posted : 23/12/2014 12:39 pm
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I think you are getting confused and confusing others by mentioning 853 and heat treated steels, when all you have is bog standard un-treated 4130?

You are still thinking about it wrongly, strength for steel isn't a huge issue, embrittling welds, causing sever oxidation or some other type of degradation is more a concern IMO.

So answer this:

1) What is the coating?

2) How is it applied?

3) What type of items does the company normally coat, and are they typically welded?


 
Posted : 23/12/2014 12:57 pm
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Just get it done, and see what happens. We are British!! This is what we're good at


 
Posted : 23/12/2014 1:13 pm
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From OP:

So will non heat-treated steel be OK?

Love how so many who are flaming me for a lack of detail skim-reading themselves?

The company I've approached don't do anything with load bearing structures or welded steel AFAIK.


 
Posted : 23/12/2014 2:17 pm
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Are you reading ANY of what I'm typing?

By heating to 1100k, you're likely to decarbonise the frame. To what degree depends upon the carbon content of the steel, the oxygen content of the Kiln and the total surface area.


 
Posted : 23/12/2014 3:56 pm
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It won't work....


 
Posted : 23/12/2014 4:47 pm
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carbon content for 4130 is nominally 0.30%

See link [url= http://www.suppliersonline.com/propertypages/4130.asp ]4130 Alloy properies[/url]

At 800 degC you are sitting around the Hot work temperature of the steel.

TBH I just wouldn't bother and send it to Argos or someone to coat normally.


 
Posted : 23/12/2014 5:05 pm
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Daffy, I've read everything, just not had time to consider/read around enought to understand.

Your post did seem the most relevant, reasoned posts and I did mean to mention that, sorry.


 
Posted : 23/12/2014 5:15 pm
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There endeth the thread

😀

Merry Xmas everybody!


 
Posted : 24/12/2014 1:14 pm
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[i]There endeth the thread

Merry Xmas everybody! [/i]

if you wait until tomorrow there'll be Three Wise Men along who might be able to offer advice?


 
Posted : 24/12/2014 1:15 pm
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I've been waiting a few days, 3 could come at once!


 
Posted : 24/12/2014 5:17 pm
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