thermal expansion of carbon steel at temperature

[sydneyjongleur]

Hi,

Does anyone know the thermal expansion rate at 1000°C on Carbon steel. A rough figure will do.

 

[TVP]

I don't have any data up to 1000 C, because it almost certainly does not exist. Carbon steels cannot be used at that temperature for any sustained amount of time. The average value from 20 to 700 C is ~ 15 μm/m·K.

 

[cloa]

I think there would such data for severe upset conditions like 9-11 type fires where you'd want to estimate the limited life of a skyscraper in severe fire for escape planning.

Otherwise it would need to be in non-oxidising environment and accept maybe 30% room temperature
strength for rather short periods as it will creep badly.
extrapolate it from this data.

http://www.engineeringtoolbox.com/thermal-expansion-pipes-d_931.html

http://www.eng-tips.com/threadminder.cfm?pid=1529

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[btrueblood]

CRC Handbook, 40th ed., 1958 lists for steel, 1.2% carbon, from Le Chatlier in 1899:

Temp. (C) Coeff. (x10^-6)
0-100 10.5
100-200 11.5
200-300 13.
300-400 15.
400-500 14.
500-600 16.
600-700 16.
above 900 29.

As TVP noted, and visible in the data, is the phase transition to austenite occurring above 900 C, which tends to honk up the numbers. Note this is also a fairly high carbon steel.

 

[sydneyjongleur]

Thanks guys,

The reason I was asking is because it was suggested to use this as a fixture and clamps used in a heat teatment process to remove distortion. It was suggested that this material would be used as a base fixture to locate a nickel alloy ring onto, and also use the steel material as clamps to hold the nickel alloy ring down, and heat treat to 1000°C in order to remove distortion. I was looking at the thermal expansion rates to prove that this wasn't possible. In any case I think the carbon steel would be so soft at that temp that the nickel alloy would be welded into it.

 

[EdStainless]

We made furnace muffles out of low C steel (1005 or so) for use at 2200F (1200C).
It is difficult to find a metal with any usable strength at that temp.

According to ASM, High temperature property data: ferrous alloys
all in 10exp-6/C
0-600C 14.6
0-700C 14.9
0-800C 16.6
0-1000 13.7
These are averages for the entire range.
Yes there is a peak in the curve.

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Plymouth Tube

 

[MagBen]

Ed, useful info on low C steel as furnace muffle at 1200C. The muffles we are using are made of a high temperature alloy, but the wedling area is the weak point. After 100-200 times of serve at 1200C, we have to change the muffle due to the leakage at welding. I am thinking welding quality may be able to be improved if using low C steel.

For the thermal expansion coeffient data, what could be the down peak at 0-1000C? somthing to do with the phase trasformation to anstenite? we know austenite is fcc, ferrite is bcc, the former has large lattice parameters. also, austenite has a higher coefficient about 24ppm/C. I expected a larger coefficient at 0-1000C, compared with 0-800C!

Carbon content is another factor to consider: carbon obviously increases lattice parameters, but the coefficient normally decreases with increasing C content, i.e. high carbon steel has a lower thermal expansion coefficient.

 

[arunmrao]

sydneyjongleur,

I am reminded of a gear manufacturing company, several years ago, who had a serious problem . They were facing distortion problem in their machined gears and there was not enough stock to correct them. The problem was they had mild steel fabrications as fixture for oil quench and temper cycle. The fixtures were severely scaled, twisted and cracked. It is not a wise option to use a mild steel fixture for heat treatment applications.

 

[Compositepro]

Placing a bead or corrugation (think bellows) in the sheet metal at appropriate spots will do more to solve your problem than changing alloys. Usually the problem is not the temperature change but the differences in temperature between one spot and another. Hot areas cannot expand freely while attached to cold areas. There has to be flexibility in the structure to accommodate this or it will crack.

 

[sydneyjongleur]

thanks guys, I will take on board what you are saying. I agree mild steel is a bad idea.

 

[MagBen]

distortion is not a big deal for my muffle applications. leakage is my main concern after long cycles (no quench).we can not get muffles made by a whole piece,and have to weld for a sealed muffle for vacuum heat treatment. leakage always started with the welding area. low carbon steel may be a good choice for a better welding!

 

[EdStainless]

At high temp (>95% of MP) plain Fe has more strength than Ni alloys.
Weird but that is how it works.
We were running pure Hydrogen on the inside.
The heating elements were wrapped on the outside (with a thin layer of ceramic paper underneath).

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

 

[racookpe1978]

Could a ceramic or poured non-metallic solid (concrete ?) hold up the material being treated without itself being distorted by the heat or losing strength so the support effect fails to hold the load without contaminating the heat-treated materiel?

 

[NickClark]

Vacuum brazing companies use graphite plates and jigs to support parts.its dimensionally stable and won't react.