Thermal conductivity of duplex

[bob330]

Hi All,

For heat exchangers, how does the thermal conductivity of duplex grades like 2205 compare to that of austenitic grades and plain carbon steels?

Bob

 

[metengr]

bob330;
Plenty of information from tubing vendors and others;

ttp://

http://www.plymouth.com/Brochures/Brochures.asp

look at the Sea Cure brochure for comparisons

for duplex ss

http://www.alleghenyludlum.com/ludlum/pages/products/xq/asp/G.3/qx/ProductLine.html

or

http://www.imoa.org.uk/Default.asp?page=57

 

[EdStainless]

It will be in between, but closer to the 304 value. In general SS has rather poor TC. It is a good thing that in most HX designs the resistance in the tube wall is one of the smaller factors.

= = = = = = = = = = = = = = = = = = = =
Rust never sleeps
Neither should your protection

http://www.trent-tube.com/contact/Tech_Assist.cfm

 

[bob330]

Thanks Guys,

The Alleheny Ludlum site referenced above is all screwed up as they report CTE values for 2205 as being identical to those of 316SS /317 SS. Why does this stuff happen? Their site is very misleading. There is no excuse for this nonsense.

Bob

 

[bob330]

Also Guys,

The CTE data for 440A stainless steel is also completely wrong. I would recommend you all avoid the AL website for technical information.

Bob

 

[sreid]

Try Matweb.

http://www.matweb.com/index.asp?ckck=1

 

[bob330]

Thanks sreid,

I wonder how many metallurgical folks have been fed severe misinformation on that A-L website. When they said that that 440A had the same thermal expansion properties as austenitic SS, I knew something was wrong. Add that to them showing the 2205 to have the same CTE as austenitic SS. They were dead wrong on 2 out of 4 that I looked at and I figured I'll try no more.........they are fountains of misinformation!!!

bob

 

[stanislasdz]

i have made thermochemical computations of the alloys yoy xant.

I want this will help you

 

[EdStainless]

Before you jump all over people about published data...
I have done a lot of research on data, esp CTE and TC. The biggest problem is that no one ever tells you which test methods they used. I have some data from a major European national lab that reports different numbers than I have ever seen. They used a different method. For TC method is everything.
I have much more reliable CTE data than I do for TC.
The TC values for 304 and 2205 can't be too different near room temp. Both alloys are ~70% Fe with Cr as the major addition. In the larger picture they are very similar. The data that I use has them within 10% of each other.

= = = = = = = = = = = = = = = = = = = =
Rust never sleeps
Neither should your protection

http://www.trent-tube.com/contact/Tech_Assist.cfm

 

[bob330]

EdStainless,

The stuff on the Al website simply looks like typo stuff where they apparently took austenitic SS CTE data and gave out those same numbers for other materials like 2205 and 440A stainless which we all know do not expand nearly as much. I didn't check too many other materials but they may have these wrong numbers for dozens of them for all I know. I didn't even check their TC data but I would not trust in light of their way off base CTE data.

Have you tabulated all your CTE data? It would be cool to distribute to the group as a spreadsheet or something.

Thanks,
bob