GEK Wiki / Metal Alloys for High Temp Operation
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Metal Alloys for High Temp Operation

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Saved by jim mason
on November 1, 2013 at 9:29:48 pm
 

return to Practical Engineering

 

A good summary of various stainless steel alloys and their properties at high temp is here:  http://www.azom.com/Details.asp?ArticleID=1175 .  The main table of relevance from this article is reproduced below.  However, there are many caveats due to carbide precipitation in mid temp ranges, and other alloy modifications with "L", "H", or other variants.

 

General summary for gasifier thermal application in ascending order of preference and price, seems to be:  304 - 321 - 310 - 253MA (2111HTR)

 

Table 1. Maximum service temperatures in dry air, based on scaling resistance (ref: ASM Metals Handbook)

Grade

Intermittent (°C)

Continuous (°C)

304

870

925

309

980

1095

310

1035

1150

316

870

925

321

870

925

410

815

705

416

760

675

420

735

620

430

870

815

2111HTR

1150

1150

 

 

Article on 304, 304L, 304H

http://www.azom.com/article.aspx?ArticleID=965

 http://www.azom.com/article.aspx?ArticleID=2867

 

General explanation of L and H grades

http://www.azom.com/article.aspx?ArticleID=1258

 

Grade 304 displays good oxidation resistance in intermittent service to 870°C and in continuous service to 925°C. Continuous use of 304 in the 425-860°C range is not recommended if subsequent aqueous corrosion resistance is important. Grade 304L is more resistant to carbide precipitation and can be heated into the above temperature range.

Grade 304H has higher strength at elevated temperatures so is often used for structural and pressure-containing applications at temperatures above about 500°C and up to about 800°C. 304H will become sensitised in the temperature range of 425-860°C; this is not a problem for high temperature applications, but will result in reduced aqueous corrosion resistance.

 

 

 

Article on 321
 http://www.azom.com/article.aspx?ArticleID=967

 

Grades 321 and 347 are the basic austenitic 18/8 steel (Grade 304) stabilised by Titanium (321) or Niobium (347) additions. These grades are used because they are not sensitive to intergranular corrosion after heating within the carbide precipitation range of 425-850°C. Grade 321 is the grade of choice for applications in the temperature range of up to about 900°C, combining high strength, resistance to scaling and phase stability with resistance to subsequent aqueous corrosion.

Grade 321H is a modification of 321 with a higher carbon content, to provide improved high temperature strength.

 

 

Article on 310

http://www.azom.com/article.aspx?ArticleID=966

 

Good resistance to oxidation in intermittent service in air at temperatures up to 1040°C and 1150°C in continuous service. Good resistance to thermal fatigue and cyclic heating. Widely used where sulphur dioxide gas is encountered at elevated temperatures. Continuous use in 425-860°C range not recommended due to carbide precipitation, if subsequent aqueous corrosion resistance is needed, but often performs well in temperatures fluctuating above and below this range.

Grade 310 is generally used at temperatures starting from about 800 or 900°C - above the temperatures at which 304H and 321 are effective.

 

 

Article on 253MA (2111HTR) 
http://www.azom.com/article.aspx?ArticleID=959

253MA is a grade combining excellent service properties at high temperatures with ease of fabrication. It resists oxidation at temperatures up to 1150°C and can provide superior service to Grade 310 in carbon, nitrogen and sulphur containing atmospheres.

 

 

 

other alloys of interest

 

3CR12

A lower cost is required, and the reduced corrosion resistance and resulting discolouration are acceptable.

http://www.azom.com/article.aspx?ArticleID=968

430

A lower cost is required, and the reduced corrosion resistance and fabrication characteristics are acceptable.

 

 

 

 

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Another good summary of metal alloys and their performance under various thermal and industrial conditions is here:

http://www.vici.com/ref/mat_met.php

 

A detailed review of the properties of Inconel, here:

http://docs.twpinc.com/Inconel-alloy-600-Sept-2008.pdf

 

 

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