Maximum service temperatures in air for stainless steels

Introduction

The maximum oxidation service temperatures for heat resisting steels is shown 'for guidance only' in table B.2 of EN 10095.
Although helpful, this only covers the steels specifically designed for heat resisting applications.

An alternative guide is shown in the ASM Specialty Handbook 'Stainless Steels', where a wider range of stainless steel grades is covered.

A comparison of these maximum service temperatures under intermittent or cyclic oxidation conditions (where protective oxide films produced may be likely to crack, hence reducing the useful service life) is summarized in this article, but it must be stressed that, these figures can only be used for guidance.

Selection of stainless steels for oxidation resistant service should also consider the the design strength requirements at the intended service temperature.

Austenitic stainless steel types

There are some apparent contradictions in the data, where EN 10095 suggests that the 321 type (1.4541 / 1.4878) is 'inferior' to the 316 and 304 types, as shown in the ASM data.

Based on the chromium content of these three types, the maximum service temperatures would be expected to be the same.
(The titanium stabilised 321 type would in fact normally be preferred, as its elevated temperature strength should be marginally better.)

Ferritic, duplex and martensitic stainless steel types

The ferritic types may be limited, in practice, to lower temperatures as they have lower strengths at elevated temperatures than the austenitic types. The ferritic types can also suffer from embrittlement with extended exposure to temperatures above about 450C.

Duplex stainless steels can also be prone to embrittlement and so although their chromium levels would suggest they may be useful steels for elevated temperature service. This steel family is limited in the European pressure vessel standard EN 10028-7 to a maximum temperature of 250C.

The martensitic types are not considered here.
These steels are usually selected for their hardness and strength, which will be reduced when their tempering heat treatment temperature is exceeded, thus limiting their usefulness for elevated temperature service.

Summary of maximum service temperatures

Grade Main Alloying Elements (%) Max. Service Temp. C Source
AISI EN Cr Others . .
Ferritic types . . . .
405 1.4002 12 0.2 Al 815 ASM
. 1.4724 12 1.0 Al 850 EN 10095
430 1.4016 17 . 870 ASM
. 1.4742 17 1.0 Al 1000 EN 10095
. . . . . .
446 1.4749 26 0.15-0.20 C, 0.2 N 1100 EN 10095
Austenitic types . . . .
304 1.4301 18 8 Ni 870 ASM
321 1.4541 18 9 Ni 870 ASM
. 1.4878 18 9 Ni 850 EN 10095
316 1.4401 17 11 Ni, 2 Mo 870 ASM
309 1.4833 22 12 Ni 1000 EN 10095
310 1.4845 25 20 Ni 1050 EN 10095
. 1.4835 20 10 Ni, 1.5 Si, 0.15 N, 0.04 Ce 1150 EN 10095
330 1.4886 18 34 Ni, 1.0 Si 1100 EN 10095

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