Depending on the operating conditions, the requirements of high temperature stainless steel may be as follows:

· High creep strength (and ductility)
· Stability of internal microstructure
· High oxidation resistance and HT corrosion
· Good resistance to erosion-corrosion

All materials selection must be determined by the application and operating conditions in each individual case. Stainless steel offer a number of special high temperature stainless steel.

Besides the common Austenitic High Temperature Alloys above (i.e., 1.4948, 1.4878,1.4828, 1.4833, and 1.4845), there are three proprietary Stainless steel alloys:  153 MA, 253 MA, and 353 MA.

These three alloys are based on the same concept:  
Improved oxidation resistance by an increased silicon content and addition of very small quantities of rare earth metals (micro-alloying  => MA). Enhanced creep strength due to increased contents of nitrogen (and carbon for 253 MA).

In many cases, the properties of these steels have proved to be equivalent or even superior to those of grades with higher contents of alloying elements. 153 MA is normally intended for use at somewhat lower service temperature than the other two grades.

Austenitic High Temperture Grades

Ferritic High Temparature Grades