253MA/S30815/1.4835/X9CrNiSiNCe21-11-2
253 MA is a lean austenitic heat resistant alloy with high strength and outstanding oxidation resistance. 253 MA maintains its heat resistant properties by advanced control of micro alloy additions. The use of rare earth metals in combination with silicon gives superior oxidation resistance up to 2000°F. Nitrogen, carbon and a dispersion of rare earth and alkali metal oxides combine to provide creep rupture strength comparable to the nickel base alloys. A wide variety of components requiring high strength at elevated temperatures such as heat exchangers, kilns, stack dampers and oven components are common applications for 253 MA.

Chemical Composition, %

Cr

Ni

C

Si

Mn

20.0-22.0

10.0-12.0

0.05-0.10

1.40-2.00

0.80 Max

P

S

N

Ce

Fe

0.040 Max

0.030 Max

0.14-0.20

0.03-0.08

Balance

Some characteristics of 253 MA

Excellent oxidation resistance to 2000°F

High creep-rupture strength

Application

Furnace components including burners, retorts, conveyor belts, fans, jigs and baskets, rollers, walking beams, radiant tubes, electric heater elements, refractory anchors, hoods, flues, grates, expansion bellows.
Petrochemical and refinery tube hangers.

Mechanical Properties Annealed Material

Specified Limits Minimum

Typical Range

Ultimate Tensile Strength, psi

87,000

90,000-114,000

.2% Offset Yield Strength, psi

45,000

45,000-69,000

Elongation in 2", %

40

42-70

Reduction of Area, %

50

-

Hardness Rockwell B

-

Rb 90

Fabrication and Welding with Stainless 253 MA

253 MA Stainless steel is readily fabricated by standard commercial procedures. In comparison to carbon steel, stainless steels are tougher and tend to work harden rapidly. However, with positive feeds and slow speeds combined with abundant cutting fluid this alloys tendency to work harden may be minimized.

Solution Treatment (Annealing) - Heat to 1050-1150°C and cool rapidly. It is recommended that the material be solution treated after 10-20% cold work to achieve maximum creep strength in service.

This grade cannot be hardened by thermal treatment.

ASTM Specifications

Plate

Bar

Pipe Smls

Pipe Welded

A240, A480, A167

A276, A479

A213, A312

A312, A358, A409, A813, A814

Heat Resistance

Oxidation - excellent resistance to air, at temperatures up to 1150°C. At high temperatures the steel quickly forms a thin, highly adherent and elastic oxide. This oxide gives good protection even under cyclic conditions.

Carburization - Under oxidizing conditions this grade can perform well, but alloys with higher nickel content are preferred if the atmosphere is reducing.

Sulphuration - good resistance to Sulphur-bearing gases in an oxidizing atmosphere, even if only traces of oxygen are present. Reducing gases prevent the protective oxide forming.

253MA has high strength at elevated temperatures so is often used for structural and pressure-containing applications at temperatures above about 500°C and up to about 900°C. Its strength at these temperatures is higher than that of alternatives such as Grade 310.

253MA will become sensitized 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.