Corrosion Resistance

Although not designed for aqueous corrosion resistance, the high chromium and nitrogen contents give the grade a pitting resistance approximating that of 316. 253MA does however have a high carbon content so is highly susceptible to sensitisation; this is likely to reduce aqueous corrosion resistance after high temperature service or fabrication.

Consult Atlas Technical Assistance for specific environmental recommendations.

 

Heat Resistance

Oxidation - excellent resistance to air, at temperatures up to 1100°C. At high temperatures the steel quickly forms a thin, highly adherent and elastic oxide. This oxide gives good protection even under cyclic conditions, much better than is the case for Grade 310. Best resistance is under noncycling conditions.

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

Sulphidation - good resistance to sulphurbearing gases in an oxidising 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. 253MA 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.

 

Heat Treatment

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.

 

Welding

Excellent weldability by all standard fusion methods. AS 1554.6 pre-qualifies welding of S30815 with matching Grade 22.12HT rods or electrodes. Grade 309 fillers can be used if lower creep strength can be tolerated. Pure argon shielding gas should be used.

 

Machining

As for other austenitic stainless steels, the machining requires sharp tools, slow speeds and heavy feeds.

 

Typical Applications

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

 

Specified Properties

These properties are specified for flat rolled product (plate, sheet and coil) as Grade S30815 in ASTM A240/A240M. Similar but not necessarily identical properties are specified for S30815 in other products such as pipe and bar in their respective specifications, and for Grade 1.4835 in specifications such as EN 10095.

 

Grade Specification Comparison

S30815 S30815 1.4835 X9CrNiSiNCe21-11-2 2368 - These comparisons are approximate only. The list is intended as a comparison of functionally similar materials not as a schedule of contractual equivalents. If exact equivalents are needed original specifications must be consulted.

 

Possible Alternative Grades

310 Carburising atmospheres require a higher nickel content 304H Lower cost alternative, with lower creep strength, for use up to about 800°C 321H Lower cost alternative, with lower creep strength, for use up to about 800°C Nickel Alloys Carburising atmospheres or temperatures above the 1100 - 1150°C maximum of S30815.

 

Limitation of Liability

The information contained in this datasheet is not an exhaustive statement of all relevant information. It is a general guide for customers to the products and services available from Atlas Specialty Metals and no representation is made or warranty given in relation to this document or the products or processes it describes.