UNS S30815 Stainless Steel

UNS S30815/253MA/EN 1.4835 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.

UNS S30815 contains a fairly low nickel content, which gives it some advantage in reducing sulphide atmospheres when compared to high nickel alloys and Grade 310.

The inclusion of high chromium, silicon, nitrogen and cerium contents gives 253MA good oxide stability, high elevated temperature (creep) strength and excellent resistance to sigma phase precipitation. The austenitic structure gives this grade excellent toughness, even down to cryogenic temperatures.

Chemical Composition:

Chemical composition (nominal) %:

C Si Mn P S Cr Ni N Ce
0.08 1.6 ≤0.8 ≤0.040 ≤0.030 21 11 0.17 0.05

To cerium should be added the quantity of other rare earth metals, since the additive
takes the form of misch metal containing about 50% Ce.

Mechanical Properties:

at 20°C:

Yield Strength

 Tensile Strength Elongation

Hardness

Rp0.2

 Rp1.0 Rm A Vickers

MPa

 MPa MPa %
≥310 ≥350 650-850 ≥40

≈190

at high temperature:

Temperature

 Proof Strength Tensile Strength

℃

 Rp0.2 Rp1.0 Rm

MPa

 MPa MPa

100

 ≥225 ≥265 ≥550

200

 ≥189 ≥215

≥475
300 ≥170 ≥200

≥440
400 ≥160 ≥190

≥425
500 ≥150 ≥180

≥400
600 ≥140 ≥165

≥340

Heat treatment
Solution annealing 1020-1120ºC. Holding time at solution annealing temperature approx. 30 min., followed by rapid cooling in air or water.

Hardening
This grade cannot be hardened by heat treatment. But it can be hardened by cold working.

Fabrication
Hot and cold forming
Hot forming should be carried out in the temperature range 1150-900°C. Solution annealing is generally not required since the material will be exposed to high temperatures when in operation. Like common austenitic stainless steels, the material can easily be formed in cold conditions. Due to its relatively high nitrogen content, the mechanical strength of EN 1.4835 is higher and greater deformation forces are required. Machining The relatively high proof strength of EN 1.4835 and its tendency to cold hardening must be taken into account in connection with machining

Product Forms:
Pipe and Tube: ASTM A213, ASTM A312, EN 10216-5/EN 10217-7
Plate, sheet Coil and Strip: ASTM A240/240M
Fittings: ASTM A403 as per ASME B16.9
Round Bar, Square Bar: ASTM A276

Applications:
Tubes in waste heat recovery systems in the metallurgical industry, e.g. recuperators
Tubes in heat treatment furnaces, e.g. radiation tubes, thermocouple protection tubes, burner components, furnace rollers
Tubes for injection of pulverized coal in blast furnaces
Tubing for fluidized-bed combustion plants
Furnace tubes for mud incineration plants
Tubes for carbon black process gas coolers/air heaters
Tubes for the glass and cement industries
Styrene reactor tubes
EDC cracking tubes
Convection tubes in ethylene cracking
Air preheater tubes in sulphuric acid gas converters
Muffle tubes in continuous wire annealing furnaces