253MA

253MA is an austenitic chromiumnickel steel alloyed with nitrogen and rare earth metals.

The grade is characterized by:

· High creep strength

· Very good resistance to isothermal and, particularly, cyclic oxidation

· Good structural stability at high temperatures

· Good weldability

· Maximum operating temperature is approx. 1150°C (2100°F)

Standards

UNS: S30815

EN Number: 1.4835

Pipe standard: ASTM A213, ASTM A312, EN10297-2

Chemical Composition

Mechanical properties

Application

The high creep strength of 253 MA, coupled with its excellent oxidation resistance and its good resistance to carburization in constantly carburizing gas, makes it a very suitable material for end uses in which 18/8 steels lack the necessary resistance to oxidation and carburization.

253 MA is often preferred instead of stainless chromium steels which have insufficient creep

strength and structural stability. Furthermore, 253 MA can very well take the place of higher alloyed materials such as 25Cr/20Ni steels and Alloy 800H, or even Alloy 600 in certain cases.

253 MA has come to be used extensively in the metallurgical, petrochemical and power industries. Typical applications are:

· Tubes in waste heat recovery systems in the metallurgical industry, e.g. re cuperators

· 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