1.4835, often known by its Outokumpu brand name of 253MA, is a heat-resistant austenitic stainless steel. It is designed to have similar heat resistance to 310 but with higher creep strength due to strengthening with nitrogen.
Approximate Composition – 21% Cr, 1.7% Si, 11.0% Ni, 0.15% N plus Ce (cerium). (EN and ASTM standards vary in chemical composition).
This grade combines the following characteristics:
- Oxidation resistance better than grade 310 particularly in cyclic conditions at lower cost due to reduced nickel content
- Higher creep strength than 310 at typical operating temperatures (850-1150°C) allowing thinner sections
- Low susceptibility to brittle sigma phase formation
- Good weldability
The high temperature resistance of 253MA derives from its combination of chromium, silicon, nickel and cerium. In particular, the combination of cerium and silicon provides a tightly adherent oxide film. Nitrogen is used to balance the austenitic microstructure allowing a reduction in nickel content and therefore cost compared to the standard heat resistant grade 310. As an example of the higher creep strength, it is 2.5 times higher than 310 at 900°C.
Applications which illustrate these features include:
Heat exchangers, furnaces, glass making, fans, flame tubes, refractory anchors, heat treatment trays, incinerators, exhaust manifolds.