253MA S30815 | 1.4835 | Ce Stainless Steel | 1150°C Oxidation | Fushun Metal

253MA / S30815 / 1.4835 — Introduction

253MA (also designated F45), UNS S30815 and EN 1.4835, is a rare-earth-microalloyed austenitic heat-resistant stainless steel developed by Outokumpu (originally Avesta) that delivers the oxidation and carburization resistance of 25Cr/20Ni (310) grades at approximately half the nickel content. Its defining innovation is the combination of elevated silicon (1.4–2.0%) with a controlled cerium addition (0.03–0.08%) as misch metal—a reactive-element doping strategy borrowed from high-temperature nickel alloys but applied economically to an iron-based, 21% Cr, 11% Ni stainless steel matrix. The cerium atoms segregate to the metal-oxide interface during high-temperature exposure, mechanically anchoring the chromia-silica protective scale and eliminating the oxide spallation that limits the cyclic oxidation life of conventional 310 and 309 grades. Simultaneously, nitrogen (0.14–0.20%) provides solid-solution strengthening that elevates creep resistance well above that of standard 18/8 and 25/20 stainless steels, enabling structural and pressure-retaining service at temperatures up to 1150°C at a material cost substantially below that of nickel-based alternatives such as Alloy 800H or Alloy 600.

At Fushun Metal, 253MA is manufactured through a fully integrated melt route under one roof. While conventional austenitic stainless steels are typically air-melted via AOD refining, Fushun Metal applies VIM primary melting for 253MA to achieve the precise cerium recovery that is fundamental to the grade’s oxidation performance—cerium is a strong oxide former that would be substantially lost to slag in conventional refining. The VIM electrode then undergoes VAR for critical applications where micro-cleanliness and segregation control justify the additional processing cost. For the most demanding furnace-component and petrochemical heater applications, PESR is available as the final stage for maximum inclusion refinement and sulfide cleanliness.

Every heat is processed, solution-annealed, and tested within Fushun Metal’s certified quality management system—ISO 9001 for manufacturing process control and AS9120B for aerospace distribution traceability. Solution annealing is performed at 1020–1150°C followed by rapid air or water cooling. Full digital traceability links each production lot from melt heat number through hot-working reduction ratio to final annealing batch. Standard deliverables include room-temperature and elevated-temperature tensile testing, grain size verification per ASTM E112, and chemical re-verification by optical emission spectrometry. Mill test certificates to EN 10204 3.1 or 3.2 accompany every shipment.

Equivalent Grades of 253MA Across International Standards

253MA is codified under multiple national and international specification systems. The table below maps its designations and governing standards across major markets. Fushun Metal certifies to all listed specifications and can dual-certify heats where required.

Applications of 253MA

253MA fills the economic and performance gap between standard 18/8 and 25/20 stainless steels and nickel-based alloys such as Alloy 800H. It is specified wherever cyclic oxidation resistance at 900–1150°C and moderate creep strength must be delivered at a material cost competitive with fabricated stainless steel rather than nickel alloy budgets. Its low nickel content (10–12%) also provides a distinct advantage over 310 and higher-nickel grades in sulfur-containing atmospheres where nickel sulfide formation accelerates attack.

253MA — Supply Range by Fushun Metal

Fushun Metal stocks and processes 253MA across all major mill forms from a single integrated facility. Our in-house multi-stand 850/550/350/250 rolling mills and 1800-ton precision radial forger (GFM) enable a broad dimensional envelope without outsourcing—ensuring uninterrupted lot traceability from melt to delivery under ISO 9001 and AS9120B. All material is supplied in the solution-annealed condition per ASTM A240 / A213 / A276 (typically 1020–1150°C, rapid air or water cool). Cold-worked material should be re-annealed after 10–20% deformation to restore maximum creep strength in service. Welding is performed with matching 22.12HT filler (UNS S30815) or Type 309 as an alternative where lower creep strength is acceptable. Post-weld annealing is generally not required for high-temperature service. Mill test certificates to EN 10204 3.1 or 3.2 accompany every shipment.

Chemical Composition of 253MA — ASTM A240 / EN 10095

All heats produced by Fushun Metal are verified against the composition limits below by optical emission spectrometry and LECO combustion analysis. Full chemical certificates are issued with every shipment under ISO 9001 and AS9120B quality management. The four defining compositional features are: 21% chromium for chromia-scale oxidation protection to 1150°C; 1.4–2.0% silicon for silica sub-scale formation that acts as a diffusion barrier; 0.03–0.08% cerium as a reactive-element dopant that pegs the oxide scale to the metal surface, eliminating spallation during thermal cycling; and 0.14–0.20% nitrogen for solid-solution strengthening that provides the creep strength necessary for structural service at temperatures where conventional 18/8 and 25/20 stainless steels soften and collapse under load.

Mechanical Properties of 253MA — Room & Elevated Temperature

253MA is a solid-solution-strengthened austenitic stainless steel; all properties are developed through solution annealing at 1020–1150°C followed by rapid cooling. It is not hardenable by heat treatment. Room-temperature values below represent minimum guaranteed properties per ASTM A240 (plate/sheet) and A276 (bar). Elevated-temperature tensile and creep data are provided as typical values. The alloy’s nitrogen content (~0.17%) is responsible for its elevated creep strength relative to standard 310 (which contains no deliberate nitrogen addition), enabling 253MA to replace more expensive nickel alloys in many structural furnace and petrochemical heater applications operating between 700°C and 1000°C.

Fushun Metal performs all solution annealing in-house under calibrated furnace controls. Hot-working: 900–1150°C. The alloy has excellent weldability by all standard fusion methods (GTAW, GMAW, SMAW). Matching 22.12HT filler metal (UNS S30815 composition) is recommended for creep-strength-critical joints. Type 309 filler provides acceptable corrosion resistance where creep strength of the weld is not the design-limiting factor. Pure argon shielding gas is recommended. The alloy will become sensitized if held in the 425–860°C range, which does not affect high-temperature oxidation performance but will reduce aqueous corrosion resistance after service—a consideration for components that see intermittent wet/dry cycling.

Physical constants: Density 8.0 g/cm³; Melting range 1371–1432°C; Hardness ≤217 HB / ≤95 HRB (annealed); Modulus of elasticity ~200 GPa at 20°C; Thermal conductivity 12.5 W/m·K at 20°C; Coefficient of thermal expansion 16.3 μm/m·°C (20–1000°C). Maximum continuous service in air: 1150°C (oxidation limit). Recommended structural temperature range: 850–1100°C. The alloy is non-magnetic in the annealed condition.