Specialty Round Bars
253MA Round Bar – Heat-Resistant Stainless Steel
253MA (UNS S30815 / EN 1.4835) is an austenitic heat-resistant stainless steel developed for service where oxidation resistance and elevated-temperature strength are important. Its chromium, nickel, silicon, nitrogen and rare-earth additions help it resist cyclic oxidation and support performance in hot industrial equipment.
This page explains the alloy, product standards, composition, typical properties and applications. Supply conditions and suitability depend on the actual operating temperature, atmosphere and applicable specification. For enquiries, state the bar diameter, quantity, required condition and inspection documents.
At a glance
253MA Round Bar quick facts
- Product
- 253MA Round Bar
- Material category
- Austenitic heat-resistant stainless steel
- Product reference
- 253MA Round Bar
- Standards and designations referenced
- UNS S30815; ASTM A276
- Enquiry details
- Grade, dimensions and supply condition
Confirm the applicable specification and availability for your required size and condition.
Buyer selection guide
How to select 253MA Round Bar
Specify 253MA for applications where sustained heat, repeated heating and cooling, and process gases influence material selection. Match the grade to the temperature, atmosphere, loading and applicable product specification; the UNS designation alone does not define every supply condition.
Where this alloy is used
253MA Round Bar Applications in Hot-Service Equipment
253MA is commonly considered for components exposed to elevated temperatures, especially when both strength and oxidation resistance matter. Round bars may be machined into shafts, pins, supports, spacers and fasteners, subject to engineering approval and the required material condition.
- Heat-treatment furnaces: fixtures, hangers, supports and equipment fittings subject to repeated thermal cycles.
- Steel and metal processing: hot-service hardware for recuperators, furnace systems and associated equipment.
- Petrochemical plants: selected high-temperature fittings where the process atmosphere and loading are suitable.
- Power and combustion equipment: components exposed to hot gases and oxidation.
- Cement and glass plants: selected hardware for elevated-temperature process service.
For related material families, explore stainless steel round bars and Inconel and Incoloy round bars. Material substitution requires an engineering review of strength, atmosphere, exposure duration and design requirements.
Designations and procurement
253MA Round Bar Standards and Supply Specifications
253MA is the common alloy name for UNS S30815 / EN 1.4835. The applicable product standard depends on whether the order is for general-purpose bar, pressure-service bar or another product form.
| Designation or document | Use for a round-bar enquiry |
|---|---|
| 253MA / UNS S30815 | Alloy identification; specify the required standard and heat/lot documentation |
| EN 1.4835 | European material designation for the corresponding heat-resistant steel |
| ASTM A276 | Austenitic stainless steel bars and shapes, where the specified grade and edition apply |
| ASTM A479 / ASME SA-479 | Bars and shapes for boiler and other pressure-vessel applications, when specified |
| ASTM A182 F45 | Forged or rolled alloy and stainless steel pipe flanges, fittings and valves; not a replacement for the bar purchase standard |
Bar details to provide: diameter, length, quantity, surface finish, straightness, tolerance, material condition and inspection requirements. Options such as hot-finished, peeled or machined bar depend on supplier availability; no particular stock range is guaranteed by this page.
Related bar forms: round bars, bright bars and forged bars.
Nominal alloy chemistry
253MA Chemical Composition (UNS S30815)
The following figures are typical nominal composition values from published 253MA material data, not complete melt-acceptance limits. The required chemical limits must come from the specified standard and applicable edition.
| Element | Typical nominal content (% by mass) | Why it matters |
|---|---|---|
| Chromium (Cr) | 21 | Supports oxidation resistance |
| Nickel (Ni) | 11 | Stabilizes the austenitic structure |
| Silicon (Si) | 1.6 | Helps form a protective scale at elevated temperatures |
| Nitrogen (N) | 0.17 | Supports high-temperature strength |
| Carbon (C) | 0.08 | Part of the grade chemistry; influences structural stability |
| Cerium / rare-earth addition | 0.05 Ce (nominal) | Helps improve oxide-scale adherence under thermal cycling |
| Iron (Fe) | Balance | Base metal |
Phosphorus, sulfur, manganese and other trace elements also have specified controls. For exact chemistry acceptance, review the mill test certificate against the governing standard.
Performance and selection
Mechanical and High-Temperature Behaviour of 253MA
253MA is valued for its creep strength and resistance to oxidation, particularly when equipment experiences repeated heating and cooling. It is not the same as a room-temperature corrosion-resistant grade selected primarily for chloride exposure.
| Characteristic | Engineering significance |
|---|---|
| Metallurgical structure | Austenitic stainless steel; not a precipitation-hardening grade |
| Oxidation resistance | Good resistance to continuous and cyclic oxidation in suitable atmospheres |
| Creep resistance | Developed for useful strength under sustained load at elevated temperature |
| Typical published upper-use range | About 1150°C in suitable service, but not a universal design temperature |
| Room-temperature tensile/yield data | Depends on product form, diameter, condition and governing material standard |
| Thermal cycling | Rare-earth and silicon additions support oxide-scale adhesion |
Important: the approximately 1150°C figure is a published material capability under suitable conditions, not an approval for every loaded component or furnace atmosphere. Specify allowable stress, exposure duration, loading and design code for the actual service.
Why this grade behaves differently
Oxidation, Creep and Fabrication Considerations
Cyclic oxidation: repeated expansion and contraction can damage oxide scales on hot metal. The silicon and rare-earth additions in 253MA help maintain a more protective surface scale in suitable conditions.
Long-duration loading: creep is gradual deformation under sustained stress at elevated temperature. Design assessments should use temperature-dependent allowable properties rather than room-temperature tensile strength alone.
Fabrication: machining, forming and joining procedures should reflect the austenitic stainless steel structure. Surface quality, product condition, post-fabrication treatment and weld procedure must be agreed for the service.
Inspection: request chemical analysis, mechanical-test results, dimensional checks, heat traceability and any project-specific inspection evidence. See quality assurance and inspection information.
Grade identity and comparison
253MA Designations and Related Heat-Resistant Alloys
| Name / grade | Relationship to 253MA |
|---|---|
| 253MA | Commercial alloy designation for the heat-resistant austenitic grade |
| UNS S30815 | UNS designation for the same alloy family |
| EN 1.4835 | European designation commonly associated with 253MA |
| 310 / 310S stainless steel | Different high-chromium, high-nickel heat-resistant alloy; not an automatic equivalent |
| Incoloy 800H / 800HT | Different nickel-iron-chromium alloys used in some elevated-temperature applications; not interchangeable by name |
253MA, UNS S30815 and EN 1.4835 are identifying designations; final acceptance still depends on the governing product specification, edition and certified chemistry. See Inconel / Incoloy grades for a separate nickel-alloy category.
Material selection checklist
What to Confirm Before Ordering 253MA Bar
Confirm the required heat-service conditions: maximum and normal temperatures, thermal-cycle frequency, combustion-gas chemistry, mechanical loading and expected life. These details can change whether 253MA is suitable.
| Purchase requirement | Information to supply |
|---|---|
| Material | 253MA / UNS S30815 / EN 1.4835 with applicable standard |
| Product dimensions | Bar diameter, length, quantity, tolerances and surface finish |
| Heat and service condition | Operating temperature, atmosphere, loading and required material condition |
| Quality documentation | Material test certificate, heat number, inspection and marking requirements |
For a quotation, use the contact and enquiry form and attach a drawing or material specification where available.
Frequently asked questions
253MA Round Bar FAQs
What is 253MA round bar?
253MA round bar is an austenitic heat-resistant stainless steel bar identified by UNS S30815 and EN 1.4835. It is used where oxidation resistance and elevated-temperature strength matter.
Is 253MA the same as UNS S30815?
UNS S30815 is the UNS designation associated with 253MA. The purchase order should also specify the relevant product standard, edition and required bar condition.
Which ASTM standard applies to 253MA round bar?
ASTM A276 may be relevant to stainless steel bars, while ASTM A479 / ASME SA-479 may apply to pressure-service bars. Confirm the exact grade listing and edition required for the order.
What is the difference between 253MA and 310S?
Both can be used in elevated-temperature equipment, but they have different compositions and performance profiles. 253MA uses silicon, nitrogen and rare-earth additions; grade selection depends on temperature, atmosphere and design requirements.
Can 253MA be used at 1150°C?
Published manufacturer information describes use up to about 1150°C in suitable conditions. Actual service limits depend on load, exposure time, atmosphere, design code and fabrication; do not treat the number as a universal working limit.
What information is required when requesting 253MA round bars?
Provide UNS S30815 or EN 1.4835, the product standard, diameter, length, quantity, finish, material condition, inspection requirements and delivery destination.