- sales@hindustansteel.com
- 390/392, Ground Floor, Shankar Mansion, Vanita Vishram Chowk, S.V.P. Road, Mumbai - 400004
Phone
+91-9820944724
+91-9820944724
Home > Our Products > Stainless Steel Plates > Grade / Standard > SS 321 / SS 347 Heat Resistant Stainless Steel Plates
Hindustan Steel Corporation is a leading supplier and stockist of SS 321 and SS 347 heat-resistant stainless steel plates, offering both Titanium-stabilized (321/321H) and Niobium-stabilized (347/347H) grades for demanding high-temperature applications. Designed to withstand thermal cycling, oxidation, and intergranular corrosion, these grades are ideal for:
We supply 321/347 plates with mill test certifications, IBR approvals, ASME/ASTM compliance, and export-ready packaging for industrial clients worldwide.
SS 321 is an austenitic stainless steel stabilized with titanium (Ti) to prevent chromium carbide precipitation during high-temperature exposure (typically 427–816°C). This stabilization makes it suitable for welded pressure vessels, furnace components, and thermal fatigue-resistant structures.
SS 347, on the other hand, is stabilized using niobium (Nb) (also referred to as columbium), offering similar protection against intergranular corrosion. However, it provides better performance in strongly oxidizing environments and higher creep strength under pressure.
Key Designations:
| Grade | UNS | Werkstoff Nr. | Common Use |
|---|---|---|---|
| SS 321 | S32100 | 1.4541 | Heat exchangers, oil heaters |
| SS 321H | S32109 | 1.4878 | High temp / pressure applications |
| SS 347 | S34700 | 1.4550 | Refineries, chemical plants |
| SS 347H | S34709 | 1.4961 | Steam piping, furnace parts |
321 = Titanium stabilized, 347 = Niobium stabilized
Both resist sensitization during welding or prolonged heat exposure.
SS 321 and SS 347 plates are preferred where temperature resistance, oxidation control, and long-term structural integrity are critical. These grades are used across:
Heat-Intensive Sectors
Petrochemical & Refineries
Aerospace & Automotive:
For thermal fatigue, oxidation, and stress rupture resistance, SS 321 and SS 347 plates are proven performers
Both 321 and 347 stainless steel plates offer excellent strength and oxidation resistance up to 850–900°C, maintaining ductility and structure in elevated service environments.
| Property | SS 321 / 321H | SS 347 / 347H |
|---|---|---|
| Tensile Strength | 515 – 750 MPa | 515 – 750 MPa |
| Yield Strength (0.2% Offset) | ≥ 205 MPa | ≥ 205 MPa |
| Elongation (in 50mm) | ≥ 35% | ≥ 35% |
| Hardness (Brinell) | ≤ 217 HBW | ≤ 217 HBW |
| Max. Operating Temp (Air) | ~870°C (continuous) | ~900°C (continuous) |
| Stress Rupture Resistance | Moderate | Higher than 321 |
321H and 347H versions offer higher carbon content for improved creep strength at elevated pressures and long-term heat exposure.
| Element | SS 321 (%) | SS 347 (%) |
|---|---|---|
| Chromium (Cr) | 17.0 – 19.0 | 17.0 – 19.0 |
| Nickel (Ni) | 9.0 – 12.0 | 9.0 – 13.0 |
| Carbon (C) | ≤ 0.08 (0.04–0.10 in 321H) | ≤ 0.08 (0.04–0.10 in 347H) |
| Manganese | ≤ 2.00 | ≤ 2.00 |
| Silicon | ≤ 1.00 | ≤ 1.00 |
| Phosphorus | ≤ 0.045 | ≤ 0.045 |
| Sulfur | ≤ 0.030 | ≤ 0.030 |
| Titanium (Ti) | ≥ 5x C (%) | — |
| Niobium (Nb) | — | ≥ 10x C (%) |
| Iron (Fe) | Balance | Balance |
Titanium and niobium act as carbide stabilizers, preventing chromium depletion at grain boundaries during thermal exposure or welding.
SS 321 and SS 347 stainless steel plates are manufactured as per leading international standards, ensuring reliability in high-pressure and high-temperature operations.
Applicable Standards:
| Standard | Description |
|---|---|
| ASTM A240 | Standard for stainless steel plate/sheet |
| ASME SA240 | Pressure vessel-grade specification |
| ASTM A182 | Forged flange & fitting compatibility |
| EN 10088-2 | European standard for flat products |
| UNS Designations | S32100 / S32109 / S34700 / S34709 |
| Werkstoff Nr. | 1.4541 / 1.4878 / 1.4550 / 1.4961 |
We supply heat-resistant stainless steel plates in cut-to-size and standard dimensions with ready stock availability for industrial buyers.
Plate Dimensions
Finishes Offered:
We also supply blanks, CNC profiles, and circles based on design drawings.
SS 321 and SS 347 stainless steel plates are engineered for continuous service in the 800°C to 900°C range, with excellent oxidation resistance and structural retention.
Key Thermal Features:
Resistance To:
321 preferred for general thermal environments; 347 better for oxidizing acids and long-term creep strength.
Both grades can be fabricated using standard stainless steel tooling and techniques.
Welding:
Forming & Machining:
Note:
We are one of India’s few suppliers with dedicated inventory for heat-resistant stainless grades like SS 321/321H and SS 347/347H.
Key Differentiators:
Our plates are individually marked, dimensionally accurate, and traceable by heat/cast number, making compliance simple and reliable.
We supply the following variants based on operating condition, temperature, and fabrication need:
🔹 SS 321H
🔹 SS 347H
🔹 Dual Grades (321/321H, 347/347H)
We help buyers select the right variant based on ASME section codes, temperature cycles, and fabrication conditions.
Hindustan Steel Corporation exports SS 321, 321H, 347, and 347H heat-resistant plates to industrial clients across the globe, including:
UAE, Saudi Arabia, Oman, Vietnam, Bangladesh, South Africa, Malaysia, Egypt, Brazil, and Europe
Our plates are used in:
Export Packaging Includes:
All shipments include:
Choosing the right grade depends on heat exposure, environment, and welding conditions.
| Use Case | Choose SS 321 | Choose SS 347 |
|---|---|---|
| Thermal cycling < 870°C | ✅ | ✅ |
| Better intergranular corrosion | ✅ (Ti-stabilized) | ✅ (Nb-stabilized) |
| Oxidizing acids / aggressive media | ❌ | ✅ |
| Stronger creep resistance | Moderate | ✅ (347H) |
| Lower thermal fatigue (weldments) | ✅ | ✅ |
Still unsure? Request our engineering team to recommend the best fit with project data.
All heat-resistant plates are shipped with full quality documentation:
Mill Test Certificate (MTC) – EN 10204 3.1 / 3.2
Ultrasonic Testing (UT) – On request
IBR Approval / PED Compliance
PMI Reports, Hardness Charts, Heat Numbers
Third Party Inspection (SGS / Lloyds / BV / TUV)
We follow ISO 9001:2015 QMS, and provide complete batch-level traceability from mill to delivery.
SS 347 is niobium stabilized and offers better creep strength and performance in oxidizing acid environments.
Up to 870–900°C in continuous service. For pressure use, 321H and 347H are better suited.
Yes, both grades are weldable. Use 321L or 347L variants for lower carbon and better post-weld corrosion resistance.
They are non-magnetic in annealed condition, but may show slight magnetism after cold working
Yes. These are high-carbon versions for better creep resistance under sustained temperature and pressure.
We stock 3 mm to 60 mm, with custom cutting up to 6000 mm in length.
We primarily offer 2B, No.1, and satin finishes. Mirror polish available on special request.
Yes. Ti and Nb stabilization prevents chromium carbide formation, resisting weld decay.
Yes. We export to UAE, KSA, Oman, Qatar, Vietnam, Malaysia, and more.
Yes. SS 321 offers better thermal stability and less carbide precipitation under heat.
Mill Test Certificate (3.1), Packing List, Invoice, COA, and optional third-party reports.
Yes. Upon request, we provide sample pieces, MTC, and heat charts before bulk order.
Yes. Request the ASTM A240 SS 321 / 347 PDF via email or WhatsApp for quick download.
Request Price, Specification PDF & MOQ for SS 321 / 347 Plates
Looking for project-ready heat-resistant stainless plates?
Send your inquiry to receive:
Response guaranteed within 24 working hours
+91-22-66159018
+91-9820944724
sales@hindustansteel.com hindustansteel1@gmail.com
390/392, Ground Floor, Shankar Mansion, S.V.P. Road, Mumbai – 400004, India
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+91-22-66159018
+91-9820944724
sales@hindustansteel.com hindustansteel1@gmail.com