348 Stainless Steel Round Bar
Grade: 348/UNS S34800
Size:
Cold drawn: φ4mm-φ60mm
Hot Rolled: φ16mm-φ230mm
Forged: φ230mm-φ1200mm
Surface Finish: Black Annealed, Polished Bright, Centerless Grinding
Diameter Tolerance: H9, H11, h9, h11 etc
- Fast Shipping / Ready Stock
- ISO 9001 Direct Factory
- Custom Cutting & Processing
- 100% MTC & SGS Inspection Supported
348 stainless steel is a columbium (niobium)-stabilized austenitic chromium-nickel stainless steel grade with controlled tantalum and cobalt content, designated as UNS S34800. It is a modified version of 347 stainless steel, developed primarily for high-temperature applications requiring excellent corrosion resistance, oxidation resistance, and structural stability during prolonged exposure to elevated temperatures.
The alloy contains chromium and nickel as the major alloying elements, with niobium and tantalum additions to stabilize carbon and prevent chromium carbide precipitation at grain boundaries. This stabilization improves resistance to intergranular corrosion after welding and during long-term high-temperature service. Compared with conventional 304 stainless steel, 348 stainless steel provides better resistance to sensitization and improved performance in thermal cycling environments.
Chromium provides excellent oxidation resistance and general corrosion resistance by forming a protective chromium oxide passive layer. Nickel maintains the stable austenitic structure, improving toughness, ductility, and resistance to thermal shock. Niobium and tantalum combine with carbon to form stable carbides, maintaining corrosion resistance and mechanical stability after exposure to high temperatures.
348 stainless steel bars are typically supplied in solution annealed condition and offer good weldability, excellent creep resistance, and reliable mechanical properties at elevated temperatures. The material is commonly used in nuclear power systems, aerospace components, chemical processing equipment, heat exchangers, furnace parts, and high-temperature pressure applications.
Due to its excellent stability under thermal conditions and resistance to intergranular corrosion, 348 stainless steel is especially suitable for welded components exposed to repeated heating and cooling cycles where long service life and dependable performance are required.
ASTM / JIS / EN Standards
| Standard System | Standard / Grade | Description |
| ASTM | ASTM A276 / A276M – UNS S34800 | Stainless Steel Bars and Shapes |
| ASTM | ASTM A479 / A479M – UNS S34800 | Stainless Steel Bars for Pressure Equipment |
| UNS | S34800 | 348 Stainless Steel Grade |
| JIS | JIS G4303 SUS348 | Stainless Steel Bars |
| EN | EN 10088-3 1.4550 (Comparable Grade) | Stabilized Austenitic Stainless Steel |
| DIN | DIN 1.4550 (Equivalent Reference) | European Material Designation |
Stainless Steel Bar Execution Standards
| Item | Specification |
| Product Type | Round Bar, Square Bar, Hexagonal Bar |
| Manufacturing Process | Hot Rolled, Cold Drawn, Peeled, Ground, Polished |
| Heat Treatment | Solution Annealing |
| Heat Treatment Temperature | Approximately 980–1150°C followed by rapid cooling |
| Surface Condition | Black Surface, Bright Surface, Ground Surface, Polished Surface |
| Dimensional Tolerance | According to ASTM A276 / customer requirements |
| Inspection | Chemical Analysis, Mechanical Testing, Dimensional Inspection |
| Supply Condition | Solution Annealed, Cold Finished, Machined Condition |
Chemical Composition (%)
| Element | Composition Requirement |
| Carbon (C) | ≤ 0.08 |
| Silicon (Si) | ≤ 1.00 |
| Manganese (Mn) | ≤ 2.00 |
| Phosphorus (P) | ≤ 0.045 |
| Sulfur (S) | ≤ 0.030 |
| Chromium (Cr) | 17.00 – 19.00 |
| Nickel (Ni) | 9.00 – 13.00 |
| Columbium + Tantalum (Nb+Ta) | ≥ 10 × C (Max 1.00) |
| Cobalt (Co) | ≤ 0.20 |
| Nitrogen (N) | ≤ 0.10 |
| Iron (Fe) | Balance |
Mechanical Properties (Annealed Condition)
| Property | Requirement |
| Tensile Strength | ≥ 515 MPa |
| Yield Strength (0.2% Offset) | ≥ 205 MPa |
| Elongation | ≥ 40% |
| Hardness | ≤ 201 HB (Typical) |
| Condition | Solution Annealed |
| Industry | Applications |
| Nuclear Industry | Nuclear reactor components, nuclear piping systems, structural parts |
| Aerospace Industry | Aircraft engine components, exhaust systems, heat-resistant parts |
| Power Generation | High-temperature steam piping, boiler components |
| Chemical Industry | Welded processing equipment, chemical reactors |
| Heat Treatment Industry | Furnace components, heat shields, supports |
| Petroleum Industry | Refinery equipment and high-temperature processing systems |
| Mechanical Engineering | High-temperature precision components |
348 stainless steel is a columbium (niobium)-stabilized austenitic chromium-nickel stainless steel grade with controlled tantalum and cobalt content, designated as UNS S34800. It is a modified version of 347 stainless steel, developed primarily for high-temperature applications requiring excellent corrosion resistance, oxidation resistance, and structural stability during prolonged exposure to elevated temperatures.
The alloy contains chromium and nickel as the major alloying elements, with niobium and tantalum additions to stabilize carbon and prevent chromium carbide precipitation at grain boundaries. This stabilization improves resistance to intergranular corrosion after welding and during long-term high-temperature service. Compared with conventional 304 stainless steel, 348 stainless steel provides better resistance to sensitization and improved performance in thermal cycling environments.
Chromium provides excellent oxidation resistance and general corrosion resistance by forming a protective chromium oxide passive layer. Nickel maintains the stable austenitic structure, improving toughness, ductility, and resistance to thermal shock. Niobium and tantalum combine with carbon to form stable carbides, maintaining corrosion resistance and mechanical stability after exposure to high temperatures.
348 stainless steel bars are typically supplied in solution annealed condition and offer good weldability, excellent creep resistance, and reliable mechanical properties at elevated temperatures. The material is commonly used in nuclear power systems, aerospace components, chemical processing equipment, heat exchangers, furnace parts, and high-temperature pressure applications.
Due to its excellent stability under thermal conditions and resistance to intergranular corrosion, 348 stainless steel is especially suitable for welded components exposed to repeated heating and cooling cycles where long service life and dependable performance are required.
ASTM / JIS / EN Standards
| Standard System | Standard / Grade | Description |
| ASTM | ASTM A276 / A276M – UNS S34800 | Stainless Steel Bars and Shapes |
| ASTM | ASTM A479 / A479M – UNS S34800 | Stainless Steel Bars for Pressure Equipment |
| UNS | S34800 | 348 Stainless Steel Grade |
| JIS | JIS G4303 SUS348 | Stainless Steel Bars |
| EN | EN 10088-3 1.4550 (Comparable Grade) | Stabilized Austenitic Stainless Steel |
| DIN | DIN 1.4550 (Equivalent Reference) | European Material Designation |
Stainless Steel Bar Execution Standards
| Item | Specification |
| Product Type | Round Bar, Square Bar, Hexagonal Bar |
| Manufacturing Process | Hot Rolled, Cold Drawn, Peeled, Ground, Polished |
| Heat Treatment | Solution Annealing |
| Heat Treatment Temperature | Approximately 980–1150°C followed by rapid cooling |
| Surface Condition | Black Surface, Bright Surface, Ground Surface, Polished Surface |
| Dimensional Tolerance | According to ASTM A276 / customer requirements |
| Inspection | Chemical Analysis, Mechanical Testing, Dimensional Inspection |
| Supply Condition | Solution Annealed, Cold Finished, Machined Condition |
Chemical Composition (%)
| Element | Composition Requirement |
| Carbon (C) | ≤ 0.08 |
| Silicon (Si) | ≤ 1.00 |
| Manganese (Mn) | ≤ 2.00 |
| Phosphorus (P) | ≤ 0.045 |
| Sulfur (S) | ≤ 0.030 |
| Chromium (Cr) | 17.00 – 19.00 |
| Nickel (Ni) | 9.00 – 13.00 |
| Columbium + Tantalum (Nb+Ta) | ≥ 10 × C (Max 1.00) |
| Cobalt (Co) | ≤ 0.20 |
| Nitrogen (N) | ≤ 0.10 |
| Iron (Fe) | Balance |
Mechanical Properties (Annealed Condition)
| Property | Requirement |
| Tensile Strength | ≥ 515 MPa |
| Yield Strength (0.2% Offset) | ≥ 205 MPa |
| Elongation | ≥ 40% |
| Hardness | ≤ 201 HB (Typical) |
| Condition | Solution Annealed |
| Industry | Applications |
| Nuclear Industry | Nuclear reactor components, nuclear piping systems, structural parts |
| Aerospace Industry | Aircraft engine components, exhaust systems, heat-resistant parts |
| Power Generation | High-temperature steam piping, boiler components |
| Chemical Industry | Welded processing equipment, chemical reactors |
| Heat Treatment Industry | Furnace components, heat shields, supports |
| Petroleum Industry | Refinery equipment and high-temperature processing systems |
| Mechanical Engineering | High-temperature precision components |
