304 Stainless Steel Round Bar
AISI 304 (UNS S30400) is the most widely used austenitic stainless steel round bar with 18% Cr and 8% Ni, offering excellent corrosion resistance and machinability. Diameter 3-500mm, available in hot rolled, cold drawn, peeled, and centerless ground conditions. Mill test certificate provided.
| Material | Austenitic Stainless Steel |
|---|---|
| Grade / Standard | AISI 304 / UNS S30400 |
| Diameter | 3mm - 500mm |
| Length | 3m / 4m / 5m / 6m (or cut to length) |
| Delivery Condition | hot_rolled / cold_rolled |
| Surface Treatment | bare / coated |
| MOQ | 1 Ton |
| Delivery Time | 10-25 Days / In Stock |
| Loading Port | Tianjin / Shanghai / Qingdao |
Overview of 304 Stainless Steel Round Bar
AISI 304 is the most widely used austenitic stainless steel grade for round bar applications worldwide, accounting for over 50% of global stainless steel bar production. Specified under ASTM A276 / ASTM A479 / EN 10088-3 standards with UNS designation S30400, 304 stainless steel round bar offers an excellent combination of corrosion resistance, machinability, formability, and weldability at a moderate cost. Containing nominally 18% chromium and 8% nickel, the grade provides the characteristic non-magnetic austenitic microstructure ideal for fasteners, machined components, and general engineering applications requiring stainless properties.
304 stainless steel round bar is the preferred raw material for CNC machining, automatic lathe production, fastener manufacturing, valve component production, pump shaft fabrication, and a wide range of precision machined components. The grade resists corrosion in atmospheric environments, fresh water, food and beverage processing chemicals, organic acids at moderate temperatures, and many industrial chemicals. With excellent cold formability and reliable hot working characteristics, 304 round bar is the international benchmark for general-purpose stainless steel bar applications across food processing, pharmaceutical, chemical, marine (non-chloride), and construction industries.
Key Features and Manufacturing Methods
304 stainless steel round bar is manufactured through multiple processes to suit different application requirements. Hot rolled (HR) bars are produced through hot rolling at 1100-1200°C from billet feedstock, providing economical solution for diameters from 16mm to 500mm with mill scale surface, suitable for general fabrication and applications where surface finish is not critical. Cold drawn (CD) bars are produced by drawing hot rolled rod through precision dies at room temperature, achieving tighter dimensional tolerance (h9/h11), better surface finish (Ra 0.8-1.6μm), and enhanced mechanical properties through cold work strengthening, ideal for diameters from 3mm to 100mm.
Peeled and turned bars are manufactured by removing the outer surface layer through precision turning, providing bright defect-free surfaces with diameters from 20mm to 300mm for high-quality machining applications. Centerless ground bars achieve precision tolerance (h6/h7) with surface finish Ra 0.4-0.8μm for hydraulic shafts and precision components. The bar is supplied in standard lengths of 3 meters, 4 meters, 5 meters, and 6 meters, with custom cut-to-length service available. Each bar undergoes mandatory chemical composition analysis (PMI verification available), mechanical property testing, intergranular corrosion testing per ASTM A262, surface quality inspection, and dimensional inspection per ASTM A484 to ensure full compliance with international standards.
Main Applications of 304 Stainless Steel Round Bar
304 stainless steel round bar is the primary material for CNC machining and automatic lathe production of precision components including hydraulic fittings, pneumatic components, sensor housings, instrument bodies, valve stems, valve trim, pump shafts, motor shafts, and industrial fasteners. The food and beverage processing industry uses 304 round bar for processing equipment shafts, mixer blades, conveyor rollers, agitator paddles, valve components, and food-contact machined parts where excellent corrosion resistance, easy cleaning, and FDA compliance are essential.
The pharmaceutical and biotechnology industries employ 304 round bar for sterile equipment fittings, bioreactor agitator shafts, valve components, and laboratory instrument parts requiring electropolished surfaces and validated material traceability. Architectural and construction applications include decorative balusters, handrail balls and finials, bolts and fasteners for stainless steel structures, signage mounting hardware, exterior building hardware, and custom architectural fittings. Other major applications include marine hardware (in non-chloride environments), automotive exhaust system mounts, household appliance internal components, dental and medical device parts, jewelry findings, kitchen equipment shafts, brewery and winery equipment fittings, water treatment equipment, swimming pool fittings, and a comprehensive range of precision machined components requiring corrosion-resistant stainless steel construction.
Why Choose Us for 304 Stainless Steel Round Bar
Shandong Tanglu Metal Material Co., Ltd. supplies premium 304 stainless steel round bar sourced from major Chinese stainless steel mills including Tisco (Taiyuan Iron & Steel), Baosteel Stainless, and Lisco with proven international export experience and certified production facilities meeting ISO 9001, ISO 14001, ASME, and PED requirements. Every 304 round bar undergoes mandatory chemical composition analysis (PMI verification available), mechanical property testing including tensile, yield, elongation, and hardness verification, intergranular corrosion testing per ASTM A262 Practice A or E, surface quality inspection, and dimensional inspection per ASTM A484 latest revision.
We offer comprehensive specification range covering diameter from 3mm to 500mm in multiple manufacturing processes (hot rolled, cold drawn, peeled, centerless ground) with surface finishes ranging from black mill finish to bright polished, in standard lengths of 3-6 meters with custom cut-to-length service. With monthly supply capacity of 5,000 tons of stainless steel bars and established export relationships with CNC machining centers, fastener manufacturers, valve and pump producers, and OEM clients in over 50 countries, we support both small trial orders and large bulk container shipments. Each shipment includes original mill test certificate (MTC) conforming to EN 10204 3.1 standard, with EN 10204 3.2, PMI report, and third-party inspection (SGS, BV, ABS, DNV, LR) available for critical applications requiring enhanced documentation.
📐 Dimension & Size Table
| Diameter (mm) | Length (m) | Weight (kg/m) | Tolerance |
|---|---|---|---|
| 3 | 3 / 4 | 0.056 | h11 (± 0.06mm) |
| 5 | 3 / 4 | 0.156 | h11 (± 0.075mm) |
| 6 | 3 / 4 | 0.224 | h11 (± 0.075mm) |
| 8 | 3 / 6 | 0.399 | h11 (± 0.09mm) |
| 10 | 3 / 6 | 0.623 | h11 (± 0.09mm) |
| 12 | 3 / 6 | 0.897 | h11 (± 0.11mm) |
| 16 | 3 / 6 | 1.594 | h11 (± 0.11mm) |
| 20 | 3 / 6 | 2.491 | h11 (± 0.13mm) |
| 25 | 3 / 6 | 3.892 | h11 (± 0.13mm) |
| 30 | 3 / 6 | 5.605 | h11 (± 0.16mm) |
| 40 | 3 / 6 | 9.964 | h11 (± 0.16mm) |
| 50 | 3 / 6 | 15.570 | h11 (± 0.19mm) |
| 60 | 3 / 6 | 22.420 | h11 (± 0.19mm) |
| 80 | 3 / 6 | 39.860 | h11 (± 0.22mm) |
| 100 | 3 / 6 | 62.280 | h11 (± 0.22mm) |
| 150 | 3 / 6 | 140.130 | ± 1.5mm (HR) |
| 200 | 3 / 6 | 249.120 | ± 2.0mm (HR) |
| 250 | 3 / 6 | 389.250 | ± 2.5mm (HR) |
| 300 | 3 / 6 | 560.520 | ± 3.0mm (HR) |
| 400 | 3 / 6 | 996.480 | ± 4.0mm (HR) |
| 500 | 3 / 6 | 1556.870 | ± 5.0mm (HR) |
* Custom sizes available upon request. Tolerances per relevant international standards.
🔬 Chemical Composition
| Element | Min | Max | Display Value | Note |
|---|---|---|---|---|
| C | - | 0.08 | ≤0.08 | Per ASTM A276 304 |
| Si | - | 0.75 | ≤0.75 | |
| Mn | - | 2.00 | ≤2.00 | |
| P | - | 0.045 | ≤0.045 | |
| S | - | 0.030 | ≤0.030 | |
| Cr | 18.00 | 20.00 | 18.00-20.00 | Corrosion resistance element |
| Ni | 8.00 | 10.50 | 8.00-10.50 | Austenite stabilizer |
| N | - | 0.10 | ≤0.10 | Optional |
| Fe | - | - | Balance | Base element |
* Chemical composition may vary by heat, thickness and specification. Please refer to the actual mill test certificate.
⚙️ Mechanical Properties
| Property | Value | Unit | Test Condition |
|---|---|---|---|
| Tensile Strength (Hot Rolled) | ≥515 | MPa | Solution annealed, per ASTM A276 |
| Yield Strength (Hot Rolled) | ≥205 | MPa | 0.2% proof stress |
| Tensile Strength (Cold Drawn) | ≥620 | MPa | Cold drawn condition |
| Yield Strength (Cold Drawn) | ≥310 | MPa | Cold drawn condition |
| Elongation (Hot Rolled) | ≥40 | % | Gauge length 50mm |
| Elongation (Cold Drawn) | ≥30 | % | Gauge length 50mm |
| Brinell Hardness (HBW) | ≤201 | HBW | Solution annealed |
| Rockwell Hardness (HRB) | ≤92 | HRB | Solution annealed |
| Vickers Hardness (HV) | ≤210 | HV | Solution annealed |
| Density | 7.93 | g/cm³ | Reference value |
| Magnetic Permeability | ≤1.02 | μ | Non-magnetic austenitic structure |
* Values shown are minimum requirements unless otherwise stated.
📦 Commercial Information
| Packaging | Standard seaworthy export packing for stainless steel round bars. Bars bundled in hexagonal bundles with steel strapping (3-5 wraps per bundle), typical bundle weight 2-5 tons depending on diameter. Each bundle clearly tagged with heat number, grade designation (304 / S30400), diameter, length, and surface finish. For bright cold drawn or polished bars, additional PE film wrapping is applied to protect surface finish, then bundled with plastic-coated steel strapping. Plastic end caps for bars over 50mm diameter to prevent end damage. Custom packaging including individual cardboard tubes and wooden crates available for premium polished bars, precision ground bars, and air shipment. |
|---|---|
| Payment Terms | T/T (Telegraphic Transfer),L/C (Letter of Credit),D/P (Documents against Payment),Western Union,PayPal |
| Price Term | FOB,CFR,CIF,EXW |
| Supply Capacity | 5,000 Tons/Month (Stainless Steel Bars) |
| Loading Port | Tianjin / Shanghai / Qingdao |
Why Choose Our 304 Stainless Steel Round Bar?
Mill Certified Premium Quality
304 stainless steel round bar supplied with original mill test certificate EN 10204 3.1/3.2, including chemical analysis (PMI verification available), mechanical properties from both hot rolled and cold drawn samples, intergranular corrosion test per ASTM A262, surface quality inspection, and complete heat number traceability per ASTM A276 standard.
Comprehensive Diameter Range
Diameter range from 3mm precision bars to 500mm heavy industrial bars, available in standard lengths of 3m, 4m, 5m, and 6m. Custom cut-to-length service supported for specific project requirements with precision dimensional tolerance per ASTM A484 (h11 for cold drawn, ASTM tolerance for hot rolled).
Multiple Manufacturing Methods
Available in four manufacturing methods: hot rolled (3-500mm, economical for general use), cold drawn (3-100mm, h11 tolerance and bright surface), peeled and turned (20-300mm, defect-free bright surface), and centerless ground (3-200mm, h6/h7 precision for hydraulic and machined components).
FDA & Multi-Industry Compliance
FDA compliant for food contact applications, with ISO 9001, CE / PED, ABS, DNV GL, Lloyd's Register, BV, SGS, NK, and RINA certifications. Suitable for food processing, pharmaceutical, chemical processing, marine (non-chloride), and architectural projects requiring code-compliant stainless steel bars.
Fast Stock Delivery Worldwide
Common diameters maintained in large stock for 7-15 days dispatch. Custom diameters and lengths production cycle 25-35 days. Container loading optimized for 25-27 tons per 20FT FCL or 27 tons per 40FT FCL with proper bundling and end protection. Established export logistics to over 50 countries.
🏭 Applications of 304 Stainless Steel Round Bar
304 stainless steel round bar is the primary material for CNC machining and automatic lathe production of precision components including hydraulic fittings, pneumatic components, sensor housings, instrument bodies, valve stems, valve trim, pump shafts, motor shafts, mixer shafts, agitator paddles, and industrial fasteners (bolts, nuts, studs, threaded rods). The food and beverage processing industry uses 304 round bar for processing equipment shafts, mixer blades, conveyor rollers, agitator paddles, valve components, food-contact machined parts, brewery equipment shafts, dairy equipment fittings, and beverage filling line components where excellent corrosion resistance, easy cleaning, and FDA compliance are essential. The pharmaceutical and biotechnology industries employ 304 round bar for sterile equipment fittings, bioreactor agitator shafts, valve components, laboratory instrument parts, vaccine production equipment, and clean room hardware requiring electropolished surfaces and validated material traceability. Architectural and construction applications include decorative balusters, handrail balls and finials, bolts and fasteners for stainless steel structures, signage mounting hardware, exterior building hardware, glass clamping fittings, and custom architectural fittings for hotels, airports, hospitals, and high-end commercial buildings. Other major applications include marine hardware (in non-chloride environments), automotive exhaust system mounts, household appliance internal components, dental and medical device parts (surgical instruments, implant components), jewelry findings, kitchen equipment shafts, brewery and winery equipment fittings, water treatment equipment shafts, swimming pool fittings, agricultural equipment components, and a comprehensive range of precision machined components requiring corrosion-resistant stainless steel construction.
📋 Quality & Certification
Our Certifications
- ✅ ISO 9001:2015
- ✅ CE Marking
- ✅ ABS
- ✅ DNV GL
- ✅ Lloyd's Register (LR)
- ✅ Bureau Veritas (BV)
- ✅ SGS Certified
- ✅ NK
- ✅ RINA
Mill Certificate Type
- 📋 EN 10204 3.1
- 📋 EN 10204 3.2
- 📋 Original Mill Certificate
- 📋 Third Party Inspection Available
- 📋 Certificate of Origin
❓ Frequently Asked Questions
What is 304 stainless steel round bar?
304 is the most widely used austenitic stainless steel grade for round bar applications, specified under ASTM A276 / ASTM A479 / EN 10088-3 standards with UNS designation S30400. The bar contains nominally 18% chromium and 8% nickel, providing the characteristic non-magnetic austenitic microstructure with excellent corrosion resistance, formability, machinability, and weldability at moderate cost. 304 stainless steel round bar is available in multiple manufacturing methods (hot rolled, cold drawn, peeled, centerless ground) and serves as the primary raw material for CNC machining, fastener manufacturing, valve component production, pump shaft fabrication, and a wide range of precision machined components across food, pharmaceutical, chemical, and architectural industries.
What is the difference between hot rolled and cold drawn 304 round bar?
Hot rolled (HR) 304 round bar is produced at elevated temperatures (1100-1200°C) from billets, available in diameter from 16mm to 500mm with rougher surface (mill scale or pickled), wider dimensional tolerance (typically ±0.5-3mm depending on diameter), and more economical pricing. It offers tensile strength ≥515 MPa and yield ≥205 MPa, suitable for general fabrication, structural applications, and parts that will undergo significant machining or forging operations. Cold drawn (CD) 304 round bar is produced by drawing hot rolled rod through precision dies at room temperature, available in diameter from 3mm to 100mm with bright smooth surface (Ra 0.8-1.6μm), tighter dimensional tolerance (h9/h11 per ASTM A484), and enhanced mechanical properties through cold work strengthening (tensile ≥620 MPa, yield ≥310 MPa). Cold drawn bars are preferred for direct CNC machining, automatic lathe production, fasteners, and precision components requiring minimal additional surface preparation.
What is the difference between 304 and 304L stainless steel round bar?
The main difference is carbon content. 304 has maximum carbon of 0.08%, while 304L has maximum carbon of 0.030% (the 'L' stands for 'Low carbon'). The lower carbon content in 304L provides better resistance to intergranular corrosion (also called sensitization) in heat-affected zones after welding, making 304L the preferred choice for welded fabrications, components that will be welded to other parts, and applications where the bar will be exposed to temperatures between 425-815°C during service. 304L is mandatory for thicker welded sections in chemical processing equipment. Mechanical properties of 304L are slightly lower than 304 (yield 170 MPa vs 205 MPa) due to reduced carbon strengthening, which can be a consideration for high-stress mechanical applications. For general machined components that won't be welded, both 304 and 304L perform similarly with 304 typically being more readily available and slightly more economical.
What is the equivalent grade of AISI 304 round bar?
AISI 304 has equivalent grades in major international standards: UNS S30400 (US Unified Numbering System), ASTM A276 / A479 304 (American specifications), EN 1.4301 / X5CrNi18-10 (European standard EN 10088-3), JIS SUS304 (Japanese standard JIS G4303), GB 06Cr19Ni10 / 0Cr18Ni9 (Chinese standard GB/T 1220), DIN X5CrNi18-10 (German standard), and AFNOR Z6CN18-09 (French standard). All these grades share virtually identical chemical composition (18% Cr, 8% Ni base) and mechanical properties, making them interchangeable for most engineering applications. ASTM A276 is the standard for general bar applications, while ASTM A479 specifies bars for boiler and pressure vessel components with stricter requirements. EN 1.4301 is the most commonly referenced equivalent in European projects.
Can 304 stainless steel round bar be used for marine fasteners?
304 stainless steel round bar has limited resistance to chloride-induced corrosion and is generally NOT recommended for direct seawater contact, marine atmospheres with high salt spray, or fasteners exposed to chloride environments. In these conditions, 304 fasteners are susceptible to pitting corrosion, crevice corrosion (especially under threaded connections), and stress corrosion cracking (SCC). For marine fastener applications, 316/316L stainless steel (containing 2-3% molybdenum) is the preferred choice and is widely accepted in marine industry standards including ISO 3506, ASTM F593, and DIN 933. For aggressive marine environments such as offshore platforms or splash zones, A4-80 (316L cold drawn), 17-4 PH precipitation hardened, or 2205 duplex grades should be specified. 304 is suitable for indoor coastal architectural fasteners, freshwater marine accessories, and properly designed marine hardware in protected environments with regular maintenance.
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