| Material Identification |
| Common Designation | 304 stainless steel | Austenitic chromium-nickel stainless steel commonly supplied as sheet, strip, slit coil, and precision strip. |
| UNS Designation | S30400 | Unified Numbering System designation for standard Type 304 stainless steel. |
| European Designation | EN 1.4301 / X5CrNi18-10 | Common European material designation indicating approximately 18% chromium and 10% nickel. |
| Typical Product Form | Cold-rolled strip coil | Continuous strip wound into a coil for slitting, stamping, roll forming, fabrication, and component production. |
| Chemical Composition, Weight Percent |
| Carbon (C) | ≤ 0.08% | Controlled carbon content helps maintain corrosion resistance after welding. Low-carbon 304L is preferred for some welded assemblies. |
| Chromium (Cr) | 18.00–20.00% | Forms the passive chromium-oxide film responsible for the basic corrosion resistance of stainless steel. |
| Nickel (Ni) | 8.00–10.50% | Stabilizes the austenitic structure and improves ductility, toughness, and formability. |
| Manganese (Mn) | ≤ 2.00% | Supports deoxidation and contributes to manufacturing control; excessive manganese is limited by the material specification. |
| Silicon (Si) | ≤ 1.00% | Used as a deoxidizing element and controlled to maintain the required material properties. |
| Phosphorus (P) | ≤ 0.045% | Limited because higher levels can reduce ductility and negatively affect weldability. |
| Sulfur (S) | ≤ 0.030% | Kept low for improved corrosion performance and weldability; higher sulfur may improve machinability but can reduce corrosion resistance. |
| Iron (Fe) | Balance | Main base metal component, with the final composition controlled by the applicable product standard. |
| Physical and Mechanical Properties |
| Density | Approximately 8.00 g/cm³ | Useful for weight estimation, material planning, and coil handling calculations. |
| Melting Range | Approximately 1,400–1,450°C | Relevant to heat treatment, welding, brazing, and high-temperature processing decisions. |
| Minimum Tensile Strength | 515 MPa | Typical minimum requirement for annealed Type 304 plate, sheet, and strip under ASTM A240/A480-related specifications. |
| Minimum Yield Strength | 205 MPa at 0.2% offset | Indicates the approximate stress at which permanent plastic deformation begins in the annealed condition. |
| Elongation | Approximately 40% minimum in 50 mm | High elongation supports deep drawing, bending, stamping, and other forming operations. |
| Hardness | Typically ≤ 201 HB or ≤ 92 HRB | Annealed 304 is relatively soft and formable; cold reduction can increase hardness and strength. |
| Thermal Conductivity | Approximately 16.2 W/m·K at 100°C | Lower than carbon steel and aluminum, so thermal gradients and heat dissipation should be considered in equipment design. |
| Electrical Resistivity | Approximately 0.72 μΩ·m at 20°C | 304 stainless steel is electrically resistive compared with copper and is not normally selected as a conductor material. |
| Magnetic Response | Generally non-magnetic when annealed; may become slightly magnetic after cold working | Cold rolling, forming, and stamping can induce some martensitic transformation and increase magnetic response. |
| Strip Coil Features and Surface Options |
| Common Thickness Range | Approximately 0.05–3.00 mm | Actual availability depends on the mill, production route, tolerance requirements, and the intended application. |
| Common Width Range | Approximately 10–1,500 mm | Slit width, edge condition, coil weight, and dimensional tolerances should be specified according to the processing equipment. |
| Typical Annealed Condition | Solution annealed and pickled | Provides a soft, ductile structure with a clean oxide-free surface suitable for forming and further processing. |
| 2B Finish | Cold rolled, annealed, pickled, and lightly skin passed | A widely used smooth reflective finish for general fabrication, kitchen equipment, appliances, and architectural components. |
| BA Finish | Bright annealed | Bright, smooth surface produced by controlled-atmosphere annealing; often selected for decorative and appearance-sensitive parts. |
| No. 4 Finish | Brushed or satin finish | Directional surface texture that helps reduce the visual impact of minor scratches and is common in architectural and food-service products. |
| Edge Conditions | Mill edge or slit edge | Slit edge is used for precise width requirements; deburring or edge conditioning may be specified for safer handling and forming. |
| Common Applications |
| Food and Beverage Equipment | Processing surfaces, sinks, worktables, tanks, and containers | Selected for its cleanability, formability, and resistance to many food-related atmospheric and aqueous environments. |
| Kitchen and Household Appliances | Cookware components, appliance panels, trim, and hardware | Combines an attractive surface with good forming performance and general corrosion resistance. |
| Architectural and Interior Products | Wall panels, elevator interiors, handrails, trims, and decorative parts | Available in multiple finishes and suitable for indoor and moderately corrosive service environments. |
| Automotive Components | Trim, brackets, clamps, exhaust-related parts, and formed details | Used where appearance, durability, corrosion resistance, and manufacturability are required. |
| Industrial Fabrication | Enclosures, guards, ducts, fasteners, brackets, and machine components | Suitable for cutting, bending, stamping, welding, and roll forming when the design accounts for work hardening. |
| Chemical and Pharmaceutical Equipment | Non-severe service vessels, piping accessories, trays, and supports | Useful for many mildly corrosive environments, although highly aggressive chemicals may require a more corrosion-resistant grade. |
| Electrical and Electronic Products | Cabinets, covers, shielding parts, clips, and precision stamped components | Provides durability and corrosion resistance; electrical conductivity is lower than that of copper or aluminum. |
| Selection and Service Considerations |
| Corrosion Resistance | Good in normal atmospheric and many mildly corrosive environments | Performance can decrease in chloride-rich, highly acidic, or high-temperature environments. Proper cleaning and drainage help reduce staining and localized corrosion. |
| Weldability | Generally very good | Common welding methods can be used; heat tint should be removed when surface corrosion performance and appearance are important. |
| Formability | Excellent in the annealed condition | 304 is suitable for bending and deep drawing, but its significant work hardening may require appropriate tooling and intermediate annealing for severe forming. |
| Cleaning Requirement | Use chloride-free or low-chloride cleaning methods where possible | Iron contamination, embedded carbon steel particles, and salt deposits can cause surface discoloration or corrosion. |
| Specification Check | Confirm applicable standard, condition, finish, dimensions, and tolerances | Mechanical values and dimensional limits may vary with product form, thickness, cold-work condition, and the governing standard. |
