Contents
302 Stainless Steel: Composition, Properties, Application, Process, Comparison, and More
- John
We introduce the composition, characteristics, processing methods, pros and cons of 302 stainless steel in detail, and help you better understand its application scenarios by comparing it with stainless steel grades 301, 303, 304, 316 and 18/8. We also provide answers to common questions about 302 stainless steel such as food safety, magnetism and anti-rust performance.
What is 302 Stainless Steel?
AISI 302 Stainless Steel is an austenitic stainless steel in the 300 series, known for its chromium-nickel composition (18%Cr, 8%Ni). 302 is a slightly higher carbon version of 304, often found in strip and wire forms. It is extremely durable, corrosion resistant, and easily formed and fabricated, making it ideal for a wide variety of applications.
Equivalent grades of 302 stainless steel
- UNS: S30200
- EN: 1.4310
- DIN: X10CrNi18-8
- JIS: SUS 302
What is the ASTM standard for 302 stainless steel?
- ASTM A240
- ASTM A276
- ASTM A580
- ASTM A313
Chemical Composition of 302 Stainless Steel
The chemical composition of 302 stainless steel plays a significant role in determining its corrosion resistance, toughness, and mechanical properties. Its composition is very similar to that of 304 stainless steel but with a slightly higher carbon content, which gives it added strength.
| Element | Composition Range |
| Carbon (C) | ≤ 0.15% |
| Manganese (Mn) | ≤ 2.00% |
| Silicon (Si) | ≤ 1.00% |
| Chromium (Cr) | 17.0% – 19.0% |
| Nickel (Ni) | 8.0% – 10.0% |
| Phosphorus (P) | ≤ 0.045% |
| Sulfur (S) | ≤ 0.030% |
Properties of 302 Stainless Steel
Key Features
302 stainless steel is known for the following attributes:
- Corrosion Resistance: With its high chromium content, 302 offers good protection against rust and corrosion in various environments, particularly in mild to moderate corrosive conditions.
- High Strength: The alloy’s higher carbon content gives it enhanced tensile strength compared to 304 stainless steel.
- Magnetic Properties: 302 stainless steel is non-magnetic in the annealed state, but becomes slightly magnetic after the cold working process.
- Excellent Formability: It is easy to machine, form, and fabricate, making it suitable for complex applications that require detailed forming.
Physical properties
| Property | Metric | Imperial |
| Density | 7.9 g/cm³ | 0.284 lb/in³ |
| Melting Point | 1425°C – 1450°C | 2550°F – 2590°F |
| Thermal Conductivity | 16.3 W/mK | 9.4 BTU/hr/ft²/°F |
| Electrical Resistivity | 720 nΩ·m | 28.3 µΩ·in |
| Specific Heat | 500 J/kg·K | 0.12 BTU/lb°F |
| Coefficient of Thermal Expansion (20-100°C) | 17.6 µm/m·°C | 9.8 µin/in·°F |
| Coefficient of Thermal Expansion (20-500°C) | 17.2 µm/m·°C | 9.6 µin/in·°F |
| Magnetic Permeability (Relative) | ≤1.02 | ≤1.02 |
Mechanical Properties
| Property | Metric | Imperial |
| Tensile Strength (Ultimate) | 620 MPa | 89,900 psi |
| Yield Strength (0.2% Offset) | 275 MPa | 39,900 psi |
| Elongation at Break (50mm) | 40 – 60% | 40 – 60% |
| Hardness (Rockwell B) | Max 92 | Max 92 |
| Hardness (Brinell / Vickers） | 147 | 147 |
| Poisson’s Ratio | 0.27 – 0.30 | 0.27 – 0.30 |
| Modulus of Elasticity (Tension) | 193 GPa | 28,000 ksi |
| Modulus of Elasticity (Torsion) | 77 GPa | 11,200 ksi |
| Shear Modulus | 77 GPa | 11,000 ksi |
| Shear Strength | 350 MPa | 50,763 psi |
| Fatigue Strength (10^7 cycles) | 240 MPa | 34,800 psi |
Forms of 302 Stainless Steel
302 stainless steel is widely used in industries such as food processing, construction, medical equipment, machinery and automobiles due to their excellent corrosion resistance, strength and formability, meeting the diverse needs from fasteners to precision parts.
Our 302 stainless steel is available in a variety of forms to suit different applications, including:
- 302 Stainless steel springs, balls, washers, strips.
- 302 Stainless steel wires, foils, plate and sheet.
- 302 Stainless steel bars, rods.
- 302 Stainless steel seamless tubes, weld pipes, tubing.
Applications of 302 Stainless Steel
The versatility of 302 stainless steel allows it to be used in various industries.
Food and Beverage Industry: Given its resistance to corrosion and hygienic characteristics, 302 stainless steel is frequently employed in the manufacture of kitchen appliances, machinery for food processing, as well as containers designed for the storage and transportation of food and beverages.
Automotive and Aerospace: The alloy’s toughness and formability make it ideal for components like springs, fasteners, and other engineered parts.
Chemical Processing: Its resistance to mild acids and corrosion allows it to be used in the manufacturing of tanks, containers, and piping systems for chemical storage and transport.
Medical Devices: Because of its non-reactive and corrosion-resistant nature, 302 stainless steel is used in surgical tools and other medical devices.
Home Appliances: Commonly found in dishwashers, washing machines, and refrigerators, 302 stainless steel is used for its strength and resistance to wear and tear.
Pros and Cons of 302 Stainless Steel
Like any material, 302 stainless steel has its advantages and disadvantages, depending on the specific use case.
Advantages
- Durability: 302 stainless steel provides excellent strength and durability in both general and high-stress applications.
- Corrosion Resistance: It performs well in mild to moderately corrosive environments, making it suitable for use in the food, medical, and chemical industries.
- Cost-Effective: Compared to higher-end stainless steel grades, 302 offers good performance at a lower cost.
- High Tensile Strength: Its higher carbon content gives it a strength advantage over 304 stainless steel.
- Formability: Easy to mold, weld and fabricate for design and manufacturing flexibility.
Disadvantages
- Not as Corrosion Resistant as 316: In more aggressive environments, such as those with high chloride content, 302 may not offer the same level of corrosion resistance as 316 stainless steel.
- Magnetic Properties: 302 stainless steel can become magnetic when cold worked, which may be undesirable in certain applications.
- Welding Challenges: Post-weld annealing is often necessary to restore corrosion resistance after welding, which can add to production time and costs.
Processing Methods of 302 Stainless Steel
302 stainless steel has excellent formability and machinability and is easy to process. 302 stainless steel can be processed using a variety of methods for a variety of applications.
Processing Methods of 302 Stainless Steel
302 stainless steel is an austenitic chromium-nickel alloy with excellent corrosion resistance, high strength, and good ductility. Below are the processing methods and techniques used for 302 stainless steel:
Forming
- Cold Forming: 302 stainless steel is highly ductile, making it ideal for cold forming operations such as bending, drawing, and forming into complex shapes. Cold forming increases the material’s strength due to work hardening, but this may require additional annealing to restore ductility.
- Deep Drawing: This method is commonly used to produce shapes like cups and shells, which leverage the material’s formability.
Welding
- Common Welding Methods: 302 stainless steel can be welded using most standard welding methods, including TIG (Tungsten Inert Gas), MIG (Metal Inert Gas), and resistance welding.
- Precautions: When welding 302 stainless steel, post-weld annealing may be required to maintain its corrosion resistance properties. Using low heat inputs and filler materials, such as 308L or 309L stainless steel, can reduce the risk of carbide precipitation and ensure a strong weld.
- Spot and Seam Welding: Suitable for thin sections of 302 stainless steel in applications where high-quality joints are required.
Cutting
- Laser Cutting: The precision and high energy of laser cutting allow for clean and intricate cuts, especially in thin sections of 302 stainless steel.
- Plasma Cutting: Plasma cutting can be used for thicker sections, offering a fast and efficient cutting method but with slightly less precision than laser cutting.
- Water Jet Cutting: This method provides a cold cutting process, preventing heat-affected zones (HAZ) and ensuring dimensional stability, especially for thicker materials.
- Mechanical Cutting (Shearing): Mechanical methods such as shearing are also commonly used, though work hardening can be a concern.
Hot Working
Hot working processes are suitable for 302 stainless steel and include:
- Forging: Forging can be performed at temperatures between 1150°C and 1260°C (2100°F to 2300°F). After forging, it’s necessary to anneal the steel to restore its structure and prevent internal stress.
- Hot Rolling: Used for shaping the material, hot rolling helps to refine grain structure and improve the material’s mechanical properties.
- Extrusion: Hot extrusion can be applied to produce complex profiles. The high temperatures used ensure good formability while reducing strain hardening.
Cold Working
- Cold Rolling: 302 stainless steel is frequently cold-rolled to enhance its mechanical properties and produce thinner, stronger sheets. Cold rolling increases strength through strain hardening but reduces ductility.
- Cold Drawing: For wire and small bar sections, cold drawing is used to achieve precise dimensions and improved surface finishes.
- Cold Bending: This process is often used in applications requiring tight bends, where 302’s ductility allows for sharp, accurate angles.
Heat Treatment
- Annealing: Annealing is done to restore ductility after cold working. The typical annealing temperature for 302 stainless steel is between 1010°C and 1120°C (1850°F to 2040°F) followed by rapid cooling to avoid carbide precipitation.
- Stress Relief: A lower temperature stress-relief anneal (around 370°C to 480°C) can be performed to reduce internal stresses introduced during cold working or welding.
- No Hardening by Heat Treatment: 302 stainless steel cannot be hardened by heat treatment due to its austenitic structure. Hardening is primarily achieved through cold working.
Surface Treatment
- Electropolishing: This is another surface treatment method that involves the electrochemical removal of material, resulting in a smoother and brighter surface, while enhancing corrosion resistance.
- Pickling and Passivation: After forming and welding, 302 stainless steel may require pickling to remove surface oxides and passivation to improve corrosion resistance by removing surface contaminants.
- Polishing: For applications that require a high-quality finish, 302 stainless steel can be mechanically polished to achieve mirror-like finishes or various degrees of brushed surfaces.
What is the Difference Between 301, 303, 18/8 and 302 Stainless Steel?
301 vs 302
301 has a slightly lower chromium and nickel content compared to 302, making it less corrosion-resistant but more formable. 301 is frequently used in applications where high degrees of flexibility and strength are required.
303 vs 302
303 contains added sulfur, which improves machinability but reduces its corrosion resistance. 302 is preferable when a balance between corrosion resistance and strength is needed.
18/8 vs 302
302 stainless steel and 18/8 stainless steel are essentially the same alloy, the difference lies in the naming method. 302 is the industrial standard name, while 18/8 refers to its composition of 18% chromium and 8% nickel, which is commonly used in daily applications. Both have the same performance and are widely used in tableware, kitchenware and medical equipment.
Which Is Better 302 or 304 Stainless Steel?
304 stainless steel is generally better than 302 stainless steel for most applications due to its superior corrosion resistance, especially in wet or corrosive environments, and better weldability. Its lower carbon content helps prevent carbide precipitation during welding.
302 stainless steel offers slightly higher tensile strength and is better for applications requiring higher strength and work hardening, such as springs or high-stress components.
For most uses, 304 is preferred due to its balance of strength, corrosion resistance, and ease of fabrication. Use 302 where extra strength or work hardening is needed.
Is 302 Stainless Better than 316?
316 stainless steel is better than 302 for corrosion resistance, especially in marine, chemical, or high-temperature environments due to the presence of molybdenum.
302 stainless steel is slightly stronger and cheaper, but 316 is superior for harsh conditions. Use 302 when strength and cost are more important, and 316 for better corrosion resistance.
Is 302 Stainless Steel Food Grade?
302 stainless steel is usually not considered food grade because it contains high levels of nickel and manganese, and will oxidize and rust when placed in acidic or alkaline liquids, which does not meet food grade requirements.
Is 302 Stainless Steel Magnetic?
302 stainless steel is not magnetic in the annealed condition. However, after cold working or forming processes, it can become magnetic due to structural changes in the steel caused by mechanical deformation. The level of magnetism is determined by the degree of cold working, the higher the degree of cold working the stronger the magnetism of the region.
If non-magnetic properties are critical to the application, a post-fabrication anneal can be performed to return the alloy to its original non-magnetic state.
Does 302 Stainless Steel Rust?
Like all stainless steels, 302 can corrode under certain conditions. For example, if it is exposed to highly corrosive environments, such as saltwater, high chloride concentrations, or acidic chemicals for extended periods, the protective layer can degrade, leading to rust.
302 Stainless Steel Manufacturer
SteelPRO Group provides comprehensive solutions for 302 stainless steel, covering all aspects from production to after-sales. We meet the various needs of customers with high-quality products and personalized customized services.
Choose us, you will enjoy rich manufacturing experience and strong production capacity. We produce more than 1 million tons of stainless steel materials every year, and ensure that every product passes strict quality tests, providing 100% quality commitment to help you meet market challenges.
We offer preferential prices directly from the factory and keep a large inventory to meet the urgent needs of customers. Whether you need standard products or customized specifications, we can supply quickly and ensure timely delivery. Contact us now to learn more about our customized services.
