Which is better, 303 or 304 stainless steel?
Dec 16, 2025
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Which is better, 303 or 304 stainless steel?
Gnee Steel
Which is better, 303 or 304 stainless steel?
303 and 304 stainless steel: The main difference lies in the addition of sulfur. 303 stainless steel contains sulfur, giving it excellent machinability (free machinability), making it ideal for manufacturing screws, nuts, and pipe fittings. 304 stainless steel (standard stainless steel) does not contain sulfur, thus offering better corrosion resistance and weldability, making it suitable for kitchen appliances, food processing, and construction. For complex machined parts, 303 stainless steel is recommended; for general-purpose, corrosion-prone, or weldable applications, 304 stainless steel is preferred.
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What are the disadvantages of 304 stainless steel?
The main disadvantages of 304 stainless steel are its poor performance in chloride-rich (salt/marine) environments, making it prone to pitting and stress corrosion cracking; limited strength at extremely high temperatures; and susceptibility to rusting after welding if the carbon content is high. Furthermore, compared to other steels, 304 stainless steel has lower hardness and is more easily scratched. Therefore, despite its good corrosion resistance and formability, it is not suitable for heavy-wear or high-strength applications.
What is 303 stainless steel?
303 stainless steel is an austenitic stainless steel with excellent machinability. Its main chemical elements are 18% chromium and 8% nickel. Furthermore, the presence of sulfur makes it an easy-to-machine alloy with moderate corrosion resistance. While sulfur affects its corrosion resistance, this alloy has wide applications in situations requiring high machinability.
What is 304 stainless steel?
304 is a standard 18/8 stainless steel grade. It offers a variety of properties compared to other grades. Despite many alternatives, it remains one of the most commonly used alloys. It has excellent formability and weldability. Compared to other alloys, it also has better corrosion resistance, and its lower carbon content makes it suitable for many construction applications. 304 has a higher nickel content, approximately 8-10%, and a chromium content of approximately 18-20%.
Comparison Table of 303 and 304 Stainless Steel
|
Property |
303 Stainless Steel |
304 Stainless Steel |
|
Chemical Composition |
17% Chromium, 8% Nickel, 0.15% Sulfur/Selenium (min) |
18% Chromium, 8% Nickel (min) |
|
Machinability |
Excellent (due to sulfur/selenium) |
Good |
|
Weldability |
Poor |
Good |
|
Formability |
Good |
Good |
|
Tensile Strength (MPa) |
510-590 |
535-750 |
|
Yield Strength (MPa) |
205-290 |
205-325 |
|
Elongation (%) |
40-60 |
40-60 |
|
Density (g/cm³) |
7.93 |
7.93 |
|
Corrosion Resistance |
Moderate |
Excellent |
|
Cost |
Lower |
Higher |
Comparison of Mechanical Properties of 303 and 304 Stainless Steel
|
Properties |
303 Grade of Stainless Steel |
304 Grade of Stainless Steel |
|
Density |
0.289 lb/in³ |
0.289 lb/in³ |
|
Melting Point |
2550 – 2590°F |
2642°F |
|
Modulus of Elasticity |
28,000 ksi |
28,000 ksi |
|
Electrical Resistivity |
0.72 x 10⁻⁶ Ω·m |
0.72 x 10⁻⁶ Ω·m |
|
Thermal Conductivity |
112 BTU-in/hr-ft²-°F |
112 BTU-in/hr-ft²-°F |
|
Shear Modulus |
11,200 ksi |
11,200 ksi |
Comparative analysis of chemical composition of 303 and 304 stainless steel
| Element | 303 stainless steel % | 304 stainless steel % |
|---|---|---|
| Carbon | 0.10 | 0.07 |
| Chromium | 17 – 19 | 18.0 – 19.5 |
| Nickel | 8 – 10 | 8.0 – 10.5 |
| Silicon | 1.00 | 1.00 |
| Manganese | 2.00 | 2.00 |
| Phosphorous | 0.045 | 0.045 |
| Sulfur | 0.015 - 0.35 | 0.015 |
| Nitrogen | 0.10 | 0.10 |
| Copper | 1.00 | - |
303 vs. 304 stainless steel strength
| Properties | 303 stainless steel | 304 stainless steel |
|---|---|---|
| Ultimate Tensile Strength | 100000 psi | 73200 psi |
| Tensile Yield Strength | 60200 psi | 31200 psi |
| Hardness (Rockwell B) | 96 | 96 |
| Elongation at Break | 40% | 70% |
303 Stainless Steel ("Machinable" Grade)
Key Characteristics: Contains sulfur, easy to cut, drill, and machine into complex shapes.
Advantages: Excellent machinability, reduced tool wear, suitable for high-speed production.
Disadvantages: Sulfur slightly reduces corrosion resistance and weldability.
Applications: Fasteners (screws, bolts), gears, shafts, bushings, electrical components, aircraft parts.
304 Stainless Steel ("Standard" Grade)
Key Characteristics: Higher chromium content and sulfur-free, with excellent corrosion resistance.
Advantages: Excellent corrosion resistance, good formability, easy to weld, wide range of applications.
Disadvantages: More difficult to machine than 303 stainless steel ("sticky").
Applications: Kitchen appliances, food/chemical containers, piping, architectural finishing, marine hardware, medical equipment.
Why choose Gnee as your stainless steel supplier?
✅ Over 18 years of export experience, with products sold to more than 80 countries
✅ ISO, SGS, and BV certified
✅ Ample global stock of 304, 316, 316L, and 321 alloy pipes, plates, and bars
✅ Customized processing services available, including cutting, polishing, CNC machining, and packaging
✅ Fast delivery in 7-15 days, supported by global logistics partners
📦 Packaging and Shipping
All stainless steel products are packaged as follows:
Wooden pallets or wooden crates
Moisture-proof packaging
Labeled with heat number, standard, and dimensions
Shipped worldwide via sea, air, or express delivery
Gnee Steel is a supplier of stainless steel 304, offering a wide range of products including: Pipes: Seamless pipes: Sizes: 4 - 219 mm; Thickness: 0.5 - 20 mm; Welded pipes: Sizes: 5.0 - 1219.2 mm; Thickness: 0.5 - 20 mm; Plates: Plate thickness 0.1 to 100 mm; Plate width 10-2500 mm; Strips; Alloy round bars: Diameter 3-800 mm; Flat bars: Thickness 2-100 mm; Width: 10-500 mm; Hexagonal bars: 2-100 mm; Wires and extruded profiles. We collaborate with steel mills to provide our customers with stainless steel 304, whose products meet or exceed numerous leading industry standards, including ASTM, ASME, SAE, AMS, ISO, DIN, EN, and BS standards.
Gnee Steel stocks and sells stainless steel 304, pipes, tubes, plates, strips, sheets, round bars, flat bars, forged billets, hexagonal steel, wires, and extruded profiles. Please feel free to contact us via email at sales@gneestainless.com for a quote.
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