316L vs. 904L Stainless Steel: What's the Difference?
316L vs. 904L Stainless Steel: What's the Difference?
Both 316L and 904L are austenitic stainless steels, but 904L is a higher-grade alloy with significantly higher nickel, chromium, molybdenum, and copper content than 316L. Therefore, it offers superior resistance to pitting corrosion, crevice corrosion, and strong acids (such as sulfuric acid) compared to 316L. 316L is more cost-effective and suitable for moderately corrosive environments, while 904L, although more expensive and more difficult to process, is an ideal choice for harsh marine/chemical environments.
Will 316L stainless steel rust?
Corrosion Resistance
316 stainless steel has stronger corrosion resistance than 304 stainless steel and other similar stainless steels. It can even withstand corrosion from some highly corrosive chemicals. Therefore, it can be used in strong acid or strong alkaline environments where other metals would be corroded.
What is 316L stainless steel?
316L stainless steel is an austenitic stainless steel alloy highly valued for its excellent corrosion resistance and weldability. The "L" in "316L" stands for "low carbon," which helps reduce intergranular corrosion during welding. Its main components include iron, chromium, nickel, and molybdenum, which give it a combination of strength, formability, and corrosion resistance.
What is 904L stainless steel?
904L stainless steel (or SS 904L) is a high-alloy austenitic stainless steel known for its superior corrosion resistance, especially in highly corrosive environments. The main components of 904L stainless steel are iron, nickel, chromium, molybdenum, and a small amount of copper, which enhances its resistance to chemicals such as sulfuric acid, chlorides, and phosphoric acid.
Chemical Composition of Stainless Steel 316L vs 904L
Element | AISI 316L Stainless Steel (%) | AISI 904L Stainless Steel (%) |
Fe | Balance | Balance |
Cr | 16.0 – 18.0 | 19.0 – 23.0 |
Ni | 10.0 – 14.0 | 23.0 – 28.0 |
Mo | 2.0 – 3.0 | 4.0 – 5.0 |
Cu | – | 1.0 – 2.0 |
C | ≤0.03 | ≤0.02 |
Mn | ≤2.00 | ≤2.00 |
Si | ≤1.00 | ≤1.00 |
P | ≤0.045 | ≤0.045 |
S | ≤0.03 | ≤0.035 |
N | ≤0.10 | ≤0.10 |
Equivalent Grades of Stainless Steel 316L and 904L
| Standard / Country | 316L (Standard Austenitic) Equivalent Grades | 904L (Super Austenitic) Equivalent Grades |
|---|---|---|
| UNS (Unified Numbering System) | S31603 | N08904 |
| ASTM / ASME | ASTM A240 / A312 / A213 Type 316L | ASTM A240 / A312 / A213 Type 904L |
| EN / DIN (Europe / Germany) | EN 1.4404 / X2CrNiMo17-12-2 | EN 1.4539 / X1NiCrMoCu25-20-5 |
| JIS (Japan) | SUS 316L | SUS 904L |
| GB (China) | 022Cr17Ni12Mo2 | 00Cr20Ni25Mo4.5Cu |
| BS (United Kingdom) | 316S11 / 316S12 | 904S13 |
| ISO | 316L | 904L |
| AFNOR (France) | Z2CND17-12 | Z2NCDU25-20-5 |
| GOST (Russia) | 03Х17Н14М3 | 03Х22Н26М2Д2Т |
Mechanical Properties of Stainless Steel 316L and 904L
Hardness of Stainless Steel 316L and 904L
| 316L Stainless Steel | 904L Stainless Steel |
| Brinell hardness | 146 – 217 | 170 – 220 |
| Vickers hardness | 152 – 209 | 180 – 230 |
| Rockwell hardness | B79-B95 | B85-B96 |
Strength of Stainless Steel 316L and 904L
The strengths of 316L and 904L are shown in the table below:
| 316L Stainless Steel | 904L Stainless Steel |
Tensile Strength | 485-620MPa | 490-690MPa |
Yield Strength | 170-310MPa | 220-450MPa |
Elastic Modulus | 193 gallons | 200 gallons |
904L vs 316L Stainless Steel Corrosion Resistance
316L Stainless Steel: Although 316L stainless steel has strong resistance to chloride and seawater corrosion, its performance may be inferior to 904L stainless steel in extremely corrosive environments (such as those containing sulfuric acid or phosphoric acid).
904L Stainless Steel: Compared to 316L stainless steel, 904L stainless steel offers superior corrosion resistance, especially in highly corrosive chemical environments. Therefore, 904L stainless steel is the preferred material for handling highly corrosive materials such as sulfuric acid.
Comparison of Strength and Durability between 904L and 316L Stainless Steel
316L Stainless Steel: 316L stainless steel has high strength and good durability, but it is generally not as strong and durable as 904L stainless steel under extreme conditions.
904L Stainless Steel: Due to its higher nickel and molybdenum content, 904L stainless steel is more durable and wear-resistant, performing particularly well in corrosive or high-temperature environments.
Comparison of Applications for 904L and 316L Stainless Steel
316L Stainless Steel: Suitable for applications in marine environments, food processing, medical equipment, and general chemical processing, where the corrosive environment is moderately severe.
904L Stainless Steel: Best suited for highly corrosive industries such as chemical processing, pharmaceuticals, oil and gas, and offshore drilling operations.
Why Choose Gnee Steel (Supplier Example)?
✅ Large stock of 304 stainless steel strip/coil, fast shipping.
✅ Factory direct sales, highly competitive prices, excellent value for money.
✅ Comprehensive quality assurance: Material Testing Certificate (MTC), Chemical Composition Certificate, and Mechanical Properties Certificate.
✅ Value-added services: Slitting, cutting, polishing, surface treatment.
✅ Worldwide shipping, secure and reliable packaging, and provision of export-required documentation.
Email: ru@gneesteelgroup.com
Gnee Steel also supplies custom stainless steel 316L products in various sizes and specifications. Please send us your drawings for a quote!
