Austenitic Stainless Steel 301, 304, 304L, 316L, 321 & 347
Austenitic Stainless Steel Grades at a Glance
| Grade | UNS | JIS | EN | GB Reference | Typical Use |
|---|---|---|---|---|---|
| 301 | S30100 | SUS301 | 1.4310 | 12Cr17Ni7 | Springs, clips and formed components |
| 301L | S30103 | SUS301L | — | 022Cr17Ni7 | Formed and welded components requiring lower carbon |
| 304 | S30400 | SUS304 | 1.4301 | 06Cr19Ni10 | Food equipment, tanks, appliances and general fabrication |
| 304H | S30409 | SUS304H | 1.4948 | 07Cr19Ni10 | Elevated-temperature applications |
| 304L | S30403 | SUS304L | 1.4307 | 022Cr19Ni10 | Welded tanks, process equipment and piping |
| 316L | S31603 | SUS316L | 1.4404 | 022Cr17Ni12Mo2 | Chemical, food, pharmaceutical and chloride-containing environments |
Grade equivalents are provided for general reference. Exact equivalence and applicable standards should be confirmed according to product form, specification and purchase requirements.
Technical Characteristics
Austenitic stainless steels are chromium-nickel or chromium-nickel-molybdenum alloys that combine good formability, weldability and corrosion resistance. Their performance varies significantly by grade and service environment.
304 and 304L are widely used general-purpose grades. 316L contains molybdenum and is generally selected when higher resistance to pitting and corrosion is required in many chemical and chloride-containing environments. Stabilized grades such as 321 and 347 are commonly considered where elevated-temperature service or resistance to sensitization after welding is important.
Final grade selection should consider temperature, chemical exposure, chloride concentration, fabrication method, required mechanical properties and applicable material standards.
Typical Applications
Austenitic stainless steel is used across food processing, chemical and petrochemical equipment, pharmaceutical production, storage tanks, heat exchangers, architectural fabrication, household appliances and general industrial equipment.
Grade selection depends on the application. 301 is commonly used where higher strength after cold working is required; 304 and 304L are widely used for general fabrication and food-processing equipment; 316L is commonly selected for more demanding chemical and chloride-containing environments; and 321 or 347 may be considered for selected elevated-temperature applications.
Other applications Computer keyboard components
Chemical Composition Limits for 301 and 301L (wt.%)
| Grade | C | Si | Mn | P | S | Ni | Cr | N |
| 301 | ≤0.15 | ≤1.00 | ≤2.00 | ≤0.045 | ≤0.030 | 6.00～8.00 | 16.00～18.00 | ≤0.10 |
| 301L | ≤0.03 | ≤1.00 | ≤2.00 | ≤0.045 | ≤0.030 | 6.00～8.00 | 16.00～18.00 | ≤0.20 |
Chemical composition limits are provided for grade-reference purposes. Final requirements should be confirmed according to the applicable ASTM, JIS, EN or customer specification and the material test certificate (MTC).
Mechanical Properties of 301 and 301L
Mechanical properties depend on product form, thickness, delivery condition and the applicable material standard. The values below are reference minimum properties for annealed or standard cold-rolled material.
| Grade | Condition | 0.2% Yield Strength (MPa) | Tensile Strength (MPa) | Elongation (%) | Typical Application |
|---|---|---|---|---|---|
| 301 | Annealed / 2B | ≥205 | ≥520 | ≥40 | Forming, clips, components and general fabrication |
| 301L | Annealed / 2B | ≥215 | ≥550 | ≥45 | Formed and welded components requiring lower carbon |
Values are provided as general material-reference data. Requirements may vary between ASTM, JIS, EN and customer specifications. Confirm the applicable standard and MTC for each order.
SUS301-CSP Spring Temper Reference
For spring and high-strength strip applications, SUS301 can be supplied in cold-worked temper conditions. The following values are reference minimum mechanical properties for SUS301-CSP spring strip according to JIS G 4313.
| Temper | 0.2% Proof Strength (MPa) | Tensile Strength (MPa) | Elongation (%) | Hardness (HV) |
|---|---|---|---|---|
| 1/2H | ≥510 | ≥930 | ≥10 | ≥310 |
| 3/4H | ≥745 | ≥1130 | ≥5 | ≥370 |
| H (Full Hard) | ≥1030 | ≥1320 | — | ≥430 |
| EH | ≥1275 | ≥1570 | — | ≥490 |
| SEH | ≥1450 | ≥1740 | — | ≥530 |
This table applies specifically to SUS301-CSP spring strip under JIS G 4313. It should not be applied automatically to standard 301 sheet, plate or coil supplied under other specifications.
Heat-Resistant Austenitic Stainless Steel Grades
| 321 | SUS321 | 06Cr18Ni11Ti |
| 321H | 07Cr19Ni11Ti | |
| 309S | SUS309S | 06Cr23Ni13 |
| 310S | SUS310S | 06Cr25Ni20(S31008) |
| 347 | SUS347 | 06Cr18Ni11Nb |
| 347H | 07Cr18Ni11Nb |
Heat-resistant austenitic stainless steels include stabilized grades such as 321, 321H, 347 and 347H, as well as high-chromium and high-nickel grades such as 309S and 310S. These grades are selected for elevated-temperature service according to oxidation resistance, creep requirements, fabrication conditions and the applicable material standard.
Technical Characteristics
321 and 321H are titanium-stabilized austenitic stainless steels, while 347 and 347H are niobium-stabilized grades. Stabilization helps reduce susceptibility to intergranular corrosion associated with chromium-carbide precipitation under appropriate service and fabrication conditions.
309S and 310S contain higher chromium and nickel levels and are commonly selected for equipment exposed to elevated temperatures and oxidizing environments. 310S generally provides greater high-temperature oxidation resistance than 309S because of its higher chromium and nickel content.
Actual service temperature limits depend on atmosphere, loading, thermal cycling, fabrication condition and applicable design code.
Typical Applications
Typical applications include industrial furnace components, heat-treatment equipment, boiler and high-temperature process equipment, exhaust components, refinery and petrochemical equipment, expansion joints, high-temperature gaskets and selected pressure-containing components.
321/321H and 347/347H are commonly considered where stabilization and elevated-temperature performance are required, while 309S and 310S are widely used for furnace and heat-resistant components exposed to oxidizing environments.
Grade and Standard References
| Grade | UNS | EN Reference | Stabilization / Main Feature |
|---|---|---|---|
| 321 | S32100 | 1.4541 | Titanium-stabilized Cr-Ni stainless steel |
| 321H | S32109 | 1.4878 / high-temperature EN references may vary by product form | Higher-carbon, titanium-stabilized grade for elevated-temperature service |
| 309S | S30908 | 1.4833 | High Cr-Ni heat-resistant grade |
| 310S | S31008 | 1.4845 | Higher Cr-Ni content for high-temperature oxidation resistance |
| 347 | S34700 | 1.4550 | Niobium-stabilized Cr-Ni stainless steel |
| 347H | S34709 | 1.4550 / 1.4912 depending on EN product specification | Higher-carbon niobium-stabilized grade for elevated-temperature service |
Standard equivalence depends on product form and specification. Confirm the required ASTM, EN, JIS or customer standard before ordering.
Chemical compositions(%)
| Grade | C | Si | Mn | P | S | Ni | Cr | Cu | Ti | Nb | N |
| 321 | ≤0.08 | ≤0.75 | ≤2.00 | ≤0.045 | ≤0.030 | 9.00～12.00 | 17.00～19.00 | ― | 5×(C+N)～0.70 | ― | ≤0.10 |
| 321H | 0.04～0.10 | ≤0.75 | ≤2.00 | ≤0.045 | ≤0.015 | 9.00～12.00 | 17.00～19.00 | ― | 4×(C+N)～0.70 | ― | ― |
| 309S | ≤0.08 | ≤0.75 | ≤2.00 | ≤0.045 | ≤0.030 | 12.00～15.00 | 22.00～24.00 | ― | ― | ― | ― |
| 310S | ≤0.08 | ≤1.50 | ≤2.00 | ≤0.045 | ≤0.030 | 19.00～22.00 | 24.00～26.00 | ― | ― | ― | ― |
| 347 | ≤0.08 | ≤0.75 | ≤2.00 | ≤0.045 | ≤0.030 | 9.00～12.00 | 17.00～19.00 | ― | ― | 10×C～1.0 | ― |
| 347H | 0.04～0.10 | ≤0.75 | ≤2.00 | ≤0.045 | ≤0.030 | 9.00～13.00 | 17.00～19.00 | ― | ― | 8×C～1.0 | ― |
Mechanical Properties According to ASTM A240/A240M
| Grade | UNS | 0.2% Yield Strength, min. (MPa) | Tensile Strength, min. (MPa) | Elongation, min. (%) | Hardness, max. (HBW) |
|---|---|---|---|---|---|
| 321 | S32100 | 205 | 515 | 40 | 217 |
| 321H | S32109 | 205 | 515 | 40 | 217 |
| 309S | S30908 | 205 | 515 | 40 | 217 |
| 310S | S31008 | 205 | 515 | 40 | 217 |
| 347 | S34700 | 205 | 515 | 40 | 201 |
| 347H | S34709 | 205 | 515 | 40 | 201 |
Values above are minimum room-temperature mechanical properties commonly specified for plate, sheet and strip under ASTM A240/A240M. Requirements may vary with product form, thickness, delivery condition and specification revision. Final acceptance should be based on the purchase specification and MTC.
Need 304, 316L, 321 or 347 Stainless Steel?
Send your required grade, product form, thickness, width, length, quantity, standard and delivery destination. JISCO JUDE can review material availability, processing requirements and quotation options for your project.
Austenitic Stainless Steel FAQ
What are the most common austenitic stainless steel grades?
Common austenitic stainless steel grades include 301, 304, 304L, 316L, 321 and 347. Heat-resistant grades such as 309S, 310S, 321H and 347H are also used for selected elevated-temperature applications.
What is the difference between 304 and 316L stainless steel?
304 is a widely used general-purpose Cr-Ni stainless steel. 316L contains molybdenum and is generally selected when greater resistance to pitting and corrosion is required in many chemical and chloride-containing environments. Final grade selection should be based on the actual service conditions.
What is the difference between 304 and 304L?
304L has a lower maximum carbon content than 304. It is commonly selected for welded structures and process equipment where reducing the risk of sensitization after welding is important.
When should 321 or 347 stainless steel be considered?
321 is titanium stabilized and 347 is niobium stabilized. These grades are commonly considered for welded components and selected elevated-temperature applications where stabilization against chromium-carbide precipitation is required.
What are 309S and 310S stainless steels used for?
309S and 310S contain relatively high chromium and nickel levels and are commonly used for furnace parts, heat-treatment equipment and other components exposed to elevated temperatures and oxidizing environments. The acceptable service temperature depends on atmosphere, loading and thermal cycling.
What information should I provide when requesting a quotation?
Please provide the stainless steel grade, applicable standard, product form, thickness, width, length or coil dimensions, surface finish, quantity and delivery destination. Any special tolerance, inspection, cutting or certification requirements should also be stated with the inquiry.
