If you are looking for the right stainless steel grade for high-temperature pressure vessels, you've likely come across 316L (1.4404) and 316 (1.4401). Both belong to the 316 family of molybdenum-bearing austenitic stainless steels, but they differ significantly in carbon content, mechanical strength, and temperature resistance - factors that directly affect performance and cost in pressure vessel manufacturing.
For high-temperature pressure vessels, grade 316 (1.4401) is used when higher elevated temperature strength is required, while grade 316L (1.4404) is more suitable for welding or high-temperature exposure applications where there is a risk of sensitized corrosion. The main difference is that 316H has a higher carbon content, which increases strength at temperatures above 500°C, while 316L has a lower carbon content, which prevents intergranular corrosion after welding or high-temperature exposure.
316L/1.4404 vs. 316/1.4401: Key Differences
|
Property / Grade |
316L / 1.4404 |
316 / 1.4401 |
|---|---|---|
|
Standard |
ASTM A240 / EN 10088 |
ASTM A240 / EN 10088 |
|
Carbon (C) |
≤ 0.03% |
0.04–0.10% |
|
Nickel (Ni) |
10.0–13.0% |
10.0–13.0% |
|
Chromium (Cr) |
16.0–18.0% |
16.0–18.0% |
|
Molybdenum (Mo) |
2.0–2.5% |
2.0–2.5% |
|
Tensile Strength (MPa) |
485 min |
515 min |
|
Yield Strength (MPa) |
170 min |
205 min |
|
Max Service Temperature |
~450°C |
~550°C |
|
Common Forms |
Coil, Sheet, Plate, Tube |
Plate, Pipe, Fittings |
High-Temperature Resistance
316 (1.4401) offers excellent high-temperature strength due to its high carbon content. It maintains excellent mechanical properties up to 550°C, making it an ideal choice for boilers, heat exchangers, and pressure vessels subject to thermal stress. 316L (1.4404), with its low carbon content, is the preferred material for welded structures requiring corrosion resistance after fabrication and exposure to temperatures below 450°C.
Corrosion Resistance
316L (1.4404)'s low carbon content provides improved resistance to intergranular corrosion, reducing the risk of carbide precipitation during welding. 316 (1.4401) performs well in oxidizing and moderately corrosive environments, but exhibits slightly less resistance to localized corrosion in chloride environments.
Cost and Manufacturing
316L is easier to form and weld, reducing production costs for medium and low-temperature applications. 316H has more stringent heat treatment and manufacturing controls, generally resulting in a slightly higher cost.
Applications
| Industry | 316L / 1.4404 Applications | 316 / 1.4401 Applications |
|---|---|---|
| Pressure Vessel Fabrication | Welded tanks, cryogenic vessels | High-pressure, high-temp vessels |
| Chemical Processing | Acidic pipelines, evaporators | Heat exchangers, reboilers |
| Power Generation | Condensers, low-temp heaters | Superheaters, boilers |
| Pharmaceutical & Food | Sanitary storage, piping | Not commonly used (due to high carbon) |
| Oil & Gas | Offshore fittings, separators | Refinery columns, reactors |
Gnee Steel supplies a wide range of 316 (1.4404) and 316H (1.4401) stainless steel sheets, coils, plates, and tubes strictly in accordance with ASTM A240, ASME SA240, and EN 10088 standards.
Over 30,000 tons of stainless steel in stock, including high-temp grades.
Full PMI and mechanical testing reports provided.
ISO 9001 / SGS / BV certified quality management.
Custom cutting, polishing, and edge finishing available.
Packaging, Payment & Delivery
Packaging: Wooden pallets or boxes, moisture-proof wrapping, and corner protection.
Payment Terms: T/T (30% deposit + 70% before shipment), L/C at sight accepted.
Delivery: 7–15 working days depending on order size.
Shipping: Available via sea, air, or rail with flexible INCOTERMS (FOB, CIF, DDP).
