The 316 series steel contains 2.0-3.0% more molybdenum (Mo) compared to the 304 series, significantly enhancing its resistance to chloride ion, acid and alkali corrosion. It is an austenitic steel without magnetic properties, and is resistant to high temperatures and acids and alkalis.

The corrosion resistance of 316/316L is much stronger than that of 304/304L. Molybdenum element can resist chloride ion pitting and crevice corrosion; it is stable in seawater, salt water, chemical salt solutions, weak acids, and bleach water environments.

After welding differences

316: For continuous welding and thick plate welding, the heat affected zone is prone to sensitization and there is a risk of cracking in the corrosion environment; after welding, it can be restored to corrosion resistance at high temperature through solid solution treatment.

316L: For multi-pass welding, on-site assembly, and thick plate welding, no heat treatment is required after welding, and the corrosion resistance of the weld seam is consistent with that of the base material. Resistant to high temperatures

Both have superior high-temperature oxidation resistance and high-temperature strength compared to 304, and can be used in equipment operating at temperatures up to 600℃.

Low-temperature toughness

316L has better low-temperature performance and is commonly used in low-temperature pressure vessels.

Processing and cost

316: slightly lower price, higher yield and tensile strength; suitable for thin plates, small-scale spot welding, dry non-corrosive conditions, and decorative parts.

Disadvantages: Use with caution when large-scale welding and heat treatment are not possible.

316L: higher price than 316, with full welding performance; preferred for chemical, seawater, food and pharmaceutical, and thick plate pressure vessels.

Chemical composition of each grade:

Performance data of various grades of metal (for reference only) :

Physical properties of each grade:

Applicable scenarios

Choose 316

For interior decoration, equipment shells, thin plate bending parts, and small-scale spot welding structures

In freshwater, dry air, environments with mild chloride ion corrosion

Budget is limited, no large welding processing parts required

Select 316L (mainstream industrial material)

Seawater equipment, seawater desalination, ship accessories, swimming pool equipment

Chemical reaction vessels, acid and alkali pipelines, sewage treatment, desulfurization equipment

Pharmaceutical, dairy products, food fermentation production lines

Pressure vessels, low-temperature storage tanks, thick plate structural components

Outdoor equipment exposed to long-term dampness, salt, and bleach

Large-scale on-site welding, multiple weld seams, components that cannot undergo heat treatment after welding