AISI 310 | 310S Stainless Steel | DIN 1.4841

310 and 310S steels belong to the high-chromium, high-nickel austenitic stainless steel category in the ASTM standard. The only difference is that 310S has a carbon content of less than 0.08%, making it a low-carbon version of 310 steel (C≤0.25%).

310 stainless steel is typically delivered in the solution-treated condition, with a room temperature tensile strength usually between 550-650 MPa, which is basically the same as 310S. Due to its excellent resistance to high-temperature oxidation, creep resistance, and good corrosion resistance, ther are widely used in high-temperature working conditions and corrosive environments.

310/310S STEEL CHEMICAL COMPOSITION

Grade	C	Si	Mn	P	S	Cr	Ni
310	≤0.25	≤1.5	≤2.0	≤0.045	≤0.03	24.0-26.0	19.0-22.0
310S	≤0.08	≤1.5	≤2.0	≤0.045	≤0.03	24.0-26.0	19.0-22.0

310 STEEL EQUIVALENT GRADE

China:06Cr25Ni20

Europe:X15CrNiSi25-20/1.4841

Japan:SUS310S

310 STEEL PHYSICAL PROPERTY

Density: 7.98 g/cm³
Melting Point: 1398~1454℃
Thermal Conductivity (20℃): 15.2 W/(m·K)
Coefficient of Linear Expansion (20~1000℃): 18.4×10^-6/℃
Resistivity (20℃): 0.78 Ω·mm²/m
Magnetic Properties: Non-magnetic / Weakly magnetic

310 STEEL HEAT TREATMENT

310 stainless steel has an austenitic structure and no magnetic phase transformation, so it cannot be hardened by quenching. Its heat treatment mainly involves solution treatment and stress-relieving annealing. The specific process is as follows:

310 Steel Solution Treatment

Heat 310 steel to 1030~1180℃, holding time determined by workpiece thickness (usually 1~2 hours for every 25mm thickness). Cooling method is water cooling or forced air cooling (air cooling is sufficient for thicknesses <6mm; thicker parts require water cooling for rapid cooling).

Core Objectives:

1. Dissolve carbides precipitated at grain boundaries (such as Cr₂₃C₆), restoring single-phase austenite structure;

2. Eliminate work hardening and internal stresses generated by cold working or welding;

3. Ensure the material’s corrosion resistance and high-temperature toughness.

310 Steel Mechanical Property in Solution Treatment Condition

Tensile,Mpa	Yield,Mpa	Elongation,%	Reduction of Area,%	Hardness,HBW
≥515	≥205	≥40	≥50	≤201

Notes: 310S, with a carbon content ≤0.08%, exhibits significantly better resistance to sensitization after solution treatment than ordinary 310, making it more suitable for components requiring long-term service at temperatures above 600℃.

310 Steel Stress-Relief Annealing

Heat 310 steel to 800~900℃, hold for 1~3 hours, then slowly cool (air cooling is acceptable if furnace cooling is below 500℃).

Applicable scenarios: Welded parts, cold-bent/stamped parts. It can eliminate residual stress and prevent stress corrosion cracking in subsequent high-temperature or corrosive environments.

Heat Treatment Precautions for 310 Steel

Prolonged holding at 600~800℃ is prohibited, otherwise chromium carbides will precipitate along grain boundaries, causing intergranular corrosion;
Tempering is not required, as tempering has no performance improvement effect on austenitic structures.

310 Steel Core Performance

High-Temperature Mechanical Properties

The core advantage of 310 stainless steel lies in its high-temperature mechanical performance, which is the key difference between it and 304/316:

High-Temperature Tensile Strength: At 900℃, the tensile strength is still ≥100MPa; at 1000℃, it is approximately 60MPa; and at 1100℃, it maintains above 30MPa, far exceeding conventional stainless steel.
Creep Resistance: Under 800℃ and 100MPa stress, the creep rupture time can reach over 1000 hours, making it suitable for high-temperature load-bearing components.
High-Temperature Fatigue: Under cyclic conditions of 600~800℃, its fatigue life is 3~5 times that of 304 stainless steel.

High-Temperature Oxidation Resistance

310 steel has a continuous operating temperature of ≤1150℃, and an intermittent operating temperature of ≤1010℃. Within this range, a stable Cr₂O₃ protective film can form without significant oxidation peeling.

310 steel can withstand temperatures up to 1200℃ for short periods (several hours), making it suitable for rapid heating and cooling conditions in high-temperature furnaces.

Chemical Corrosion Resistance

310 steel exhibits excellent corrosion resistance to dilute nitric acid and oxidizing acids (e.g., nitric acid concentration <65%).

310 steel has some resistance to dilute sulfuric acid (concentration <10%, temperature <60℃), but the corrosion rate increases significantly with increasing concentration or temperature.

Weaknesses: 310 steel is prone to pitting/crevice corrosion in hydrochloric acid and high-concentration chloride environments, making it unsuitable for coastal areas or chlorine-containing wastewater conditions.

Due to its low carbon content, 310S exhibits significantly better intergranular corrosion resistance than ordinary 310, passing the copper sulfate-sulfuric acid intergranular corrosion test.

Typical Application Areas

The application of 310 stainless steel relies entirely on its high-temperature performance, primarily concentrated in the following scenarios:

Industrial Furnaces and Thermal Equipment

Core Components: Furnace liner, furnace bottom plate, radiant tubes, thermocouple protective sheaths, furnace door frame, high-temperature conveyor belts;
Typical Equipment: Ceramic sintering furnaces, metal heat treatment furnaces, glass melting furnaces.

Metallurgical and Chemical Industries

Metallurgical Sector: Coking plant flue baffles, blast furnace hot blast stove heat-resistant components, non-ferrous metal smelting furnace linings;
Chemical Sector: High-temperature heat exchangers in sulfuric acid plants, high-temperature reactors in phosphate fertilizer production, high-temperature pipelines in organic synthesis.

Energy and Environmental Protection Equipment

Waste Incineration Power Generation: Incinerator liner, high-temperature section of secondary combustion chamber, high-temperature pipelines in flue gas purification systems;
Biomass Energy: Biomass boiler heating surfaces, high-temperature cyclone separator linings;
Thermal Power Sector: Boiler superheater supports, high-temperature components in denitrification systems.

Special Applications

Protective sleeves for high-temperature heating elements (such as outer sheaths for resistance wires);
Heat-resistant structural components for aerospace ground testing equipment;
Material trays and fixtures for high-temperature calcination equipment.