Din933 Din931 Stainless Steel 321 Half Thread Hex Bolt Hex Head Bolt Hexagonal Bolt Special Material Hex Bolt

321 stainless steel is a Ni-Cr-Ti type austenitic stainless steel, featuring excellent corrosion resistance, high temperature resistance, and creep resistance.

321 stainless steel is applied in outdoor machinery for the chemical, coal, and petroleum industries with high requirements for anti-corrosion performance, as well as in boiler pipes, drying machine spiral welded pipes, aircraft, etc.

1. High-temperature industrial equipment

Heat treatment furnaces - Furnace body structure, furnace door fixation, heating element support

Incinerators and boilers - High-temperature flue gas channels, burner components

Tempering furnaces and quenching furnaces - Internal workholding fixtures, conveyor belt connection

Ceramic and glass kilns - Kiln fixture fixation, observation window fastening

2. Petrochemical and chemical industry

Refining plants - High-temperature reactors, distillation towers, pipeline flange connections

Synthetic ammonia plants - Equipment fastening in high-temperature and high-pressure environments

Ethylene cracking furnaces - Tube hangers, radiation section connectors

Chemical reaction vessels - Sealing fastening of high-temperature corrosive media

3. Power and energy sector

Thermal power plants - Superheaters, reheaters, economizers - Tube row fixation

Gas turbines - High-temperature combustion chambers, turbine components connection

Nuclear power plants - Auxiliary equipment fastening in some high-temperature areas

Waste incineration power generation - Furnace grate, pusher device's high-temperature connection

4. Metallurgy and casting industry

Steel mills - Blast furnaces' hot air furnaces, coke ovens, continuous casting machines' high-temperature parts

Non-ferrous metal smelting - Aluminum electrolytic cells, copper smelting furnaces' high-temperature fastening

Casting equipment - Sand processing system, smelting furnace's structural connection

5. Automotive and aerospace

Automobile exhaust systems - Turbochargers, exhaust pipes, catalytic converters

Aircraft engines - Test fixtures for some high-temperature areas

Racing sports - High-performance exhaust systems and high-temperature components

6. Environmental protection and new energy equipment

Sulfur dioxide removal (FGD) systems - Absorption towers, flues' high-temperature and high-humidity areas

Biomass boilers - Fuel transportation system, furnace interior

Solar thermal power generation - Concentrating collectors' high-temperature connections

1. Excellent intergranular corrosion resistance

Titanium stabilization treatment - Titanium combines with carbon preferentially to form TiC, preventing the precipitation of Cr23C6 at the grain boundaries

Sensitization immunity - Welding or the heat-affected zone at 450-850°C is less prone to intergranular corrosion

Post-welding no annealing - In most cases, no solid solution annealing treatment is required after welding

2. Outstanding high-temperature performance

High-temperature strength - Can operate for a long time at 800-900°C, superior to 304 stainless steel

Antioxidation - Forms a stable Cr2O3 oxide film on the surface, resisting high-temperature oxidation

Creep resistance - Maintains structural stability at high temperatures, suitable for thermal fatigue conditions

Upper usage temperature limit - Approximately 900°C (oxidizing environment), superior to 800°C of 304

3. Excellent processing performance

Cold workability - Easy to be stamped, bent, and deep drawn

Welding performance - Suitable for various welding processes such as TIG, MIG, and arc welding

Cutting processing - Easier for mechanical processing compared to 316

4. Good corrosion resistance

Aerobic corrosion - Resists industrial and marine atmospheric corrosion

Weak acid medium - Resistant to dilute sulfuric acid and organic acids (such as citric acid, acetic acid)

Chloride environment - Certain intergranular corrosion resistance (but weaker than 316/316L)

Alkali solution - Resistant to most alkali corrosion

5. Cost-effectiveness advantages

Moderate price - Cheaper than 316 series, slightly higher than 304 but with better performance

Low maintenance cost - Simple post-welding treatment, reducing subsequent processing costs

Longer service life - Significantly superior to 304 in high-temperature environments

Petrochemical industry

Equipment such as oil refining units, chemical reactors, transportation pipelines, and heat exchangers are tightly connected. 2205 and 2507 duplex steel perform exceptionally well in media containing hydrogen sulfide and chloride ions; 904L is suitable for non-oxidizing acid environments such as sulfuric acid and phosphoric acid.

Marine engineering

Offshore oil platforms, seawater desalination devices, ship equipment, etc. 2507 super duplex steel has excellent resistance to pitting and crevice corrosion in seawater and is the preferred material for marine engineering fasteners.

Nuclear energy

Nuclear island equipment, conventional island equipment, flue gas desulfurization devices, etc. 660 precipitation hardening steel is used for high-temperature and high-pressure components; 321 stainless steel is used for pipeline systems. rail traffic

High-speed rail, subway vehicle and track infrastructure construction. The products possess high strength, fatigue resistance, vibration resistance and other characteristics, ensuring operational safety.

Environmental protection equipment

Equipment for desulfurization and denitrification of flue gas, sewage treatment, and waste incineration. 317L and 904L have excellent corrosion resistance in environments with chlorine-containing exhaust gas and acidic wastewater.