Din933 Stainless Steel 904l Full Thread Hex Bolt Hex Head Bolt Hexagonal Bolt

It is particularly suitable for non-oxidizing acid environments such as sulfuric acid and phosphoric acid, as well as strong corrosive media containing chloride ions. It is widely used in fields such as environmental protection equipment, food processing, paper industry, and chemical plants.

Compared with 316L, the corrosion resistance and resistance to pitting of 904L have significantly improved, but the cost has also increased accordingly; compared with duplex steel 2205, 904L performs better in resisting strong acids but has lower strength; compared with nickel-based alloys such as Hastelloy C-276, 904L has better cost-effectiveness in mild corrosive environments, but is slightly inferior in extreme reducing acid environments.

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. Extremely strong resistance to pitting corrosion and crevice corrosion

904L contains up to 4-5% molybdenum (Mo) and 1.5% copper (Cu), significantly enhancing its resistance to pitting corrosion and crevice corrosion in chloride-containing environments. Its pitting resistance equivalent (PREN) is approximately 35-38, much higher than that of ordinary 316 stainless steel (about 24-26), making it perform exceptionally well in seawater, salt fog, and halide-containing media.

2. Excellent resistance to acid corrosion

904L exhibits outstanding stability in various strong corrosive acid media:

Sulfuric acid: Can be used for a long time at medium concentrations and temperatures

Phosphoric acid: Resistant to corrosion by various concentrations of phosphoric acid

Organic acids: Such as formic acid, acetic acid, citric acid, etc.

Hydrochloric acid: Has certain corrosion resistance at low concentrations and low temperatures (better than 316)

3. Outstanding resistance to stress corrosion cracking

The high nickel content (23-28%) combined with molybdenum and copper elements gives 904L a high resistance to chloride-induced stress corrosion cracking (SCC). This characteristic is crucial in harsh environments such as chemical and marine industries.

4. Good weldability and processing performance

904L can be welded using conventional welding methods (TIG, MIG, manual arc welding), and no complex heat treatment is required after welding. Although its high strength leads to a significant tendency for cold work hardening, it can still undergo conventional bending, stamping, and deep drawing operations.

5. Non-magnetic property

As a fully austenitic stainless steel, 904L remains non-magnetic at room temperature, suitable for special applications where magnetic sensitivity is a concern, such as electronic devices and medical instruments.

6. Low carbon content design

The carbon content is controlled at less than 0.02%, effectively reducing the risk of carbide precipitation in the weld and heat-affected zones, and ensuring good intergranular corrosion resistance after welding, reducing the need for post-weld heat treatment.

7. Performance stability over a wide temperature range

904L maintains good toughness and corrosion resistance in the temperature range of -196°C to 400°C, suitable for both deep cold environments and certain high-temperature conditions.

Chemical industry: Sulfuric acid and phosphoric acid production equipment, reaction vessels, heat exchangers, piping systems

Petroleum and natural gas: Offshore platform equipment, desulfurization units in refineries, acid gas treatment systems

Ocean engineering: Desalination units, seawater cooling systems, ship components, tidal energy equipment

Environmental protection field: Flue gas desulfurization (FGD) systems, wastewater treatment equipment, scrubbers in waste incineration plants

Paper industry: Pulp bleaching equipment, chlorine dioxide production systems

Pharmaceutical and food: High-purity chemical storage tanks, special reaction vessels (must meet hygiene standards)