Stainless Steels

Property	Specification
Thickness Range	0.1mm – 30mm (coil); 3.0mm – 50mm (plate)
Inner Coil Dia.	508mm, or slitting and leveling as per customer request
Width	100 – 2000mm
Surface Treatment	NO.1, NO.3, NO.4, 2B, 2D, BA, HL, 6K, 8K, Antibacterial, Anti-fingerprint, etc.
Standards	GB, ASTM, EN, JIS etc.

Stainless steel is an alloy steel with excellent corrosion resistance, primarily composed of iron, chromium, and small amounts of other alloying elements such as nickel, molybdenum, titanium, and aluminum. It offers outstanding oxidation resistance, corrosion resistance, and good mechanical and processing properties, making it widely used in various industries. Stainless steel can be classified and manufactured according to different alloy compositions and performance requirements.

Stainless steel is an alloy material based on iron, containing at least 10.5% chromium and other elements such as nickel, molybdenum, titanium, and copper. Chromium forms a dense chromium oxide film on the surface of the steel, which effectively prevents oxidation and corrosion under normal temperatures and various chemical environments. Different alloy compositions and manufacturing processes result in varying properties and application fields of stainless steel.

The production of stainless steel mainly involves the following steps:

• Smelting and Alloying
  • Raw materials such as iron ore, scrap steel, and alloying elements (chromium, nickel, molybdenum, etc.) are melted in an electric furnace at high temperatures. The smelting process requires precise control of temperature, alloy composition, and impurities to ensure the quality of the stainless steel.
• Casting and Forming
  • After smelting, the molten steel is cast into ingots, plates, bars, and pipes through casting and continuous casting processes for further processing.
• Heat Treatment
  • Heat treatment enhances the mechanical properties, grain structure, and corrosion resistance of stainless steel. Common methods include annealing, solution treatment, and aging treatment. Heating and slow cooling eliminate internal stress and improve hardness and ductility.
• Cold Working and Surface Treatment
  • After heat treatment, stainless steel typically undergoes cold working processes such as rolling, drawing, and extrusion to achieve the desired size and surface quality. Surface treatments like polishing, sandblasting, and electro-polishing improve both appearance and corrosion resistance.
• Inspection and Quality Control
  • Each stage of production involves strict control over chemical composition, mechanical properties, and surface quality. Testing includes chemical analysis, tensile strength, hardness, elongation tests, and surface defect inspection to ensure product quality meets the required standards.

Stainless steel can be classified into the following main types based on structure, composition, and performance:

• Austenitic Stainless Steel – Austenitic stainless steel is the most commonly used type, characterized by high chromium and nickel content, excellent corrosion resistance, and good formability and weldability.
  • 304 Stainless Steel – Widely used in kitchenware, chemical equipment, and medical instruments.
  • 316 Stainless Steel – Contains molybdenum for enhanced corrosion resistance, ideal for marine and chemical applications.
• Ferritic Stainless Steel – Ferritic stainless steel primarily consists of iron and chromium, without nickel. It offers good corrosion and heat resistance at a lower cost but has lower ductility compared to austenitic stainless steel.
  • Common grades: 430, 444
• Martensitic Stainless Steel – Martensitic stainless steel contains higher carbon content, providing high strength and hardness but lower corrosion resistance. It’s commonly used in applications requiring strength and wear resistance.
  • Common grades: 410, 420
• Duplex Stainless Steel – Duplex stainless steel combines austenitic and ferritic structures, offering superior corrosion resistance, strength, and ductility. It is mainly used in oil, gas, and chemical industries.
  • Common grades: 2205, 2507
• Precipitation-Hardening Stainless Steel – Precipitation-hardening stainless steel achieves high strength through aging treatment and has good corrosion resistance.
  • Common grades: 17-4PH, 15-5PH
  • Used in aerospace and chemical industries.

Stainless steel production and application follow international and national standards:

Category	Features	Grades (China/GB)	Grades (USA/ASTM/UNS)	Grades (Europe/EN)	Applications
Austenitic Stainless Steel	Strong corrosion resistance, good plasticity, high toughness, suitable for forming processes.	304, 316, 321, 304L, 316L	304 (S30400), 316 (S31600), 321 (S32100), 304L (S30403), 316L (S31603)	1.4301, 1.4404, 1.4541	Chemical equipment, food processing equipment, architectural decorations, pharmaceutical equipment, etc.
Ferritic Stainless Steel	High chromium content, good corrosion resistance, low cost, average welding performance.	430, 409, 439	430 (S43000), 409 (S40900), 439 (S43035)	1.4016, 1.4512, 1.4509	Automotive exhaust systems, home appliances, construction decoration, chemical equipment, etc.
Martensitic Stainless Steel	High strength, high hardness, moderate corrosion resistance.	410, 420, 440C	410 (S41000), 420 (S42000), 440C (S44004)	1.4006, 1.4021, 1.4125	Knives, valves, bearings, medical instruments, etc.
Duplex Stainless Steel	Combines features of austenitic and ferritic grades, offering high strength and corrosion resistance.	2205 (S31803/S32205), 2507	S31803, S32205, S32750	1.4462, 1.4410	Oil and gas pipelines, chemical storage tanks, marine engineering equipment, etc.
Precipitation Hardening Stainless Steel	Achieves high strength and good corrosion resistance through heat treatment.	17-4PH (0Cr17Ni4Cu4Nb), 15-5PH	17-4PH (S17400), 15-5PH (S15500)	1.4542	Aerospace, nuclear industry, chemical equipment, and other high-performance applications.
Super Austenitic Stainless Steel	Exceptional corrosion resistance for specialized environments.	254SMO	UNS S31254	1.4547	Seawater desalination, chemical industries.
High Chromium Heat-Resistant Stainless Steel	Heat resistant, suitable for high-temperature environments.	310S	UNS S31008	1.4845	High-temperature industrial equipment, boiler components.

Standards:

ASTM A240, A268, A276, A297, A312, A693, A789; GB/T 1220, GB/T 3280, GB/T 4237, GB/T 21833; EN 10088-1, 2, 3, 4.

Stainless steel’s superior corrosion resistance, strength, and high-temperature performance make it widely used across industries:

• Construction and Architectural Decoration – Due to its elegant appearance and corrosion resistance, stainless steel is widely used in building facades, roofing, railings, and window frames.
  • Common grades: 304, 316
• Food and Pharmaceutical Industry – Stainless steel is non-toxic, easy to clean, and corrosion-resistant, making it ideal for food processing equipment, pipelines, tanks, and containers.
• Chemical and Petrochemical Industry – Stainless steel is widely used in pressure vessels, reactors, pipelines, and heat exchangers, particularly in corrosive environments.
  • Common grade: 316
• Medical Instruments – Stainless steel is biocompatible and widely used for surgical instruments, implants, and medical devices.
• Automotive and Transportation – Stainless steel is used in structural components, exhaust systems, and wheels in the automotive and transportation industries.
  • Common grades: 304, 430
• Energy and Environmental Protection – Stainless steel is used in nuclear, solar, and wind energy equipment, as well as in environmental protection systems such as wastewater treatment and exhaust gas purification.
• Home Appliances – Stainless steel enhances the durability and corrosion resistance of home appliances such as refrigerators, washing machines, and microwave ovens.

Stainless steel is a key material known for its excellent corrosion resistance, strength, and high-temperature resistance. Its versatility makes it widely applicable in construction, food, pharmaceuticals, chemicals, energy, transportation, and home appliances. The diverse alloy compositions and performance characteristics of stainless steel allow it to meet the requirements of various industries.