The 200 series, 300 series, and 400 series of stainless steel are classified according to their composition and microstructure. They have significant differences in composition, performance, and use.
The following are their differences and uses:
1.200 series stainless steel
Main components: low content of chromium (Cr), manganese (Mn), and nickel (Ni), and part of nickel is replaced by manganese and nitrogen.
Features:
Low cost, poorer corrosion resistance than 300 series, but better than 400 series.
High strength and hardness, but poor welding performance and formability.
Non-magnetic or weakly magnetic.
Common grades: 201, 202, etc.
Uses:
Suitable for occasions with low requirements for corrosion resistance, such as architectural decoration, kitchen equipment, home appliances, tableware, etc.
Often used to replace 304 stainless steel to reduce costs.
2.300 series stainless steel
Main components: high content of chromium (Cr) and nickel (Ni), usually without manganese.
Features:
Excellent corrosion resistance, especially acid, alkali and high temperature oxidation resistance.
Non-magnetic or weakly magnetic, with good toughness, weldability and formability.
High cost, but superior performance.
Common grades:
304: The most common austenitic stainless steel, widely used in food processing, kitchen utensils, medical equipment, architectural decoration, etc.
316: Contains molybdenum (Mo), has stronger corrosion resistance, suitable for marine environment, chemical equipment, medical equipment, etc.
321: Contains titanium (Ti), has good high temperature resistance, suitable for aviation, heat exchangers, etc.
Use:
Suitable for fields with high corrosion resistance requirements, such as chemical, food, medicine, marine engineering, etc.
3.400 series stainless steel
Main components: high chromium (Cr) content, no or small amount of nickel (Ni).
Features:
Corrosion resistance is worse than 300 series, but strength and hardness are higher.
It has magnetism, poor welding performance, but good wear resistance.
Low cost, suitable for general use.
Common grades:
430: Ferritic stainless steel, general corrosion resistance, commonly used in home appliances, building decoration, automobile decoration, etc.
410: Martensitic stainless steel, high hardness, suitable for knives, bearings, valves, etc.
420: High carbon content, higher hardness, suitable for surgical instruments, knives, etc.
Use:
Suitable for occasions where corrosion resistance is not high but high strength and hardness are required, such as knives, bearings, automotive parts, etc.
Summary Comparison
| Characteristics | 200 Series | 300 Series | 400 Series |
|---|---|---|---|
| Main Components | Chromium, Manganese, Small Amount of Nickel | Chromium, Nickel | Chromium, Small Amount or No Nickel |
| Corrosion Resistance | General | Excellent | Poor |
| Magnetism | Non-magnetic or Weakly Magnetic | Non-magnetic or Weakly Magnetic | Magnetic |
| Strength/Hardness | Relatively High | Low | High |
| Weldability | Poor | Good | Poor |
| Cost | Low | High | Low |
| Typical Grades | 201, 202 | 304, 316, 321 | 430, 410, 420 |
| Applications | Architectural decoration, home appliances, tableware & food industry, chemical, medical, marine engineering, cutlery, bearings, automotive parts | ||
Selection suggestions
200 series: suitable for cost-sensitive occasions with low corrosion resistance requirements.
300 series: suitable for areas with high corrosion resistance and high hygiene requirements.
400 series: suitable for occasions requiring high strength and hardness, such as mechanical parts and knives.
Choosing the right stainless steel series according to specific needs can balance performance and economy.