You should have heard of 304 and 316 stainless steel, which are almost ubiquitous in daily life, from kitchen sinks, cookware, to architectural decoration.
But in fact, the “family” of stainless steel is far more than just these two members.
Different grades of stainless steel have significant differences in performance, cost, and corrosion resistance. Improper selection can affect the product’s lifespan and even increase unnecessary manufacturing costs.
This article will introduce one by one the most commonly used stainless steel grades and their characteristics.
The following is a summary of stainless steel grades commonly used in industrial manufacturing. It covers their classification, magnetic properties, corrosion resistance, and mechanical characteristics, making it easy for beginners to understand and reference quickly.
Summary of Common Stainless Steel Grades
| Grade | Type | Magnetic | Corrosion Resistance | Brief Description |
|---|---|---|---|---|
| 304 | Austenitic | No | Good | Balanced cost and versatility, widely used |
| 316 | Austenitic | No | Excellent (Chloride) | Molybdenum added for enhanced resistance |
| 316L | Austenitic | No | Excellent | Low-carbon version of 316, safer welding |
| 430 | Ferritic | Yes | Fair | Low cost, strong magnetic, household usage |
| 430F | Ferritic | Yes | Fair | Improved machinability for automatic lathes |
| 410 | Martensitic | Yes | Below Average | Heat-treatable, high hardness and wear resistance |
| 2205 | Duplex | Partial | Very Excellent | High strength, resistant to pitting/stress corrosion |
| 904L | Austenitic | No | Extremely High | Mo and Cu alloyed, strong acid resistance |
304 Stainless Steel
304 is the most widely used austenitic stainless steel, valued for its corrosion resistance and formability, making it common in everyday life. For example, kitchen sinks, cutlery, cookware, refrigerator interiors, and commercial kitchen equipment are mostly made from 304. It is non-magnetic, easy to clean, and resistant to oxidation—ideal for food contact.
However, it is not suitable for seaside BBQ grills or equipment frequently exposed to saltwater, as chlorides accelerate corrosion.
316 Stainless Steel
Building on the base of 304, 316 stainless steel includes 2%–3% molybdenum (Mo), significantly enhancing its resistance to chloride environments.
It is particularly suitable for marine environments, chemical equipment, and even implant-grade medical devices. For instance, dock railings and seaside outdoor furniture often use 316 to prevent rust.
316 maintains excellent weldability and high-temperature strength, widely used in food processing, pharmaceuticals, and laboratory equipment.
Although more costly than 304, it is a worthwhile investment in applications demanding greater corrosion resistance.
316L Stainless Steel
316L is the low-carbon version of 316, where the “L” stands for Low Carbon.
Compared to standard 316, 316L is less prone to intergranular corrosion during welding, making it particularly suitable for structurally complex or heavily welded components.
It retains the excellent corrosion and mechanical properties of 316 and is commonly used in pharmaceuticals, medical equipment, chemical processing, and high-end construction.
For products requiring high cleanliness or sensitive to weld integrity, 316L is the more reliable option.
For example, sterile hospital operating tables, IV stands, and cleanroom equipment frames are made with 316L to avoid welding corrosion.
430 Stainless Steel
430 is a ferritic stainless steel with about 16–18% chromium and minimal or no nickel content. It is naturally magnetic, has good thermal conductivity, and is less expensive than 304 and 316, making it a cost-effective choice.
Although it is not as corrosion-resistant as the austenitic series, it performs stably in dry indoor settings or environments with minimal corrosion demand (such as refrigerator panels, microwave oven linings, and dishwasher trims). Its ductility and weldability are average, making it unsuitable for complex forming.
For instance, household appliance panels and trims frequently use 430; its magnetism also allows fridge magnets to stick easily.
It’s suitable for dry environments with modest corrosion resistance and is not recommended for outdoor or humid settings.
430F Stainless Steel
430F is a modified version of 430 with added sulfur (S) to improve machinability. It offers good automated machining performance and is suitable for high-efficiency equipment like automatic lathes.
While the sulfur addition slightly compromises corrosion resistance, 430F remains a practical choice for mass production and machining-focused scenarios such as screws, nuts, and electrical connectors.
410 Stainless Steel
410 is a classic martensitic stainless steel containing 12–13% chromium. It can be heat-treated to achieve high hardness and strength, making it well-suited for cutting tools, industrial valves, and pump shafts.
However, 410 has relatively weak corrosion resistance and is not recommended for long-term use in moist or acidic environments. Material selection should balance strength and corrosion resistance. For better corrosion performance, consider 420 or high-chromium martensitic grades.
In daily life, kitchen knives and tools may use lower-end 410 variants.
2205 Stainless Steel
2205 is a duplex stainless steel consisting of approximately equal parts austenite and ferrite. Compared to 304 and 316, its yield strength is more than double and it exhibits superior resistance to stress corrosion cracking, pitting, and crevice corrosion.
This material is ideal for pressure vessels, marine structures, pulp and paper processing, and any chloride-containing applications. Though more expensive and technically demanding in welding, it is a stable and long-term solution for high-corrosion or high-strength demands.
For project leads facing extreme environments or high safety requirements, 2205 offers a compelling “strength plus corrosion resistance” path.
In daily life, 2205 is less visible directly, but related bridge railings and public infrastructure may use it to ensure long-term durability.
904L Stainless Steel
904L is a super low-carbon, high-alloy austenitic stainless steel with high nickel, molybdenum, chromium, and added copper content. This combination provides excellent acid resistance, especially against sulfuric and phosphoric acids.
It is commonly used in acid production equipment, petrochemical systems, high-end cosmetics production machinery, and is even adopted in the luxury watchmaking industry. 904L exhibits good weldability and stable mechanical properties, though it is costly and difficult to process. It is generally reserved for specialized industries or high-value-added products.
Due to its high cost and processing difficulty, it’s rare in everyday life but ensures reliability under extreme conditions.
FAQs
What does “Austenitic” stainless steel mean?
“Austenitic” stainless steel refers to steels with a face-centered cubic (FCC) crystal structure, named after British metallurgist William Austen. This structure provides excellent corrosion resistance, good formability, and non-magnetic properties. Common grades include 304 and 316.
What does “Ferritic” stainless steel mean?
“Ferritic” stainless steel refers to steels with a body-centered cubic (BCC) structure. The term comes from “Ferrum,” Latin for iron. These steels are magnetic, more affordable, and used in less corrosive environments. Grade 430 is a typical ferritic stainless steel.
What does “Martensitic” stainless steel mean?
“Martensitic” stainless steel is named after German metallurgist Adolf Martens. It has a body-centered tetragonal (BCT) crystal structure and can be heat-treated to achieve high hardness and wear resistance. Commonly used in blades, tools, and mechanical shafts, such as grade 410.
What does “Duplex” stainless steel mean?
“Duplex” stainless steel combines both austenitic and ferritic structures, offering a balance of high strength and excellent corrosion resistance. The name means “dual-phase.” Grades like 2205 are used in demanding environments such as offshore platforms and chemical processing.
What are the common methods for processing stainless steel parts?
It depends on the grade and the application. For most structural or precision parts, CNC machining (such as milling or turning) is widely used. For thin-walled parts like housings or enclosures, sheet metal fabrication and laser cutting are common. Some high-wear parts use injection mold inserts made from hardened martensitic stainless steel.
Is there a comparison table for stainless steel grades in different countries?
Yes. Different countries and industries use their own stainless steel designation systems—for example, China (GB), Japan (JIS), the United States (ASTM/UNS), and the European Union (EN). While the naming conventions vary, many grades are functionally equivalent across these standards. The following table compares commonly used austenitic stainless steel grades across major national systems, making it a useful reference for international sourcing or technical document conversion. International Stainless Steel Grade Equivalents Table.
