As a widely used alloy material, stainless steel plays an important role in many fields. Among the many types of stainless steel, 304 and 316 stainless steel are the two most common austenitic stainless steels. Both have excellent rust resistance. One is positioned as a “food grade” metal, called “universal grade stainless steel”, commonly known as “white iron” in Taiwan, China. The other is positioned as a “marine grade” metal, called “the noble among stainless steels”, corresponding to 304 and 316 stainless steels. Both are widely used in medicine, food, chemicals, home decoration, etc. This article will compare 304 stainless steel and 316 stainless steel in detail from the aspects of definition, composition, characteristics, performance, price and use, in order to provide you with a comprehensive understanding and selection reference.

Chemical composition comparison

The main difference between 304 and 316 stainless steel is their chemical composition, especially the addition of molybdenum (Mo) element.

Elements	304 stainless steel (%)	316 stainless steel (%)	Effects
Carbon (C)	≤0.08	≤0.08	Increase hardness, but an excessive amount will reduce corrosion resistance
Silicon (Si)	≤1.00	≤1.00	Increase high-temperature oxidation resistance
Manganese (Mn)	≤2.00	≤2.00	Increase strength and processing performance
Phosphorus (P)	≤0.045	≤0.045	Excessive amounts will reduce the toughness
Sulfur (S)	≤0.030	≤0.030	Excessive amounts will reduce corrosion resistance
Chromium (Cr)	18.0-20.0	16.0-18.0	Form a passivation film to improve corrosion resistance
Nickel (Ni)	8.0-10.5	2.0-3.0	Stabilize austenite structure, improve toughness and corrosion resistance
Molybdenum (Mo)	None	2-3	Significantly improve pitting and crevice corrosion resistance, especially in chloride environments
Nitrogen (N)	≤0.10	≤0.10	Increase strength and corrosion resistance

Differences between stainless steel grades
304 stainless steel: 06Cr19Ni10	316 stainless steel: 0Cr17Ni12Mo2

Theoretical weight calculation formula

304 stainless steel plate

Length x width x thickness x 7.93g/cm³ = weight

316 stainless steel plate

Length x width x thickness x 8.03g/cm³ = weight

Stainless steel round tube

0.02466*wall thickness* (outer diameter-wall thickness) x length = weight

Stainless steel square tube

(side width x4÷3.14-thickness) x thickness x 0.02491 = weight

Definition

Both 304 stainless steel and 316 stainless steel are austenitic stainless steels. They have similar crystal structures, which makes them similar in processing performance, toughness, and weldability.

However, by adding different alloying elements, these two stainless steels show different characteristics in corrosion resistance, heat resistance, and applicable environment.

Property

Both have good processing properties, are easy to cut, bend, and weld, have smooth surfaces, are easy to clean, and are scratch and wear resistant, but there are differences in the following aspects:

1. Hardness and strength

316 stainless steel has slightly higher hardness and strength, but the difference is not significant.

2. Density

316 has a slightly higher density, but the impact is small in practical applications. The same density value can sometimes be used to calculate weight.

3. High temperature resistance

316 stainless steel has better high temperature tolerance, with a maximum temperature resistance of 925°C, while 304 stainless steel has a maximum temperature resistance of 870°C.

4. Corrosion resistance

316 contains 2-3% molybdenum, while SS 304 does not, which determines that 316 has better resistance to crevice corrosion and pitting corrosion, even in marine or other chloride environments.

Corrosion resistance comparison

304 stainless steel	316 stainless steel
Good corrosion resistance in most environments, especially in oxidizing media	The corrosion resistance in chloride environment is significantly better than 304 stainless steel
Can resist corrosion from ordinary atmosphere, fresh water, steam and weak acid media	It has better corrosion resistance in acidic media such as sulfuric acid, phosphoric acid, and acetic acid
Chloride environments (such as seawater, salt water) are prone to pitting and crevice corrosion	It performs well in marine environments, chemical equipment, and high temperature and high humidity environment

Mechanical properties comparison

The mechanical properties of 304 and 316 stainless steel are similar, with slight differences in some aspects.

Performance parameters	304 stainless steel	316 stainless steel
Tensile strength	≥515 MPa	≥515 MPa
Yield strength	≥205 MPa	≥205 MPa
Elongation	≥40%	≥40%
Hardness (Brinell hardness)	≤201 HB	≤217 HB
Density	7.93 g/cm³	7.98 g/cm³

Application Comparison

Industry	304 stainless steel	316 stainless steel
Construction and decoration	Indoor and outdoor decoration, railings, doors and windows	Decoration in extreme environments, such as building facades on the seaside
Chemical industry	Ordinary industrial storage tanks, pipelines, heat exchangers	Reactors, storage tanks, pipelines, valves, especially in highly corrosive media
Food processing	Storage tanks, pipelines, conveyor belts, suitable for non-corrosive environments	High-demand food processing equipment, high-precision equipment
Furniture and home appliances	Kitchen equipment, tableware, washing machines, refrigerators, etc.	–
Medical industry	Surgical instruments, dental instruments	Surgical instruments, implants, dental equipment, pacemakers, joint replacements, etc.
Marine engineering	–	Submarine pipelines, seawater desalination equipment, ship parts, offshore platforms
Automotive industry	Exhaust systems and body structures	–
Conclusion: 304 stainless steel is suitable for ordinary environment and general industry, 316 stainless steel is suitable for highly corrosive environment and high-end applications.

Price Comparison

The price of 316 stainless steel is usually higher than that of 304 stainless steel. The main reasons are as follows:

1. Molybdenum cost: 316 stainless steel contains 2-3% molybdenum, which is an expensive alloying element.

2. Production process: The production process of 316 stainless steel is more complicated, which increases the cost.

 

According to market conditions:

– 304 stainless steel: The price per ton is about 2000-3000 US dollars.

– 316 stainless steel: The price per ton is about 3000-6000 US dollars.

 

Conclusion:

Summary

304 and 316 stainless steel each have their own advantages. Which material to choose depends on the specific application, environment, and budget. Here are the selection suggestions:

In general environments, 304 is sufficient and more cost-effective. In highly corrosive environments (such as marine, chemical) or high-end precision equipment, 316 stainless steel is more suitable.

 

Which material is chosen, proper use and maintenance can extend its service life and maximize its performance. I hope this article can help you better understand the difference between 304 and 316 stainless steel and choose the most suitable material for your project.

 

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