What is the difference between 304 and 316 stainless steel?

304 and 316 are the two most common grades of stainless steel encountered in everyday life; they can be found everywhere, from thermoses and cookware to industrial equipment. Both belong to the austenitic stainless steel family, offering excellent overall performance and non-magnetic properties. Compared to 304, 316 contains an additional 2%–3% molybdenum (Mo) —molybdenum is the key element for enhancing corrosion resistance, thereby significantly improving the material's ability to withstand corrosion.

Comparison of Chemical Compositions

The differences in the chemical compositions of 304 and 316 are primarily concentrated in three elements: chromium (Cr), nickel (Ni), and molybdenum (Mo). The national standard grade for 304 is 06Cr19Ni10 (old grade 0Cr18Ni9), while the national standard grade for 316 is 06Cr17Ni12Mo2 (old designation 0Cr17Ni12Mo2).

Element	304 Stainless Steel	316 Stainless Steel
Carbon (C)	≤0.08%	≤0.08%
Silicon (Si)	≤1.00%	≤1.00%
Manganese (Mn)	≤2.00%	≤2.00%
Phosphorus (P)	≤0.045%	≤0.045%
Sulfur (S)	≤0.030%	≤0.030%
Chromium (Cr)	18.0%–20.0%	16.0%–18.5%
Nickel (Ni)	8.0%–11.0%	10.0%–14.0%
Molybdenum (Mo)	—	2.0%–3.0% (Key Difference)

Data source: GB/T 20878 standard and Baosteel International product specifications

304 is known as"18/8 stainless steel" (18% chromium + 8% nickel). 316, on the other hand, builds upon 304 by:

Increased nickel content: raised from 8.0%–11.0% to 10.0%–14.0%
Added molybdenum: 2.0%–3.0% (this is the most critical distinguishing feature between 316 and 304)

The pitting resistance equivalent number (PREN) of 304 is approximately 19, while that of 316 is approximately 25, which is 4 to 5 points higher than 304. This directly demonstrates 316's superior resistance to pitting corrosion in chloride-ion environments.

Corrosion Resistance Comparison

The corrosion resistance of 316 stainless steel is superior to that of 304. In general atmospheric environments and most everyday media, there is little difference between the two; however, in specific corrosive media containing chloride ions (Cl⁻), the advantage of 316 is significant.

304 stainless steel is prone to pitting corrosion in environments containing chloride ions, such as brine, seawater, and disinfectants. Because 316 contains approximately 2% molybdenum, its corrosion resistance in seawater and other chloride-containing media is better than that of 304, making it a fully viable substitute for 304.

Experimental data confirms that in tropical marine environments, the pitting depth of 316 stainless steel is shallower than that of 304 stainless steel. In corrosion tests conducted in brick-red soil, the corrosion susceptibility ranking at different Cl⁻ concentrations is 304 > 304L > 316L, with 316L exhibiting the best corrosion resistance.

A comparison of PREN values also supports this—the pitting resistance equivalent number (PREN) for 304 is 18–20, while that for 316 is 24–26, indicating that its resistance to chloride corrosion is significantly better than that of the 304 series.

Comparison of Application Scenarios

304 is the most common and widely used stainless steel, accounting for more than half of total stainless steel production. The Chinese national standard classifies 304 as "food-grade" metal—it is safe for normal contact with water, tea, coffee, milk, oil, salt, soy sauce, vinegar, and similar substances.

Household goods: tableware, kitchen cabinets, indoor piping, water heaters, bathtubs, boilers
Food industry: Food processing, storage, and transportation equipment
Medical devices: Medical instruments
Architectural and decorative applications: Railings, building materials
Automotive parts: Windshield wipers, mufflers, decorative trim

316 is the second most widely used steel grade after 304, commonly known as "marine steel".

Marine Environment: Seawater equipment, coastal facilities
Chemical and Pharmaceutical Industries: Chemical processing equipment, dye, paper, oxalic acid, and fertilizer production equipment
Medical Devices: Surgical instruments
Nuclear Industry: Nuclear fuel recovery systems
Food Industry: Food processing applications requiring higher corrosion resistance

Material Selection Principles

Evaluation Criteria	Recommended Choices	Reasons
Daily household use, food contact	304	Fully meets requirements, offers high value for money
Beach and coastal areas	316	Stronger resistance to chloride ion pitting corrosion
Contact with brine and seawater	316	Excellent resistance to seawater corrosion
Chemical, pharmaceutical, and paper industries	316	Better resistance to acids, alkalis, and corrosive media
High-temperature environments	316	Better high-temperature strength
Cost-sensitive, general-purpose applications	304	Lower price, most widely used

Frequently Asked Questions

304 is a general-purpose austenitic stainless steel with a composition of 18% chromium and 8% nickel; its Chinese national standard designation is 06Cr19Ni10. 316 adds 2% to 3% molybdenum (Mo) to the 304 composition; its GB grade is 06Cr17Ni12Mo2. Molybdenum is the key element that enhances corrosion resistance, giving 316 superior resistance to pitting corrosion in chloride-containing environments.

304 is the most widely used grade and is suitable for everyday and industrial applications such as tableware, kitchen cabinets, indoor piping, water heaters, food processing equipment, medical devices, railings, building materials, and automotive parts. Under the Chinese National Standard, 304 is classified as a "food-grade" metal and is safe for normal contact with water, tea, coffee, milk, oil, salt, soy sauce, and vinegar.

316 is suitable for equipment used in seawater, facilities in coastal areas, chemical processing equipment, dye production, papermaking, fertilizer production equipment, surgical instruments, and nuclear fuel recovery systems. Due to its excellent resistance to chloride corrosion, it is also known as "marine-grade steel."

In general atmospheric environments and most everyday media, there is little difference between the two. However, in environments containing chloride ions (such as brine, seawater, and disinfectants), 316—which contains 2% to 3% molybdenum—exhibits significantly better corrosion resistance than 304. The pitting resistance equivalent number (PREN) for 304 is approximately 19, while that for 316 is approximately 25—a difference of 45 points. However, in concentrated sulfuric acid environments, 316's corrosion resistance may actually be lower than expected.

For everyday household use, 304 is entirely sufficient and offers better value for money. 316 is better suited for complex scenarios such as long-term high-temperature simmering, preparing sweet-and-sour side dishes, and storing beverages in thermoses. Regardless of which you choose, ensure it meets the GB 4806.9-2023 national standard for food contact testin

No, they are not suitable. Both 304 and 316 have very low carbon content (≤0.08%), so products made from them lack wear resistance and will dull quickly after being sharpened. Knives should be made from martensitic stainless steel with a higher carbon content (such as 440C).

Differences Between Q235 and Q355 Steel and Their Applications

Back to List