The Difference Between 304 And 316 Stainless Steel
By admin . January 06, 2020 | News
The main difference between 304 vs 316 stainless steel is the composition and corrosion resistance, SS304 doesn’t contain molybdenum while SS316 contains 2-3% molybdenum. The addition of molybdenum provides pitting resistance in phosphoric acid, acetic acid and dilute chloride solutions and provides corrosion resistance in sulfurous acid. In addition, AISI 304 has a 18% Chromium and 8% Nickel content while AISI 316 has a 16% Chromium and 10% Nickel.
The Difference Between 304 and 316 Stainless Steel in Chemical Composition
SS304 vs SS316 Chemical Composition (%) |
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|---|---|---|---|---|---|---|---|---|
| Steel Grade | C, ≤ | Si, ≤ | Mn, ≤ | P, ≤ | S, ≤ | Cr | Ni | Mo |
| 304 | ≤0.08 | ≤1.00 | ≤2.00 | ≤0.045 | ≤0.030 | 18.0-20.0 | 8.0-11.0 | – |
| 316 | ≤0.08 | ≤1.0 | ≤2.00 | ≤0.045 | ≤0.030 | 16.0-18.0 | 10.0-14.0 | 2.0-3.0 |
| 304L | ≤0.03 | ≤1.00 | ≤2.00 | ≤0.035 | ≤0.030 | 18.0-20.0 | 8.0-12.0 | – |
| 316L | ≤0.03 | ≤1.0 | ≤2.00 | ≤0.045 | ≤0.030 | 16.0-18.0 | 10.0-14.0 | 2.0-3.0 |
SS304 /SUS304 Stainless Steel
304 stainless steel is the most common form of stainless steel used around the world, largely due to its excellent corrosion resistance and value. It contains between 16 and 24 percent chromium and up to 35 percent nickel, as well as small amounts of carbon and manganese.
The most common form of 304 stainless steel is 18-8, or 18/8, stainless steel, which contains 18 percent chromium and 8 percent nickel.
SS304 can withstand corrosion from most oxidizing acids. That durability makes 304 easy to sanitize, and therefore ideal for kitchen and food applications. It is also common in buildings, décor, and site furnishings.
304 stainless steel does have one weakness: it is susceptible to corrosion from chloride solutions, or from saline environments like the coast. Chloride ions can create localized areas of corrosion, called “pitting,” which can spread beneath protective chromium barriers to compromise internal structures. Solutions with as little as 25 ppm of sodium chloride can begin to have a corrosive effect.
SS316/SUS316 Stainless Steel
SS316 grade is the second-most common form of stainless steel. It has almost the same physical and mechanical properties as 304 stainless steel, and contains a similar material make-up. The key difference is that 316 stainless steel incorporates about 2 to 3 percent molybdenum. The addition increases corrosion resistance, particularly against chlorides and other industrial solvents.
316 stainless steel is commonly used in many industrial applications involving processing chemicals, as well as high-saline environments such as coastal regions and outdoor areas where de-icing salts are common. Due to its non-reactive qualities, 316 stainless steel is also used in the manufacture of medical surgical instruments.
Alternative 300-series grades can contain up to 7 percent molybdenum. They provide even better chloride resistance, but such heavy-duty resistance is only necessary in industrial or high concentration exposure conditions.
SS304 vs SS316 Mechanical Properties
SS304 vs SS316 Mechanical Properties |
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|---|---|---|---|---|---|---|---|---|---|
| ASTM | UNS | AISI | Tensile Strength, MPa (ksi), ≥ |
0.2% Yield Strength, MPa (ksi), ≥ |
Elongation in 50 mm, %, ≥ |
Reduction in area, %, ≥ |
Brinell Hardness (HBW) ≤ |
Rockwell Hardness (HRBW) ≤ |
Condition |
| ASTM A276/ A276M |
UNS S30400 |
304 | 515 (75) | 205 (30) | 40 | 50 | _ | _ | Annealed, Hot finished |
| UNS S31600 |
316 | ||||||||
| UNS S30400 |
304 | 620 (90) | 310 (45) | 30 | 40 | _ | _ | Annealed, Cold finished, ≤ 12.7 mm |
|
| UNS S31600 |
316 | ||||||||
| ASTM A240/ A240M |
UNS S30400 |
304 | 515 (75) | 205 (30) | 40 | _ | 201 | 92 | |
| UNS S31600 |
316 | 217 | 95 | ||||||
SS304 vs SS316 Stainless Steel Cost
304 vs 316 stainless steel cost: Taking steel plates as an example, the cost of 316 is about 1.5 times the cost of 304. The price of stainless steel depends on the price of the alloying element and the amount of the alloy (eg Ni, Cr and Mo). The price of molybdenum (Mo) is about twice that of nickel (Ni), six times that of chromium (Cr), 316 nickel content is higher than 304, and 316 contains molybdenum, while 304 does not contain it, so the cost of 316 is higher than 304.
SS304 vs SS316 Corrosion
Since Mo is added to SS316, Mo can improve the pitting resistance and is therefore more resistant to corrosion than SS304. So SS316 more suitable to Offshore buildings and chemical plants where highly corrosive environment.
All above is the comparision between Stainless Steel 304 and 316. Contact our experts now for detailed advice on the most suitable materials for your project via email : Sales@blackcatjsc.com.vn or Call us: +84 254 3577 450
Reference: www.worldsteelgrades.com
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