The difference between 304 304L 316 316L materials
Today we will continue to share the difference between 304,304L,316,316L steel materials in the following aspects.
ANSI B36.19 SS304 SCH30 concentric reducer
Ⅰ.Chemical Components
316 and 316L stainless steels are molybdenum-containing stainless steels. The molybdenum content of 316L stainless steel is slightly higher than that of 316 stainless steel. Because of molybdenum in steel, the overall performance of 316L stainless steel is better than that of 310 and 304 stainless steel. At high temperature, 316 stainless steel has a wide range of uses when the concentration of sulphuric acid is lower than 15% and higher than 85%. 316 stainless steel also has good chloride corrosion performance, so it is usually used in marine environment. The maximum carbon content of 316L stainless steel is 0.03, which can be used in applications where annealing cannot be carried out after welding and maximum corrosion resistance is required.
| Type | C max |
Mn max |
P max |
S max |
Si max |
Cr | Ni | Mo | Other |
| 304 | 0.08 | 2.0 | 0.045 | 0.03 | 1.0 | 18-20 | 8-12 | — | |
| 304L | 0.03 | 2.0 | 0.045 | 0.03 | 1.0 | 18-20 | 8-12 | — | |
| 316 | 0.08 | 2.0 | 0.045 | 0.03 | 1.0 | 16-18 | 10-14 | 2-3 | — |
| 316L | 0.03 | 2.0 | 0.045 | 0.03 | 1.0 | 16-18 | 10-14 | 2-3 | — |
ASTM A403 WP304L Caps
Ⅱ. Corrosion resistance
The corrosion resistance of 316 stainless steel is better than 304 stainless steel. It has good corrosion resistance in pulp and paper production. Moreover, 316 stainless steel is also resistant to marine and corrosive industrial atmospheric erosion.
Generally speaking, 304 stainless steel and 316 stainless steel have little difference in chemical corrosion resistance, but there will be different performance in some specific media.
Stainless steel forged threaded elbow A182 F316 90 degree
Ⅲ. Heat resistance
316 stainless steel has good oxidation resistance in discontinuous use below 1600 ℃ and continuous use below 1700 ℃. In the range of 800-1575 ℃, it is better not to continuously act on 316 stainless steel, but when 316 stainless steel is continuously used outside this temperature range, the stainless steel has good heat resistance. The carbide precipitation resistance of 316L stainless steel is better than that of 316 stainless steel, which can be used in the above temperature range.
ASME B16.9 ASTM A403 WP316L 90° Pipe Bend 3D
Ⅳ. Mechanical properties
| Type | UTS | Yield | Elongation | Hardness | Comparable DIN number | |
| N/mm | N/mm | % | HRB | wrought | cast | |
| 304 | 600 | 210 | 60 | 80 | 1.4301 | 1.4308 |
| 304L | 530 | 200 | 50 | 70 | 1.4306 | 1.4552 |
| 316 | 560 | 210 | 60 | 78 | 1.4401 | 1.4408 |
| 316L | 530 | 200 | 50 | 75 | 1.4406 | 1.4581 |
Among all steels,austenitic stainless steel has the lowest yield point.Therefore,considering the mechanical properties, austenitic stainless steel is not the best material for the stem, because to ensure a certain strength, the diameter of the stem will increase. Yield point can not be improved by heat treatment,but can be improved by cold forming.
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