Differences between 304 and 316 stainless steel
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These two materials are often used; both are stainless steel. Why are there two different ways of denoting them? They are also frequently used in different applications.
The compositions are different: 304: 0Cr18Ni9; 316: 0Cr17Ni12Mo2Ti. This post was last edited by Hai Bian Shi Bei on 2009-2-9 at 17:00.]
ASTM GB C Si Mn P ≤ S ≤ Cr Ni Mo Others Tensile strength Yield strength Elongation 304 0Cr18Ni9 ≤0.08 ≤1.00 ≤2.00 0.045 0.03 18.0-21.0 8.0-10.5 / N≤0.10 515 205 30 CF8 ZG0Cr18Ni9 ≤0.08 ≤2.00 ≤1.50 0.04 0.04 18.0-21.0 8.0-11.0 / / 485 205 35 304L 00Cr18Ni10 ≤0.03 ≤1.00 ≤2.00 0.045 0.03 18.0-20.0 8.0-12.0 / / 480 170 30 304L/CF3 ZG00Cr18Ni10 ≤0.03 ≤2.00 ≤1.50 0.04 0.04 17.0-21.0 8.0-12.0 / / 485 205 35 316 0Cr17Ni12Mo2 ≤0.08 ≤1.00 ≤2.00 0.045 0.03 16.0-18.0 10.0-14.0 2.0-3.0 515 205 30 CF8M ZG0Cr18Ni12Mo2Ti ≤0.08 ≤2.00 ≤1.50 0.04 0.04 18.0-21.0 9.0-12.0 2.0-3.0 / 485 205 30 316L 00Cr17Ni14Mo2 ≤0.03 ≤1.00 ≤2.00 0.045 0.03 16.0-18.0 10.0-14.0 2.0-3.0 N≤0.10 480 170 30 CF3M / ≤0.03 ≤1.50 ≤1.50 0.04 0.04 17.0-21.0 9.0-13.0 2.0-3.0 / 485 205 30 317L 00Cr19Ni13Mo3 ≤0.03 ≤1.00 ≤2.00 0.045 0.03 18.0-20.0 11.0-15.0 3.0-4.0 N≤0.10 585 240 55
There are many types of stainless steel; 316 and 304 are actually just the two most common acid-resistant stainless steel grades of the 18-8 type. 316 has better ductility and corrosion resistance compared to 304.
As mentioned above, the choice between 304 and 316 depends mainly on the corrosivity of the medium in contact; of course, 316 is more expensive than 304.
The description on the 2nd floor is incorrect; 316 corresponds to 0Cr17Ni12Mo2, while in the 2007 version of the new national standards it corresponds to 06Cr17Ni12Mo2. As for the differences between these two steel grades, since they are both commonly used steels and there is plenty of information available on forums, no further explanation is needed.
You can refer to this: http://bbs.hcbbs.com/viewthread.php?tid=268473&page=1#pid1258719 – it contains information on 304L, 304, 316L, and 316!
What are the other characteristics of 304/304L dual-certification steel? Where is it used?
I remain skeptical regarding 304/304L dual-certified steel. Although 304 and 304L overlap in terms of their elemental composition, and their mechanical properties are generally similar (with the yield strength and tensile strength of 304L being slightly lower than those of 304), 304L has a relatively higher manufacturing cost. Some imported materials are claimed to be 304/304L dual-certified steel; it seems that the principle of downward compatibility, whereby 304L can replace 304 but 304 cannot replace 304L, should be applied in this case.
Regarding welding properties, what are the characteristics of each? For example, if the material of the pipeline is 304/304L steel with dual certification, does the valve body of the instruments and valves necessarily have to be made of 304/304L steel as well? 304L seems to be an acceptable option, but 304 is not suitable. Is that right?