Friday 10 February 2012

What is the difference between SS304 and SS316

                          
Both SS304 and SS316 are austenitic stainless steels.
         CHEMICAL COMPOSITION OF SS304 AND SS316               

              C       Mn       P         S        Si           Cr              Ni             Mo
        
SS304  0.08    2.0    0.045   0.03    1.0    18.0-20.0     8.0-10.0        -

SS316  0.08    2.0    0.045   0.03    1.0    16.0-18.0    10.0-14.0    2.0-3.0 

 From the above chemical composition chart we can see the main difference between SS304 and SS316 is that SS316 contains 2%-3% molybdenum and SS304 has no molybdenum.Now the question arises that we are paying double money for SS316 only for that 2.5% 'Moly'.The answer is yes, because this  "molybdenum" is added to improve the corrosion resistance to chlorides (like sea water).That is why in coastal area plants SS316 is used.

Why addition of molybdenum improves resistance against chloride corrosion?

15 comments:

  1. How would you identify the difference by seeing them physically ?

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    1. I don't think you can. They look almost the same. The only way you can identify the difference is by using the XRF Analyzer

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    2. you can test it by just sticking a Hard drive Magnet, the SS304 magnet will stick while SS316 magnet will slide down.

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    3. the difference between 2 can be identified by using molybdenum test kit....... put a drop of kit solution on surface of steel.. now put the negative terminal of a 9volt battery on steel surface n positive terminal on that droplet... if droplet turns to pink that means it is ss316. if it turns black than ss302 and if green than ss304.

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    4. Thanks a lot. I have been looking for this answer for quite a good time.

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    5. you can use electrolyte solution & 9 v battery to identify grades between SS 304 & SS 316
      SS316 :-Appears red in colour
      SS304:- Appears red colour but in 2 sec. its being colourless

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  2. Thanks for such valuable information.

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  3. Friends ,
    Can any body give an idea about maximum machining(turning , milling & grinding) finish can be achieved on ss304 and ss316 - very urgent- help

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  4. Hello,

    Does anybody know if SS316 is suitable to be used with NH3 liquid cargoes in marine applications or due to corrosion issues we need to use a more robust type of steel?

    Many thanks!

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    Replies
    1. ss316 can withstand with nh3. even nh3 is used for cleaning of ss316

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  5. in ss304, 304 stands for what??

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  6. Mechanical Properties very urgent ss304 halp.

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  7. We want to manufacture Front fork links for scooters . Currently , these are made from forged iron and heat treated ? Can we do them from SS 316 ? Strength is a major concern as this is a safety item .

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  8. Hi,
    There is more difference between stainless steel 304 & stainless steel 316.

    We are leading stainless steel wire India manufacturers, deals into wires like MIG Wire & TIG Wire.

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  9. exactly, molybdenum is very high resistant towards corrosion

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