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Is SS304 is a good cost cutting solution for SS316 ?

We want to use SS304 instead of SS316 as a part of cost reduction in our valve. Our valve is used for the Pharmaceutical Industries and have a cast bonnet. Will SS304 serve all the purpose for casting as SS316? Will it have any majour difference with SS316 in terms of strength? Please guide us.

Samer Sawant
Design Engineer - Vadodara
October 24, 2008

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First of two simultaneous responses -- October 24, 2008

304 and 316 are fairly near to each other in terms of strength. However, you need to specify which technical measurement of strength you mean. These are available in some libraries and any decent university library. Look it up and do not trust unverified comments on the internet. Also, it is my belief that cast is never as strong as wrought.
The primary difference is the much higher corrosion resistance of 316 over 304.
Since you are doing this for pharmaceutical, you should have to comply with appropriate specifications.

James Watts
- Navarre, Florida

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Second of two simultaneous responses -- October 24, 2008

In almost every conceivable aggressive environment, 304 will have inferior corrosion resistance to 316.

Mechanically, there would be little difference in strength.

You need to check whether any regulations governing the pharmaceutical industry in your client's country permit the use of 304-type material in the particular application. Even if permitted, you then need to assess whether 304 would in fact have adequate corrosion resistance for the application.

You refer to a casting. You should note that 304 and 316 are chemical specifications for wrought sections. If you wish to source castings, you should use the casting specifications for the casting alloys that correspond to (but are slightly different from) the wrought 304 and 316 specs.

Bill Reynolds [deceased]
consultant metallurgist - Ballarat, Victoria, Australia
We sadly relate the news that Bill passed away on Jan. 29, 2010.