Austenitic Stainless Steel 316 3

[kpm21443]

I have specs of Gate Valve with Body & Bonnet A351 CF3M (316L). The specs also mentions to submit report of microstructure / average grain size as per ASTM E112 for austenitic stainless steel as per applicable ASTM Specification. Though 316L is austenitic stainless steel, but it is not clear for me if this test is required for 316L as per E112. I read the standard but could not find this point. Can anyone help me.

 

[Ripz]

ASTM E112 details how to go about performing the measurement of teh grain structure, but it doesn't actually tell you when the grain measurement should be taken. This is captured in the material specification, which in this case is ASTM A351.
A report of grain structure isn't needed to fulfil the requirements of ASTM A351.

 

[reverman]

Typically austentic A351 casting micro-structures are examined per ASTM A262. Because the main thing of concern when dealing with the microstructure of these materials is the susceptibility to intergranular attack.


Normally you do a Practice A but if the results are inconclusive you move to a practice B or C.

 

[SJones]

The test appears to be required by the purchase specifications for information, rather than the manufacturing specifications for acceptance/rejection. With a good etch, ASTM E112 can be applied. Any reasonable metallographic laboratory should be capable of undertaking the measurements and reporting.

Steve Jones
Corrosion Management Consultant

http://www.linkedin.com/pub/8/83b/b04

All answers are personal opinions only and are in no way connected with any employer.

 

[kpm21443]

Many thanks Ripz for your advise. I saw A351 & learned that it does not call for microstructure / average grain size tests.

Dear reverman (Mechanical)& SJones - Many thanks for your advise. Based on advise from Ripz, I saw A351 & learned that it does not call for microstructure / average grain size tests. Please send your advise.

 

[jwhit]

Grain size per E112 is uncommon but not unheard of for A351 CF3M. ASTM A262 Prac. A is commonly used to look for carbide precipitation, as reverman mentioned. Since the customer asks for it, you have the options of questioning the need, or just going ahead and satisfying the requirement, which is probably where you will finally end up, regardless. The most important thing for you is to make sure you charge for the additional testing.