Fastener material

[LahaneD]

one of my project valve datasheet sheet specifies the valve body material as A182 Gr 316L & fastener as A320 GrL43(phosphated) & A194 L7.The min temp in datasheet is -29 deg C.
I have referred A320 which states L43 grade is for ferritic material, but here my body material is austenitic.

Can I suggest alternate material for Body as A479 Gr 316L & Fastener as A193 Gr B8M/A194 Gr 8M.
What is the difference in A182 & A 479?

 

[rmw]

The A320 L43 may be being driven by ASME B31.1 due to being below -20F. Get a copy of B31.1 and read table 12 (or 112 can't remember-my stuff is at the office) on page 33, I believe.

There are alternate choices for low ambients in B31.1. If your valve is built to conform to B31.1, you may find another choice there.

rmw

 

[TVP]

You can review the title and abstract of ASTM standards at their website:

http://www.astm.org

The short answer is ASTM A 479 covers bars, not forged fittings, valve bodies, etc. With regards to the fasteners, B8M Class 1 are considerably lower in strength than L43. B8M Class 2 are strain hardened instead of annealed, so they are closer to L43, but still lower in strength. Have you accounted for this?

 

[metengr]

In addition to the above,

First comment; If you review A/SA 182, it is permitted to manufacture valves and parts under this specification using bar and shapes supplied under A/SA 479, provided the product form under A/SA 182 specification is 10,000 lbs or under in weight, and of similar grade as material specified under A/SA 182.

Second comment;
The use of grade L43 ferritic material is permitted for use in this application as long as the bolting material has been accounted for in design. Changing to an alternate material requires further evaluation to determine suitability for service conditions - preload, etc.