Continue to Site

Eng-Tips is the largest engineering community on the Internet

Intelligent Work Forums for Engineering Professionals

  • Congratulations KootK on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!

304L specification Threaded Fittings 1

prk7734

Mechanical
Oct 24, 2024
1
I am preparing 304L SS material specification for water service (design pressure 193 psi, temp 212 F). While selecting threaded fittings (1/4"-4"), confusion is arising in specifying fittings as per ASTM A403. Does ASTM A403 covers 3000# fittings?
Example: (1) TEE, SCH10S, FNPT, ASTM A403-WP304L Size 1/4"-4"
(2) TEE, 3000#, FNPT, ASTM A403-WP304L Size 1/4"-4"
Which option is correct? If 3000# fittings are not covered, can ASTM A182 be used as its only for higher temp service?
Thanks
 
Replies continue below

Recommended for you

ASTM A403: This specification is typically used for wrought austenitic stainless steel fittings but primarily covers butt-welded fittings (elbows, tees, reducers, etc.) and does not include pressure ratings like 3000#. So ASTM A403 is generally not used for 3000# threaded fittings.

ASTM A182: This specification covers forged or rolled alloy and stainless steel pipe flanges, forged fittings, and valves for high-temperature service, and it includes pressure-rated fittings such as 3000# and 6000#. Therefore, ASTM A182 is the correct standard for specifying 3000# forged threaded fittings in 304L.

Suitability of ASTM A182 for Water Service
Although ASTM A182 is generally used for high-temperature service, it is also suitable for ambient and moderate temperatures like your application at 212°F. So, it is appropriate to use ASTM A182 F304L for threaded 3000# fittings in water service at your specified pressure and temperature.
 
If the water is high in Cl, crevice corrosion is highly likely in all of the 300 series alloys at your operaing temp.
 
What is the rational of using SS304L fittings in Cooling water service, where the pressure is not very high? 212DegC (100DegC) is high enough to cause Cl related issue for SS300 series alloys. In my opinion CS fittings are good option for water service at low pressure and moderate temperature.
 
Cl levels and pH will determine if a 300 SS will survive.
I have seen a lot of cooling water systems built in 316L, but some of them didn't make it.
If you are set on using a CRA you might need to look at 2205.
 

Part and Inventory Search

Sponsor