Materials of Different Grade

[maintennance]

For a Coker Heater CHarge pump , vendors are offering different grades of material. For example for the pump shaft one vendor is offering Material ASTM A 276-431 whereas the other vendor is offering ASTM A 276 type 410. Similarly for the Shaft sleeve one vendor is offering ASTM A 276-431 and the other vendor is offering ASTM A 426-CPCA 15. What could be the selecting criteria for a pump vendor to select a material grade? The service is Fractionator bottoms and the temperature of the service fluid is 292 Deg C .Are there any major differences between the above two grades mentioned? Which one is superior? Both the pump vendors have offered the same Between bearing two stage pumps only. Thanks to clarify.

 

[arunmrao]

410 and 431 are hardenable martensitic type stainless steels,excepting that 431 has better corrosion properties approaching that of 302 grade. I used 17/4 PH for pump shaft sleeves in preference to CA15 .