ASTM A352 LCB and LCC 1

[amirparviz]

Dear All,

Could somebody help me to undrestanding what is differences between Casting valve material ASTM A352 LCB and A352 LCC,
we request in our material requsition for castin valve body
in Low Temperature ASTM A352 LCB while Vendor quotation offer ASTM A352 LCC, I realy could not find a rational reason for accepting or rejection?
Does anybody knows?

 

[terje61]

Hello Amirparviz,

The tensile strength of LCB is 450 - 620 N/mm2
The tensile strength of LCC is 485 - 655 N/mm2

The yield of LCB is min. 240 N/mm2
The yield of LCC is min. 275 N/mm2

All other properties are identical. This means that LCC is a better grade than LCB and normally automatically qualifies in case LCB is requested.

Best regards,
Terje

 

[abscott]

Amirparviz,

I agree with the comments from terje61. The American National Standard for rating valves is ANSI/ASME B16.34 and the rating tables are based on the material yield strength at various temperatures. Below is a comparison for Class 600 valves:

ASTM A352,LCB @100F, 1390 psig, @500F, 1165 psig
ASTM A352,LCC @100F, 1500 psig, @ 500F, 1330 psig

LCC is rated higher based on the increased strength and is generally accepted as a substitute for LCB

 

[PeterIgg]

Guys,

Unless my specs are well out of date the main difference I see is that the carbon content of LCB is 0.3% max and LCC is 0.25% max. Consequently LCC is better if welding is a consideration. My normal response is that LCC is basically a subset of LCB, that is all LCC will comply with the requirements of LCB but not the reverse. ASME B16.34 gives differing MOP for LCB and LCC (LCC > LCB), in line with the min tensile properties noted in the above replies. The same holds true for WCB and WCC. The max Manganese content of the "C" is higher than the "B" but in the notes the "B" allows more Manganese the lower the Carbon is relative to the maximum allowance to such an extent that if you have WCB/LCB with Carbon 0.25% (i.e. as per WCC/LCC limits) the max allowable Manganese is as per WCC/LCC!

I have seen WCB/LCB specified with a max Carbon of 0.25%, why the specifying engineer did not just specify WCC/LCC is beyond me.