SAE Grade 8 Bolting in low temperature service

[JohnKTexas]

I have 4000 bronze bodied three piece ball valves with Grade 8 bolting. The manufacturer has rated the valves to -20 F service conditions.

I am using the valves at 1/3rd the rated valve pressure and want to know how I can justify a lower working temperature based on the lower working pressure I am using the valves in.

I do not want to change out all 4000 valves with SS bolting if I can help it.

Can someone show me a method to rate Grade 8 bolts to temperatures of -30 F. The bolt sizes wre 5/16" to 1/2"

 

[vpl]

Just because your pressure is lower doesn't mean you can lower the temperature that the valves can take.

Also, you can't just replace the bolting; you also need to verify that the valve themselves will withstand the lower temperature.

I suggest contacting the manufacturer and asking about the servicibility of the valves at the temperatures you need.

Patricia Lougheed

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