Flange bolts to ASME B31.1

[borobam182]

Hello,

I have a question regarding bolt material. I'm hoping someone can help me.

I have a stainless steel flange (Gr304), class 600, 550oC design temperature, 27barg design pressure, and I'm designing to ASME B31.1.

I dont know if I should be using A453 Gr 660 bolts or A193 Gr B8 Class 1 bolts.

I've had a look in ASME B16.5 and it recommended using A193 Gr B8 Class 1 for class 150 and class 300 flanges, and A453 Gr 660 for class 600 and upwards.

I have my doubts about this as ASME B31.1 doesn't provide allowable stress values for A453 Gr 660 bolts, which confuses me, so I'd like the opportunity to discuss with someone else.
Any help would be greatly appriceated.

Thank you

 

[keyen]

Why not use A193 B8 Class 2?

 

[borobam182]

Hi Keyen,

A193 B8 Class 2 doesn't have allowable stress values at the elevated temperatures like A193 B8 Class 1 does.