Bolting material

[AMinati]

I have to use bolting material SA 320 B8M in the temperature range between -170 °C to + 65 °C.

Bolting material according to SA 193 B8M Cl.2 and SA 320 B8M seem to be the same. Same chemical composition and stresses.

Why the first can be used up to +427 °C and the second up to +38 °C only?

It is possible to have bolting material with both certification according SA193 and SA 320?

Best regards

AMinati

 

[blacksmith37]

The A 320 is defined for low temperature service; It is one of the puzzlements of ASME that they don't have the same high temp limit as A 193. Similarly, 304 L grade has much lower elevated temperature rating than 304 grade.

 

[metengr]

The reason for the two material specifications is that you have other alloys besides austenitic stainless steel grades that are not suitable for either low or elevated temperature service. Yes, the B8M can be used for low or elevated temperature service.

Low carbon grades have lower creep strength because of the lower carbon content and as a result lower value stress lines.

 

[AMinati]

Many tanks to all, I will try to certificate the bolting material with both SA-193 and SA-320 B8M!

AMinati