Average expected tensile strength B31.3

[enggr1981]

Please refer to thread292-238083 for previous discussion.

As per ASME B31.3, 302.3.2 "Bases of Design Stresses" -
(f) Unlisted Materials: For a material which conforms to para. 323.1.2, the tensile (yield) strength at temperature
shall be derived by multiplying the average expected tensile (yield) strength at temperature by the ratio of ST (Sy)
divided by the average expected tensile (yield) strength at room temperature.

Could anyone inform what is the exact meaning of "Average expected tensile strength" ?
Cheers


rahul
Engineering without discipline.. without boundaries...

 

[metengr]

Yes, you need to evaluate multiple heats of submitted material. Typically, for new ASME B&PV Code Case material specification submittals three heats are desirable.

 

[enggr1981]

thanks mitengr,
The material I am using is AISI 4130. This has been documented to have Tensile strength = 95ksi and yield strength = 75ksi.
For design purpose, Can i use these values directly? For quick design i am using a temperature derating factor of 85% from 25C to 200C.
Will this be acceptable to conform ASME code?
Cheers

rahul
Engineering without discipline.. without boundaries...

 

[metengr]

enggr1981;
Yes, as long as the mechanical property values and chemistry are from a published specification.

Rules for determining allowable stress values for unpublished material are detailed in ASME B31.1 paragraph 102.3.1 (c).