Property variation in metals
Property variation in metals
(OP)
Can anyone give an estimate of what the expected property variation would be in metal components of the same type and design. For example, if 1000 steel beams are manufactured using the same process with the same grade steel and the same heat treatment from the same batch of raw material, I would assume the tensile strength to vary by less than 5% between each beam. Is this assumption realistic??
Any web links discussing this would be great.
Thanks for any help.
Any web links discussing this would be great.
Thanks for any help.





RE: Property variation in metals
RE: Property variation in metals
RE: Property variation in metals
In structurals you might find 5% from one part of the shape to another.
The other part of this issue is what the real properties are. If the spec requires 40ksi yield and 60ksi tensile as minimums, will you get 45/70 or 55/90? For a lot of grades most actual strenghts are way above the minimums.
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RE: Property variation in metals
RE: Property variation in metals
The one variable in your quote above that really influences properties, given all other factors as being equal (especially heat treatment), is the "same batch of raw material". I can tell you that having seen submittals for new material for adoption by ASME Section II Part D, 5% variation in properties is reasonable for material that is heat treated under similar conditions and was supplied from a master heat. This is the reason why Appendix 5 of ASME B&PV Code, Section II requires three different heats of new material to assure a range of mechanical properties for similar heat treatment conditions before endorsing the material for use.
RE: Property variation in metals
Thanks for your help.
RE: Property variation in metals
Are these steel bolts? If so, this is on the low side of available properties. It is very possible that a manufacturer might supply higher strength bolts because it was cheaper to use some leftover higer strength bolts than to make a few lower strength ones.
Regards,
Cory
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