huangyhg

determing grade of steel
i have a client who has a steel beam he has had laying around for awhile that he wants to use in a project. is there anyway to determine if its 30 or 50ksi steel? i couldn't find any stamping on it. somebody told me that not to long ago everything was grade 30, is this true? i have always speced grade 50 but i'm a young buck.. maybe its just safe to assume it's grade 30??
i would believe 36, not necessarily 30.
i think that you are refering to a-36 (36,000 psi), but if it looks older than 40 years, i probably would assume a-7 (33,000 psi).
unless your calcs show you need 50 ksi steel, it would not be worth the hassle to find out the grade. if i re
a-36 steel is still very common in hot roll plate, s beams and channels. i am told by the people at one of our steel service centers that gr 50 wf beams became prevelant in the late 90's.
i've seen an article on a hand held electrical device that claims to provide the grade of material. i have not tried it. has anyone else?
a36 is still used in most industrial settings. i just finished a project that used 30 to 40 tons of a36.
chris
"in this house, we obey the laws of thermodynamics." homer simpson
alot of steel was used for a period of time that had dual certification (36 and 50).
i've heard of a portable chemistry tester. you can use hardness as a very rough approximation of strength.
hg
doee your client need the entire beam length or can a sample be strategically removed for chemistry and tensile tests by an independent lab? i would think this is the correct method to certify a beam for use. hardness is limited to uts approximation, not ys, and portable alloy analyzers cannot measure carbon, unless you have a portable arc emission spectrograph. do it right.
just assume a36 and you will be safe unless the beam is like 100 years old
if it is 50 years old, it would be a-7 (33 ksi). if it is 80 years old, it is a-9 (30 ksi). over 100 years, it might be wrought iron.

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