Tensile & Yield Mins Calculated from Tested Brinell hardness - not physical testing - Acceptable
Tensile & Yield Mins Calculated from Tested Brinell hardness - not physical testing - Acceptable
(OP)
Has anyone ever used heat-treated steel certification having Tensile and Yield strength minimums calculated from the tested Brinell hardness value rather than a physical strength test? Is this accurate enough to say steel meets the certification minimums if the conversion meets the min?
The material specs required on the drawing are:
AISI 4340 with tensile, yield, and hardness callout.
TENSILE: 142200 PSI MIN.
YIELD: 127980 PIS MIN.
HARDNESS: 290-340 HB
Is it acceptable practice to calculate the values from the hardness?
The material specs required on the drawing are:
AISI 4340 with tensile, yield, and hardness callout.
TENSILE: 142200 PSI MIN.
YIELD: 127980 PIS MIN.
HARDNESS: 290-340 HB
Is it acceptable practice to calculate the values from the hardness?
RE: Tensile & Yield Mins Calculated from Tested Brinell hardness - not physical testing - Acceptable
RE: Tensile & Yield Mins Calculated from Tested Brinell hardness - not physical testing - Acceptable
RE: Tensile & Yield Mins Calculated from Tested Brinell hardness - not physical testing - Acceptable
RE: Tensile & Yield Mins Calculated from Tested Brinell hardness - not physical testing - Acceptable
If the spec has tensile requirements then tensile testing is required.
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P.E. Metallurgy, consulting work welcomed
RE: Tensile & Yield Mins Calculated from Tested Brinell hardness - not physical testing - Acceptable
Even when converting to tensile, the accuracy depends heavily on materials and the material conditions (e.g. annealed vs heavily cold worked).
RE: Tensile & Yield Mins Calculated from Tested Brinell hardness - not physical testing - Acceptable
RE: Tensile & Yield Mins Calculated from Tested Brinell hardness - not physical testing - Acceptable
Hardness is shown to correlate well with tensile strength but only very loosely to yield strength and ductility. For steel, hardness and tensile strength are roughly proportional (see ASTM A 370-68 Steel Tables). The drawing that generated my question was for a small finished part where checking hardness was the only way to determine if the heat treatment was performed properly. I learned that we have always used hardness to verify the tensile for this particular part. As mrfailure wrote, converting hardness to tensile is a practical matter when tensile testing cannot be performed.
RE: Tensile & Yield Mins Calculated from Tested Brinell hardness - not physical testing - Acceptable
RE: Tensile & Yield Mins Calculated from Tested Brinell hardness - not physical testing - Acceptable
if additional tensile test are required during heat treat, sometime tensile are manufactured from any certified AISI 4340. or if it is required from the same material it must be specified
on the engineering drawing or heat treat specification. tensile must be manufactured from the same material as the parts and are manufactured from the raw stock.
if that can not be done permission must be give to use any certified material.
RE: Tensile & Yield Mins Calculated from Tested Brinell hardness - not physical testing - Acceptable
RE: Tensile & Yield Mins Calculated from Tested Brinell hardness - not physical testing - Acceptable
RE: Tensile & Yield Mins Calculated from Tested Brinell hardness - not physical testing - Acceptable