HOW to read a hardness value on ITT curve ?
HOW to read a hardness value on ITT curve ?
(OP)
Please what is the value of this hardness ?
How to read value on ITT curves ?
How to read value on ITT curves ?
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HOW to read a hardness value on ITT curve ?
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RE: HOW to read a hardness value on ITT curve ?
Normally, if hardness data is reported it would be provided for CCT (continuous cooling transformation) diagrams on the abscissa versus TTT diagrams. The reason is that the hardness will vary as a function of cooling rate, which is more appropriate for CCT diagrams.
The hardness data reported on the ordinate in the above TTT diagram may be after complete transformation has occurred at ambient temperature for this material. I would suspect the hardness data was added in the text where this TTT diagram was referenced.
RE: HOW to read a hardness value on ITT curve ?
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Cory
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RE: HOW to read a hardness value on ITT curve ?
" All that is necessary for triumph of evil is that good men do nothing".
Edmund Burke
RE: HOW to read a hardness value on ITT curve ?
Hardness range between 95HRb to 27 HRc.
RE: HOW to read a hardness value on ITT curve ?
In fact i need to know what is the Hardness of this alloy after tempering at 550°C during 6 hours.
Is it the correct way to use TTT Curve ?
RE: HOW to read a hardness value on ITT curve ?
The above posts adequately explain how to use the hardness scale superimposed on the above TTT diagram. The TTT diagram and superimposed hardness scales, however, should not be used for determining hardness after tempering.
A 6 hour tempering duration requires actual hardness testing. Most tempering charts for steels provide hardness data after tempering only 1 hour at temperature. Your only other option is to calculate a tempering parameter from known hardness data (a graph of hardness versus tempering temperature) and use the relationship similar to the Larson Miller parameter, where the hardness is a function of tempering time and temperature.