02-26-2018, 12:22 PM
Thanks Mike, much appreciated.
Yes, tempering is always a necessary step from full hardened state, even if recognized full hardness is not achieved.
In other words, say the maximum hardness for 52100 is HRC 65, and that hardness is achieved.
Normal tempering for maximum hardness would be something like 350°F for 2 hours, and tempering is always done twice. It would only drop the HRC to about 63, and the blade wouldn't break if you dropped it, but it would be chippy and inflexible without breaking.
There are different reasons you may not achieve maximum hardness, but if you achieve HRC 63, and use the same temper for maximum hardness, it should probably still drop HRC 2 points. Your blade would probably still be about the same level of chippy and inflexible, depending on why you didn't reach maximum hardness.
If you reach HRC 65, and temper for maximum toughness, that would probably be 450°F (twice for 2 hours being a constant). That would probably drop your hardness to about HRC 56, but the blade would be much tougher, as in more flexible and difficult to break.
Tempering does more than soften and toughen a blade, but those are the most recognized effects.
Yes, tempering is always a necessary step from full hardened state, even if recognized full hardness is not achieved.
In other words, say the maximum hardness for 52100 is HRC 65, and that hardness is achieved.
Normal tempering for maximum hardness would be something like 350°F for 2 hours, and tempering is always done twice. It would only drop the HRC to about 63, and the blade wouldn't break if you dropped it, but it would be chippy and inflexible without breaking.
There are different reasons you may not achieve maximum hardness, but if you achieve HRC 63, and use the same temper for maximum hardness, it should probably still drop HRC 2 points. Your blade would probably still be about the same level of chippy and inflexible, depending on why you didn't reach maximum hardness.
If you reach HRC 65, and temper for maximum toughness, that would probably be 450°F (twice for 2 hours being a constant). That would probably drop your hardness to about HRC 56, but the blade would be much tougher, as in more flexible and difficult to break.
Tempering does more than soften and toughen a blade, but those are the most recognized effects.