yacpro13
Mechanical
- Oct 14, 2012
- 17
Good day,
This has been bothering me for a while:
The table attached is from the MIL-HDBK-5H.
We often specify heat treatment on these steels in the range of 125-145 KSI (usually purchased in the heat-treated condition) or 145-160 KSI (requires additional heat treating). Both these ranges are below the minimum tensile strength in the table.
Now looking at this table, it appears that for everything below 180 KSI, 4140 can only be used up to 1'' diameter, and 4340 should be used above 1'' up to 3.5'' for 90% martensite at center.
Is this really the case? I ask because I found other threads on Eng-Tips where users specify much larger limiting ruling sections for these steels (with no reference, however).
So my question is, what reliable references are available for the limiting ruling sections for these 3 materials?
Thanks.
This has been bothering me for a while:
The table attached is from the MIL-HDBK-5H.
We often specify heat treatment on these steels in the range of 125-145 KSI (usually purchased in the heat-treated condition) or 145-160 KSI (requires additional heat treating). Both these ranges are below the minimum tensile strength in the table.
Now looking at this table, it appears that for everything below 180 KSI, 4140 can only be used up to 1'' diameter, and 4340 should be used above 1'' up to 3.5'' for 90% martensite at center.
Is this really the case? I ask because I found other threads on Eng-Tips where users specify much larger limiting ruling sections for these steels (with no reference, however).
So my question is, what reliable references are available for the limiting ruling sections for these 3 materials?
Thanks.