Interpret German HT requirements
Interpret German HT requirements
(OP)
I have a German drawing calling out a heat treament requirement. I think it is based on the Vickers scale. It is a large centering ring for a hub that helps keep a shaft centered while in the hub and the ID of the ring is hardened to resist wear.
The drawing has 740 #40HV then beneath that it says Eht 2 +0.5
Is that case depth of 2mm to 2.5mm? Is that a Vickers of 740 using a 40 kg weight to determine hardness?
In German it says: "vorgedreht zurn Aufkohlen und Härten einsatzgehärtet und angelassen" showing an area outlined.
Another line says "geschützt vor Aufkohlung" showing an area outlined. I am guessing it means protect from carburizing.
Thanks for the help.
The drawing has 740 #40HV then beneath that it says Eht 2 +0.5
Is that case depth of 2mm to 2.5mm? Is that a Vickers of 740 using a 40 kg weight to determine hardness?
In German it says: "vorgedreht zurn Aufkohlen und Härten einsatzgehärtet und angelassen" showing an area outlined.
Another line says "geschützt vor Aufkohlung" showing an area outlined. I am guessing it means protect from carburizing.
Thanks for the help.





RE: Interpret German HT requirements
Vorgedreht means rough turned. Zurn is not correct - it is zum. Aufkohlen means carburized, härten means hardening, and angelassen means tempered. I think this means to rough turn the part up to the region that has been carburized, hardened, and tempered.
Yes, the second clause means protect from carburization.
Regards,
Cory
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