huangyhg

calling out material condition, ie: hardness
what is the proper way to specify the material hardness or heat treatment on a drawing? should i be using a "h0000" condition or just a "rc" number?
thanks.
if not covered in the material spec, i would use the h condition.
chris
systems analyst, i.s.
solidworks 06 4.1/pdmworks 06
autocad 06
the heat treatment condition gives you more important information than a hardness value. i can achieve a hardness value by many methods, but a specific heat treatment "recipe" brings with it a specific strength, fracture toughness, corrosion resistance, etc. use standards like astm, iso, mil, etc. when possible.
for hardness, please use industry standard nomenclature:
hbw - brinell with wc indenter
hrx - rockwell with x scale (where x can be a, b, c, etc.)
hv - vickers
hk - knoop
regards,
cory
it depends on what material and what hardness you're trying to achieve. for example, if i want a 17-4 ph ss condition h900 then it has a hardness associated with that condition which is rc 45. where as, if i were calling out a s-2 tool steel it could come in several different hardness depending on the quenching process.
i hope that helps.
best regards,
heckler
sr. mechanical engineer
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thanks for the help.
one more question: what's the proper definition of the "h" condition? or, better yet, where do i find a source for that?
additionally, is there a y14. standard for guidence on this matter?
thanks.
a start:
here is where i do my material research
i use the same as heckler also.
so, if i was looking to get h13 at hrc 31-33, the "h" condition would be "h1250"? so, the material callout would be "aisi h13h1250"?
thanks.
this is my reference to the above post:
rltw,
aisi no longer maintains alloy designations, so you shouldn't use it on drawings.
the "h" designations have been developed for a few alloys and are described in documents like sae ams standards. there is no h1250 developed for h13, so you shouldn't use it either.
if you know what heat treatment you need, you can write it entirely:
material: type h13 according to astm a 681
heat treatment: austenitize at 1020 °c for 30 minutes, quench in 25 °c water, temper at 560 °c for 30 minutes
hardness: 52 hrc minimum, 58 hrc maximum
if all you know is your desired final hardness, then just write that. however, this will lead to variation in final properties that may affect your parts.
regards,
cory

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