Calling out Material Condition, ie: Hardness

[rltw]

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.

 

[ctopher]

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
ctopher's home (updated 06-21-06)

 

[CoryPad]

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

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[Heckler]

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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[rltw]

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.

 

[ctopher]

A start:

http://www.incodema.com/1-607-277-7070/terms/index.cfm?showletter=H

http://www.aksteel.com/pdf/markets_...ta_Bulletin.pdf#search="condition h hardness"

hardness - the property of being rigid and resistant to pressure; not easily scratched; measured on Mohs scale



Chris
Systems Analyst, I.S.
SolidWorks 06 4.1/PDMWorks 06
AutoCAD 06
ctopher's home (updated 06-21-06)

 

[Heckler]

Here is where I do my material research

http://www.matweb.com/index.asp?ckck=1

Best Regards,

Heckler
Sr. Mechanical Engineer
SW2005 SP 5.0 & Pro/E 2001
Dell Precision 370
P4 3.6 GHz, 1GB RAM
XP Pro SP2.0
NVIDIA Quadro FX 1400
o
_`\(,_
(_)/ (_)

Never argue with an idiot. They'll bring you down to their level and beat you with experience every time.

 

[ctopher]

I use the same as Heckler also.
Another good one:

http://assist.daps.dla.mil/quicksearch/

Chris
Systems Analyst, I.S.
SolidWorks 06 4.1/PDMWorks 06
AutoCAD 06
ctopher's home (updated 06-21-06)

 

[rltw]

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.

 

[rltw]

This is my reference to the above post:

http://www.matweb.com/search/SpecificMaterial.asp?bassnum=MSH13A

 

[CoryPad]

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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