Mechanical Properties of A681 tool steel 1

[kertaker]

I am looking for the yield and tensile strengths of ASTM A681 tool steel. Can anyone out there provide a resource?

Thanks,

 

[jbknudsen]

I have had the same problems with A7 tool steel. I cant find material specs easily on it. What I have found in the past, and someone please correct me if i am misleading or have false info, is that I need to call our heat treater. The material begins as another base material and the material properties vary depending on the heat treat, annealing, quenching and Rockwell hardness that is desired. My suggestion, not an easy one, is to call your heat treater and discuss the process required to get the known properties that you are looking for in the A681 tool steel. If there is an easier way, someone please help out both of us.

Sorry I couldn't gie you some specifics on your material.

Best regards,
Jay

 

[TVP]

First, ASTM A 681 is a standard that covers a wide range of tool steel grades, not one specific alloy. Second, as Jay mentioned, mechanical properties are highly dependent upon composition (including uniformity/homogeneity), heat treatment, etc. And third, there is not much information available regarding yield and tensile strengths of tool steels, because they are predominantly quenched and tempered to very high hardness levels, which gives them excellent wear resistance and high resistance to compression, but poor tensile ductility. Hence, tensile testing is not performed often. If you can provide an alloy, product form, condition (heat treated, normalized, etc.), and a description of your problem, perhaps we can assist you further.

 

[kertaker]

The actual grade of the material is ASTM A681(0-1).
What I have found thus far is that ASTM does not publish strength or hardness specifications for A681 (and most other) tool steels. Their very purpose is to be made into a tool of some sort and then heat treated to obtain the desired mechanical properties. Therefore, unless someone has done some testing on this material, the data is probably not available.
Background: For several years, this off-the-shelf "drill rod" has been succesfully utilized in a pinned connection on a machine. As there are several pins used in any one machine and replacement is not too difficult, the occassional pin breakage has been just shrugged of as a part of life. My inquiry comes from the curiosity of what magnitude of load can cause these to shear.
The obvious course of action is to start using a material with known values and material certification. For proper selection, however, I'd still need to get a handle on the load. Testing a couple of samples seems to be my best bet. Any other ideas????

 

[CoryPad]

kertaker,

Physical testing of parts is the best solution. If you are interested in shear properties, the specifications below may provide guidance on how to conduct the testing:

ISO 8749 Pins and grooved pins -- Shear test , available from ISO at:

http://www.iso.ch

ASTM B769 Standard Test Method for Shear Testing of Aluminum Alloys , available from ASTM International at:

http://www.astm.org

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

 

[arto]

check these guys out:

http://www.crucibleservice.com/eselector/selectorindex/selectorindextitle.html

you can use the Tensile strength estimate from Shigley:
Su [psi] = 500*HB [Brinell hardness]
Su [MPa] = 3.45*HB

 

[Tgatica]

If the application is for a pinned joint, I suggest using hardened ground steel dowel pins. They have a single shear strength of 130,000 psi and are capable of handling double shear loads. They are available up to 1 inch diameter, which will handle a 204,000 lbf double shear load.

I got this information from Machinery's Handbook, 24th ed, page 1486-1487.

I hope this helps. Dowel pins are pretty cheap and you can easily grind snap ring grooves into them.

Tony