ASTM A48 cast iron test bar size

[Tmoose]

We are ordering some fairly large castings made of ASTM A48 Class 35 cast iron. Each casting weights Around 1000 lbs. It is a hub with bores machined for a large roller bearing. Very low stress, with service temperatures less than 200°F. It will be LP or MT inspected for surface soundness.

For years or even decades I suspect we would have ordered "ASTM A48 Class 35" cast iron.
By rights, according to ASTM A48, when placing the order we are supposed to also specify the size of the separately cast test bars that will be used for the required tensile testing. test bar sizes are A, B, C, or S.
The size of the test bar should be based on the thickness of "controlling section" of the cast part.

Thickness of the Wall of the Controlling Section of the Casting, in. [mm] Test Bar
Under 0.25 [under 5] S
0.25 to 0.50 [5 to 14] A
0.51 to 1.00 [15 to 25] B
1.01 to 2 [26 to 50] C
Over 2 [over 50] S
​

The current casting wall ranges from about 1.0 " to 2.33".
I'm thinking Test Bar C would be OK.

"Unless the size of the tension test specimen to be machined from test bar C is specified in writing by the purchaser, the decision whether to use tension test specimen B or C shall be made by the manufacturer of the castings"

I am reluctant to get much more "scientific" with the ASTM spec.

Am I unintentionally looking for trouble sticking with Test Bar C ?

thanks,

Dan T

 

[EdStainless]

Which test bar size are they using? It should be listed on the MTR.
If specs says that you can specify then do so, but there may be a cost involved.
I would start this as a discussion (maybe a personal visit) to figure out what the current practice is.
For these lower strength grades I am not sure that the size matters that much.

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P.E. Metallurgy, consulting work welcomed

 

[casting supplier]

If i was the foundry, it is not necessary to specify the test bar to me , i will simply cast a cast on round bar dia. 50mm, and machined it according to astm norm, and test it on tensile tester.

you dont have to be bothered

Pike Li
uxitech.net