4140 Investment Cast Steel Strength Properties?
4140 Investment Cast Steel Strength Properties?
(OP)
What should the hardness be for 4140 investment cast steel? As cast, not heat treated.
One reference shows an Rb of 100. Checked some parts which show Rb 80-85 (converted from Rc scale). Having to check using Rc tester and getting Rc of 0 to 2. Looks like Rb 100 should convert to approx. Rc 22.
We have seen ususual wear on 2 parts hardness checked on.
Thanks,
One reference shows an Rb of 100. Checked some parts which show Rb 80-85 (converted from Rc scale). Having to check using Rc tester and getting Rc of 0 to 2. Looks like Rb 100 should convert to approx. Rc 22.
We have seen ususual wear on 2 parts hardness checked on.
Thanks,





RE: 4140 Investment Cast Steel Strength Properties?
Also need to know the chemistry of the parts and how they were cooled to ambient temp.
RE: 4140 Investment Cast Steel Strength Properties?
The hardness of 4140 investment castings in the as-cast condition can vary widely. The values you get are going to depnend on the cooling rate from the casting temperatures, the amount of surface decarburization you have, and the amount of surface preparation done prior to taking the hardness test.
I don't know why you would use 4140 investment cast without a specified heat treatment after casting. If you aren't interested in the mechanical properties (or, put another way, if 80-85 HRB is acceptable), there are steel chemistries that would be easier to process (read: cheaper to make). Depending on the size of the casting and the application, I suspect you should be specifying either a quench and temper or normalize and temper heat treatment.
rp
RE: 4140 Investment Cast Steel Strength Properties?
Was there a hardness requirement in the original spec?
RE: 4140 Investment Cast Steel Strength Properties?
Even though our dwg does not specify a hardness range, does this range look too broad?
Part is running against a steel part which has a hardness of Rc 33 with grease between the running surfaces, so may not want it heat treated so as to be closer to the hardness of the mating part.
RE: 4140 Investment Cast Steel Strength Properties?
RE: 4140 Investment Cast Steel Strength Properties?