Forging Surface finish - 1020 Steel 2

[JSBCintl]

What standard or normal surface finish can be expected of a 1020 Steel forging of a simple shape. See attached drawing. Also, what dimensional tolerance could be expected, ie -+ .XXX etc.

 

[unclesyd]

I believe your part is going to difficult if not impossible to forge unless the quantity is very large. I've never seen a step forging with the number of lands as in you part. You cannot easily get close to the square corners on your scale.

Can you tell the Forum as to the reason for calling out a forging instead of a machined part?
What would be an open order number per order?
Could you use a hollow bar and machine?

i would contact some one like Scot Forge to discuss your requirements. The link to Clifford-Jacobs will give you some ideas of the as forge dimensional tolerances using impression forging.

http://www.scotforge.com/index.htm

http://www.clifford-jacobs.com/capabilities/impression-forging/

 

[JSBCintl]

Thanks so much uncleyd,
The part is a mud pump piston subject to significant pressure and stress. It will be urethane coated after forging. Production quantities are 4000. Machining from bar stock is an option, but way to expensive for an aftermarket consumable wear part like this piston. Thanks for the links, I will contact them.

 

[TVP]

JSBCintl,

Here are some guidelines for achievable surface roughness:

http://www.forgingmagazine.com/feature/feature/87249/tracking_forging_fatigue_through_surface_finish

http://mdmetric.com/pdf/surfruff.pdf

http://www.engineersedge.com/manufacturing/forging-design.htm