Machining Gray Iron vs. Ductile Iron
Machining Gray Iron vs. Ductile Iron
(OP)
I have been asked by a customer to give them a new quote on machining a casting that is currently cast in 65-45-12 ductile. They want to know what the cost savings would be if it was machined from Class 30 Gray Iron. Is there a rule of thumb for quickly figuring a new time? I'm thinking in the way of a percentage factor such as adding or subtracting a certain percentage of the machine time to obtain a new time to go by.
Thanks.
Thanks.





RE: Machining Gray Iron vs. Ductile Iron
RE: Machining Gray Iron vs. Ductile Iron
I am unable to quantify the benefit,but I am certain that it will be substantial.
Why is the component being down graded from ductile iron to gray iron?
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RE: Machining Gray Iron vs. Ductile Iron
You should see some decrease in the machining time, but unless the numbers are high enough, is it worth the effort?
Consider these items:
1) requote the job - quantity of parts per year
2) retool the job - machining time and machine operation type, milling, turning or drulling, etc.
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Ben Loosli
RE: Machining Gray Iron vs. Ductile Iron
RE: Machining Gray Iron vs. Ductile Iron
g ductile iron on their equipment, so they would job it out to other shops. You should see about a 20 % decrease in time but an increase in time for clean up. I have been in the machining business for about 36 years now and ductile iron is one of the most messiest and abrasive materials i have used. It will ruin your equipment unless you stay on top of cleaning up and taking precautions to protect your equipment
RE: Machining Gray Iron vs. Ductile Iron
Machinery's Handbook (25thEd) list cutting speeds for these as follows for the respective cutter type:
Gray BHN 190-220; HSS 80 fpm / Carbide 275 fpm
Ductile BHN 140-190; HSS 100 fpm / Carbide 450 fpm
The dust comes primarily from the flake graphite in gray iron which also acts as a lubricant (ways in machine bases are made from gray iron). The abrasion is probably coming from sand which has adheared to the outside or inside of the casting. Advise the foundry to use proper cleaning methods.
Tim
www.dom-met.com