ethod of using Si.sub.3 N.sub.4.Y.sub.2 O.sub.3.SiO.sub.2 ceramic system for machine cast iron
AssigneeFord Motor Company
InventorsShyam K. Samanta, Krishnamoorthy Subramanian, Andre Ezis
Life of this patent
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Abstract
A process for machine cutting of cast iron with a shaped tool which is a ceramic having as constituent ingredients about 4 to about 12% by weight Y.sub.2 O.sub.3 and a balance consisting essentially of Si.sub.3 N.sub.4 and which has a density of at least 3.25 gm./cm.sup.3.
Claims10
A process for machine cutting of cast iron stock with a shaped ceramic cutting tool, comprising moving said shaped ceramic cutting tool relative to and in engagement with said cast iron stock to remove a cast iron chip, said ceramic cutting tool being the densified and fused product of compacting and heating together about 4 to about 12% by weight Y.sub.2 O.sub.3 with a balance (about 96 to about 88% by weight) consisting essentially of Si.sub.3 N.sub.4 until said product has a density of at least 3.25 gms./cm.sup.3.
A process for machine cutting of cast iron stock with a shaped ceramic cutting tool, comprising moving said shaped ceramic cutting tool relative to and in engagement with said cast iron stock to remove a cast iron chip, said ceramic cutting tool being the densified and fused product of compacting and heating together about 4 to about 12% by weight Y.sub.2 O.sub.3 with a balance (96 to 88% by weight) consisting essentially of Si.sub.3 N.sub.4 until said product has a density of at least 3.25 gms./cm.sup.3 and a thermal shock parameter determined by the formula
- KS/.alpha.E
- wherein K is the thermal conductivity of the material, S is the modulus of rupture, .alpha. is the coefficient of thermal expansion and E is Young's modulus, said thermal shock parameter at 1200.degree. C. being at least 26.times.10.sup.9 (BTU-lbs.)[hr. (in..sup.3)].
A process for machine cutting of cast iron stock with a shaped ceramic cutting tool, comprising moving said shaped ceramic cutting tool relative to and in engagement with said cast iron stock to remove a cast iron chip, said ceramic cutting tool being the densified and fused product of compacting and heating powder having as constituent ingredients about 4 to about 12% by weight Y.sub.2 O.sub.3 and a balance (about 96 to about 88% by weight) consisting essentially of Si.sub.3 N.sub.4 until said product has a density of at least 3.25 gms./cm.sup.3, a hardness level of at least 86 using the Rockwell 45-N standard and a physical strength as measured by the 4-point bend test of at least 70,000 psi at 700.degree. C.
A process for maching cutting of cast iron stock with a shaped ceramic cutting tool, comprising moving said shaped ceramic cutting tool relative to and in engagement with said cast iron stock to remove a cast iron chip, said ceramic cutting tool being the densified and fused product of compacting and heating together about 4 to about 12% by weight Y.sub.2 O.sub.3 with a balance (about 96 to about 88% by weight) consisting essentially of Si.sub.3 N.sub.4 and containing SiO.sub.2 until said product has a density of at least 3.25 gms./cm.sup.3, said SiO.sub.2 being present in an amount such that the Y.sub.2 O.sub.3 /SiO.sub.2 weight ratio exceeds 1.60.
Dependencies are inferred from the claim text.