Process of making a composite bearing race or the like

Claim 2

A process of making a unitary annular member of integral metal of varying composition across the member to permit the metal of the member to be substantially harder and less ductile near one periphery of the annular member than is the metal near the opposite periphery of the annular member, which process comprises centrifugally Casting a metal of a first composition in a hollow zone of generally circular cross section that is rotated about an axis passing through the center of the cross section, and then before appreciable solidification of the first metal centrifugally casting inside of said first metal a metal of another composition, the centrifugal casting being carried out so that said metals form after solidification a unitary annular cast body of integral metal of a varying composition across the cross section of the solidified body between its inner and outer peripheries; and hot working an annular member formed of said body at hot working temperature by subjecting said annular member to a substantial generally radial compressive force on opposite peripheral sides thereof around its entire circumference until the grain structure thereof is such that after the annular member has been cooled and the portion at a peripheral side thereof is subjected to heat-hardening treatment so that the hardened portion has substantial greater hardness than the remainder of said annular member and the remainder of said annular member is substantially more ductile and tough than said hardened portion.

Claim 3

The process of claim 1 in which said annular member is hot-worked by subjecting it to compressive general radial forces on opposite peripheral sides thereof as the annular member is rotated relative to the location of application of said forces to cause said forces to be applied entirely around the circumference of the ring, the forces being sufficient to cause a substantial reduction in the thickness of the annular member.

Claim 4

The process of claim 1 in which said annular member while at hot-working temperature is subjected to hot-working by substantially compressing it generally transversely of the annular member to cause a substantial reduction in the width of said annular member.

Claim 5

The process of claim 1 in which said annular member while at hot-working temperature is subjected to hot-working by substantially compressing it generally transversely of the annular member before said annular member is subjected to hot-working by subjecting it to said radial compressive forces.

Claim 6

The process of claim 1 in which said first and second metals that are centrifugally cast are steels of different compositions, one of said compositions containing ingredients in proportions that will cause the solid metal to achieve substantial hardness on heat-hardening and the other of said metals being a steel of a composition containing ingredients in proportions such that the steel will be substantially more ductile and tough than said hardened portion.

Claim 7

A process of making a unitary annular member of integral metal of varying composition across the ring to permit the metal of the annular member to be substantially harder and less ductile near one periphery of the annular member than is the metal near the opposite periphery of the annular member, which process comprises centrifugally casting a metal from a first composition in a hollow zone of generally circular cross section that is rotated about an axis passing through the center of the cross section, and then before appreciable solidification of the first metal centrifugally casting inside of said first metal a metal of another composition, the centrifugal casting being carried out so that the metals form a unitary annular tubular cast body of integral metal of varying composition across the cross section of the solidified body between its inner and outer peripheries; forming a unitary annular member of said integral metal from said tubular cast metal body; heating said annular member to a temperature sufficient to permit it to be hot-worked; and hot working said annular member while at hot-working temperature by subjecting it to substantial generally radial compressive forces on opposite peripheral sides thereof throughout the circumference of the annular member until the grain structure thereof is such that after the annular member has been cooled and the portion aT a peripheral side thereof is thereafter subjected to hardening treatment the hardened portion has a substantially greater hardness than the remainder of said annular member and the remainder of said annular member is substantially more ductile and tough than said hardened portion.

Claim 8

A process of making a unitary annular member of integral metal of varying composition across the ring to permit the metal of the annular member to be substantially harder and less ductile near one periphery of the annular member than is the metal near the opposite periphery of the annular member, which process comprises centrifugally casting a metal from a first composition in a hollow zone of generally circular cross section that is rotated about an axis passing through the center of the cross section, and then before appreciable solidification of the first metal centrifugally casting inside of said first metal a metal of another composition, the centrifugal casting being carried out so that the metals form a unitary annular tubular cast body of integral metal of varying composition across the cross section of the solidified body between its inner and outer peripheries; forming a unitary annular member of said integral metal from said tubular cast metal body; heating said annular member to a temperature sufficient to permit it to be hot-worked; and hot working said annular member while at hot-working temperature by subjecting it to substantial generally radial compressive forces on opposite peripheral sides thereof throughout the circumference of the annular member until the grain structure thereof is such that after the annular member has been cooled and the portion aT a peripheral side thereof is thereafter subjected to hardening treatment the hardened portion has a substantially greater hardness than the remainder of said annular member and the remainder of said annular member is substantially more ductile and tough than said hardened portion.

Claim 9

The process of claim 6 in which said annular member is hot-worked by subjecting it to compressive general radial forces on opposite peripheral sides thereof as the annular member is rotated relative to the location of application of said forces to cause said forces to be applied entirely around the circumference of the annular member.

Claim 10

The process of claim 6 in which said annular member while at hot-working temperature is subjected to hot-working by substantially compressing it generally transversely of the annular member.

Claim 11

The process of claim 6 in which said annular member while at hot-working temperature is subjected to hot-working by substantially compressing it generally transversely of the annular member before said annular member is subjected to hot-working by subjecting it to said radial compressive forces.

Claim 12

The process of claim 6 in which said metals that are centrifugally cast are steels of different compositions, one of said compositions containing ingredients in a proportion which will cause the solid metal to achieve substantial hardness on heat-hardening and the other of said metals being a steel of a composition containing ingredients in proportion such that the steel will be substantially more ductile and tough than said hardened portion.

Claim 13

The process of claim 6 in which three metals are centrifugally cast to form said tubular cast body, each of said metals having a different composition, and the resulting solid tubular cast body is formed of integral metal throughout its cross section from one periphery to the other.

Claim 14

The process of claim 11 in which said three metals are steels of different compositions.

Claim 15

The process of claim 1 in which said annular member is machined to form a bearing race, including a raceway on the peripheral side thereof at which the metal has maximum hardenability, and in which the portion of the metal forming the raceway is subjected to heat-hardening treatment to harden the metal forming the raceway surface.