Patent ID: 11885289
Assignee: CATERPILLAR INC.
Field: Materials, metallurgy (Chemistry)
Classification: CPC C  F | IPC C  F

Claim 5:
6. A fuel system for a machine comprising one or more fuel injection components, wherein at least one of the fuel injection components comprises a body having:
an outer layer including an outer surface having a first hardness of at least about 55 Rockwell Hardness Scale C (HRC) and compressive stress and positioned on an external surface of the body, wherein the outer layer has a first carbon content in a first range of about 0.7% by weight to about 1.6% by weight and has a thickness of at least 300 microns (μm); and
a core layer encased by the outer layer, the core layer having a second hardness less than about 55 HRC, a second carbon content in a second range of 0.17% by weight to about 0.5% by weight, and tensile stress, wherein the second range and the first range are non-overlapping,
wherein, a third hardness at a first depth of about 250 microns (μm) from the external surface is at least about 59 HRC and a fourth hardness at a second depth of about 600 μm from the external surface is less than about 53 HRC after the one or more fuel injection components is exposed to a temperature of at least about 300° C. in an operating environment for at least about 3 hours.