Patent Number: 6,165,597

Title: Selective case hardening processes at low temperature

Abstract: A selectively case hardened steel article by low temperature carburization includes a body made of a chromium bearing nickel or ferrous based alloy (for example, stainless steel), a first portion of the body having a first hardness characteristic, and a second portion of the body having a second hardness characteristic; the second portion being less than the entire body and substantially free of carbides. One method for selective case hardening by low temperature carburization includes the steps of applying a carbon blocking mask over surface areas of the article that are not going to be carburized; activating those surface areas that are to be carburized; diffusing carbon into the activated surface areas at a temperature below which carbides readily form; and removing the carbon blocking mask.

Inventors: Williams; Peter C. (Cleveland Heights, OH), Marx; Steven V. (University Heights, OH)

Assignee: Swagelok Company

International Classification: C23C 8/04 (20060101); B32B 007/02 ()

Expiration Date: 12/26/2017