Method for hardening stainless steel and molten salt bath for realizing said process

US7909943B2 · kind B2 · utility

Assignee

• Durferrit GmbH · DE

Inventors

• Ulrich Baudis · Hanau, DE
• Michael Niedermeyer · Neulußheim, DE

Key dates

• Filing date: Jun 11, 2007
• Grant date: Mar 22, 2011
• Expiry date: Oct 2, 2029

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C23C8/56
• WIPO field: Surface technology, coating
• WIPO sector: Chemistry

Abstract

A process for hardening a work piece of stainless steel through diffusion of the elements carbon and/or nitrogen into the work piece surfaces. The work piece is submerged into a molten salt bath and subjected to the molten salt bath for a period ranging from 15 minutes to 240 hours at temperatures below 450° C. In addition to potassium chloride and lithium chloride, the molten salt bath contains an activator substance consisting of barium chloride, strontium chloride, magnesium chloride and/or calcium chloride, and a free or complex cyanide as carbon-donating substance.