Patent ID: 7540402
Filing Date: 2009-06-02
Classification: B23K,C21D

Abstract:
1. A method of forming a steel structure comprising the steps of: providing a first surface of a hardenable ferrous alloy having a carbon content equal or greater than 0.08% by weight; providing a second surface of a hardenable ferrous alloy having a carbon content equal or greater than 0.08% by weight; positioning said first surface adjacent to said second surface; welding said first surface to said second surface by applying a first heat source to said first surface and said second surface at a sufficiently high temperature to said first surface and said second surface above their melting points to form a weld; applying a second heat source to said weld immediately after said step of welding so as to be prior to said weld cooling below the martensitic finish temperature for said ferrous alloys, said second heat source being at a temperature lower than said first heat source but at a sufficiently high temperature and maintained for sufficient long time period so as to reduce the hardness of said weld; and subsequent to applying the second heat source to said weld, allowing said weld to cool to ambient temperature.