Drill rod and method of manufacture thereof

US7571779B2 · kind B2 · utility

Assignee

• Sandvik Intellectual Property AB · SE

Inventors

• Ann-Cathrin Hedlund · Sandviken, SE
• Kenneth Larsson · Sandviken, SE

Key dates

• Filing date: Mar 24, 2005
• Grant date: Aug 11, 2009
• Expiry date: Sep 6, 2026

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C21D9/22
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

A drill rod for percussive rock drilling includes a first rod part and an additional second rod part. The first rod part includes first and second ends, an inner duct, and an external thread disposed adjacent the first end, wherein the external thread is at least partly hardened by heat treatment. The additional rod part includes first and second ends, an inner duct, and an internally thread disposed adjacent the first end thereof, wherein the internal thread is at least partly hardened by heat treatment. The first ends of the respective first and second rod parts are threadedly secured to one another, and the second ends of the respective first and second rod parts are welded together to define a weld zone having a substantially martensitic structure. If there is further provided an intermediate hollow rod part, then the second ends of the respective first and second rod parts would be welded to respective ends of the intermediate hollow part to define weld zones having a substantially martensitic structure.