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.

Abstract: A threaded rock drill element for percussive rock drilling includes a body forming a center axis and having a hardened thread. The thread includes thread crests and thread bottoms and a hardened zone having increased hardness. The hardened zone includes first and second hardened areas extending radially from a crest and bottom (valley), respectively, of the thread, to a boundary curve of the hardened zone. The boundary curve has convex portions extending along the thread crests, and concave portions extending along the thread bottoms.

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.

Abstract: A threaded rock drill element for percussive rock drilling includes a body forming a center axis and having a hardened thread. The thread includes thread crests and thread bottoms and a hardened zone having increased hardness. The hardened zone includes first and second hardened areas extending radially from a crest and bottom (valley), respectively, of the thread, to a boundary curve of the hardened zone. The boundary curve has convex portions extending along the thread crests, and concave portions extending along the thread bottoms.