DRILLING ELEMENT FOR DRILLING ON HARD ROCKS AND METHOD FOR HARDENING DRILLING ELEMENT

摘要

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.