FOERFARANDE OCH ANORDNING FOER VAERMEBEHANDLING AV STAOLSTAENGER.

摘要

A method and apparatus for the direct heat treatment of a medium- to high-carbon steel rod in which the formation of martensite is prevented, even if the starting billet contains segregation. A hot-rolled rod is transported on a conveyor in the form of a sequence of non-concentric rings. The rod is then subjected to controlled cooling in a coolant so that the greater part of any austenite in the entire length of the rod is substantially uniformly transformed to a fine pearlite structure. The sequence of non-concentric rings of the rod is next held at a temperature of 450 DEG -630 DEG C. for a period of 60-300 seconds, with the pitch between each ring being made smaller than at the inlet of the conveyor. Accordingly, a pearlite transformation is effected of any residual austenite.