Quenching of large forged pieces from the forging temperature

Abstract

1. No cracks form in 300 mm samples of steel No. 45 quenched directly after forging and subsequently tempered regardless of the area of the original ingot from which the sample was made. No cracks are formed in 300 mm samples of 40KhN steel quenched from the forging temperature, and the steel acquired immunity to crack formation: no cracks occur after subsequent heat treatment — quenching followed by tempering at high temperatures. Samples 500 mm in diameter of 40KhN steel made from the top of the ingot may develop cracks after quenching from the forging temperature. 2. The mechanical properties of forgings 300 mm in diameter made from carbon steel No. 45 satisfy the technological requirements after quenching from the forging temperature followed by tempering at high temperatures. 3. The results of the experiments lead us to recommend quenching from the forging temperature to prevent crack formation in medium carbon steel up to 500 mm in diameter and in alloyed steels (40KhN, 40Kh, 34KhM, 50G, 60G, 40KhNM, etc.) up to 300 mm in diameter instead of the usual prolonged annealing after forging.