Exploring the low temperature tempering range of low alloy quenched and tempered steels

摘要

It is well known that quenched and tempered alloy steel components with ultimate tensile strength in excess of 1400 MPa are seldom employed as mechanical components, due to their not adequate ductility, as ascertained by multiple researches performed during World War II and soon after. Nevertheless, use of low temperature tempered steels in some niche applications, as well as researches performed on surface heat treated high carbon steels and on their behavior upon tempering in the vicinity of 200°C have stemmed into renewed interest in quenched and low temperature tempered low alloy steels. Application to 36NiCrMo16 steel bars is examined here, by means of tensile and hardness tests and fractographic and metallographic examinations after quenching and tempering in the 160 to 440°C temperature range.