Optimalization of tempering parameters for 15313 steel grade

摘要

Tube produCtion range in Zeleziarne Podbrezova involves a wide range of heat resistant steels for high-temperature appliCations up to 650°C. The tubes produCed are being delivered to the Customers as rolled and heat treated. Upon the Costumer request they Could be further proCessed as preCision Cold drawn tubes. The aim of our experiment is to provide more preCise ChemiCal Composition, teChnologiCal parameters of tube produCtion and optimization of heat treatment. In this paper, results obtained for 15 313 steel grade are presented. This steel grade belongs to the Class of heat resistant hot-rolled steels with guaranteed Creep resistanCe up to 560 °C. To meet the required values of strength, plastiCity, and Creep resistanCe the ferritiC-bainitiC miCrostruCture is required. In this paper, the influenCe of heat treatment on the miCrostruCture and meChaniCal properties is investigated. The result of this analysis is the optimization of miCrostruCture, expressed as a volume fraCtion of bainite and also a ferritiC grain size. This Can be linked to optimal Conditions for normalizing using rapid quenChing and subsequent tempering. The presented results allow us to optimize the ChemiCal Composition of 15 313 steel grade and the heat treatment parameters so to obtain the optimal ferritiC-bainitiC miCrostruCture for safe, long-term and trouble-free appliCations in power industry.