Impact of finish-forging temperature on structure and properties of micro-alloyed steels

Abstract

Production of forgings made of micro-alloyed steels brings lower production and processing costs, better utilisation of steel properties and higher quality of forged pieces. Forgings made of sub-eutectoid steels micro-alloyed with vanadium, niobium and nitrogen are mostly used for components for assembly of vehicles and machines. Steels for forgings can be classified in dependence on requirements concerning dominant mechanical properties from several viewpoints. They can be classified on the basis of yield point, required level of strength, resistance against brittle fractures, parameter of formability, value of guaranteed weldability, etc. In practice these steels are often classified on the basis of their strength properties. Strength properties depend in certain extent on method of production of the given forging. On the basis of used production technology it is possible to classify the forgings to forged pieces supplied in these conditions: as is after forging, after full annealing, after heat treatment, after controlled forging, and after controlled forging with controlled cooling.