EFFECT OF HEAT TREATMENT ON MECHANICAL PROPERTIES AND STRUCTURE OF HIGH-STRENGTH PIPE STEELS WITH A FERRITE-BAINITE STRUCTURE

摘要

The effect of heat treatment on mechanical properties and microstructure of high-strength low-alloy ferritebainite pipe steels is studied. Specimens are heated in a laboratory furnace up to a temperature in the range 100–850℃. Dependences for the change in mechanical properties on heating temperature and the main features of steel structure are determined. TEM is used to study excess phase precipitation, including Nb and V carbonitrides, during heating. Unfavorable temperature ranges are determined for heating pipe steels with a ferrite-bainite structure. The results obtained may be used in industrial production and during development of new technology for thermomechanical treatment.