Instrumented testing of simulated Charpy specimens made of microalloyed Mn−Ni−V steel

Abstract

Standard Charpy specimens were thermally treated using “SMITHWELD” device to simulate different areas of HAZ in the base metal and in the weld metal. The base metal was microalloyed Mn−Ni−V steel of StE 460 class, welded by submerged arc process with S2 Ni welding wire and OP 121 TT welding flux. Simulation of HAZ in base metal was carried out under different regimes, including re-heating. Specimens for simulation of different areas of HAZ in weld metal were cut from welded joints transverse to the welding direction and also simulated under different regimes. Testing of simulated specimens from base metal was performed at +20, −20 and −60°C, whereas simulated specimens from weld metal were tested at −60°C. Using Charpy instrumented pendulum with osciloscope the total energy (A t ) was separated into the energy for crack initiation (A i ) and the energy for crack propagation (A p ). Using metal was determined. The microstructure was also examined in order to explain the values of toughness obtained by Charpy instrumented pendulum.