Experimental determining of fracture behaviour of P460NL1 steel welded joint specimens

Abstract

This paper is focused on the experimental measuring of impact energy as a part of the doctoral dissertation involving the fatigue behaviour of welded joints, made of fine grain normalised micro-alloyed low carbon high strength steel P460NL1 [1,2], typically used for pressure vessels working at subzero temperatures. VAC 65 [3] was used as filler material, and two plates were welded using the MAG welding procedure (with 82% Ar + 18% CO2 shielding gas). The specimens were taken from two opposite ends of the welded plate, taking into account the measured values of groove edge temperature in these locations, wherein the temperatures in Location 2 (near the end of the weld) were higher than those in Location 1 (near the weld's beginning). Based on their specific position, in terms of temperature and notch position (weld root or face), the specimens were divided into four groups of three. This testing was performed using a SCHENCK-TREBEL instrumented Charpy pendulum. The total impact energy was determined, along with its components, crack initiation and crack propagation energy. The obtained results have confirmed that the test specimens were of high toughness, with total impact energy ranging from 165200 J, at room temperature. The crack propagation energy was the dominant component, being several times greater than the crack initiation energy, as was expected.