Austenite Grain Growth Analysis in a Welded Joint of High-Strength Martensitic Abrasion-Resistant Steel Hardox 450

Abstract

The paper presents the results of tests of a welded joint of Hardox 450 steel, belonging to the group of weldable high-strength boron steels with increased resistance to abrasive wear. As a result of the conducted research, apart from the basic structural indicators, an attempt was made to determine the correlation between the grain size of the prior austenite in the characteristic weld zones and its basic mechanical properties, such as yield point, tensile strength, percentage elongation after fracture, reduction of area, and impact strength. The scope of research quoted above was carried out for a welded joint of the considered steel at delivery state (directly after welding), in the normalising annealed state, as well as in water-quenched state, using different austenitisation temperatures in the range of 900–1200 °C. The results obtained showed a large influence of the parameters of the applied thermal heat treatment on the selected structural and mechanical properties of the welded joint.

Materials Selection and Design Options Analysis for a Centrifugal Fan Impeller in a Horizontal Conveyor Dryer

“…This steel has high wear resistance, good bending and stamping, and good welding ability. The results obtained in [44] showed a large influence of the parameters of the preliminary heat treatment on the selected mechanical properties of the welded joints of this steel. Although the relatively high price, the combination of these properties makes it the good choice for centrifugal fan impeller manufacture with considerably increased strength and service life.…”

Evaluation of the Properties and Microstructure of Thick-Walled Welded Joint of Wear Resistant Materials

“…In [ 39 ], it has been demonstrated that the increase in the prior austenite grain size in Hardox 450 steel from 18 μm to 124 μm results in a more than a 3.5-time reduction in the impact energy. The significant prior austenite grain growth in Hardox steel which has a material impact on the properties of this group of steels is observed at above 1000 °C [ 42 ]. In turn, the Authors of [ 5 ] indicate that the time of cooling in the range of 800–500 °C to ensure the proper toughness of the welded joint should not be less than 3 s. The fracture toughness of high-strength steel joints is also significantly affected by the heat input; its value greater than 20–30 kJ/cm results in a significant reduction in the impact energy of the produced test joint not only in room but also at a reduced temperature [ 5 ].…”

Investigation fatigue crack initiation and propagation cruciform welded joints by extended finite element method (XFEM) and implementation SED approach

“…he Hardox 450 steel is characterised by a microstructure of quenching, contains lamellar crystals, which are likely due to γ → α shear transformation, and fragmented α phase crystals with weak misorientations, consist of the martensite with a slate-like morphology with areas of tempered martensite Fig. 5 [56,57]. According to the cooling rate and the amount of carbon, the microstructure consists of the refined and tempered lowcarbonlath-type martensite with fine acicular ferrite, widmanstatten ferrite and pearlite were formed Fig.…”