Heat treatment conditions to prevent failure in die cast X38CrMoV5 steel parts

Measurement of martensitic packet size by EBSD in the high strength steel X38CrMoV5-1 and estimation of its influence on cleavage fracture

“…In previous studies, the authors have shown that parts manufactured by wax casting can be used as safety components in equipment such as lifts, despite the fact that dendritic microporosity can cause brittle fracture at loads well below the yield strength [1]. In the present work, a X38CrMoV5-1 steel has been manufactured by continuous casting and hot rolling to obtain a 25 mm thickness porosity-free plate.…”

“…Other authors have also used Eq. (1) to seek a connection between the microstructural unit and "d". For martensite laths, where a high dislocation density may cause a brittle fracture without any plastic deformation, some researchers accept a γ p value of between 7-9 J m −2 [21,22] while others increase this value up to 14 J m −2 [23].…”

“…It is interesting to note that in bainitic steels with an upper bainitic microstructure, the microstructural characteristic or unit responsible for crack formation and its propagation presents larger dimensions that in this studied case, which justifies a higher toughness in martensitic steels than in bainitic steels with similar ultimate strength. Equation (1) has been used in this study to determine the critical microcrack length that propagates when subjected to loads, irrespective of where the crack origin is located. In this tempered martensitic microstructural steel with approximately spherical VCN precipitates, Curry and Knot [22] consider that crack nucleation will be originated in the breakage of some precipitate, particularly the larger ones.…”

“…X38CrMoV5-1 (H11) steel is widely employed in hot forming applications such as pressure die casting for light alloy injection. Its martensitic microstructure presents a hardness ranging between 40 and 56 HRC depending on the tempering temperature, which is usually between 550 and 600 • C. Its most common application is as hot work tool steel, but its high strength makes it suitable for manufacturing safety parts that require high strength (1400 MPa) and a minimum absorbed energy of 12 J [1].…”

Selected Properties of Hardfacing Layers Created by PTA Technology

“…Using a smaller grit size or lubrication during the grinding process can greatly improve surface roughness and minimize surface defects. The ground surface then exhibits residual tensile stresses in the grinding direction and residual compressive stresses perpendicular to the grinding direction [16][17][18]. When machining 303 steel with specific parameters and in various environments, it is shown that the lowest values of microhardness and roughness were achieved when machining in a dry environment.…”