Evaluation of dynamic fracture toughness parameters of locomotive axle steel by instrumented Charpy impact test

Abstract

The analysis of the energy of fracture of specimens from steel OSL, which is widely used for the manufacture of railway axles under shock loading, is performed. The nature and quantitative parameters of the typical stages of the processes of plastic and brittle fracture, depending on the test temperature and stiffness of the stress state at the tip of the crack‐like defect, are established. It is shown that impact loading at 20 °C leads to the formation of the local zone of plasticity and ductile–brittle fracture of the material. An increased stiffness of the stress state at the tip of the defect at −40 °C causes brittle fracture. An approach is developed, which is based on using the size of shear lips as a quantitative parameter of fracture under normal and low temperatures, similar in its physical essence to deformation approaches of nonlinear fracture mechanics. Based on this approach and the quantitative analysis of specimen fracture zones, the physical and mechanical scheme of specimen fracture is proposed in the presence of localized plasticity and in its absence near the tip of the concentrator.

Influence of Fracture Parameter on the Shear Lips for 080M40 Carbon Steel in Charpy-v Impact Resistance at Different Temperatures

“…In this paper, we propose an approach, which helps to understand the relationship between the energy micro parameters of fracture and deformation parameters, as well as the fracto-graphy data and developed computer-aidedautomatic methods. On the basis of such an integrated approach and a quantitative analysis of specimen fracture zones, physical and mechanical interpretation of the mechanisms of specimen failure is possible, taking into account the developed and localized plasticity in the vicinity of the concentrator tip [25], which can be used in fracto-diagnostics and developed computer-aided-automatic methods when analyzing the causes of fracture of real structures [21]. From figure 6, the influence of shear lips height to the impact resistance was observed by the pattern of the slope or the gradient of the graph.…”

“…where (Ar) is the making for crack initiation; h, (v) is the height and the notch depth; and (Wi) is width of the sample. As a review of the literature [21]. The chemical composition of the 080M40 Carbon Steel material is presented in the table 1 below.…”

Evaluation of temperature‐sensitive fatigue crack propagation of a high‐speed railway wheel rim material

“…Examples are sandstorm conditions, low‐temperature conditions, and high‐humidity conditions. Here, the temperature condition is one of the most important factors for high‐speed railway wheels . Extensive studies have been conducted and report that the temperature plays an important role in fatigue crack propagation.…”

“…Here, the temperature condition is one of the most important factors for high-speed railway wheels. 5,6 Extensive studies have been conducted and report that the temperature plays an important role in fatigue crack propagation. For martensite steel, such as Q420B high-strength steel 7 and X65 pipeline steel, 8 the fatigue crack growth rate (FCGR) decreases with decreasing temperature.…”

A suitability assessment using an instrumented impact test of the use of selected structural steel grades on the basis of their changes in response to exposure to fire

“…4. Mixed fracture areas [own study according to(Lin at al., 2017),(Sorochak at al., 2017),(Tanguy at al., 2005)]…”