Determination of the KIC Fracture Toughness of the X210Cr12 High-Strength Material

Abstract

Purpose: It is an important problem that the machines become unusable due to the deformation of the machine elements produced before the planned time. In this study, it was aimed to determine the KIC value of X210Cr12, which is a high strength material. In this way, more accurate load values can be used in the design. Methods: In the experimental study to determine the KIC value, the sample geometry, the crack depth, the load-dependent parameters and calculations and some conformity checks were carried out. Experimental system; KIC consists of 3-point flexure specimens, a press, an electronic circuit capable of detecting the change in load crack opening, and a logger. Findings: In the study, the loads were determined from experimental graphs. Subsequently, load-crack opening values were determined. With these data, the KIC values were calculated as 719,7 and 839,7 MPa.mm1/2 as the minumum and maximum values, respectively. Conclusion: The experimental graphs are in the form of curves that break abruptly with unstable crack propagation without showing plastic deformation. There is no study in the literature on the KIC value of X210Cr12 and it has been determined that it has a low KIC value compared to the high-strength steels studied. It is valuable to determine the KIC value, as fracture problems may occur in designs prepared with the material. The results of the study are data at room temperature.

Keywords

• fracture mechanics
• fracture toughness
• crack opening displacement
• high strength steels
• X210Cr12