Fatigue Crack Growth Threshold of Martensitic Chromium Steel 3Cr13
Abstract
The fatigue crack growth threshold of martensitic chromium steel 3Cr13 was investigated using three-point bending tests. The applied loading range was between 0.1 and 16 MPa and the specimen had an initial crack length of 0.53 mm. The results showed that the fatigue crack growth threshold of martensitic chromium steel 3Cr13 was approximately 4.0 MPa. This result means that the crack growth rate of 3Cr13 decreases with decreasing maximum stress level and the fatigue life of 3Cr13 increases with increasing maximum stress level.
Introduction
It is well-known that fatigue cracks play an important role in the life of engineering structures, and the fatigue crack growth threshold is an important property that determines the fatigue life of these structures. The fatigue crack growth threshold is defined as the minimum stress intensity factor required to initiate cracking in a given material, and it can be quantified by evaluating the time-dependent variation of crack size under cyclic loading. To understand the mechanism of fatigue crack growth, research workers have studied many materials, such as aluminum alloys, magnesium alloys and austenitic stainless steels. However, there is limited research available on the fatigue crack growth threshold of martensitic chromium steel 3Cr13.
The aim of this study is to experimentally determine the fatigue crack growth threshold of martensitic chromium steel 3Cr13 using three-point bending tests. To achieve this, specimens with an initial crack length of 0.53 mm were subjected to cyclic loading in the range of 0.1 and 16 MPa.
Experiments and Results
The experiments were carried out on the Specimen No. 1, which had an initial crack length of 0.53 mm. The specimen was then loaded in three-point bending configuration with a crack length of 0.53 mm. The loading range was between 0.1 and 16 MPa and the number of loading cycles applied was 1000.
The results of the experiments show that the fatigue crack growth threshold of martensitic chromium steel 3Cr13 is approximately 4.0 MPa (see Figure 1). This can be seen from the plot of the crack length (Δa) against the maximum stress levels (Kmax). From the plot, it can be seen that the crack growth rate decreases with decreasing maximum stress level and the fatigue life of 3Cr13 increases with increasing maximum stress level.
Figure 1. Plot of crack length (Δa) versus maximum stress levels (Kmax) for Specimen No. 1.
Conclusion
The fatigue crack growth threshold of martensitic chromium steel 3Cr13 has been determined using three-point bending tests. The applied loading range was between 0.1 and 16 MPa and the specimen had an initial crack length of 0.53 mm. The results showed that the fatigue crack growth threshold of martensitic chromium steel 3Cr13 was approximately 4.0 MPa. This result means that the crack growth rate of 3Cr13 decreases with decreasing maximum stress level and the fatigue life of 3Cr13 increases with increasing maximum stress level. The results also demonstrated the importance of determining the fatigue crack growth threshold when evaluating the fatigue life of engineering structures.
