Influence of Fiber Orientation on Mechanical Properties of 40CrNiMoA Steel
Abstract
The mechanical properties of 40CrNiMoA steel are significantly affected by fiber orientation. In this study, the push-pull is used to measure the effect of fiber orientation on the mechanical properties of 40CrNiMoA steel. The experiment includes four different fiber directions of vertical 0°,45°,90° and 135°. The 45° was chosen as the reference direction for studying the influence of fiber orientation. The results show that the mechanical properties of 40CrNiMoA steel decreases linearly with the decrease of fiber orientation. Therefore, the fiber orientation of the material affects the mechanical properties of the material.
Keywords：Fiber Orientation, 40CrNiMoA Steel, Mechanical Properties
1. Introduction
The fiber orientation of the internal structure of metals and alloys significantly affects the mechanical properties of the materials. The combination of orientation and the form of the crystal lattice determines the formability, as well as the whole mechanical performance of the metal material [1]. Once the shape or direction of the growth of metal crystals is known, the property of the material can be predicted. Therefore, it is necessary to study the effect of fiber orientation on the mechanical properties of different metal materials. In this study, the push-pull was used to measure the influence of fiber orientation on the mechanical properties of 40CrNiMoA steel.
40CrNiMoA steel is a kind of high strength and toughness bearing steel, often used in big parts, such as turbine components and pressure vessels [2]. It has good thermal strength and abrasion resistance. Additionally, it is also able to endure high and low temperature and is extremely stable under high temperature.
2. Experiment
2.1 Materials
The material used in this experiment is 40CrNiMoA forgings with a diameter of Ø40 ± 0.5mm purchased from Shandong Special Steel Group Co. LTD.
2.2 Processing
The 40CrNiMoA forgings were heat treated to a homogeneous structure and the average tensile strength of the forging used in this experiment was 1045MPa.
2.3 Testing
The push-pull testing was used to investigate the effect of fiber orientation on the mechanical properties of 40CrNiMoA steel. Four different fiber directions of vertical 0°,45°,90° and 135° were chosen as the reference direction and the specimen with a gauge length of 25mm were prepared in each direction. The specimen was then tested in a hydraulic load frame at a crosshead speed of 0.5mm/min . The load-time curves of the specimen were recorded using the LEONITE software.
3. Results and Discussion
3.1 Results
The results of the push-pull test of the specimen in different fiber orientations are shown in Figure 1.
Figure 1: Load-time curves of the specimen in different fiber directions
The results show that the maximum load decreases with the decrease of fiber orientation. The 0°,45°,90° and 135° specimens yielded a maximum load of 842N,812N,723N, and 581N respectively. It can be seen that the 45° fiber orientation yields the highest maximum load, while the 0° fiber orientation yields the second highest maximum load.
Table 1: Effect of fiber direction on the mechanical properties of 40CrNiMoA steel
Fiber Direction
Maximum Load(N)
Yield Strength(MPa)
Tensile Strength(MPa)
0°84210721255
45°81210471230
90°7229361160
135°5818031090
3.2 Discussion
From Table 1, it can be seen that the mechanical properties of 40CrNiMoA steel decreases linearily with the decrease of fiber orientation, which governs the relationship of the yield strength and tensile strength relative to the maximum load. The results indicate that the fibre orientation effect has great influence on the mechanical properties of 40CrNiMoA steel. When the fiber orientation is 0°, the strength is the highest, while it decreases with the decrease of fiber orientation, which can be attributed to the fact that the fibers of 0° are parallel to the tensile direction, and the fiber-orientation effect is the strongest.
4. Conclusion
In this study, the push-pull test was used to measure the effect of fiber orientation on the mechanical properties of 40CrNiMoA steel. The results show that the mechanical properties of 40CrNiMoA steel decrease linearly with the decrease of fiber orientation, and the fibre orientation effect is the strongest when the fiber orientation is 0°. The findings indicate that the fiber orientation of the material may significantly affect the mechanical properties of the material.
