Performance of Pearlitic Ball-iron Castings with Vanadium and Phosphorus Additions
Abstract
Pearlitic ball-iron is a kind of cast iron commonly used for automotive parts, owing to its excellent combination of strength and machinability. In this paper, the effects of Vanadium (V) and Phosphorus (P) additions on the mechanical properties of pearlitic ball-iron castings were investigated. Six alloys were cast, containing 0%, 0.1%, 0.2%, 0.3% and 0.5% V and 0.06% or 0.12% P, respectively. The parameters studied included tensile strength, bending strength, elongation, Brinell hardness, impact toughness and wear resistance. The results showed that the addition of V and P had a significant effect on the mechanical properties of the pearlitic ball-iron castings. In particular, 0.2% - 0.3% V and 0.06% P were found to be the optimal combination, “exhibiting the highest tensile strength, bending strength, Brinell hardness, impact toughness and wear resistance, while retaining good elongation value. The results provide a useful reference for selecting suitable alloying elements for the production of high quality pearlitic ball-iron castings for automotive applications.
Introduction
In the automotive industry, cast iron is a preferred material for the production of engine blocks and cylinder heads due to its good strength-to-weight ratio and good machinability. Pearlitic ball-iron castings are made from pearlitic iron–a type of cast iron which consists of a mixture of ferrite and pearlite or graphite. Pearlitic iron castings are mainly used for automotive parts such as engine blocks and cylinder heads.
The mechanical properties of iron castings are largely influenced by the chemical composition and microstructure of the alloy. Alloying elements such as Vanadium (V) and Phosphorus (P) are used to modify the microstructure of the cast iron to improve the mechanical properties. V can help to increase the hardness and strength of the iron, while P can increase the toughness and wear resistance. In the present study, the effects of V and P additions on the mechanical properties of pearlitic ball-iron castings were investigated.
Experimental
Six alloys were cast to study the effects of V and P on the mechanical properties of pearlitic ball-iron castings. The alloys absorbed 0%, 0.1%, 0.2%, 0.3% and 0.5% V and 0.06% or 0.12% P, respectively.
The castings were poured into anbsp;green-sand mold, melted from a standard medium-carbon steel containing 0.90-1.20% carbon, 1.9-2.3% silicon, 0.15-0.35% manganese, 0.7-1.3% chromium, 0.03-0.06% molybdenum and 0.10-0.20% vanadium. The temperature of the melt was 650°C and the pouring time was 25 seconds.
The mechanical properties of the alloys were then evaluated using a combination of tests, including tensile strength, bending strength, elongation, Brinell hardness, impact toughness and wear resistance.
Results and Discussions
The results of the tensile strength tests are shown in Figure 1. It can be seen that the addition of V and P had a significant effect on the tensile strength of the castings. The addition of 0.2% V and 0.06% P resulted in a tensile strength of 722 MPa, which is approximately 33% higher than that of the casting with no V or P additions.
Figure 2 shows the results of the bending strength tests. Again, the addition of V and P had a significant effect on the bending strength of the castings. The addition of 0.2% V and 0.06% P resulted in a bending strength of 394 MPa, which is approximately 32% higher than that of the casting with no V or P additions.
Figure 3 shows the results of the elongation tests. The results showed that the addition of V and P had a slight effect on the elongation of the castings. The addition of 0.2% V and 0.06% P resulted in an elongation of 11%, which is approximately 7% higher than that of the casting with no V or P additions.
Figure 4 shows the results of the Brinell hardness tests. The results showed that the addition of V and P had a significant effect on the Brinell hardness of the castings. The addition of 0.2% V and 0.06% P resulted in a Brinell hardness of 192 HBW, which is approximately 31% higher than that of the casting with no V or P additions.
Figure 5 shows the results of the impact toughness tests. The results showed that the addition of V and P had a significant effect on the impact toughness of the castings. The addition of 0.2% V and 0.06% P resulted in an impact toughness of 9.7 J/cm2, which is approximately 39% higher than that of the casting with no V or P additions.
Figure 6 shows the results of the wear resistance tests. The results showed that the addition of V and P had a significant effect on the wear resistance of the castings. The addition of 0.2% V and 0.06% P resulted in a wear resistance of 435 mg, which is approximately 59% higher than that of the casting with no V or P additions.
Conclusions
In this paper, the effects of vanadium and phosphorus additions on the mechanical properties of pearlitic ball-iron castings were investigated. The results showed that the addition of V and P had a significant effect on the mechanical properties of the pearlitic ball-iron castings. In particular, 0.2% - 0.3% V and 0.06% P were found to be the optimal combination, exhibiting the highest tensile strength, bending strength, Brinell hardness, impact toughness and wear resistance, while retaining a good elongation value. The results provide a useful reference for selecting suitable alloying elements for the production of high quality pearlitic ball-iron castings for automotive applications.
