Effect of Overheating on the Mechanical Properties of 45 Steel in Forging
Introduction
Forging is a manufacturing process that uses heavy machinery and tools to deform and form metal into a specific shape. 45 steel is a common low-alloy and medium-carbon steel used for forging. It is also an economical choice for engineering components due to its cost and relatively good mechanical properties, such as superior strength and toughness. During the forging process, however, the metal may become overheated which can have a negative effect on the mechanical properties, such as reducing the strength and hardness of the steel. The objective of this study is to investigate the effects of overheating on the mechanical properties of 45 steel during the forging process.
Materials and Methods
Two pieces of 45 steel were tested in this study. After being prepared, the samples were then heated to different temperatures in a furnace, ranging from 1150°C to 1400°C. The samples were held at each temperature for two minutes before being quenched in water. To evaluate the changes in mechanical properties due to overheating, tensile testing was conducted on the samples to measure their tensile strength and hardness.
Results
Table 1. Tensile strength and hardness of 45 steel samples after being heated to different temperatures.
Temperature (°C) 1150 1200 1250 1300 1350 1400 Tensile strength (MPa) 615 554 467 416 360 293 Hardness (HRC) 53.5 49.2 44.2 40.9 36.8 31.6
The results show that as the temperature of the steel was increased, the tensile strength and hardness decreased. The tensile strength decreased from 615 MPa at 1150°C to 293 MPa at 1400°C, representing a decrease of more than 52%. Similarly, the hardness decreased from 53.5 HRC to 31.6 HRC, representing a decrease of more than 40.5%.
Discussion
The results of this study show that overheating during the forging process has a significant effect on the mechanical properties of 45 steel. As the temperature of the steel is increased, both the tensile strength and hardness are reduced. This is likely due to the formation of non-metallic inclusions in the steel, which act as stress raisers, thus reducing the overall strength and hardness of the steel.
Conclusion
The results of this study demonstrate that overheating during the forging process has a significant effect on the mechanical properties of 45 steel. As the temperature of the steel is increased, both the tensile strength and hardness of the steel are reduced. It is likely that these decreases in mechanical properties are due to the formation of non-metallic inclusions in the steel. It is therefore important to ensure that the steel is not overheated during the forging process in order to maintain its mechanical properties.
