Strength and hardness of 4140 steel at different temperatures
4140 steel is a popular steel alloy that is used in a wide variety of applications due to its excellent mechanical properties and toughness. The steel contains chromium, molybdenum and other alloying elements that increase its strength and hardness. However, the strength and hardness of 4140 steel can be affected by a variety of factors, including temperature.
Strength of 4140 steel at different temperatures
The yield strength of 4140 steel is usually around 655 MPa at room temperature. However, with the increase of temperature, the yield strength of steel decreases. At 200℃, the yield strength drops to about 480 MPa, and at 400℃, the yield strength drops to about 350 MPa.
Hardness of 4140 steel at different temperatures
Hardness is another key mechanical property of 4140 steel affected by temperature. Typical hardness of 4140 steel is about 28-32 HRC(Rockwell C scale) at room temperature. However, as the temperature increases, the hardness of the steel decreases. At 200°C the hardness drops to about 25-28 HRC and at 400°C to about 22-25 HRC.
The influence of temperature on the properties of 4140 steel
The performance of 4140 steel at different temperatures is a key consideration for many applications. For example, in high-temperature applications, such as gas turbine engines, the material may experience temperatures of several hundred degrees Celsius. In this case, the decline in strength and hardness of 4140 steel at high temperatures may be a matter of concern. A decrease in steel’s strength can cause it to deform or fail prematurely, while a decrease in hardness can lead to increased wear.
However, the effect of temperature on the properties of 4140 steel can also be exploited in some applications. For example, in applications where the material needs to be shaped or worked, such as forging or cutting, heating the material can make it easier to handle. This is because heat can increase the ductility of steel, reducing its hardness and making it more malleable.
