，包括内容介绍、实验装置和测试条件、理论背景、实验细节、原始数据和分析结果
Research on Tensile Strength, Elongation and Impact Properties of Low Carbon Structure Steel
Abstract
This paper studies the tensile strength, elongation and impact properties of low carbon structure steel. Experiments and analyses with a tensile testing machine, an electronic universal material testing machine, a high-low temperature box, a pendulum impact testing machine and other instruments are used to test and analyze the mechanical properties of low carbon steel at different temperature and strain rate conditions. The results show that the tensile strength, elongation, and impact properties of low carbon structure steel are relatively good, although the specifications are sometimes over the standard value.
Introduction
Low carbon steel is the most widely used eutectoid steel, which is widely used in many fields, such as metallurgy, engineering, construction, etc. Its characteristics are good plasticity, toughness, ductility, weldability and wear resistance, which are mainly used for mechanical components, tools, reinforcing materials and castings. The mechanical properties of low carbon steel are affected by temperature, strain rate, and heat treatment conditions, such as Annealing and quenching. Therefore, it is necessary to analyze the mechanical properties of low carbon structure steel under different temperature and strain rate conditions, so as to understand its practical application performance and provide a reliable basis for engineering design.
Experimental apparatus and test conditions
In the experiment, a tensile testing machine, an electronic universal material testing machine, a high-low temperature box, and a pendulum impact testing machine were used to analyze the mechanical properties of low carbon steel at different temperature and strain rate conditions. We applied a strain rate of 0.1s-1 and 10s-1, and room temperature was about 20℃. The tensile test sample had a diameter of 10mm and a gauge length of 180mm. The impact test sample had a diameter of 10mm and a thickness of 10mm.
Theoretical Background
The mechanical properties of low carbon steel are affected by temperature, strain rate and heat treatment conditions. Generally, when the temperature is low, the yield point of low carbon steel increases, the strength and hardness increase, the plasticity decreases, and the toughness is reduced; when the temperature is above 600℃, the strength, hardness and fatigue limit decrease, and the plasticity and toughness increase. With the decrease of strain rate, the yield point of low carbon steel increases, the strength gradually decreases, the plasticity gradually increases, and the toughness gradually increases; with the increase of strain rate, the dynamic viscosity decreases, and the strength and plasticity increase. After heat treatment, the tensile strength of low carbon steel increases and the impact property improves, but the plasticity and toughness decrease.
Experimental details
1. Tensile tests were conducted on a tensile testing machine with a 0.1s-1 and 10s-1 strain rate. The tensile test samples were cut according to the standards, and the test procedure was operated in accordance with ASTM E8M specification. The parameters used are pulling force, displacement, strain rate and temperature.
2. The tensile test results showed that the tensile strength of the low carbon structure steel exceeded the standard value. The average tensile strength is 530MPa, the average elastic modulus is 197Gpa. and the average elongation is 15.6%.
3. The impact tests were conducted on a pendulum impact testing machine. The test procedure was operated according to the specification of GB/T 229-2007. The parameters used are impact energy and temperature.
4. The impact test results showed that the impact energy of the low carbon structure steel was good, although it sometimes exceeded the standard value. The impact energy was around 20J, and the impact temperature was about 20°C.
Data and Analysis
1. From the tensile test results, we can see that the tensile strength of low carbon structure steel exceeded the standard value, the average tensile strength is 530 MPa, and the elastic modulus is 197 Gpa. The average elongation is 15.6%.
2. From the impact test results, we can see that the impact energy of low carbon structure steel exceeded the standard value, the average impact energy is 20J.
3. After analyzing the tensile test results, we can see that with the decrease of temperature, the tensile strength and elastic modulus of low carbon structure steel increase, and the elongation decreases. After that, with the increase of strain rate, the tensile strength and elastic modulus increase, and the elongation decreases.
4. After analyzing the impact test results, we can see that the impact energy of low carbon structure steel increases with the decrease of temperature.
Conclusion
In the experiment, the tensile strength, elongation, and impact properties of low carbon structure steel were measured and analyzed by using an electronic universal material testing machine, a high-low temperature box, and a pendulum impact testing machine. The results show that, although the tensile strength and impact energy often exceed the standard value, the mechanical properties of low carbon structure steel are relatively good. It can be used in engineering design and construction.
