Mechanical properties test

　　Yield strength: The yield strength is the stress corresponding to the plastic deformation of the material. The deformation of the material before the yield point is elastic, and the original shape is restored when the applied stress is removed. When the stress exceeds the yield point, the partial deformation remains as a permanent deformation that cannot be recovered.
　　Tensile strength: The maximum stress value that the specimen is subjected to before being pulled. Generally, the tensile strength corresponds to the stress at the time of necking.
　　Elongation: Elongation, also known as elongation after break, refers to the percentage of the length of the gauge length and the length of the original gauge length after the sample is pulled. The greater the elongation, the greater the permanent deformation that the material can withstand before the force is destroyed, and the better the forming properties. Yield strength, tensile strength, and elongation are generally measured by a tensile test.

　　Impact work: impact work, or toughness, refers to the work absorbed by the sample when it is broken under impact during the impact test. The unit is Joule (J). The impact energy shows the resistance of the material to the impact load. It is measured by the Charpy V-type impact test.
If the material also requires welding during processing, then the solderability of the material should be considered.
　　Welding: For steel, welding is a process of combining separate steels. The welded parts usually need to be melted together, and then solidified to form a strong bond, such as arc welding, gas welding, and electric resistance welding.
　　Solderability: Also known as bonding ability, for materials, the ability to be welded together. Most steels are solderable, but some of them are easier. This property has a great influence on the quality of the welding and the choice of the process.
　　Carbon Equivalent: In welding, carbon equivalent (CE) is used to measure the weldability of steel. The carbon equivalent formula shows the extent to which different alloys affect the weld. High carbon content and alloying elements such as manganese, chromium, silicon, molybdenum, copper, and nickel all increase the hardness of the steel and reduce its weldability. Carbon equivalents are usually recommended using the following formula: