1. Strength
The strength index of steel is determined by the elastic limit σ e. Yield limit σ y. And tensile limit σ u. The design is based on the yield strength of steel. High yield strength can reduce the weight of the structure, save steel, and reduce cost. tensile strength σ U is the maximum stress that the steel can withstand before failure. At this time, the structure loses its performance due to large plastic deformation, but the structural deformation is large and does not collapse, meeting the requirements for resisting rare earthquakes' σ U/ σ The value of y can be regarded as a parameter for steel strength reserve.
2. Plasticity
The plasticity of steel generally refers to the property of significant plastic deformation without fracture after the stress exceeds the yield point. The main indicator for measuring the plastic deformation capacity of steel is elongation δ And the reduction in area ψ.
3. Cold bending performance
The cold bending performance of steel is a measure of its resistance to cracking when subjected to plastic deformation during bending at room temperature. The cold bending performance of steel is tested through cold bending experiments to verify the bending deformation performance of steel under specified bending degrees.
4. Impact toughness
The impact toughness of steel refers to the ability of steel to absorb mechanical kinetic energy during the fracture process under impact load. It is a mechanical property that measures the resistance of steel to impact load, which may lead to brittle fracture due to low temperature and stress concentration. The impact toughness index of steel is generally obtained through the impact test of standard specimens.
5. Welding performance
The welding performance of steel refers to the ability to obtain high-performance welded joints under certain welding process conditions. Welding performance can be divided into two types: welding performance during the welding process and welding performance in terms of usability. The welding performance during the welding process refers to the sensitivity of the weld seam and the metal near the weld seam to not produce hot cracks or cooling shrinkage cracks during the welding process. Good welding performance refers to the absence of cracks in both the weld metal and nearby base metal under certain welding process conditions. The welding performance in terms of usability refers to the impact toughness at the weld and the ductility performance in the heat affected zone. It is required that the mechanical properties of the weld and the steel in the heat affected zone are not lower than those of the base metal. Our country adopts welding performance testing methods based on welding processes, as well as welding performance testing methods based on usability and usage properties.
