Material Requirements for Steel Structures – ROYAL GROUP

1. Strength
The strength index of steel consists of elastic limit, yield limit, and tensile limit. The design is based on the yield strength of steel. High yield strength can reduce the weight of the structure, save steel and reduce the cost. Tensile strength is the maximum stress that steel can withstand before failure. At this time, the structure loses its performance due to plastic deformation, but the structure deformation is large and does not collapse, which should be able to meet the requirements of structural resistance to rare earthquakes.
2. Plasticity
The plasticity of steel generally refers to the properties of significant plastic deformation without fracture after the stress exceeds the yield point. The main index to measure the plastic deformation capacity of steel is elongation stone and section shrinkage u.
3. cold bending performance
The cold bending property of steel is a measure of the resistance of steel to crack when plastic deformation occurs in bending process at normal temperature. The cold bending property of steel is to test the bending deformation property of steel under specified bending degree by cold bending experiment.
4. Impact toughness
The impact toughness of steel refers to the ability of steel under impact load to absorb mechanical kinetic energy in the process of fracture. It is a mechanical property that measures the effect of steel resistance to impact load cutting and may result in brittle fracture due to low temperature and stress concentration. Generally, the impact toughness index of steel is obtained by impact test of standard specimen.
5. Welding performance
The welding performance of steel refers to the welding joint with good performance obtained under constant welding process conditions. The welding performance can be divided into two kinds: the welding performance in the welding process and the welding performance in use. The welding performance in the welding process refers to the sensitivity of no thermal crack or cooling shrinkage crack in the weld and the metal near the weld during the welding process. Good welding performance means that there is no crack in the weld metal and the nearby base metal under certain welding process conditions. The welding performance in terms of service performance refers to the impact toughness of the weld and the ductility property in the heat affected zone. It is required that the mechanical properties of the steel in the weld and heat affected zone are not lower than that of the base material. Our country adopts the welding performance test methods in the welding process, and also adopts the welding performance test methods on use properties.
6. Durability
There are many factors affecting the durability of steel. First of all, the corrosion resistance of steel is poor, and protective measures must be taken to prevent steel corrosion and rust. Protective measures are: regular maintenance of steel paint, the use of galvanized steel, acid, alkali, salt and other strong corrosive medium conditions, the use of special protective measures, such as the offshore platform structure using "anode protection" measures to prevent jacket corrosion, fixed on the jacket zinc ingot, seawater electrolyte will automatically corrosion zinc ingot, so as to protect the function of steel jacket. Secondly, because the steel under high temperature and long-term load, its failure strength is reduced more than the short-term strength, so for the steel under the long-term high temperature action, to determine the lasting strength. Steel hardens and becomes brittle over time, a phenomenon known as aging. The impact toughness of steel under low temperature load should be tested.