Factors to consider when choosing steel structure

The load of steel structure workshop can be static or dynamic;Acting often, sometimes, or occasionally (as in an earthquake);Often or infrequently fully loaded, etc.Appropriate steel should be selected according to the above characteristics of the load, and the necessary quality assurance project requirements should be put forward.Steel with good quality and toughness should be selected for the structural members bearing the direct dynamic load.Steel of general quality may be used for structural members subjected to static or indirect dynamic loads.

The plasticity and toughness of the steel decreased with the temperature, and the ductility decreased sharply at low temperature, especially in the brittle transition temperature zone, and brittle fracture occurred easily.Therefore, for steel structures that often or may work under low negative temperature, especially for welded structures, steel with good chemical composition and mechanical properties and brittle transition temperature lower than the working environment temperature of the structure should be selected.Structural steel connections may be welded or non-welded (bolts or rivets).For the welded structure, the non-uniform heating and cooling during welding often causes high welding residual stress in the components.The welding structure and welding defects which are difficult to avoid often cause crack-like damage to the structure.The overall continuity and rigidity of the welded structure are good, which makes the defects or cracks penetrate each other and expand.In addition, the high content of carbon and sulfur will seriously affect the weldability of steel.

Therefore, the quality requirements of welded structural steel should be higher than the same situation of non-welded structural steel, carbon, sulfur, phosphorus and other harmful elements content should be lower, plasticity and toughness should be better.