Experimental Study Of Residual Stresses In Q460 High-strength Steel Welded T-type Sections Compression Bar

In recent years,high-strength steel in the high-rise,large span and other buildings have been widely used,high-strength steel has been rapid development,thus ensuring high-strength steel structure safety is essential.Welding residual stress is one of the important factors that affect the safety of high strength steel structure.The existence of residual stress will greatly reduce the service life of the structure.Therefore,it is necessary to study the residual stress of high strength welding.The research work relies on the National Natural Science Foundation of China "Q460 high strength steel welding T-section of the overall stability of the bar," to carry out Q460 high-strength steel welded T-section bar material performance and residual stress test study,to be the steel of the Structure relationship model and residual stress distribution model,which can provide reference for the subsequent stability test of concrete bar.The specific contents and conclusions are as follows:(1)According to the tensile test results of steel,the constitutive model of steel is established.In accordance with the provisions of the standard sampling and preparation of the tensile test of the standard specimen,the thickness of 8mm and 12 mm standard test pieces of the preparation of the three.With reference to GB / T 228.1-2010 "metal material tensile test part 1: room temperature test method" requirements,in the 300 t tensile testing machine on the standard specimen for one-way tensile test,the Q460 steel stress-strain Curve,and access to mechanical properties of steel indicators.The experimental data were analyzed and the constitutive model of Q460 steel material was proposed for subsequent theoretical analysis.The results show that the mechanical properties of Q460 low alloy high strength structural steel-yield strength,tensile strength and elongation are in accordance with GB / T 1591-2008 "low alloy high strength structural steel" specification requirements.And the yield ratio is less than 0.85,in line with GB50011-2010 "Building Seismic Design Code" on the yield ratio performance limits of the requirements.(2)According to the residual stress test results of the specimen,the residual stress distribution model of the press bar is established.In accordance with GB50661-2011 "steel structure welding specifications" of the relevant technical conditions,the production of eight Q460 welded T-shaped section of the residual stress of the specimen,the thickness of 8mm and 12 mm.According to the requirements of the specification and the main points of the sawing method,the residual stress distribution of the residual stress specimen is measured.Based on the data of the test method,the distribution law of the residual stress is studied,and the residual stress distribution model of the Q460 high strength steel welded T-section compression bar can be used for the subsequent theoretical analysis.The results show that the distribution of the residual stress distribution of the Q460 high strength steel is basically the same as that of the ordinary strength steel.The thickness of the weld in the central part of the flange and the web is less than the yield strength of the steel.There is a small tensile stress in the middle of the flange;the central part of the web has a constant compressive stress;the rest is from the tensile stress to the compressive stress transition area.