Experimental Study On Static And Fatigue Property Of High Strength Steel Welded Joints

The current specification "Code for Design of Steel Structures" (GB50017-2003) did not make provision of welding connection design method, electrode selection principle, strength index and structure for tensile strength on more than 420MPa high strength structural steel, In this paper, the mechanical performance of high strength steel weld connecting are studied through experimental research and numerical simulation. The mechanical properties such as strength, ductility and impact toughness of weld connections under different matching is focused on research. Simultaneously, The fatigue performance of different weld type connections is compared with code for "Code for Design of Steel Structures" (GB50017-2003)and ANSI/AISC360-10 Specification for Structural Steel Buildings.For domestic homogeneous steel of Q460D and dissimilar steel of Q460D and Q345 on welded joints under the low and equal intensity, This paper design four groups of 12 test pieces,Mainly studying the mechanical properties of specimens after welded, analyzing the mechanical properties change of the heat affected zone, weld and base metal of the welded joint . At the same time, the mechanical properties of domestic Q690D high strength steel on higher strength grade under different matching is studied. to provide a scientific basis for welded joint performance evaluation and welding materials selection criteria of high strength structural steel.In this paper, the low temperature impact toughness of Q460D and Q690D high strength steel welding joints is studied. Preparation of weld zone and heat affected zone of the standard impact specimen carry on impact of different temperature test. The influence of the impact energy of weld zone and heat affected zone on the temperature is analyzed under the low and strong intensity. At the same time, the Boltzmann function is used to proceed the impact energy with the temperature change relationship of regression analysis to get the weld zone and the heat affected area of ductile-brittle transition temperature .The test for tension--tension fatigue of Q460D parent metal, butt weld and cross angle weld joint are designed to study the corresponding cycle index and the maximum stress. From the comparation of "Code for Design of Steel Structures" (GB50017-2003) and ANSI /AISC360-10 "Specification for Structural Steel Buildings",the paper make suggestions on the fatigue design parameters C and ? of high strength steel.In this paper, finite element software is used to establish the nonlinear finite element model of high strength steel tensile joint. The simplified folding line model is obtained for the heat affected zone, weld zone and base metal area of the welded joint. The nonlinear finite element model verify the Q460D and Q690D Force tensile test results and reduce the workload about large-scale steel structure of the finite element calculation .