Wei, Zhou; China University of Petroleum-Beijing; China
Zhou, W.; China University of Petroleum-Beijing - College of Mechanical and Transportation Engineering; China
Session: Oil & Gas 3
Time: 10:00 - 10:20
The riser is an indispensable key component in the process of offshore oil drilling. Suffering complex alternating loads in the corrosive environment of the sea, the riser is easy to crack, riser is made up of pipeline steel by soldering, in the process of soldering the welding joints experience a series of complex non-equilibrium physical and chemical change, the mechanical properties of welding joint material are lower than the base material of the riser, so the welding joints are prone to corrosion and fatigue during the use of the riser.
In this paper, in order to simulate the composition of the riser welding joints, the specimens are made up of X80 pipeline steel plates by soldering, the weld joints of a specimen include two horizontal weld joints and a longitudinal weld joint, the shape of the weld joints presents “工”，the horizontal weld joints simulate the connection between the pipe body of riser and flanges, the longitudinal weld joint simulates the connection joint of the pipe body of riser. The specimens’ weld joints are divided into three types: non-defect, slag and undercut, Tensile test and tensile fatigue test are carried on these three kinds of specimens. The sensor which is based on the giant magneto resistance effect has a high detection sensitivity on the Ferromagnetic materials, stress concentration and micro-cracks of ferromagnetic materials can be found without external excitation device, so use the sensor which is based on giant magneto resistance effect to detect the specimens, analyze the magnetic signals which are got from different kinds of specimens, in different tensile loads and fatigue cycles of a specimen the magnetic signals is variation, so use finite element method to analyze the stress distribution of the specimens which are in different tensile loads and fatigue cycles, establish the relationship between the stress concentration and magnetic signals, which provides technical support for the detection method of the riser based on the giant magneto resistance effect.