This paper introduces mechanical and metallurgical properties of 27mm thick Grade X80 high strain line pipe steel which aims at constructing long distance natural gas over permafrost and seismic areas.The steel is mol...This paper introduces mechanical and metallurgical properties of 27mm thick Grade X80 high strain line pipe steel which aims at constructing long distance natural gas over permafrost and seismic areas.The steel is molybdenum and boron free.Dual phase of the X80 steel plates are regulated by thermal-mechanical controlled processing.The outer diameter of 1219mm pipes are manufactured by UOE process.DWTT toughness and longitudinal tensile properties including the Rt0.5/Rm,Rt1.5/Rt0.5 and Rt2.0/Rt1.0 are analyzed on both the plates and the pipes.Strain aging properties are also evaluated on the base material of the pipe,demonstrating that the pipe complies well with the pipeline construction requirements.Strengthening effects of precipitates are analyzed,revealing a 58.1MPa strengthening contribution by precipitates less than 20nm in size.Dislocation hardening is approximately 176MPa in the present studied steel.展开更多
Based on plastic bending engineering theory and machine vision technology, the intelligent control technology for forming steel pipe with JCO process is presented in this paper. By ‘twice pre-bending method’ in the ...Based on plastic bending engineering theory and machine vision technology, the intelligent control technology for forming steel pipe with JCO process is presented in this paper. By ‘twice pre-bending method’ in the first forming step, the springback law can be obtained. With the springback law and the target angle, the exact punch displacement which determines the formed angle in each bending step is predicted. In the succedent forming steps, the bending process is carried out with the exact punch displacement by real-time revising the springback law. And the angle error in each forming step is calculated by comparing the actual formed angle with the target angle. By conducting compensation for the last angle error in the next forming step, each precise bending process step is realized. A system of intelligent control technology for forming the steel pipe was developed. A calibration method is proposed to calculate the exterior parameters of the CCD camera, in which the equilateral triangle is em-ployed as the calibrating board and only one image needs to be captured. A mathematical model, which converts the angle in the image into the actual formed angle, is derived. The experimental results showed that the ellipticity of the formed pipes was less than 1.5% and the high-quality pipes can be manufactured without the worker's operating experience by employing the in-telligent control technology.展开更多
文摘This paper introduces mechanical and metallurgical properties of 27mm thick Grade X80 high strain line pipe steel which aims at constructing long distance natural gas over permafrost and seismic areas.The steel is molybdenum and boron free.Dual phase of the X80 steel plates are regulated by thermal-mechanical controlled processing.The outer diameter of 1219mm pipes are manufactured by UOE process.DWTT toughness and longitudinal tensile properties including the Rt0.5/Rm,Rt1.5/Rt0.5 and Rt2.0/Rt1.0 are analyzed on both the plates and the pipes.Strain aging properties are also evaluated on the base material of the pipe,demonstrating that the pipe complies well with the pipeline construction requirements.Strengthening effects of precipitates are analyzed,revealing a 58.1MPa strengthening contribution by precipitates less than 20nm in size.Dislocation hardening is approximately 176MPa in the present studied steel.
基金Supported by the National Natural Science Foundation of China (Grant No. 50805126)the Hebei Natural Science Foundation (Grant No. E2009000389)
文摘Based on plastic bending engineering theory and machine vision technology, the intelligent control technology for forming steel pipe with JCO process is presented in this paper. By ‘twice pre-bending method’ in the first forming step, the springback law can be obtained. With the springback law and the target angle, the exact punch displacement which determines the formed angle in each bending step is predicted. In the succedent forming steps, the bending process is carried out with the exact punch displacement by real-time revising the springback law. And the angle error in each forming step is calculated by comparing the actual formed angle with the target angle. By conducting compensation for the last angle error in the next forming step, each precise bending process step is realized. A system of intelligent control technology for forming the steel pipe was developed. A calibration method is proposed to calculate the exterior parameters of the CCD camera, in which the equilateral triangle is em-ployed as the calibrating board and only one image needs to be captured. A mathematical model, which converts the angle in the image into the actual formed angle, is derived. The experimental results showed that the ellipticity of the formed pipes was less than 1.5% and the high-quality pipes can be manufactured without the worker's operating experience by employing the in-telligent control technology.
