Delivered by Ingenta to: Chinese University of Hong Kong IP: 185.14.194.111 On: Mon, 13 Jun 2016 07:05:44 Copyright: American Scientific Publishers RESEARCH ARTICLE Copyright © 2012 American Scientific Publishers All rights reserved Printed in the United States of America Journal of Computational and Theoretical Nanoscience Vol. 9, 1175–1179, 2012 Numerical Simulation of Lined Steel Pipe Hydro-Forming Process Zeng Dezhi 1 , Lin Yuanhua 1 ∗ , Yang Bin 2 , Zhu Dajiang 1 , Zhu Hongjun 3 , and Shi Taihe 1 1 State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu, 610500, China 2 Chongqing University of Science and Technology, Chongqing, 401331, China 3 CNPC Key Laboratory for Tubular Goods, Southwest Petroleum University, Chengdu, 610500, China At present, the corrosion of oil tubular goods is becoming more and more serious in the exploitation of oil and gas wells, so it is very significant to study new anti-corrosion measures of lined steel pipe. A finite element analysis (FEA) numerical model concerning mechanical problem of lined steel pipe hydro-forming is established in this paper. Based on numerical simulation of lined steel pipe hydro-forming process, the correlation of forming force and bonding force between inner and outer pipes after forming of lined steel pipe is studied. Furthermore, physical experiment of lined steel pipe hydro-forming is conducted, and deformation laws of inner and outer pipes in the process of lined steel pipe hydro-forming are analyzed by resistance-strain test data. Test results show that forming force calculated by numerical simulation is close to the experimental data, so FEA model established in this paper is reasonable and can provide theoretical reference for the industrial manufacturing of lined steel pipe. Keywords: Corrosion, Lined Steel Pipe, Hydro-Forming, Numerical Simulation. 1. INTRODUCTION In the exploitation of oil and gas fields, oil tubular goods (tube and surface transportation line) is the only path- way for oil and gas production. In the production process, petroleum and natural gas that contain corrosive materials such as H 2 S, CO 2 , Cl - contacting with inner surface of oil tubular goods directly, leading to chemical and elec- trochemical corrosion. Particularly in the high production rate or high sour gas fields, corrosion of ordinary carbon steel is more serious, and facing severe safety problems in production. 1–3 So many oil companies are concerned about the anti-corrosion measures. Lined steel pipe is a new product in oil tubular goods anti-corrosion area, the outer pipe of lined steel pipe is ordinary carbon steel and mainly bearing mechanical load, and the inner pipe of lined steel pipe is a kind of anticorrosion alloy which is selected from the corrosive environment of gas fields. 4–6 Lined steel pipe can be divided into mechanical combined pipe and metallurgic combined pipe. 7 8 Cost of metallurgic combined pipe is 50% of anticorrosion alloy, and mechan- ical combined pipe is 30%. Finite element analysis and experiments are conducted for the mechanical combined pipe hydro-forming in this paper to provide theoretical ∗ Author to whom correspondence should be addressed. reference for the industrial application of lined steel pipe hydro-forming. 2. FINITE ELEMENT MECHANICAL MODEL The inner and outer pipes of lined steel pipe are assumed as ideal round pipes in this paper. According to the mechanical process of lined steel pipe hydro-forming, the geometric characteristics and distribution of loading pressure are axially symmetric. So the problem can be simplified as an axially symmetric plain stress problem. 2.1. Finite Element Grid Model Finite element geometric model is established on the basis of geometry of lined steel pipe used in the hydro-forming experiment. Outer diameter of outer pipe is 70 mm, inner diameter of outer pipe is 63.02 mm, outer diameter of inner pipe is 63 mm, wall thickness of inner pipe is 0.76 mm. The finite element model of combined pipe is shown in Figure 1. 2.2. Material Model The inner pipe is stainless steel and the outer pipe is carbon steel. Basic mechanical parameters of inner and J. Comput. Theor. Nanosci. 2012, Vol. 9, No. 9 1546-1955/2012/9/1175/005 doi:10.1166/jctn.2012.2166 1175