title: Theoretical and Experimental Study of Bimetal-Pipe Hydroforming.
abstract: The corrosion of oil country tubular goods (OCTG) gets more and more serious especially in the acidic environment. So, it is very important to develop a perfect anticorrosion technology for exploring sour oil and gas fields economically and safely. Analysis indicates that the bimetal-pipe (BP) which consists of the base layer of low carbon steel and a corrosion resistant alloy (CRA) cladding layer is an economic and reliable anticorrosion technology and has broad application prospects in the transportation of acid medium. However, theoretical study of hydraulic expansion mechanism for BP is not enough. In this paper, the deformation compatibility condition of BP was obtained by studying the deformation rule of the (CRA) liner and the outer pipe of carbon steel in the forming process; the mechanical model which can compute the hydroforming pressure of BP has been established based on the nonlinear kinematic hardening characteristics of material; furthermore, based on the stress strain curve of inner pipe simultaneously, the calculation method of the plastic hardening stress has been proposed. Thus, the accurate method for computing the forming pressure was obtained. The experimental data show that results are consistent with results of the proposed model. It indicates that the model can be used to provide theoretical guidance for the design and production as well as use of BP.
authors.affiliation: State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University , Chengdu, Sichuan 610500 , China ;
authors.forename: Zeng
authors.initials: Z
authors.lastname: Dezhi
authors.affiliation: CNPC Key Lab for Tubular Goods Engineering, Southwest Petroleum University , Chengdu, Sichuan 610500 , China.
authors.forename: Deng
authors.initials: D
authors.lastname: Kuanhai
authors.affiliation: State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University , Chengdu, Sichuan 610500 , China.
authors.forename: Shi
authors.initials: S
authors.lastname: Taihe
authors.affiliation: State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University , Chengdu, Sichuan 610500 , China e-mail:  yhlin28@163.com.
authors.forename: Lin
authors.initials: L
authors.lastname: Yuanhua
authors.affiliation: CNPC Key Lab for Tubular Goods Engineering, Southwest Petroleum University , Chengdu, Sichuan 610500 , China.
authors.forename: Zhu
authors.initials: Z
authors.lastname: Hongjun
authors.affiliation: China Petroleum Engineering Co., Ltd., Southwest Company , Chengdu, Sichuan 610017 , China.
authors.forename: Li
authors.initials: L
authors.lastname: Tianlei
authors.affiliation: Drilling and Production Engineering Technology Research Institute (CCDC) , Guanghan, Sichuan 618300 , China.
authors.forename: Sun
authors.initials: S
authors.lastname: Yongxing
keywords: bimetal-pipe; deformation compatibility condition; hydraulic forming experiment; mechanical model; the nonlinear kinematic hardening characteristics of material