【Ten Years of Rapid Development in Chemical Engineering Equipment】The first domestic JCOE steel pipe in China, with a diameter of 1219 mm and a length of 18 meters, produced between 1997 and 2023

The new energy pipeline manufacturing project is a key construction project designated by the Ministry of Industry and Information Technology and China National Petroleum Corporation. It represents a crucial measure for China National Petroleum Corporation’s Baoji Petroleum Pipe Company to implement the **\"dual carbon\" strategy and China National Petroleum Corporation’s plans for new energy development, to effectively respond to changes in the business environment, to seize strategic development opportunities, and to achieve high-quality development while continuously optimizing the industrial structure and product portfolio. Its production lines are capable of manufacturing new energy pipelines such as marine risers and marine transmission pipes, LNG cryogenic transmission pipes, as well as oil and gas transmission pipes. The core equipment on the production line, the JCO molding machine, uses the world’s first high-precision 18-meter die-type molding machine manufactured by German company Siemens. It offers advantages such as a wider range of applicable products and better product quality compared to traditional molding machines; it is the world’s first molding machine with an 18.3-meter die-type structure. The new production line also set three national firsts: it was the first 18.3-meter JCOE production line, the first production line to achieve automated centralized control of the forming and precision welding stages, and the first production line to enable internal and external welding at the same workstation for straight-seam pipes. It is understood that the new energy project of CNPC Baoshishun (Qinhuangdao) Steel Pipe Co., Ltd. was launched in April 2022; in May of this year, the installation of the main equipment was completed successfully, and the project entered the stage of production line debugging. Next, CNPC Baoshishun (Qinhuangdao) Steel Pipe Co., Ltd. will work tirelessly to carry out equipment debugging and staff training, striving to get the production line up and running by the scheduled deadline, so as to make a positive contribution to the \"dual carbon\" strategy and the transmission of new energy.

The JCOE straight-seam steel pipe manufacturing process is a new type of welding steel pipe forming technology that emerged in the 1990s. The main steps in this process involve first milling (or planing) the edges at the joints where the steel plates are to be welded together, followed by pre-bending the plates in the width direction. The pipes are then gradually shaped in the sequence of J shape → C shape → O shape. During this shaping process, multiple pressure stamping operations are carried out, with each stamping step being based on the principle of three-point bending using specialized molds. JCOE is a tube manufacturing technique for producing large-diameter, thick-walled steel tubes, based primarily on the double-sided submerged arc welding process. The products go through various processes such as edge milling, pre-bending, bending, seam joining, internal welding, external welding, straightening, and end trimming. Its forming process can be divided into N+1 steps (where N is a positive integer); the steel plate is automatically fed laterally at set intervals and bent, thereby achieving CNC progressive J—C—O forming. The steel plate enters the forming machine horizontally, and driven by the feeding trolley, it undergoes multiple sequential bends in N/2 steps during the first stage, thereby achieving a \"J\" shape for the front half of the steel plate ； In the second stage, the steel plate that has been shaped into a “J” shape is first rapidly fed horizontally to the designated horizontal position; then, starting from the other end, the unshaped steel plate is bent in multiple steps of N/2 increments, thereby shaping the latter half of the steel plate and completing the “C” shape ； Finally, the lower part of the \"C\"-shaped tube blank is bent to achieve an \"O\" shape, with each stamping step being based on the principle of three-point bending. Since the raw material steel plates for straight-seam steel pipes are formed through multiple progressive die presses, it is necessary to address the following basic issues: 1. How to determine the shape of the die, as well as the stroke of the upper die and the distance between the dies on the pressing machine; 2. How many times stamping is required to achieve an appropriate bending radius and an open O-shaped pipe. And these issues are related to the different materials of the steel plates, to the mechanical properties of those specific steel plate materials as produced by the manufacturers, as well as to the specifications of the steel pipes (diameter and wall thickness). Whenever new specifications or new steel sheet materials are introduced into production, a certain quantity of samples is taken for pressure testing in order to determine the appropriate manufacturing parameters. The trial-and-error method is relatively reliable, as it is based on data from scientific German-imported JCOE molding equipment. Due to the numerous process parameters involved in the JCOE process for straight-seam steel pipes, the production process parameters were determined not only through trial and error; to develop a mature process, several months of tuning are even required.