Study the causes of pitting corrosion in carbon steel water pipeline at the site of advanced chemical industries complex

There are many factors that affect the pitting corrosion of carbon steel (Q235A) some of them are related to the pipeline material such as material chemical composition specifications and other related to water specifications such as water temperature, pH of the water, and chemical and physical specification of water. In this study, the investigation was done for both water quality and materials of pipelines (Q235A), four samples from on a piece of same rolled sheet welded pipe(carbon steel (Q235A) were prepared and tested for chemicals composition, microstructure, roughness, and thickness, the test results shown that no difference observed for all results only on one sample have difference roughness value near to the welded joint, these test applied for 4 pieces took from one pipe to check the effect of rolling of these pipes that can cause dissimilarity .which enhance corrosion rates. Then the water quality was investigated for temperature 45C, pH equal to 9, chloride, TDS, and water pressure, the test result showed that the temperature of the water was 45 C pH 9 and contain chloride with a concentration quite enough to initiate pitting. From the collected data this study specified the causes of pitting corrosion in the studied area of water pipelines and summarized in the flowing, this pipelines exposed to high pressure than the required, and temperature of water reach over 45C in summer, and chloride iron have the main contribution on pitting corrosion of these pipes.

Solutions to enhance technology in the fabrication process and installation of marine pipelines

The article describes possible solutions of the problem connected with shortening shipbuilding construction time as well as reducing production costs. To reduce the total amount of labour involved in the manufacture and installation of ship piping systems, which is 20% compared to the total labour volume of shipbuilding, authors provide the research on the possibility of manufacturing straight pipe sections with permissible deviations in combination with free flanges, analysis of deviation compensation for pipelines through the use of straight pipe sections manufactured with permissible tolerance and proposing new theoretical solutions to improve manufacturing and installing ship piping systems. Introduction of these technologies contributes to reduction of cycles of building and decrease in labour-intensiveness of pipeline works when carrying out marine orders. The chart of modeling the system of pipelines is presented. A straight pipe manufactured with an allowable deflection on a flat support and a loose flange attached to the end of the welded pipe are shown. The scheme of a permissible deviation α at mounting the connections between pipes is considered. The possibility of assembling curved pipelines using straight pipe sections is described in detail. The compensation zone is illustrated using the rotation of two pairs of deflected straight pipes. A block diagram of the application of research results in manufacturing and mounting a pipeline system has been developed

Spinning process optimization and microstructure of stainless-steel welded pipe

Defects, such as cracks, typically occur in the spinning process of ternary catalyst shells. This study investigates the optimization of spinning process parameters to prevent such defects. An orthogonal simulation is performed using a finite element model of the spinning process of a ternary catalyst shell. The simulation results are verified by performing spinning tests using a 439 stainless steel welded pipe. The microstructure, hardness, and quality of formed parts are analyzed. The simulation and test results demonstrate that when the spinning temperature is 1000 °C, the roller fillet radius, roller speed, and feed ratio are 5 mm, 40 r/s, and 1.2 mm/r, respectively. In addition, the error rates of the forming thickness, port diameter, and roundness error are 1.37%, 1.25%, and 4.8%, respectively. This verifies the accuracy of the simulation. No defects are generated during spinning, and the spinning quality is high. The feed ratio is the main factor that affects the roundness error, followed by the roller speed. As deformation increases, hardness increases and the crystal size decreases. The results of this study can provide important theoretical guidance for practical spinning applications.

Optimization of the Cutting Tool for Internal Flash Removing Operations in the Production of Electric-Welded Tubes

The article considers the structural optimization results for the process of mechanic removing inside flash during the production of longitudinal electric-welded pipes with a diameter of 60.3 ... 89.0 mm. Mechanical processing was performed with a pipe electric welding unit, designed for the manufacture of pipes with a diameter of 60.0 ... 178.0 mm, using various cutting tools and grades of hard alloys. The influence of the parameters of chip formation and cutting forces on the quality of inside flash removing in a longitudinal electric-welded pipe is found. The experiments were carried out using both the basic and experimental geometry of the cutting tool. The dependence of the tool durability at the operation of flash removing on the hardness of the alloy and the wear resistance of the coating has been studied. The analysis of the results of the study of annular inserts made of a three-carbide hard alloy with a multilayer wear-resistant coating showed the possibility of reducing the consumption of cutting tools and emergency stops of the mill, improving the quality of processing and the rate of yield.