Stress and Springback Analyses of API X70 Pipeline Steel Under 3-Roller Bending via Finite Element Method

Abstract

3-Roller bending is a widely applied manufacturing process, particularly in structural steel pipe industry. However, due to the difficulty and high cost of measuring stress distribution inside sheet material via traditional method, internal stress/strain response during forming is largely unexplored. The focuses of this study are two: (1) to map the radii of curvature as well as the stress inside the work piece during forming by utilizing the meshing mechanism of finite element method, and (2) to further provide some numeric guidelines for the configuration of the rolling system in order to improve production efficiency and product quality. The results of this study indicate that: (1) it is crucial to properly choose forming parameter in order to produce product with desired radii; (2) much like a gradual springback process, the radii of curvature gradually increase from the top roller to the exit-side bottom roller; (3) under the assumptions made in this study, to produce pipes with a specified diameter with varying configurations of the 3-roller system will not significantly change the final residual stress; and (4) finally, shifting of the neutral axis up to 2.0% of the thickness toward the compressing side during the forming process is observed.

Design of Automatic Seaming Machine for Fire Air Ducts with 3D Model and Its Experiment

“…Automated processing equipment has a shorter processing time for air ducts with small cross-sections due to their good rigidity and high rolling speed. In the 1.0mm group (experiments [14][15][16][17][18][19], the automated processing times is 40 seconds and the manual processing takes between 500 seconds and 600 seconds. The automation time for the 1.2mm group (experiments 20-22) and the 1.5mm group (experiments 23-28) is 50 seconds, and the manual processing time is between 600-980 seconds.…”

“…According to the number of rollers, the roll bending process can be divided into three forms, namely two rolls, three rolls, and four rolls [10]. Scholars have conducted extensive research on the relationship between forming curvature, bending, defect formation, and structural optimization for different forms of rolling processes using theoretical analysis, numerical simulation, and experimental research methods [18,19]. A large number of automated equipment are applied to sheet metal bending processes to improve processing efficiency [20].…”