Research On Nc Bending Process Of Thin-walled Stainless Steel Tube With Large Diameter And Small Bending Radius

In this paper,we chose 0Cr18Ni9-Solid-G90×1 thin-walled stainless steel tube with large diameter and small bending radius(R=106mm)as a research object.The tube numerical-control bending mold,heat treatment and surface treatment involved in the tube numerical control bending forming are designed.The friction characteristics of CNC tube bending and the selection of lubricating materials,the installation and debugging of CNC tube bending molds,and the parameter optimization of the key elements during CNC tube bending process have been theoretically analyzed and experimentally researched.The methods of structure design,heat treatment and surface treatment involved in the tube numerical control bending forming are mastered through the exploration and research on the design technology of numerical control bending forming,which combined with a large amount of experience and basic data accumulated in the actual production.Furthermore,the forming test of thin-walled stainless steel tube with large diameter and small bending radius has been done in the practical application,which satisfies the requirements of the numerical control bending for thin-walled stainless steel tube with large diameter and small bending radius.The friction law of different lubrication conditions between the metal tube and the mold material during bending catheter process are researched and summarized.At the same time,the friction coefficient of various catheter materials with35 Cr Mo A and aluminum bronze under different lubricant conditions are measured.The optimal series of lubricants between different materials are listed in order to apply different lubricants to different parts according to requirements,so as to achieve a reasonable friction force distribution.The conclusion provides an important ways to choose the suitable lubricant for thin-walled stainless steel tube with large diameter and small bending radius.The installation and debugging status of the mold and the influence of the forming parameters such as the clamping force of the mold,the pressure of the mold,the boosting speed of the mold,the bending speed,and the position of the mandrel on the forming effect are studied.We have deeply understand and grasp the law of the influence of various process parameters on the forming defects and forming accuracy of the elbow via theoretical analysis and experimental research.Moreover,combined the bending test phenomenon with the forming quality of the catheter,the bending forming parameters are compared and analyzed.And the typical process parameters for CNC tube bending process are selected.Finally,the specific process parameters meet the requirements of conduit parts,which paves the way to design the similar tubes based on the necessary technical foundation.