Variation of elastic modulus of high strength 21-6-9 tube and its influences on forming quality in numerical control rotary draw bending

Abstract

Elastic modulus is one of the most crucial mechanical property parameters that affects the plastic forming quality of bent parts, especially for springback. Elastic modulus practically varies with plastic deformation, and its precise description is necessary to enhance simulation precision for tube bending and gain steady, high-precision bent components by actual bending. Using repeated loading-unloading tensile tests (RLUTTs), the variation of elastic modulus of high strength 21-6-9 stainless steel tube (21-6-9-HS tube) in terms of plastic strain has been obtained, which its decreases rapidly at the beginning, then decreases tardily and tends to be stable in the end with increasing the plastic strain. The variation can be expressed as a first order exponential decay function. By embedding the variation of elastic modulus with the plastic strain into ABAQUS software to simulate numerical control (NC) rotary draw bending of the 21-6-9-HS tube, the prediction precision for the springback angle, springback radius, maximum cross section distortion ratio and maximum wall thinning ratio can be improved by 11.98%, 7.62%, 35.53% and 11.55%, respectively.

Application of Internet of Things Technology in Mechanical Automation Control

“…(1) IOT CNC can fully control and manage the mechanical and electromechanical automatic machining program [9]. The production program data in the mechanical electromechanical automation system can be systematized through the Internet of things numerical control technology, and relevant management personnel can retrieve the mechanical electromechanical automation production program parameters at any time, which is conducive to timely maintenance of hardware equipment and improvement of automation level [10] (2) The Internet of things numerical control technology is applied to ensure the safety of mechanical electromechanical automation parameters.…”

Wall thinning behaviors of high strength 0Cr21Ni6Mn9N tube in numerical control bending considering variation of elastic modulus

“…The tangential tensile stress considering the varied elastic modulus is larger than that when ignoring the elastic modulus variation. 21 Since the wall thinning in tube bending is caused by the tangential tensile stress, increasing the tangential tensile stress will help to improve the simulated precision of the wall thinning degree. Thus, the FE model considering the variation of elastic modulus can precisely describe the tube bending deformation and can further address the wall thinning characteristics of the 0Cr21Ni6Mn9N-HS tube in NC bending under different geometrical and process parameters.…”

“…Where E 0 is the initial elastic modulus, E c is the elastic modulus for current moment, which can be expressed as 21 :…”

The precise control of end flare with residual stresses of UHSS thin-walled component in roll forming process

“…In numerical simulation, Liu et al [11] had applied the developed material model to predict and compensate the springback more precisely in RF process. Fang et al [12] embedded the variation of elastic modulus into ABAQUS to improve the prediction precision for springback in numerical control rotary draw bending. Those studies show that material model considered the reduction of Young’s modulus can effectively increase prediction precision of FEA model.…”