Guo Yankuo, Shi Yongjun, Guo Feng
School of Mechanical and Automotive Engineering, Qingdao University of Technology, No. 777, Jialingjiang Road, Huangdao District, Qingdao 266520, China.
College of Mechanical & Electronic Engineering, China University of Petroleum, Qingdao 266580, China.
Materials (Basel). 2023 Jan 1;16(1):407. doi: 10.3390/ma16010407.
Thickness thinning is one of the processing defects that tend to occur in traditional stamping or mechanical bending of the plate and tube. In the field of high mechanical performance requirements (such as pressure vessels), the thinning phenomenon cannot be ignored. Thermal stress forming has excellent characteristics of forming without thinning, but the forming angle of this method is small, thus limiting the promotion and application of the process in the field of the form. To solve the problem, thermal stress forming with the baffle pressure method (BPM) is proposed. The coupled thermodynamic model of BPM is established, and the bending angle and deformation mechanism of the BPM are investigated. Lastly, the grain size and microhardness are measured and discussed. Results of the bending angle show that the proposed method can increase the bending angle by 57.71 times compared with the traditional method. The bending angle of BPM is determined by both the thermal buckling and the baffle, and the baffle plays a major role. The results of grain size and microhardness analysis show that the method refines the grain size, increases the material microhardness by 1.31 times and thickens the deformation zone by about 2.75%. In addition, the analytical equation of beam bending with laser as the heat source is given in this paper; this has some significance for further enrichment and development of the basic theory of beam thermoplastic bending.
厚度变薄是板材和管材传统冲压或机械弯曲过程中容易出现的加工缺陷之一。在对机械性能要求较高的领域（如压力容器），这种变薄现象不容忽视。热应力成形具有无厚度变薄的优异成形特性，但该方法的成形角度较小，从而限制了该工艺在成形领域的推广应用。为解决这一问题，提出了采用挡板压力法（BPM）的热应力成形方法。建立了BPM的耦合热力学模型，并研究了BPM的弯曲角度和变形机制。最后，对晶粒尺寸和显微硬度进行了测量和讨论。弯曲角度结果表明，与传统方法相比，该方法可使弯曲角度增大57.71倍。BPM的弯曲角度由热屈曲和挡板共同决定，且挡板起主要作用。晶粒尺寸和显微硬度分析结果表明，该方法细化了晶粒尺寸，使材料显微硬度提高了1.31倍，变形区增厚约2.75%。此外，本文给出了以激光为热源的梁弯曲解析方程；这对进一步丰富和发展梁热塑性弯曲的基础理论具有一定意义。
