Hu Zhenghuan

Study on internal wall's deformation of steel pipe by hot skew rolling

In the forming process of V-type ring groove on steel pipe by hot skew rolling, because the technology and metal flow characteristics in skew rolling process result in deformation of internal wall during modeling process and the deformation effects directly on the dimensional accuracy of parts. This paper is to analysis finite element simulation of the forming process of V-type ring groove by hot skew rolling, the effect rules of process parameters on the deformation rate were obtained. Research results have theoretical sense for realizing precision-forming of V-type ring groove, optimizing die design, and determining technological parameters by hot skew rolling.

Study on shaping curve of inside oblique step for cross wedge rolling elliptical shaft

Elliptical shaft has been using widely in blank forming for various kinds of precision forging and its step is mostly formed into cone shape with cross wedge rolling (CWR) process. To solve the spiral cone volume, a mathematic model was established by the analysis of rolling process for the CWR elliptical shaft, and shaping curve of oblique step was calculated with the volume invariance principle. In addition, using the finite element software DEFORM-3D, simulations of the CWR forming process for the elliptical shaft were performed to test the correctness of shaping curve, which had achieved good results. The study provides theoretical basis for shaping curve design of inside oblique step for the CWR elliptical shaft and further reduces the tool debugging time.

Analysis of process parameters influence on axial force of Cross wedge rolling

Axial force in CWR plays an important role in studying the forming quality of asymmetric shaft-parts, section shrinkage of rolled part and rolling of heavy area reduction. This paper proves that calculating axial force by FEM has favorable reliability and versatility; by using ANSYS/LS-DYNA FE software, a certain number of axial forces have been obtained successfully and the formula of axial force has been regressed; in the mean time, influence rules of process parameters and their interactions on axial force have been gotten from theoretical analysis, primary and secondary factors effecting on axial force have also been synthesized. The research results provide useful reference for solving process problems caused by axial force.