Effects of mold parameters on microscopic properties of cross wedge rolling (CWR) GH4169 alloy shaft parts

Shaft grain size and uniformity play an important role in improving its mechanical properties. Using DEFORM-3D finite element software, the effects of broadening angle and forming angle on the micro performance of the GH4169 alloy shaft parts were studied systematically. The results show that grain refinement is mainly completed in the stretching section. As the broadening angle increases, the grain size expands constantly, and the fluctuation value decreases and then increases, while as the forming angle increases, the grain size and the fluctuation value decrease and then increase. The accuracy of the finite element model was verified through cross wedge rolling experiments

Influence of process parameters on the forming mechanics parameters of the three-roll skew rolling forming of the railway hollow shaft with 1 : 5

This paper presents the new technology applied in a three-roll skew rolling railway hollow shaft. The three-roll skew rolling forming simulation is conducted in railway hollow shaft with 1 : 5. The rotation condition of the three-roll skew rolling is deduced and the rolling force and rolling torque are calculated and validated. The influence of process parameters on mechanics parameter is analyzed, from which it concludes that the mechanics parameters of the skew rolling are obviously smaller than those acquired by the cross-wedge rolling when rolling the same size of the railway hollow shaft. The results of this study lay a theoretical foundation for the realization of accurately forming the three-roll skew rolling railway hollow shaft with short process and low cost

Effect of aluminum alloy wheel forging and spinning process parameters on forming force

In order to study the influence of process parameters on the forming force during the forging and spinning process of the wheel hub, five parameters were selected: die preheating temperature, blank temperature, upper die down speed, friction coefficient and feed rate.Use Deform and Simufact software to simulate and obtain the influence law of each process parameter on forming force. The results provide a certain reference for reasonable selection of process parameters in the forming process

Effect of process parameters on volume loss of one-sided head of 42CrMo billet cross wedge rolling

A three-di mensional rigid-plastic Finite element model(FEM) for cross wedge rolling of square billet was established by using DEFORM finite element software. The influence of forming angle, broadening angle and section shrinkage on the volume of one-sided blank head was analyzed based on orthogonal experiments of three factors and three levels. It is concluded that the influence degree of forming angle, section shrinkage and broadening angle on the volume of one-sided blank head decreases in turn, and the influence degree of corresponding process parameters in different sections is also different. The results of this study can provide references for expanding the types of cross wedge rolling billets and choosing reasonable process parameters in square billet rolling

Study on the variation law of temperature field in three-roll skew rolling of variable diameter specimen

This paper takes the simplified high-speed train hollow axle variable diameter section sample as the research object, uses Simufact.Forming simulation software for simulation, analyze the rolling piece inner variable diameter section, equal diameter section, outer variable diameter section three stages in the forming process of temperature field distribution characteristics and variation, and discusses the causes of temperature field variation

Effect of feed rate on forming quality of cross wedge rolling of gear shaft teeth

In order to improve the forming quality of cross wedge rolling of gear shaft teeth, this paper adopts the single factor research method and uses DEFORM - 3D software to carry out the finite element simulation of the rolling process with different feed rate dies.The results show that the total feed rate of 2,75 mm is the most appropriate, and the tooth top defect of rolled piece gear can be repaired under this condition. The feed rate in the first stage is more important than that in the other stages, and the suitable range of it is 1,0 mm - 1,2 mm

Study on the variation law of temperature field in three-roll skew rolling of variable diameter specimen

This paper takes the simplified high-speed train hollow axle variable diameter section sample as the research object, uses Simufact.Forming simulation software for simulation, analyze the rolling piece inner variable diameter section, equal diameter section, outer variable diameter section three stages in the forming process of temperature field distribution characteristics and variation, and discusses the causes of temperature field variation

A unique distant submillimeter galaxy with an X-ray-obscured radio-luminous active galactic nucleus

We present a multiwavelength study of an atypical submillimeter galaxy in the GOODS-North field, with the aim to understand its physical properties of stellar and dust emission, as well as the central AGN activity. Although it is shown that the source is likely an extremely dusty galaxy at high redshift, its exact position of submillimeter emission is unknown. With the new NOEMA interferometric imaging, we confirm that the source is a unique dusty galaxy. It has no obvious counterpart in the optical and even NIR images observed with HST at lambda~<1.4um. Photometric-redshift analyses from both stellar and dust SED suggest it to likely be at z~>4, though a lower redshift at z~>3.1 cannot be fully ruled out (at 90% confidence interval). Explaining its unusual optical-to-NIR properties requires an old stellar population (~0.67 Gyr), coexisting with a very dusty ongoing starburst component. The latter is contributing to the FIR emission, with its rest-frame UV and optical light being largely obscured along our line of sight. If the observed fluxes at the rest-frame optical/NIR wavelengths were mainly contributed by old stars, a total stellar mass of ~3.5x10^11Msun would be obtained. An X-ray spectral analysis suggests that this galaxy harbors a heavily obscured AGN with N_H=3.3x10^23 cm^-2 and an intrinsic 2-10 keV luminosity of L_X~2.6x10^44 erg/s, which places this object among distant type 2 quasars. The radio emission of the source is extremely bright, which is an order of magnitude higher than the star-formation-powered emission, making it one of the most distant radio-luminous dusty galaxies. The combined characteristics of the galaxy suggest that the source appears to have been caught in a rare but critical transition stage in the evolution of submillimeter galaxies, where we are witnessing the birth of a young AGN and possibly the earliest stage of its jet formation and feedback.Comment: 13 pages in printer format, 10 figures, 1 table, accepted for publication in the A&

Study on the control of end quality by one closed cross wedge rolling based wedge block

The paper presents a new method of one closed cross wedge rolling (CWR) based wedge block to achieve near net forming of CWR shafts. The modeling is performed by using the Finite Element Method (FEM) software DEFORM-3D. The metal flow rule of the shaft is clarified by analyzing the strain and displacement field of the shaft. The results demonstrate that the concave heart value of rolled part end will be reduced by about 70 % by one closed CWR based wedge block, comparing it with the case without wedge block. And also the rolling experiments are performed the result of which provides reliable theoretical basis for achieving near net forming of CWR