The Design & Calculation for Hydraulic Cylinder of Workpiece Hydraulic Clamping System of a Special CNC Machine for Guide Disc

AbstractThis paper describes and introduces the design of hydraulic cylinder, which has ensured the safety and reliability of workpiece hydraulic clamping system of a special CNC Machine Tool for Guide Disc

A new micro scale FE model of crystalline materials in micro forming process

Micro forming of metals has drawn global attention due to the increasing requirement of micro metal products. However, the size effects become significant in micro forming processes and affect the application of finite element (FE) simulation of micro forming processes. Dividing samples into small areas according to their microstructures and assigning individual properties to each small area are a possible access to micro forming simulation considering material size effects. In this study, a new model that includes both grains and their boundaries was developed based on the observed microstructures of samples. The divided subareas in the model have exact shapes and sizes with real crystals on the sample, and each grain and grain boundaries have their own properties. Moreover, two modelling methods using different information from the microstructural images were introduced in detail. The two modelling methods largely increase the availability of various microstructural images. The new model provides accurate results which present the size effects well

Comparative study of two rolling bond process for super-thick Q235B

In paper, two rolling bond processes for heavy-gauge steel plate Q235B were studied and the processes were simulated by MARC software. The mechanical properties and microstructure at the interface were comparative analyzed for the two bonded plates using different rolling process. Using MARC software analysis for two rolling process, the ratio of equivalent stress in rolling process /yield stress in current temperature from surface to center portion was relatively uniform for rolling bonded

Ex situ analysis of high-strength quenched and micro-alloyed steel during austenitising bending process: numerical simulation and experimental investigation

This paper compares the microstructure and mechanical evolution in a high-strength quenched and micro-alloyed steel during the austenitising bending process. Simulation results indicated a new finding that the stress neutral layer (SNL) tends to move to the tension zone during straining. The hardness gradient detected from the centre to compression/tension zones was resulted from comprehensive factors: First of all, the location of SNL revealed a prominent impact on strength. Second, the dislocation accumulation would be responsible for the hardness gradient on the surfaces. In addition, the overall strength decrease during straining was mainly ascribed to integrated effects of dynamic recovery (DRV) and dynamic recrystallisation (DRX). Apart from that, overall smaller martensite packet size and coarser prior austenite grains resulted in the increased hardness value at a lower bending degree. Also, the high consistency between experimental and simulation results is instructive for the practical forming process of railway spring fasteners

Analysis of Springback Behaviour in Micro Flexible Rolling of Crystalline Materials

,is paper presents a constitutive modelling of the polycrystalline thin metal strip under a state of combined loading in microflexible rolling. ,e concept of grained inhomogeneity is incorporated into the classic Chaboche hardening model that accounts for the Bauschinger effect, in order to provide more precise description and analysis of the springback mechanism in the particular forming operation. ,e model is first implemented in the finite element program ABAQUS to numerically predict the stress-strain relationship of 304 stainless steel specimens over a range of average grain sizes. After validation of the developed model by comparison of predicted curves and actual stress-strain data points, it is further applied to predict the thickness directional springback in microflexible rolling of 304 stainless steel strips with initial thickness of 250 μm and reduction changing from 5 to 10%. ,e model predictions show a reasonable agreement with the experimental measurements and have proven to be more accurate than those obtained from the conventional multilinear isotropic hardening model in combination with the Voronoi tessellation technique. In addition, the variation of thickness directional springback along with the scatter effect is compared and analysed in regard to the average grain size utilising both qualitative and quantitative approaches in respect of distinct types of data at different reductions

Micro forming of metallic composites

As the popularisation of electronical devices, the development of micro systems has attracted the attention of the researchers. Therefore, it is crucial to identify the effects of relevant parameters in micro forming process. This study mainly focuses on the impact of holding time in heat treatment process on the properties of Cu-Al-Cu laminate composite materials during micro deep drawing process. The results demonstrate that the Cu-Al-Cu laminate composite material that experiences 10-minute holding time can obtain better properties. Furthermore, a simulation model of the micro forming process is developed and the simulation results are compared with the experimental ones

Effect of grain size on springback and system energy in micro V-bending with phosphor bronze foil

In this paper, the effect of grain size on springback in the micro V-bending process of phosphor bronze foil (face-centered cubic structure) is investigated. Grain size effect is expressed by the ratio of material thickness (T) to average grain size (D), and these T/D values are divided into three groups: larger than 1, less than 1, and approximately equal to 1. It has been found that springback angles were the lowest when T/D ≈ 1. Electron backscattering diffraction (EBSD) measurement results show that the twinning boundaries change with the ratios of T/D before and after bending. When T/D \u3e 1, the high relative frequency of Σ3 implies that the specimen has a high system energy, which can result in large springback behavior. The equal relative frequencies of Σ3 for specimens with three ratios also prove that twinning boundaries can be regarded as an indicator of system energy. The effect of grain size on grain reorientation during bending is also discussed, and it was found that the least quantities of high surface energy {110} planes in the T/D ≈ 1 material could contribute to the least springback angles

Deformation work in strip tension leveling

In tension leveling, elongation is determined by a combination of tension and deformation curvature, so how to set up optimization of the processing parameters has been emphasized by researchers. In this paper, the deformation work in tension leveling was introduced. According to the calculation used in a tension leveler, the tension and deformation curvature which results in less deformation work under a certain elongation is presented. The method can determine the leveling processes parameters for different strip with various properties and sizes

Analysis of Springback Behaviour in Micro Flexible Rolling of Crystalline Materials

This paper presents a constitutive modelling of the polycrystalline thin metal strip under a state of combined loading in microflexible rolling. The concept of grained inhomogeneity is incorporated into the classic Chaboche hardening model that accounts for the Bauschinger effect, in order to provide more precise description and analysis of the springback mechanism in the particular forming operation. The model is first implemented in the finite element program ABAQUS to numerically predict the stress-strain relationship of 304 stainless steel specimens over a range of average grain sizes. After validation of the developed model by comparison of predicted curves and actual stress-strain data points, it is further applied to predict the thickness directional springback in microflexible rolling of 304 stainless steel strips with initial thickness of 250 µm and reduction changing from 5 to 10%. The model predictions show a reasonable agreement with the experimental measurements and have proven to be more accurate than those obtained from the conventional multilinear isotropic hardening model in combination with the Voronoi tessellation technique. In addition, the variation of thickness directional springback along with the scatter effect is compared and analysed in regard to the average grain size utilising both qualitative and quantitative approaches in respect of distinct types of data at different reductions