Key Engineering Materials Vols. 340-341

Abstract: High speed multi pass wet wire drawing has become very common for production of high carbon steel cord because of the increase in customer demand and production rates in real industrial fields. Although the wet wire drawing is preformed at a high speed usually above 1000 m/min, greater speed is required to improve productivity. However, in the high carbon steel wire drawing, the wire temperature rises greatly as the drawing speed increase. The excessive temperature rise makes the wire more brittle and finally leads to wire breaks. In this study, the variations in wire temperature during wet wire drawing process were investigated. A multi pass wet wire drawing process with 21 passes, which was used to produce steel cord, was redesigned by considering the increase in temperature. Through a wet wire drawing experiment, it was possible to increase the maximum final speed from 1000 m/min to 2000 m/min.

Abstract: The main goal of this study was to develop the technique of process design and manufacturing for a rectangular deep drawn cup with very narrow width by using finite element analysis scheme and a series of experiments. The manufacturing process of this rectangular cup required several intermediate steps to generate the final shape. The multi-stage deep drawing process was applied to finite element analysis, and a continuous progressive press was employed in a series of experiments. Final specifications of the rectangular deep drawn cup were length of 33.70mm, height of 48.30mm and width of 3.46mm, respectively. In this study, finite element analysis for this drawing process was carried out from the first to the seventh stage, and a series of practical experiment was performed. These simulated results of the rectangular cup were compared with the prototypes of the experiments in view of the deformed shape in each mid-part. The results of finite element analysis showed good agreement with those from the experiments.

Abstract: In twin-roll strip casting process, metal flow and temperature distribution in the molten pool directly affect the stability of the process and the quality of products. In this paper, a 3D coupling temperature-flow finite element simulation during twin-roll strip casting has been carried out, and the influences of the outlet angle and the submerged depth on the temperature and flow fields in the molten pool were investigated for the twin-roll casting of stainless steel. An inverse method was used to determine the boundary conditions between the roll and molten pool. Simulation results are consistent with the experimental values. Numerical simulation is helpful to optimise the twin-roll strip casting process and to improve the quality of products in practice.

Abstract: Based on optimization setup technology, an online adaptive calculation method for improving accuracy of strip coiling temperature control on the run-out table (ROT) has been developed and implemented in hot strip mill (HSM). Multi-objective control strategies, which include coiling temperature, middle target temperature and appropriate cooling rates have been finalised. Cooling strategies, elements tracking, and dynamic correction are employed in the control system. In addition, the model optimization and soft-measure method are also introduced in the study. Rolling tests with various grades of steel covering a wide range of thickness show that the developed model can improve the accuracy of coiling temperature control to obtain an uniform mechanical properties. Good correlation has been found between the predicted temperatures and the actual coiling ones.

Abstract: Asymmetric rolling is used to produce thinner strip, which can reduce rolling force significantly. When a thinner strip is rolled on a rolling mill, work roll edge may contact each other, which affects the mechanics of this special asymmetric rolling and the crown of the rolled strip. In this paper, the authors developed a numerical model to simulate this special rolling and obtained the rolling force, intermediate force, roll edge contact force, the crown of the rolled strip and the edge contact length. The effects of the initial thickness of strip and the friction variation at upper and lower work rolls on the rolling force and crown of the rolled strip are also discussed.

Abstract: Effects of the extrusion ratio, on-line solution temperature and cooling speed on the microstructures, mechanical properties and conductivity of AA-6201 feedstock have been investigated. Experimental results show that the size of the grain of the feedstock grows slowly with an increase of on-line solution temperature, the size of strengthening phase becomes smaller and the density becomes bigger with an increase of extrusion ratio. The tensile strength of AA-6201 feedstock after T-6 treated increases with an increase of extrusion ratio, on-line cooling speed, and with a decrease of solution temperature, and the conductivity is a little penalty. Under the conditions of the extrusion ratio 16.5, on-line solution temperature 793.15K and ageing temperature 423.15K, the tensile strength, elongation and conductivity are 324 MPa, 10.1 % and 53.0% IACS respectively. A feedstock with high quality can be produced by a method of continuous casting and extrusion.

Abstract: The outer race of the constant velocity(CV) joint is an important load-supporting automotive part, which transmits torque between the transmission and the wheel. The outer race is difficult to be forged, because its shape is very complex and the required dimensional tolerances are very stringent. Therefore, the internet based shape inspection system is developed in this study to provide quick and accurate measuring data. Proposed system uses mechanical displacement sensors to measure the shape of CV joint that has six inner ball grooves, and commercially available Lab- View program is used to process measured data into the dimensional shape. Developed program provides a simple user interface that enables users to have real-time access of data measured from industrial production lines. Furthermore, the measured data can be exchanged via the internet between users and forging system operators. A java applet helped the system connection via internet. A data, IP access, is transmitted to the packet by TCP/IP. Our proposed system has many advantages over current measuring systems including fast and efficient data processing by real-time measuring, and system flexibility.

Abstract: The heat rheological forming of the TC11 titanium alloy vane disk has been studied. The dies of rheological forming were 3D-modeled based on UG and the heat rheological forming of the TC11 titanium alloy under a certain temperature and a low strain rate was analyzed by DEFORM 3D based on variation principle of rigid viscoplastic non-compressed material. A series of results including rheological forming procedure, equivalent strain field, temperature field and load-stroke curves of punch and cavity die, were obtained by finite element method. The deformation characteristic of the TC11 titanium alloy was well known and its heat rheological forming process and parameters were determined. Moreover, the local underfilled phenomenon in practical manufacture was predicted and analyzed, and we found that the defects could be restricted by reducing the forming velocity.

Abstract: In this paper, single action die and double action die hot forging problems are analyzed by a combined FEM, which consists of the volumetrically elastic and deviatorically rigid-plastic FEM and the heat transfer FEM. The volumetrically elastic and deviatorically rigid-plastic FEM has some merits in comparison with the conventional rigid-plastic FEMs. Differences of calculated results for the two forging processes can be clearly seen in this paper. It is also verified that these calculated results are similar to those of the conventional rigid-plastic FEM in comparison with analyses of the same numerical examples by the penalty rigid-plastic FEM.