钣金折弯成型加工中的缺陷处理策略

本文针对钣金折弯成型加工的特点,从钣金折弯成型的基本原理出发,通过采用大量参考文献的分析法、对比法,分析了钣金折弯成型的基本原理。本文通过结束语的形式总结了该处理策略的应用给钣金折弯成型加工带来的积极影响,希望为相关工作人员提供有效的参考。     

Components with Optimised Properties due to Advanced Thermo‐mechanical Process Strategies in Hot Sheet Metal Forming

The increasing demand for car body structures with optimised energy absorption capacity and the ability to maintain their structural integrity even under the highest dynamic load has stimulated the development of new thermo‐mechanical process routes for the production of pressed and roll‐formed sheet metal parts in order to combine both extreme formability and a highest level of strength for the final product. These process routes offer a high potential for further improvements in the field of strength‐strain correlation and load adapted property distribution of the components, as well as an enhanced process productivity. A new type of thermo‐mechanical tailored processing of sheets and profiles is presented, based on the adequate application of differential heating and cooling strategies. By the control of local microstructural effects, the components develop a property distribution adapted to complex load situations. New tooling concepts complement these developments in order to ensure high process efficiency and reliability.     

矫直机压弯量计算法的探讨

随着计算机设定矫直机压弯量（俗称压下量）的精确化需要,初步提出一种解析方法和数值方法。并在大挠度压弯时把弹复挠度与残留挠度分开计算,在计算残留挠度时,将其作为假想外力作用所产生的等效挠度,再将此等效挠度分为弹性挠度与弹塑性挠度使用数值积分法计算,可获得相当精确的结果。与现场经验值对比验证,可得出切实可行的结论     

DTA‐Measurements to Determine the Thixoformability of Steels

Semi‐solid metallurgy (SSM), also known as “thixoforming” or “thixoprocessing”, is of special interest as a new potential manufacturing technology for components in the automobile, machine and electronic industries. The aim of this technology is to produce complex shapes which cannot be produced with conventional processing methods. An important process step of semi‐solid processing (SSP) is the reheating and isothermal holding of the billet within the solid‐liquid range in order to obtain the required fraction liquid content and the desired globular microstructure. Aside from the investigation of billet heating and the development of a suitable tool design, the development and evaluation of adequate microstructures over a wide temperature area is very important. The focus of this paper is to determine the semi‐solid area of different steels through Differential Thermal Analysis (DTA) measurements. To determine a process window for handling the alloys in the semi‐solid state, the DTA‐results can be combined with microstructure parameters. Subsequent quenching experiments show the development of the microstructure parameters (e.g. grain size, phase distribution, volume fraction, shape factor, matrix character, contiguity, and particle density of the primary solid and liquid phases). A comparison of the slopes of the determined solid‐liquid areas for different steels show the width of the melting or freezing intervals to evaluate the possible process windows. DTA‐experiments performed at different heating rates show the influence of faster heating and cooling rates on the solidus‐liquidus interval. To evaluate the suitability for the thixoforming processes, this paper describes, and then compares, the semi‐solid intervals of different steel grades, which have been investigated in the Department of Ferrous Metallurgy at the RWTH Aachen University. The tool steel HS 6‐5‐3 and the cold work tool steel X210CrW12 have a wide semi‐solid area, which can be explained due to the dissolution of different carbides. In contrast to this, the steels C45, 42CrMo4, 16MnCr5, 34CrNiMo4, 100Cr6, X220CrVMo13‐4 and the Alloy 33 show a much smaller semi‐solid area.     

中板轧机滑板间隙对板形控制影响的初步探讨

中板轧机滑板的有效间隙具有承载和导向作用。滑板间隙偏差将导致轧制不稳定,影响板形质量,并使设备受损。为保持有效间隙,应减少支撑辊轴承座滑板与轧机滑板的磨损,提高滑板的利用率。