Evaluation of sheet metal covers to improve tool life in forging

评估金属板覆盖层以提高锻造工具寿命

基本信息

批准号：
262370983
负责人：
Professor Dr.-Ing. Gerhard Hirt
金额：
--
依托单位：
Institut für Bildsame Formgebung (IBF)
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2014
资助国家：
德国
起止时间：
2013-12-31 至 2019-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/262370983?language=en
关键词：
Evaluation sheet metal covers improve

项目摘要

This research project within the German Brazilian research cooperation BRAGECRIM proposes a new method for wear protection in closed die forging using exchangeable sheet metal die covers. The aim of this project is the development of an inexpensive and easily exchangeable sheet metal die cover which is used to protect the engraving. Generally, the results of the first funding period proved that the proposed concept of die cover can be applied to reduce the tool wear and increase the die lifetime in closed-die forging. For an example geometry, the maximum thermal shock was reduced by 140 K and the main principal stress by 10% due to a reduction of the notch effect in the radius of the die. Based upon a die lifetime calculation, an increase of the die lifetime by more than 200% can be expected. Furthermore, in the first funding period, a FEM model was developed, which can realistically predict the material flow of the billet and the behavior of the die cover. The model was validated for different die geometries by forging experiments. Besides these positive results, the first funding period revealed problems like thinning and wrinkling which lead to a destruction of the die cover after just a small number of forging cycles. Both numerical and experimental investigation allowed to analyze the mechanisms for the observed phenomena. The wrinkling and thinning of the die cover are mainly caused by tensile stresses within the sheet resulting from different friction coefficients at the contact between billet and die cover, respectively, die cover and die. Furthermore, the first funding period focused on the investigation of simple die geometries involving strip-like die covers which do not have a self-stiffening 3D curvature. Related work has shown that these self-stiffening effects provide a realistic opportunity to overcome these problems. Therefore, in close cooperation with the Brazilian partner institute LdTM the main focus of the second funding period is put on the analysis of boundary conditions, die geometries and process chains, where the limitations observed in the first funding period do not prevent a successful application of the die cover concept. To eliminate the tensile stresses within the sheet, the influence of different friction coefficients at both contact surfaces will be investigated. In addition, an enhanced fixation of the sheet within the die will be tested in order to prevent a relative movement between the die cover and the forging die. Besides this variation of the boundary conditions, a second main aim will be the investigation of 3D die covers geometries offering a larger stiffness to reduce the undesired effects considerably. After the second funding period, the concept shall be progressed to a point where a transfer to industrial application is realistic. It is planned to cooperate with ThyssenKrupp Metalúrgica Campo Limpo Ltda.

这项在德国巴西研究合作的研究项目Bragecrim提出了一种新的方法，用于使用可交换的钣金模具盖封闭伪造的磨损保护。该项目的目的是开发廉价且易于交换的金属模具盖，用于保护雕刻。通常，第一个融资期的结果证明，可以应用拟议的模具盖概念来减少工具磨损并增加闭合锻造中的死亡寿命。对于一个示例几何形状，最大的热冲击减少了140 K，由于模具半径中的缺口效应的降低，主要主应力减少了10％。基于死亡寿命计算，可以预期将死亡寿命的增加超过200％。此外，在第一个融资期内，开发了一种FEM模型，该模型可以实际预测钢坯的材料流和模具覆盖的行为。该模型通过锻造实验对不同的几何几何验证。除了这些积极的结果外，第一个融资期还揭示了诸如稀疏和包装之类的问题，这些问题仅在少量宽恕周期之后就导致了模具盖的破坏。数值和实验研究都可以分析观察到的现象的机制。模具盖的包裹和稀疏主要是由于纸板内的拉伸应力引起的，这是由于方坯和模具盖之间的接触时不同的摩擦系数而导致的，是模具盖和模具。此外，第一个资金时期的重点是调查简单的模具几何形状，这些几何形状涉及带有脱皮的模具覆盖物，这些覆盖物没有自换3D曲率。相关工作表明，这些自我启动效应为克服这些问题提供了现实的机会。因此，在与巴西合作伙伴研究所LDTM的密切合作中，第二融资期的主要重点是分析边界条件，模具几何形状和过程链，其中在第一筹时期观察到的限制并不能阻止成功应用模具封面概念。为了消除薄板内的拉伸应力，将研究两个接触表面上不同摩擦系数的影响。此外，将测试纸板内部的增强固定，以防止模具盖和遗忘模具之间的相对运动。除了这种边界条件的这种变化外，第二个主要目的还将是3D模具的投资涵盖几何形状，可提供更大的刚度，以减少未预期的效果。在第二个融资期之后，该概念应发展到转移到工业应用是现实的地步。计划与ThyssenkruppMetalúrgicaCampo Limpo Ltda合作。