Papers by Keyword: Die Life

Abstract: The work purpose is to evaluate the application of nickel-based CrNi73CuBeTeAl superalloy (tungsten-free), made by electroslag remelting as a die tool material for isothermal forming. Isothermal deformation was simulated by tests for high-temperature cyclic creep. The specimens with high and × in plan dimensions (both parallel and perpendicular to the ingots central axis) were cut from the bottom, top and central zone, near the lateral surface and in the ingots central axis area. The tests were performed at 900, 940 and 980 °C constant temperature with 100, 200 and 300 MPa cyclic pressure in 0.02, 0.2 and 2.0 mm/s velocities range corresponded to 10-3-10-1 1/s strain rates. Such tools application field is compressor blades Ti-forgings die forging and sizing with ε = 1.0-3.0% residual upsetting deformation of dies during operation. It is shown that the die life can be extended to 400-700 loading cycles at 850-950 °C operating temperature and pressure up to 150 MPa.

Abstract: The difficulties and issues associated with the economics of the process and die life in casting aluminium alloys, as experienced by the high pressure die casting industry, were reasons behind undertaking this research project. The use of a tungsten alloy able to withstand high temperature process conditions without the welding problems experienced by standard die construction materials, such as H13, was examined in an extensive series of casting trials. The importance of operating dies at elevated temperatures to minimize heat checking has been demonstrated previously, both through theoretical thermal modelling and experimentation. This paper describes both aspects of die life extension and possibilities to reduce the amount of alloy material used in the cast part feed system, including overflows. CSIR intends using the results of this research for further development and application of high temperature die construction materials in high pressure die casting processes of light metal alloys.

Abstract: Based on a modified form of Archard’s wear theory, significant data were obtained using the finite element analysis code DEFORM during the process of warm extrusion, including instantaneous interface temperature, sliding velocity, and interface pressure distribution of every node. From the acquired data, the wear of the punch, the temperature–wear coefficient curve, temperature–wear depth curve, and temperature–hardness curve were acquired. The results show that the maximum wear occurred in the front working tape of the punch. The results are in agreement with actual conditions, and therefore, lay a foundation for forecasting die life and optimizing die cavity profiles using this method.

Abstract: In this paper, the influence factors of liquid die forging die life are talked about, mainly for example with the key universal parts Squeeze chamber of indirect liquid die forging. In the Premise to guarantee product quality, the mould preheating temperature, pouring temperature, casting alloy type, suitable and reliable cooling methods and effective paint could influence bigger on the peak and variation range of the mold temperature. These factors should be taken into consideration and remembered its effects for mould design in order to improve die life, further a new direction and thinking of liquid forging die life design criterion will be given.

Abstract: Isothermal forging die plays an increasing important role in plastic forming. During isothermal forging process, die bears high and long-time thermomechanical loading, which leads to short service life and poor reliability. Therefore, estimating isothermal forging die life using traditional method will engender great errors. In this paper, an average strain of fatigue process zone in danger region is introduced to estimate service lifetime of isothermal forging die. An upper die of a Ti-4Al-6V disc is analyzed to investigate the service life of die. The result shows that using average strain method can estimate service life of isothermal forging die more exactly.

Abstract: As an important forged part of an automobile, the inner hole of the half-shaft bushing must be formed directly. However, the process requires many steps, and how the forging, or deformation, is spread over the production steps directly affects the die life and forging force required. In this paper, the three steps involved in directly forging a half shaft bushing's inner hole are simulated using the two-dimensional finite element method. Further more, we improve the forging process. From numerical calculation, the improved necessary forging force is found to be only half the original force, and the die life is doubled.

Abstract: Micro-alloyed cold forging steel has been developed to rule out heat treatment process before forging in order to save energy consumption. These non heat-treated cold forging steels utilize the work hardening during cold working to ensure the mechanical properties. In other words, the required strength of forged part is achieved by work hardening with the accumulation of plastic strain during the cold working. Therefore, the plastic deformation characteristics should be carefully understood for successful process design. Evolution of both microstructure and plastic characteristics of micro-alloyed cold forging steel has been investigated in the present study. For the optimization of forging processes, finite element analysis and die life predictions were carried out.