Contribution in the evaluation of a performance index of hot forging dies (original) (raw)
Related papers
Performance Evaluation of Forging Dies
faculty.kfupm.edu.sa
Hot working tool steels are frequently used to make forging dies. These are high performance alloy steels, which can withstand substantial mechanical and thermal stresses encountered in forging processes. Producing forging dies is technically a demanding process, at all stages of its evolution and manufacturing. During use the forging dies can fail due to variety of failure modes, such as, wear, cracking and mechanical & thermal fatigue. The objective of this paper is to evaluate in service performance of these forging dies. This performance evaluation will be based on industrial data of time to failure of the forging dies. The time to failure shows a significant variability around its average value. Keeping in view both the average value and dispersion in the die life the nature of their failure rate will be explored and appropriate reliability characterization will be provided. Using the parameters of the fitted reliability models a strategy is outlined to have a comparative evaluation of forging tools produced by two competing die manufactures or die materials and /or heat treatments. Reliability analysis of tool life data is done for a variety of forging dies. Various modes of failure and their underlying damage mechanisms are discussed. Important features of the damage processes are identified, and approaches to minimise the tool damage are highlighted. Major focus of the paper is on the reliable life modelling of these metal-forming tools, and to discuss some possibilities to enhance their life. An interpretation of tool quality in view of Taguchi's loss function is also provided, which can be used as a criterion of tool performance, as well as for comparative evaluation of tools.
2016
Di e wear, which is defined as a surface damage or removal of material from one or both of two s olid surfaces in a s l iding, rolling or impact motion relative to one a nother, is considered the main cause of tool failure. Wear i s res pons i bl e for 70% of tool failure and a potential s ource of high costs; a s much as 30% per forging uni t i n the forgi ng i ndus tri es [1]. Thi s paper presents a unique wear prediction and measurement method for open di e forgi ng us i ng a modi fi ed Archa rd equation, 3D FE simulation (to represent the a ctual forging process precisel y) a nd a n i ndus tri a l s ca l e forgi ng tri a l. The proposed tool and experimental design is aimed at facilitating a cost effective method of tool wear a nalysis and to establish a repeatable method of measurement .It creates a platform to test different type of lubricants and coatings on i ndus tri a l s ca le environment. The forging tri al was ca rried out using 2100T Schuler Screw pres s. A full factorial experiment design was us ed on 3D simulation to identify the process setting for creating a measurable amount of tool wea r. Wea r predi cti on of 28.5 μm ba s ed on the simulation correlated wi th both Infi ni te Focus Opti ca l Mi cros cope a nd Coordi na te Mea s uri ng Ma chi ne (CMM) measurement results of the practical trial. Thermal ca mera reading showed temperature raise o n the a rea wi th ma xi mum wea r, whi ch s ugges ts tha t i ncrea s e i n conta ct ti me, ca us es therma l s ofteni ng on tool s teel. The mea surement s howed that a brasive wear and adhesive wear a re dominant failure modes on the tool under thes e proces s condi ti ons .
2014
The service lives of dies in forging processes limited by wear, fatigue fracture and plastic deformation, etc. in hot forging processes, wear is the predominant factor in the operating lives of dies. In this study, the wear analysis of a closed die hot forging process has been realized. This study aims to reduce die wear. As part of these initiative guidelines has been developed for a) Die design under hot and warm forging Conditions, and b) Selection of optimum lubrication systems for increased die life.
Application of design of experiments to forging simulations to increase die life expectancy
International Journal on Interactive Design and Manufacturing (IJIDeM)
Wear and fracture of steel dies employed in hot forging were evaluated through metallographic study with the aim of qualifying a Finite Element Simulation of the productive process. Apart from providing useful insights into the causes of die damaging, the simulation was exploited in a Design of Experiments to prevent fracture and to counter different mechanisms of wear. The objective is the optimization of die life acting only on process parameters that are directly adjustable in the actual industrial process. In the examination of stress distribution on the dies and the estimation of die wear, the complete forging cycle has been taken into consideration. Despite the considerable variability of the process, the study demonstrates that it is possible to prevent fracture insurgence and to increase the life expectancy of the die by a careful tuning of standard process parameters. Possible stakeholders of the study are not only process designers but also production managers, as most pro...
The goal of this research was to provide a preliminary step into developing a complete forging die life model. The research involved analyzing the initial effects of (1) friction, (2) work-piece temperature, (3) die temperature, and (4) forging press stroke speed on effective die stresses, die surface temperatures, die/workpiece sliding velocities, die/work-piece contact pressures, and die surface temperatures were examined. To obtain the results the forging process was modeled (SolidEdge 3D Solid Modeling Software), simulated (MSC.Superforge Software), and statistically setup and examined using two-level full factorial design of experiments (
Simple upsetting tests were used to assess the wear of hot forging dies. The influence of forging variables such as die-billet contact time and lubrication is described. A "white" layer is formed at the surface of lubricated dies when die-billet contact times exceed 5 ms. This layer was identified as martensite of increased wear resistance. Lubrication affects the frictional condition at the die-billet interface thus facilitating the relative movement of the billet material over the die surface resulting in the increased wear of flat dies.
IJERT-Analysis and Optimization of Die Failure
International Journal of Engineering Research and Technology (IJERT), 2019
https://www.ijert.org/Analysis-and-Optimization-of-Die-Failure https://www.ijert.org/research/Analysis-and-Optimization-of-Die-Failure-IJERTCONV7IS06054.pdf The die fatigue life is determined by the design of metal-formed product and die, forming process configuration, die stress and the entire metal-forming system. In the metal formed industries die is an important tool for fabrication of metal formed product. At the same time failure of tool steel take place because of many numbers of causes and insufficient material selection criteria. Main objective is to select the most preferable material for Die Block. For the hardness test, tensile test and Impact test is done. By that test we get the appropriate results.
Cost Calculation of Dies and Molds : Challenges , Developments and Future Trends
2007
The degree of accuracy in generation quotations has a direct impact on the die and mold manufacturer’s profitability. Die and mold manufacturers use their experience and expertise and often guess the price with varying success. Numerous tests have shown that the quotations for a die or mold can vary by more than 100% under the same circumstances. Due to modern information technologies cost calculation of dies and molds can be supported in each phase. In this paper, challenges, problems and the state-of-the-art technology of cost calculation of dies and molds will be discussed. Developments and future trends of cost calculation systems will be presented on the experience and knowledge base of the author in development of die and mold cost calculation systems.