Papers by Keyword: Warm Working

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Authors: Chun Ho Liu, A Cheng Wang, Cheng Han Lee, You Min Huang
Abstract: At present, quite a lot of enterprises, small or medium-sized, are engaged in developing the various necessaries of livelihood. And, the forming processes are generally adopted for the methods of parts manufacture. Though various forming technology progress rather well, but the warm working process often cannot obtain fine finished products in the process of manufacturing. The warm working process still needs more adequate techniques. This study is focused on the analyzing of the warm forging-flaring process of brass tube, and the improving of the die design and the working procedures. In this paper, two sets of forging and flaring die are designed for experimental works. The results of simulation are compared with the experiments, the formability of brass tube showed a good agreement. Therefore, we suggest a multi-pass of forging process instead of single-pass process. The stress distributions and loading history in forming processes are also assessed in details. The method used in this study is available in the relative warm forming processes and die design. It is helpful to increase the additional value of products and promote the level of competition in manufacturing industry.
Authors: Xin Zhao, Xiao Ling Yang
Abstract: A new kind of die steel, WD1 used for warm work dies, was developed. The behavior of carbide dissolution and precipitation in WD1 steel during heat treatment was investigated by using optical microscopy, X-ray diffractometer and transmission electron microscopy. The results show that there are three types of carbide, namely MC, M6C and M7C3 carbide, in the annealed WD1 steel; and M6C and M7C3 carbides are dissolved totally during heating for quenching; then MC, M2C, M6C and M7C3 carbides are precipitated during tempering. The secondary hardening peak is reached after tempering at 520°Cfor two hours. This hardening is mainly caused by the precipitation of Mo2C carbide.
Authors: H.J. McQueen
Abstract: After 1780, wrought iron (WI) provided a structural material and steel was cherished for its hardness and cutting qualities. When available in quantity after ~1860, steel’s structural strength and wear resistance were recognized in normalized condition in armor plates, rails and drawn wire. The responsible microstructure component was pearlite in which the lamellar spacing of ferrite and carbides could be refined by simple bulk heat treatments that are practiced with small modification until today. The strength and toughness rose as the layer thickness decreased the ferrite slip length and the carbide cracking. In hot working, the strength rises as much as 200% (while ductility falls) with fraction of pearlite; below the transus compared to austenite just above it, strengths are equal at about 0.7C (ductilities equal at 0.35C).
Authors: Xin Zhao, Xiao Ling Yang
Abstract: A new kind of die steel, WD1 used for warm work dies, was developed. The secondary hardening behavior and its affecting factors were studied. The results show that the secondary hardness increases with the content of C, Mo and V elements and Si element can significantly improve the secondary hardening effect though it’s not one of secondary hardening elements. The hardness of WD1 steel tempered at 520°C is more than HRC60, which can meet the requirements of warm work dies.
Authors: Tomohiko Hojo, Takuya Kochi, Koh Ichi Sugimoto
Abstract: The effects of warm working on microstructural, retained austenite characteristics and shear deformation properties of 0.2C–1.5Si–1.5Mn–1.0Cr–0.2Mo TRIP-aided martensitic (TM) steel for applications to automotive frame and forging parts were investigated. When warm working at 550 °C and post cooling at 1 °C/s was conducted to the TM steel, volume fractions of retained austenite and martensite-austenite constituent phase increased and mixture matrix of ultra fine granular bainitic ferrite and fine bainitic ferrite lath was obtained, whereas microstructure of TM steel warm worked at 750 °C exhibited granular bainitic ferrite matrix. These were caused by the dynamic recrystallization and the promotion of bainitic transformation of austenite due to the worm forging at 550 °C with the post cooling rate of 1 °C/s. Maximum shear stress decreased and total shear displacement increased with decreasing working temperature in TM steel. These were caused by the effective strain induced transformation of a large amount of retained austenite and the refined matrix structure.
Authors: N. Ethiraj, V.S. Senthil Kumar
Abstract: Deep drawing is one of the most widely used metal forming process to produce sheet metal parts especially in automobile industries. Warm working is the plastic deformation of metal at temperatures below the temperature range for recrystallization and above the room temperature. In this investigation, 1.0mm thick circular specimen of stainless steel AISI 304 were warm deep drawn and the influence of temperature on the deformation behaviour of material and the drawing loads which is required to draw the component was studied. The results show that the warm working has positive effects like reduced drawing load, negligible amount of increase in thinning and thickening of a drawn component when compared to the conventional drawing and also there is no necking or cracking occurs due to the temperature influence.
Authors: The Vinh Do, Quang Cherng Hsu, Wei Lin Chen, Ying Lun Jian
Abstract: Hand-tool is one of the important products which are widely used in manufacturing industry as well as in human life. The torx is one kind of hand-tools which is considered as a case study in this research. There are two trial preforms designed to analyze their influence on forgings formability. Firstly, DEFORM-3D software was used to simulate and analyze forming processes of different preform shapes for observing the formability of each trial preform and defects during the forming processes. Die stress analysis was also conducted to investigate the die stress of the forming stages in different forming processes. Secondly, according to the formability and the die stress, the most suitable forming processes and preform were selected for actual experiments. Finally, to verify the simulation results accuracy, the feature matching and hardness test were performed. The result of this research show that appropriate forming processes and preform applied improve the quality of product compared to original product.
Authors: N Ethiraj, V.S Senthil Kumar
Abstract: Deep drawing is one of the sheet metal forming processes used widely in industries like automobile, aerospace etc. In drawing operation, the limiting draw ratio (LDR) is used as an index of drawability of a material. In this investigation, stainless steel AISI 304 grade blanks of 1.0 mm thickness with different diameters are drawn into a circular cups in single stage. The experiments were conducted at room temperature as well as at temperatures 100oC, 200oC, and 300oC. The LDR values obtained in each condition were analyzed. The experimental results show that there is a significant improvement in LDR values by warm working.
Authors: Oleg D. Sherby, Manuel Carsí, Woo Jin Kim, Donald R. Lesueur, Oscar A. Ruano, C.K. Syn, Eric M. Taleff, Jeffrey Wadsworth
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