Development of Die Lubricants for Forging and Extruding Ferrous and Nonferrous Materials

Shaw, H.L.; Boulger, F. W.; Lorig, C. H.

doi:10.21236/ad0094742

Cited by 4 publications

(4 citation statements)

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“…(a) dry friction is reduced (b) most lubricants are more effective mainly because of hydrodynamic action (c) metal flow is more homogenous. 3 With graphite as a lubricant, friction is greatly influenced by ,the carrier fluid. Oily carriers reduced lubricating efficiency relative to aqueous dispersions at press speeds but gave lower friction at hammer speeds because they developed hydrodynamic squeeze films.…”

Section: Discussionmentioning

confidence: 99%

Closure to “Discussion of ‘Speed Effects in Forging Lubrication’” (1971, ASME J. Lubr. Technol., 93, pp. 322–323)

Wallace

Schey

1971

Journal of Lubrication Technology

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ipm and resulted in the curves shown in Fig. 11; similar results were obtained at 400 ipm. All specimens were compressed to approximately 55 percent reduction in height which increased the final D/H ratio to 3.3 times its initial value. For tall specimens of D 0 /H 0 -0.5, end-face expansion was negligible; ii became significant only at values of D o /H 0 = 1 (D/H = 3.3) for both lubricated and unlubricated conditions.Although end-face expansion began when the final diameter/ height ratio (D/H) was approximately 3, it did not approach the theoretical maximum even for lubricated conditions until the initial value, D a /H 0 , was equal to 3. In the latter circumstances, end-face expansion was about 80 percent of the theoretical maximum (Fig. 11) and gave a surface appearance which indicated very little folding over of the sides. Thus deviation from homogeneous deformation under these conditions is due to barreling only and not to folding over of the sides.Lubrication, therefore, plays a significant part, in increasing the expansion of the end faces and the homogeneity of deformation, although expansion still begins only after a diameter/height ratio of approximately 3 is reached.Although not shown here, it is worth mentioning that the glass was sarprisingly inefficient in promoting end-face expansion. Apparently, the squeeze-film that formed on impact became sealed in at the periphery of the billet end face and acted essentially as an immobile mass. Pheripheral breakdown of squeeze-films was previously noted [13] and was probably accentuated in the present work by cooling of the glass on the colder anvils.

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Section: Discussionmentioning

confidence: 99%

Closure to “Discussion of ‘Speed Effects in Forging Lubrication’” (1971, ASME J. Lubr. Technol., 93, pp. 322–323)

Wallace

Schey

1971

Journal of Lubrication Technology

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“…Of special interest for the production of forgings might be the report by Shaw et al [25] concerning the effect of lubrication on the forming behavior, and the work of Sabroff et al [26]. The investigation on lubricants used for the forming of various materials from 1955 showed that the best results for Mg alloys were achieved by graphite-based lubricants [25]. The report of Sabroff et al [26] from 1964, a manual on forging of all kinds of metals, describes the forging practice of Mg alloys as well.…”

Section: Historymentioning

confidence: 99%

“…According to the study on lubricants on AZ80A, conducted by Shaw et al [25], very good results have been achieved with both, a mix of graphite also with powdered MoS 2 in water. For a further improvement of penetration into die cavities not only the dies can be lubricated but the stock material as well.…”

Section: Lubricationmentioning

confidence: 99%

Mg-Alloys for Forging Applications—A Review

et al. 2020

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Interest in magnesium alloys and their applications has risen in recent years. This trend is mainly evident in casting applications, but wrought alloys are also increasingly coming into focus. Among the most common forming processes, forging is a promising candidate for the industrial production of magnesium wrought products. This review is intended to give a general introduction into the forging of magnesium alloys and to help in the practical realization of forged products. The basics of magnesium forging practice are described and possible problems as well as material properties are discussed. Several alloy systems containing aluminum, zinc or rare earth elements as well as biodegradable alloys are evaluated. Overall, the focus of the review is on the process control and processing parameters, from stock material to finished parts. A discussion of the mechanical properties is included. These data have been comprehensively reviewed and are listed for a variety of magnesium forging alloys.

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“…In some extrusion tests, average friction stress or average friction factors could be measured without any additional conditions to generate frictional forces. Some investigations have been published, for example extrusion force by open die extrusion [31], force±displacement curve measured by closed die extrusion [32,33], punch and die load obtained with separate die set-up in closed die extrusion [34], constant pressure obtained in closed die rib extrusion [35], punch and die load measured with separate die set-up in cup extrusion [36,37], friction load on container bore by cup extrusion with separate die setup [38] and extrusion load measurement and ®nite element simulation by forward rod extrusion [39]. Friction stress can be obtained from the slope of load± displacement curve after the maximum load in forward extrusion.…”

Section: Introductionmentioning

confidence: 99%

Friction measurement and modelling in forward rod extrusion tests

Tan

Bay

Zhang

2003

Proceedings of the Institution of Mechanical Engineers, Part J:

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Forward extrusion is one of the important processes in bulk metal forming. Friction stress can be estimated from the slope of the load-displacement curve at the steady state after the maximum load in a forward extrusion test. In this paper, forward rod extrusion tests are carried out to determine experimentally friction stress at various normal pressures, reductions in area, billet heights and lubrications. Tested materials include aluminium alloy, low carbon steel and stainless steel. Two lubrication methods are applied, conversion coating followed by either alkaline soap or molybdenum disulphide as the lubricant. Friction stresses are obtained from measurements of slopes of extrusion pressure-punch travel curves at the steady state stage. Normal pressures are evaluated by using Mohr's circle, in which shear flow stresses are estimated at the maximum elastic deformation points from the same extrusion pressure-punch travel curves. It is found that the relationship between normal pressure and friction stress appears linear, and therefore Coulomb's friction model fits the experimental data very well. Extrusion pressure-punch travel curves before the steady state can be divided into four stages: elastic deformation, filling container deformation, filling die aperture deformation and exiting inhomogeneous deformation.

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Development of Die Lubricants for Forging and Extruding Ferrous and Nonferrous Materials

Cited by 4 publications

References 0 publications

Closure to “Discussion of ‘Speed Effects in Forging Lubrication’” (1971, ASME J. Lubr. Technol., 93, pp. 322–323)

Closure to “Discussion of ‘Speed Effects in Forging Lubrication’” (1971, ASME J. Lubr. Technol., 93, pp. 322–323)

Mg-Alloys for Forging Applications—A Review

Friction measurement and modelling in forward rod extrusion tests

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