Disk And Strip Forging With Side Surface Foldower: Part 2: Evaluation Of The Upper-bound Solutions

The upper-bound solutions developed in Part 1 are evaluated with regard to their ability to produce a lower value for required power (load, pressure, or work). Comparisons made with existing solutions such as the triangular field solution and one-zone bulge solution show that for strip, each solution has a domain of geometry and friction in which it is superior. The new solution produces a lower upper-bound for conditions of high interface, friction and relatively thin specimen, the area where fold over is the observed mode of flow. For solid cylindrical disks, the solution fails to improve upon existing analyses, but comes sufficiently close to warrant additional study. After evaluation, these solutions were then used in an incremental technique to model the geometry and flow as a function of reduction in height. Results appear most encouraging, and the relative simplicity of the technique when compared with present alternatives is quite attractive. © 1978 ASME

Measurement of the Wear Properties of Metallic Solids with a Falex Lubricant Testing Machine

A modified Falex Lubricant Testing Machine has been used to determine wear properties of metallic solids. In particular, wear mass loss, wear volume loss, wear rates, and other parameters have been determined for a basic steel, as heat treated and after ion implantation. Wear rate improvements of more than an order of magnitude were found in a nickel-chrome steel (SAE 3135) implanted with 2.5x1017 N+2/cm2. Wear tests were conducted with a cylinder-in-groove geometry in a mild lubricating oil with loads greater than 540 N, which corresponded to pressures which exceeded 108N/m2. A detailed analysis of the data is presented

Disk and Strip Forging with Side Surface Foldover 2

The upper-bound solutions developed in Part 1 are evaluated with regard to their ability to produce a lower value for required power (load, pressure, or work). Comparisons made with existing solutions such as the triangular field solution and one-zone bulge solution show that for strip, each solution has a domain of geometry and friction in which it is superior. The new solution produces a lower upper-bound for conditions of high interface friction and relatively thin specimen, the area where foldover is the observed mode of flow. For solid cylindrical disks, the solution fails to improve upon existing analyses, but comes sufficiently close to warrant additional study. After evaluation, these solutions were then used in an incremental technique to model the geometry and flow as a function of reduction in height. Results appear most encouraging, and the relative simplicity of the technique when compared with present alternatives is quite attractive

Disk and Strip Forging with Side-surface Foldover 1

With the assumptions of a Mises\u27 rigid, perfectly-plastic material and constant shear stress friction prevailing between the forge platens and deforming solid, the upper-bound analysis technique was applied to the upset forging of rectangular strip and solid cylindrical disks in an effort to incorporate the combined phenomena of bluge and fold. A two-zone velocity field was proposed for each geometry with Zone I occupying the interior volume and Zone II, the region near the free-surface periphery. The velocity field in Zone I was chosen as the exponential cusp-type used successfully in several previous analyses. Zone II was represented by a velocity field compatible with a foldover phenomenon and kinematically admissible with respect to boundary conditions and compatibility with Zone I. Solutions based on the above assumptions provide the forging pressure as a function of specimen geometry, interface friction, material strength, rate of bulge formation and relative size of Zone II. Minimization with respect to the last two variables provides the optimum rate of barreling or bulging and determines the degree of foldover expected

Cryogenic Treatment of Tool Steels: Questions Posed and Answers Sought

There is much controversy in the industry regarding the effectiveness of cryogenic treatment. This article reviews some of the existing literature available to the industry and poses many questions that need to be answered before the process can be fully understood. These questions may help to guide future research efforts aimed at achieving a better understanding the process

Disk and Strip Forging for the Determination of Friction and Flow Strength Values

For forging operations, process parameters, such as workpiece geometry, forging load, and material properties of the deforming body, can all be measured by well-established techniques. Interface friction, however, is a far more elusive quantity, yet its significant role in determining forging forces and mode of material flow is well-recognized. Three new techniques are proposed to enable friction determination during forging. The first of these permits friction measurement over a small but finite increment of deformation; the second, removes the controversy over measuring geometry changes of a barreling surface and, therefore, provides for increase measurement accuracy; the third technique extends measurement to forging under plane strain conditions and introduces a new approach to the problem. The use of forging to measure flow stress and provide stress-strain data for the material being formed is discussed briefly

DeGarmo\u27s Materials and Process in Manufacturing, -11/E

The new edition of DeGarmo\u27s Materials and Processes in Manufacturing focuses on updates and more coverage of non-metallic materials, sustainability, lean manufacturing, rapid prototyping and revised end of chapter and case study content. It emphasizes application and design, present mathematical models and analytic equations sparingly and uses case studies to highlight real world examples of manufacturing. Other revisions and updates include the addition of frontend Learning Objectives; elimination of weak problems and addition of new problems; more relevant and current case studies as well as additional new ones where appropriate; new chapter on Rapid Prototyping; expanded coverage of non-metallic materials such as composites, polymers, etc. ; a discussion about sustainability and green, and engineering and how it relates to manufacturing; coverage of lean manufacturing and production; and updated references and chapter summaries