This work per unit volume can be divided into three components, namely uniform work, redundant work, and friction work. Study 20 terms ch 15 multiple choice qs flashcards quizlet. Offerings are typically of twodays duration, although shorter, more focused presentations have been made available. Wire drawing is usually performed cold, although there are some cases where metal is drawn hot to improve ductility. If no friction or redundant work occurred in drawing, true strain could be determined as follows. It is a severe deformation process resulting in massive shape change. In connection with the steel wire drawing there is a risk of drawing wire breaking creation. Assume that the redundant work is 40 percent of the ideal work of deformation and the. Metal forming processes indian institute of technology guwahati. The total energy for drawing or work for drawing is the sum of ideal deformation work, redundant work and frictional work. Numerical and experimental analysis of tube drawing with. The numerical analysis of drawing processes with use of drawing 2d programme, for steel wires made from trip steel with 0,29% has been shown in the work. Utilizing the upper bound methods based on the trapezoidal and spherical velocity fields, the redundant deformation factors in different deformation conditions are calculated and the achieved results are compared with the results of the fem and superposition method presented.
On the basis of numerical analyses of the wire drawing process, the distributions of longitudinal residual stresses on the cross section of wires, temperatures and redundant strain have been determined. The original course is now updated and features a unique workbook, with practical process design and trouble shooting exercises suitable for work aday formats. Illustration of a homogeneous, b frictional, and c redundant work in wiredrawing. Under normal drawing conditions, typical losses are on the order of 20 % for frictional work and around 12 % for redundant work. Factor for redundant work in wire drawing cylindrical shape is 0. A study is carried out of the mechanics of the process of hydrostatic extrusion, i. The surface areatovolume of the work is relatively small. The faying surfaces are the contacting surfaces in a welded joint.
If redundant work is neglected, the absolute value of true strain in the extrusion process is. Bulk deformation atures relative to the melting point of the metal. Doitpoms tlp library analysis of deformation processes. Number of drawing steps or passes required are more if larger reductions are desired. The course is a practical and basic introduction to modern wire drawing engineering with an emphasis on questions, answers and everyday examples.
Sep 26, 2018 this video examines the rich history of copper and wiredrawing, tracing developments and techniques through the ages. Jun 25, 2009 on the strain inhomogeneity in drawn copper wires. Identification of the work of plastic deformation and the friction shear stress in wire drawing. In wire drawing of conventional metals and alloys, the total drawing work per unit volume is given by the uniform work, redundant work, and frictional work. A study on the computation of the redundant deformation. Redundant deformation happens during wire drawing due to shear of the material in the deformation zone. Three dimensional finite element analysis of wire drawing process. Solved theoretically, the maximum reduction possible. In wire drawing of conventional metals and alloys, the total drawing work per unit volume is given by the uniform work, redundant work, and. Aug 23, 2018 so many drawing passes are needed to achieve large overall reduction how dose drawing work prof. Monitoring and evaluation of the wire drawing process. In this work, the cold drawing of tubes with fixed plug was simulated by fem with the commercial software msc. Nov, 2016 under normal drawing conditions, typical losses are on the order of 20 % for frictional work and around 12 % for redundant work.
Metal forming processes indian institute of technology. Because redundant and frictional deformations are concentrated near the wire surface, higher levels. Because instead of forcing the metal through the opening we would be stretching it through the opening. Wire drawing, making of wire, generally from a rod or bar. Horace pops leads the discussion, which also includes some details on the. Redundant work and frictional work have adverse effects on wire. Therefore, understanding the drawing mechanics is an important issue to broaden applications of niti smas. On the strain inhomogeneity in drawn copper wires springerlink. Therefore, the present work makes an attempt to assess the in.
Wright is an industrial short course, offered in public forums, and available on a customized, private basis. The theoretical analysis of wire drawing process for. Redundant work and friction in the hydrostatic extrusion. Wiredrawing 101 may 2324, 2006, boston, ma, usamay 2324. Extrusion ratio is defined as the ratio of billet initial area to final area. So many drawing passes are needed to achieve large overall reduction how dose drawing work prof. Thus, the extrusion ratio affects the extrusion force directly in an ideal situation.
The papers deals with the theoretical basis of a computer program drawin2d designed for analysis of technological process of wire drawing in several passes. According to the video on forming, what is the primary factor that makes the mechanical. One consequence is that mechanical properties will not be homogeneous across the wire cross section. The wire drawing mechanics of nearequiatomic niti sma. Wire drawing with deformation direction change in order to determine the e. Pdf the theoretical analysis of wire drawing process for. Apr 01, 2008 a study on the redundant deformation factor in wire drawing process of an austenitic 304 stainless steel is carried out. Pdf in the work has been shown the theoretical analysis the influence of different friction coefficients on strain intensity, redundant strain and. The ideal force required for drawing ignoring friction and redundant work is a 4. A redundant work factor can be employed to account for redundant work.
The drawing stress equals the work expended per unit of drawn wire volume. The microhardness distribution was studied over the transverse and longitudinal crosssections. In contrast to wire drawing, deep drawing is a sheet metal process where the material is stretched over a male. Components of work that operate during wiredrawing. Wiredrawing 101 may 2324, 2006, boston, ma, usamay 23. Upperbound solutions are obtained for the redundant work and friction which together with the work for homogeneous deformation lead to an expression for the extrusion pressure in terms of the stress. Monitoring and evaluation of the wire drawing process using. Redundant work and frictional work have adverse effects on wire properties in addition to increasing the energy needed for drawing. There are many applications for wire drawing, including electrical wiring, cables, tensionloaded structural components, springs, paper clips, spokes for wheels, and stringed musical instruments. Unfortunately, those investigations are made for the wires drawn on a bull block with a small drawing speed, which usually did not reach 2 ms. Identification of the work of plastic deformation and the. The second part of this paper shows that redundant work in rod drawing may be approached either from considerations of the mechanical properties that result after the metal is drawn or from considerations of the stress necessary to draw down the rod. Wire drawing wire drawing involves stock that can be easily coiled and subjected to sequential or tandem drawing operations with as many as a dozen or more draws occurring with a given drawing machine.
Much of the previous work related to rod or wire drawing. Calculate the force required in direct extrusion of 1 aluminum from a diameter of 6 in. Hot working occurs at temperatures above tjlle recrystallization temperature of the metal. The distributions of redundant strains xy are illustratedin fig. Van tyne colorado school of mines, golden, colorado, u. A material with a true stress strain curve sigma 350 epsilon0. In a wire drawing operation, diameter of a steel wire is reduced from 10 mm to 8 mm. A theoretical evaluation is presented of the redundant work in wire drawing by the slab method. One can also define an optimum for the deformation zone geometry as. Redundant work the summation of up, uf and ur gives.
Three different wire drawing schedules were attempted to examine the effects of reduction of area, dieangle and friction coefficient on the strain inhomogeneity of drawn copper wires. Assuming zero redundant work and frictional work to be 20% of the ideal work, derive an expression for the maximum reduction in area per pass for a wire drawing operation for a material with a truestress strain curve of. On this channel you can get education and knowledge for general issues and topics. In wire drawing, why must drawing stress never exceed yield strength of work metal. Solved problemsextrusion and wire drawing 51 a collection. Solved problemsextrusion and wire drawing 51 a collection of solved problems in extrusion and drawing prepared by dr anwar khalil sheikh as a help. Work hardening causes this to increase to a slightly higher value. The experimental and numerical analysis of trip steel wire. The stress that results from this ideal deformation is given by. This factor is multiplicative in expression for draw stress. Ignoring friction and redundant work we can write the draw pressure as.