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M. Suliga

The influence of the High Drawing Speed on Mechanical-Technological Properties of High Carbon Steel Wires

In this work the influence of the drawing speed on mechanical-technological properties of high carbon steel wires has been assessed. The drawing process of ϕ5.5 mm wires to the final wire of ϕ1.6 mm was conducted in 11 passes, in industrial conditions, by means of a modern Koch multi-die drawing machine. The drawing speeds in the last passes were: 5, 10, 15 and 20 m/s. For ϕ1.6 mm wires the investigation of mechanical-technological properties has been carried out, in which yield strength, tensile strength, uniform and total elongation, reduction of area, the number of twists and the number of bends were determined. On the basis of numerical analyses wire drawing process, the influence of the drawing speed on effective strain has been determined. The investigations have shown the essential influence of high drawing speed on mechanical-technological properties of high carbon steel wires. In the case of the wires drawn with speed 20 m/s the increase by 15% their strength properties and the decrease of plasticity properties about 25% have been noted. It has been shown that the increase of strength properties in wires drawn with high drawing speed is related to the occurrence in their bigger effective strain. The data of investigations prove the negative influence of high drawing speed on technological properties. The wires drawn with 20 m/s do not comply with the internal standard connected with torsional strength of wire, and despite having high strength properties, they cannot be used as the material for ropes, tyre cords or springs. The obtained data investigation can be applied in wire industry while implementing the new technologies of high speed drawing process of high carbon steel wires.

Open access

M. Suliga

The Influence of the Multipass Drawing Process in Clasical and Hydrodynamic Dies on Residual Stresses of High Carbon Steel Wires

In the paper the influence of the multipass drawing process on residual stresses of high carbon steel wires has been assessed. The drawing process of ϕ5.5 mm wires to the final wire of ϕ1.6 mm was conducted in 11 passes, in industrial conditions, by means of a modern Koch multi-die drawing machine. The drawing speed in the last passes was 10 m/s. The experimental measure of residual stresses in wires drawn in classical and hydrodynamic dies by Sachs-Linicus method has been done. 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 investigations have shown the essential influence of the multipass drawing process in hydrodynamic dies on residual stresses of high carbon steel wires. In the case of the wires drawn with hydrodynamic dies, in comparison to the wires drawn in classical dies, the 30% decrease of longitudinal residual stresses have been noted.

It has been shown that the decrease of residual stresses in wires drawn in hydrodynamic dies is connected with a lower redundant strain by 14.7%. In addition, the application of hydrodynamic dies in the multipass drawing process leads to significant decreasing of temperature of the wire surface (in the last pass above 500 °C). Undoubtedly, the large increase of temperature in the sub-layer of wires drawn in classical die caused the rise of internal stresses related to the thermal expansion of steel. In consequence, it caused the increase of residual stresses.

Open access

M. Suliga

In the paper the influence of the value of a single draft on the properties of rope wires has been assessed. The drawing process of φ5.5 mm wire rod to the final wire of φ2.18 mm was conducted in 6, 11 and 17 drafts, by means of a block drawing machine with the drawing speed of 1.6 m/s. For the wires drawn with the medium single draft: 10.4%, 15.5% and 26.5% the investigation of mechanical-technological properties has been done, in which yield strength, tensile strength, elongation, contraction, number of twists and number of bands were determined. In order to explain the effect of value of a single draft on properties of rope wires, the fatigue strength, roughness and residual stresses of drawn wires have been also determined. In addition, the numerical analysis of the drawing process on the base of Drawing 2D in which distribution of redundant strain, effective strain, longitudinal residual stresses and temperature of drawn wires has been shown.

The theoretical-experimental analysis of drawing of rope wires have enabled the evaluation of optimal value of single drafts by which relatively the most advantageous and useful properties of wires can be used. The investigation has shown, that in manufacturing of rope wires small single draft in 10% range should be applied. It allowed to obtain products of good plasticity properties, low deformation inhomogeneity and residual stresses, high bending and fatigue strength.

The obtained data investigation can be applied while designing the production process of high carbon steel wires.

Open access

M. Suliga

In this work the influence of the drawing speed on fatigue strength of high carbon steel wires has been assessed. The drawing process of φ5.5 mm wires to the final wire of φ1.6 mm was conducted in 11 passes, in industrial conditions, by means of a modern Koch multi-die drawing machine. The drawing speeds in the last passes were: 5, 10, 15 and 20 m/s. For φ1.6 mm wires the investigation of fatigue strength has been carried out.

In order to explain the effect of drawing speed on fatigue strength of rope wires, the roughness of drawn wires have been also determined. In addition, the numerical analysis of the drawing process on the base of Drawing 2D in which distribution of redundant strain, has been shown.

The data of investigations prove the favourable effect of high drawing speed on fatigue strength of drawn wires. It was found that the better fatigue strength of wires drawn at the speed of 20 m/s compared to the wires drawn at the speeds of 5-15 m/s is associated with a better geometric structure of the surface of those wires. In addition to the high fatigue strength of the wires drawn with high speed is related to theirs higher redundant strain.

The obtained data investigation can be applied in wire industry while implementing the new technologies of high speed drawing process of high carbon steel wires.

Open access

M. Suliga

Abstract

In this work the analysis of the wire drawing process in hydrodynamic dies has been done. The drawing process of φ5.5 mm wire rod to the final wire of φ1.7 mm was conducted in 12 passes, in drawing speed range of 5-25 m/s. For final wires of φ1.7 mm the investigation of topography of wire surface, the amount of lubricant on the wire surface and the pressure of lubricant in hydrodynamic dies were determined. Additionally, in the work selected mechanical properties of the wires have been estimated.

It has been shown that in the drawing process under hydrodynamic lubrication by drawing speed of 25 m/s the phenomena of uncontrolled formation of the surface and the diameter of the wire appears, and in the process the compressive stresses eliminating cracks on the wire surface occur, causing further smoothing. The wires drawn hydrodynamically in speed of 25 m/s, besides clearly worse properties compared to the wires drawn hydrodynamically at speeds in the range of 5 to 20 m/s, also exhibit large dimensional variations.

Open access

M. Suliga

Abstract

In this work the influence of the drawing speed on lubrication conditions and mechanical properties of high carbon steel wires drawn in conventional and hydrodynamic dies has been assessed. The drawing process of ϕ5.5 mm wires to the final wire of ϕ1.7 mm was conducted in 12 passes, in industrial conditions, by means of a modern Koch multi-die drawing machine. The drawing speeds in the last passes were: 5, 10, 15, 20 and 25 m/s. For final wires ϕ1.7 mm the investigation of mechanical properties has been carried out, in which yield strength, tensile strength, uniform and total elongation and also number of twists were determined. It has been shown that the increase of drawing speed from 5 m/s up to 25 m/s caused the increase by 6% strength properties and decrease of plasticity properties by 10%. Higher values of tensile strength and yield strength of the wires drawn conventionally with high speeds are associated with worse conditions, while in case of wires drawn hydrodynamically the main factor which caused the increase of strength properties was high lubricant pressure in hydrodynamic die, which caused the increase of total draft.

Open access

M. Suliga

Abstract

The analysis of the heating of the wire including theoretical studies showed that in the multistage drawing process a increase drawing speed causes intense heating of a thin surface layer of the wire to a temperature exceeding 1100°C, which should be explained by the accumulation of heat due to friction at the interface between wire and die. It has been shown that with increasing of drawing speed the heated surface layer thickness measured at the exit of the wire from the dies is reduced significantly and at drawing speed of 25 m/s is equal to about 68 μm. The decrease in the thickness of this layer can be explained by a shorter time of heat transfer to the wire, which causes additional heat accumulation in the surface layer. Thus fivefold increase in drawing speed caused an approximately 110% increase in the temperature in the surface layer of the wire. Experimental studies have shown that the increase of drawing speed of 5 to 25 m/s will increase the temperature of the wire after coiled on the spool more than 400%.

Open access

M. Suliga

Abstract

The paper analyzes force parameters in the process of multistage drawing of steel wires in conventional and hydrodynamic dies. The drawing process of the wire rod with a diameter of 5.5 mm for wires with a diameter of 1.70 mm was performed in 12 drafts with the usage of the multistage drawbench Koch KGT with the speed range of 5-25 m/s.

Modern software of multistage drawbenches allows direct reading of many parameters during the drawing process, including drawing power. The force and drawing stress in each drafts were determined relying on experimental measurements. A complement to the research was a theoretical analysis of the drawing process. The results of the theoretical studies were compared to those obtained by experiment.

The significant impact of the drawing speed on the force parameters of the drawing process in conventional and hydrodynamic dies was demonstrated. Depending on the real conditions of the drawing, ie. temperature, friction and lubrication, enhancing the drawing speed can result in both an increase and a decrease in drawing stress.

Open access

M. Suliga, R. Wartacz and J. Michalczyk

Abstract

The paper contains the theoretical and experimental analysis of the impact of the drawing angle on the drawing process and the properties of low carbon steel wires. A multi-stage drawing wire rod with a diameter of 5.5 mm on a wire with a diameter of 1.0 mm has been carried out in two stages. The first one consisted of preliminary drawing wire rod for the wire with a diameter of 2.2 mm which was next subjected to the drawing process at a speed of 25 m/sec at the final wire with a diameter of 1.0 mm. The wires were drawn in conventional dies with drawing angle α = 3, 4, 5, 6, 7 degrees.

For the wires drawn in respective variants, the investigation of the mechanical properties was performed and the amount of lubricant on the surface of steel wires was determined. Numerical analysis of the process of drawing in the Drawing 2D complemented the experimental studies.

It has been shown that when drawing at high speeds, properly chosen the value of the angle of the working part of the die can improve the lubrication conditions and mechanical properties of steel wires.

Open access

M. Suliga, L. Borowik and K. Chwastek

Abstract

Residual stress present in wires after drawing process affects their magnetic properties. The paper presents a concept to estimate the level of residual stress on the basis of measurements of hysteresis loops. In order to describe the effect qualitatively the Jiles-Atherton-Sablik description is adapted. On the basis of variations in hysteresis loop shapes the average values of residual stress in wires for different single draft values are determined. It was found that the estimated average values by magnetic stresses are comparable with the results of numerical modeling and experimental studies.