Influence of hybrid plastic deformation on the microstructure and mechanical properties of carbon-steel wire

Since the mechanical properties of metals and alloys with ultrafine-grain structure are of great practical interest, the development of continuous methods of intense plastic deformation deserves attention. The introduction of nanostructuring methods in existing production processes is subject to numerous constraints, mainly associated with the dimensions of the machined workpiece. Continuous methods of intense plastic deformation must be introduced, with corresponding gains of expediency and productivity. The combination of different types of plastic deformation is promising. Carbon-steel wire is studied in the present work. If drawing is combined with external loading, its applicability in wire production may be greatly expanded. If drawing is combined with flexure and torsion, a new production technology may be developed for the production of ultrafine-grain components. In this approach, continuously moving wire is subjected to tensile deformation (by drawing), flexural deformation (on passing through a system of rollers), and torsional deformation. The instruments employed are versatile and compatible with existing industrial equipment. If drawing is combined with flexure and torsion, the carbon-steel wire produced are characterized by ultrafinegrain structure. This approach permits modification of the mechanical properties of the wire over a broad range, without loss of strength or plasticity.     

Forming ultrafine-grain structure in steel wire by continuous deformation

Attention focuses on means of increasing the strength of steel wire, without loss of plasticity. A fundamentally new continuous method of free extension in bent uniform channels permits the formation of ultrafine-grain wire structure.     

Structure and properties of nickel-molybdenum steel wire rod after thermomechanical treatment

The mechanical properties and structure of low-carbon nickel-molybdenum steel wire rod after softening thermomechanical treatment in a high-speed wire mill are studied. Dislocations may move through insular martensite and bainite sections of the structure under the action of deformation. Good plasticity of wire rod in deformational shaping may be ensured by the presence of a small proportion (up to 10%) of sections with bainite-martensite structure and the motion of dislocations through those sections.     

The structure and mechanical properties of fine diameter Al-1pct Si wire

Metallurgical and Materials Transactions B - The structure and mechanical properties of fine diameter Al-1pct Si alloy wires have been investigated. The mechanical behavior of wires as received...     

Effect of cryogenic deformation on the structure and properties of chromium-nickel steels

The effect of rolling at a temperature of 77 K and subsequent tempering on the structure and properties of chromium-nickel 05Kh14N14T2 and 15Kh14N14Yu1 steels is investigated. The formation of a nanocrystalline martensite phase in an austenitic matrix has been established. It is shown that additional hardening of the metal occurs due to the precipitation of intermetallic phases during heat treatment. The steels under study are high-strength and hard-magnetic after cryogenic deformation and heat treatment.     

Multiscale structure and properties of cast and deformation processed polycrystalline NiTi shape-memory alloys

The objective of this study is to examine fundamental processing-structure-property relationships in polycrystalline NiTi bars. Three different polycrystalline Ti-50.9 at. pct Ni (Ti-55.7 wt pct Ni) materials were examined: (1) cast, (2) cast then hot rolled, and (3) cast, hot rolled, then cold drawn. The structure of the materials was investigated at various scales ranging from nanometers to micrometers. The cast materials contained random crystallographic textures along the loading axis of the extracted samples. The hot-rolled and cold-drawn materials contained a strong 〈111〉 texture parallel to the deformation-processing direction. The high-temperature hot-rolling process facilitated recrystallization and recovery, and curtailed precipitate formation, leaving the hot-rolled and cold-drawn materials in near solutionized states. The cold-drawn material contained a high density of dislocations and martensite. After a mild aging treatment, all three materials contained distributed coherent Ti₃Ni₄ precipitates on the order of 10 nm in size. The cast material was capable of full shape-memory transformation strain recovery up to approximately 5 pct strain at room temperature under both tension and compression. The hot-rolled and cold-drawn materials demonstrated significant tension-compression stress-strain asymmetry owing to their strong crystallographic texture. Under compression, the deformation-processed materials were only capable of 3 pct transformation strain recovery while under tension they were capable of nearly 7 pct transformation strain recovery. Based on the present results, the presence of small coherent Ti₃Ni₄ precipitates is determined to be the driving force for the favorable strain transformation strain recovery properties in all three materials, despite drastically different grain sizes and crystallographic textures. The unique dependence of elastic modulus on stress-state, temperature, and structure is also presented and discussed for the deformation-processed materials. In addition, we demonstrate that the appearance of a Lüders band transformation under tensile loading can be controlled by material structure. Specifically, the presence of significant martensite and dislocations in the cold-drawn materials was shown to mitigate the Lüders band propagation and result in a more gradual transformation.     

Nonuniformity of deformation in drawing corrosion-resistant steel and alloy wire

Analysis of the nonuniformity of deformation over the wire cross section in axisymmetric drawing is based on the additional shear strain, determined analytically or by measuring the microhardness distribution. An expression for the additional shear strain is determined by the upper-limit method, using the kinematically possible disruptive velocity field. The influence of the geometric parameter of the deformation source on the nonuniformity is analyzed. As an example, the calculated and experimental data are compared for the drawing of X18H9T steel wire.     

Effect of combined deformation on the structure and properties of copper and titanium alloys

The effect of a combination scheme of severe plastic deformation and subsequent cold rolling or electroplastic rolling on the deformability, microstructural evolution, and mechanical properties of copper, titanium of various purities, and a titanium alloy of an equiatomic composition is studied. The combined deformation method is shown to create a number of new nanostructured and ultrafine-grained states with a high strength and ductility.     

A study of the deformation of patented steel wire

Comparisons of transmission electron micrographs of transverse sections of heavily drawn patented steel wire with existing metallographic and strength data were made with the aid of a computer. Both fragmentation of the cementite and the local deformation mode within the wire,i.e., plane strain elongation, an effect of the <110> wire texture of the ferrite, were taken into account in order to obtain a model for large-strain deformation of pearlitic or bainitic microstructures which is consistent with the observed microstructural changes and strain hardening rate. The functional dependence of this model on true strain and original substructural spacing is similar to the equation of Embury and Fisher for the strain hardening of drawn pearlite because their assumptions (no fragmentation of the cementite and homogeneous, axially symmetric elongation) produced offsetting errors. The present model allows for additional sensitivity of the strain hardening rate of drawn patented steel wire to metallurgical and processing variables over and above the simple dependence on original substructural scale predicted by the model of Embury and Fisher.     

Effect of cementite morphology on pearlitic wire drawing deformation

A comparative study was conducted on the effects of lamellar cementites and globular cementites on the cold drawing process and the mechanical properties of pearlitic wire steel, with the help of metallographic microscope, scanning electron microscope, transmission electron microscope, tensile tester and hardness tester. The lamellar cementites showed the deformation capacity to some extent during the cold drawing process. As the drawing strain increased, the pearlitic wire with globular cementites evolved into the fibrous form gradually and no obvious defects were found in the microstructure. The globular cementites turned to the drawing direction without any deformation of itself during the deformation process. And micro- cracks occurred in the cementite/ferrite interface due to stress concentration caused by pinning dislocations in spherical cementites. The strength and hardness of both pearlitic wires gradually increased as the drawing strain rose. And the pearlitic wire with lamellar cementites had a higher drawing hardening rate. The ferrite <110> texture formed in both pearlitic wires during the cold drawing process. Compared with the globular pearlite, the pearlitic wire with lamellar cementites had higher ferrite <110> texture intensity. And the difference of their ferrite <110> texture intensity became bigger and bigger as the drawing strain increased.     

Crystal structure and magnetic properties of SmCo5 permanent magnets produced by deformation sintering

Conclusions The phase composition and structure requirements for the optimization of the magnetic properties of SmCo₅ magnets are largely fulfilled in deformation sintering. Deformation sintering of magnets from single-phase powder enables, by ensuring the formation of an optimum structure, magnets of good magnetic properties [B^HC=7.5–8 kOe, (BH)_max=21–22 MG-Oe] to be obtained. The optimum deformation sintering conditions are: deformation load P_d=0.59 GPa; sintering temperature T_d=550°C; and sintering time _d=10–30 min.Translated from Poroshkovaya Metallurgiya, No. 1(217), pp. 75–82, January, 1981.     

微合金及控冷对高碳硬线组织性能的影响

在生产高碳硬线时,通过添加微量合金元素Cr、V并配以合适的控冷工艺,可获得较完全的索氏体组织和较高的机械性能,满足更高级别的钢绞线生产要求.     

Structure and strength properties of a corrosion-resistant austenitic-ferritic medical steel after thermoplastic deformation

The structural features, the temperature ranges of formation of intermetallic phases, and the strength after thermoplastic treatment of a new low-carbon austenitic-ferritic Fe-Cr-Ni steel with a ratio of 50: 50 of its structural constituents are studied.     

Structure and properties of 10Γ2ΦБ steel after hot plastic deformation

Recrystallization in 10Γ2ΦgB steel (strength class K60) is investigated. The influence of key parameters of two-stage thermomechanical treatment on the ferrite grain size and the work of impact is shown. Thermomechanical treatment of 10Γ2ΦgB steel intended to improve the strength and viscoplastic properties is tested industrially.     

Structure and mechanical properties of iron after surface severe plastic deformation under friction with simultaneous nitrogen saturation: I. structure formation

The structure of armco iron after severe plastic deformation under friction with simultaneous nitrogen saturation has been studied by microstructure analysis, X-ray diffraction, and transmission and scanning electron microscopy. A gradient surface layer, in which the grain size varies from micro- to submicro- and nanometer-scale values, is found to form. A mutual intensifying effect of the deformation-induced refinement of a grain structure and the diffusion of nitrogen atoms in iron is shown. The formation of a nanocrystalline state is discussed as a result of dynamic recrystallization.     

Permissible deformation of wire blank with specified margin of strength

The permissible deformation of wire blank is calculated and displayed graphically as isolines of the margin of strength at the drawplate output. The margin of strength is characterized by values of Perlin’s coefficient of 1.0, 1.4, and 1.8. Each graph permits the determination of rational values of three deformation parameters. Consequently, there is no need to plot a set of Cartesian graphs to obtain such information.