Values Of Plastic Deformation Research Articles

Effect of Plastic Deformation on Torsional Fatigue Properties of a Low Carbon Steel

This paper is aimed to investigate the effect of roller working on the torsional fatigue properties of a typical low carbon steel referring by the resutls of FEM analysis. Three types of specimens had been prepared with plastic deformation value of 0, 0.5 and 1.0mm, respectively. The main results obtained in this study are as follows: (1) The torsional fatigue strength of roller-worked specimen with 1.0mm plastic deformation is increased more than twice of that of non-rollerworked specimens. (2) Surface hardness of roller worked specimen is much higher than that of the non-roller worked one, and compressed and elongated structure is formed at the notch bottom of the specimen. (3) Crack length along the axial direction of roller worked specimens is longer than that of the non-roller worked specimen, and plural cracks initiated and propagated in the roller worked specimens. (4) The residual stress distribution at the specimen’s notch bottom was analysed using FEM analysis and it is verified the same tendency as the experimental results.

Application of magnetic and electromagnetic-acoustic methods for assessing plastic deformations under cyclic loading of annealed intermediate-carbon steel

The influence of cyclic loading of annealed steel 45 during low-cycle fatigue on changes in its magnetic characteristics, in particular, the coercive force and the residual magnetic induction, for the major and minor magnetic-hysteresis loops and on changes in the propagation velocity of a longitudinal acoustic wave is studied. The sensitivity of the considered physical characteristics to the value of plastic deformation stored under cyclic loading in the region of both large and small strains is determined. The residual mechanical properties displayed after cyclic loading are determined, and the steady-state correlations between the coercive force measured on minor hysteresis loops in weak fields (the Rayleigh region) and the remanent clongation are obtained. The possibility of monitoring the stored plastic deformation and assessing the residual life of a material during its cyclic loading from the values of its magnetic parameters is shown.

Effect of Roller-Working on Fatigue Strength Improvement of Notched Structural Stainless Steel

In order to study the effect of plastic deformation on fatigue behaviors of plastically deformed specimen, bending fatigue tests had been performed on notched deformed stainless steel specimens. Also pulsating fatigue tests were done on notched non-deformed specimens to evaluate the influence of mean stress on fatigue behavior of notched non-deformed specimens. The result showed that according to increase of deformation value, the fatigue limits of these specimens also significantly increase. Fatigue limit of rolled specimen does not linearly increase with increase in plastic deformation value. Based on fatigue limit diagram, the effect of compressive residual stress on fatigue limit improvement of stainless steel is higher than that of work-hardening. In case of non-deformed specimen, when the compressive mean stress increases, the fatigue limit and the number of cycles to failure increase. In case of tensile mean stress, this kind of mean stress decreases the fatigue limit.

Structure Changes in Stainless Steels Used in Nuclear Reactors and Turbo Generators after Minor Low Cycle Fatigue Deformation

The structure of austenitic steel before and after 25% of total number of cycles of low cycle fatigue tests conducted at room temperature is studied using TEM. It is shown that the cyclic deformation of the steel proceeds heterogeneously. The microstructure of the steel is investigated in the area between the deformed and undistorted parts of the samples. The crystallography of the observed twins and the slip bands is specified. The value of local plastic deformation within a micro area of a grain is measured, and the influence of microstructure on crack initiation is discussed.

Structure Changes in Stainless Steels Used in Nuclear Reactors and Turbo Generators after Minor Low Cycle Fatigue Deformation

The structure of austenitic steel before and after 25% of total number of cycles of low cycle fatigue tests conducted at room temperature is studied using TEM. It is shown that the cyclic deformation of the steel proceeds heterogeneously. The microstructure of the steel is investigated in the area between the deformed and undistorted parts of the samples. The crystallography of the observed twins and the slip bands is specified. The value of local plastic deformation within a micro area of a grain is measured, and the influence of microstructure on crack initiation is discussed.

Roller Working Effect on Fatigue Strength of Ti-6Al-4V Alloy

The fatigue strength have been investigated about the plastic deformed specimens by roller working in Ti-6Al-4V alloy with a notch by 4 kinds of plastic deformation ratio. The plastic deformation values (Δ t) are employed 0.05, 0.1, 0.25 and 0.4 mm on notched specimens of Ti-6Al-4V alloy by roller-working. The hardness test, fatigue test and SEM observation was carried out on non-roller worked specimens and roller-worked specimens at room temperature. Based on the results of these tests, Though the hardness number of roller worked materials are higher than those of non-deformed Ti-6Al-4V alloy, the fatigue limit of roller worked materials becomes deteriorated in spite of roller working. Fatigue fracture had occurred in the non- deformed area where tensile residual stress exists. From the results of the SEM observation, stepped defect could be notch effect for reducing the fatigue strength of Ti-6Al-4V alloy.

Relation between Fatigue Strength of Notched Specimen and Plastic Deformation Value by Roller-Working.

In this study, the fatigue test has been carried out to investigate the effect of plastic deformation value by roller-working on the fatigue strength of notched specimen. Herein, the authors have tested four types of specimens whose deformation values have been changed by roller-working and final shape and dimensions are the same. The reason why fatigue strengh changes with different plastic deformation value, has been examined by analyzing the residual stress, hardness distribution and crack tip opening displacement etc. The main results obtained in this test are as follows : (1) The resistance of the fatigue crack initiation increases with the increase of plastic deformation value. (2) When deformation value becomes too large by roller working, the residual stress may be released by cycle stress and the critical stress of non-propagating crack tip opening becomes decrease. (3) The fatigue limit of notched specimen by roller-working tends to deteriorate gradually when the plastic deformation value becomes too large, the optimum deformation value would exist for improvement of fatigue limit of notched specimen by roller-working.

Effect of Plastic Deformation by Roller-Working on Fatigue Strength of Notched Specimen.

In this study, the fatigue test is performed to investigate the effect of plastic deformation by roller-working on the fatigue limit of a notched specimen. Three types of specimens are tested, whose different deformation values are obtained by roller-working and whose final finishing shape and dimensions are the same. The reason why fatigue limit changes with a change in the plastic deformation value is examined by analyzing residual stress, micro-Vickers hardness distribution and crack-tip opening displacement. The main results are as follows : (1) The resistance against fatigue crack initiation increases with an increase in the plastic deformation value. ( 2 ) When the deformation value becomes too large by roller-working, residual stress is released by cycle stress amplitude and the critical stress amplitude of non-propagating crack tip opening decreases. (3) The fatigue limit of the roller-worked notched specimen does not necessarily increase when the plastic deformation value becomes too large. (4) The optimum deformation value exists and is about 0.5 mm, to improve the fatigue limit of the roller-worked notched specimen.

844 Optimum Deformation Value of Notched Specimen by Roller-working

In this study, fatigue tests had been carried out to investigate the optimum value of deformation of notched specimen by roller-working. Here, the specimen which has a deformation value of 0.25mm is tested. The deformation values are 0,0.5 and 1.0mm to compare to the former testing results by keeping the final shapes and dimensions except for deformation value. The main results are obtained as follows : (1) The potimum value of deformation of notched specimen by roller-working is 0.5mm. (2) Fatigue strength of notched specimen by roller-working increase with increasing plastic deformation value when the deformation value is les than 0.5mm, but when the value is larger than 0.5mm the result is opposite.

Multiaxial determination of the resistance to creasing of clothing wool fabrics

In this paper, values of deformation components (elastic, viscoelastic, plastic) of clothing wool fabrics by measuring the crease recovery angle in various directions to the warp direction (0°‐warp, 30°, 45°, 60°, and 90°‐weft) were determined. The size as well as the change of deformation component from warp to weft direction was presented through polar diagrams. On the basis of the results of investigation it is possible to conclude that all investigated fabrics (plain, 2/2 twill, cross twill), regardless of the biaxiality concerning quickly reversible (elastic) deformation, tend toward isotropy in total reversible deformation (elastic + viscoelastic). Concerning the plastic deformation value, mentioned investigated fabrics also express tendency toward isotropy.

Short pitch corrugation on straight tracks—Practical experiences

One possibility to reduce rolling noise is to reduce roughness excitation. The basis of the paper is measurements of profile irregularities on a test section of the track between Baarn and Amersfoort in the networks of Nederlandse Spoorwegen (NS). In one of two segments, periodic wear pattern (short pitch corrugation) appears with wavelength from 3.5 to 4 cm, whereas the second one is uncorrugated. The line is used only in one direction and mainly by passenger cars with medium speed. Starting from the measured track data, systematic calculations with the program of Müller, which is presented in a separate paper, have been undertaken. The aim is to estimate the roughness growth and to find hints about how the growth can be stopped or at least reduced. In Müller’s paper it is explained in detail that roughness growth is restricted to a wavelength range between 2 and 10 cm. Numerical results will be presented in order to clarify how different track components influence the RGG process. The model only takes into account wear as a long-term mechanism. It shall be discussed how the long-term behavior is influenced by plastic deformation, hardness variations, or different values of micro-roughness.

Soft-x-ray-emission study of the influence ofLi+-doping, irradiation, and plastic deformation on CuO

The influence of ${\mathrm{Li}}^{+}$ doping, shear under pressure, and irradiation with ${\mathrm{He}}^{+}$ or electrons on the oxygen $2p$-band and valence states of copper ions in CuO was studied using soft-x-ray emission spectroscopy. In the case of irradiation and shear under pressure the transformation of the spectrum shape is explained by the appearance of ${\mathrm{Cu}}_{2}\mathrm{O}.$ The doping with lithium leads to the appearance of copper ions with formal valency of $3+.$ It was also established that the presence of lithium ions prevents ${\mathrm{Cu}}_{2}\mathrm{O}$ phase forming without a dependence on the plastic deformation value. The reasons and possible mechanisms of the $\mathrm{CuO}\ensuremath{\rightarrow}{\mathrm{Cu}}_{2}\mathrm{O}$ transitions in the oxides studied are discussed.

Properties of alloy steel coatings oxidized during plasma spraying

Plasma spraying of metals in air is usually accompanied by oxidation reactions resulting in the presence of oxides in plasma deposited coatings. Oxides in plasma sprayed high-alloy steel coatings can strongly affect their protective and mechanical properties. Two high-alloy steels were plasma sprayed onto plain steel substrates using a water-stabilized plasma gun. Both coating types, composed as usual of metallic lamellae (splats), contained considerable amounts of oxides present mainly as thin oxide films enveloping the splats. The compressive behaviour of cubic samples cut out of the coatings was studied. The results indicate an appreciable anisotropy of the response to compressive loading. If the pressure is parallel to the coating surface, strong cracking occurs. For loading perpendicular to the surface, cracking is less pronounced and high values of plastic deformation are observed. Though the coating structure and the presence of oxides preclude a satisfactory tensile strength, the coating can withstand high purely compressive loading. In this respect, plasma sprayed steels are comparable to those produced by conventional metallurgy.

Waxes for functional impressions.

The aim of this study was to develop a wax suitable to serve as a functional impression material. Several binary mixtures of paraffin, beeswax and rosin were prepared. They were characterized by differential thermal analysis (DTA), and tested for plastic deformation, thermal expansion, detail reproduction and mechanical properties. It was found that the combinations of paraffin with rosin can function well as impression materials, as they combine a high value of plastic deformation at 37 degrees C with relatively low values at room temperature. Concentrations of rosin as small as 1% or 2% are adequate to produce this result. The flow of paraffin was significantly reduced by the addition of beeswax. A linear relationship was found between the 37 degrees C flow values of paraffin-beeswax mixtures and the proportions of the ingredients.

高強度鋼の水素誘起現象に及ぼす水素侵入方向の影響について

To study the effects of hydrogen charging direction on the hydrogen-induced phenomena and susceptibility to hydrogen embrittlement of SCM435, static bending tests, and observations of hydrogen blistering and hydrogen-induced cracking were carried out, and the plastic deformation on the specimen surface due to hydrogen introduction was investigated by X-ray diffraction technique.The main results obtained are summarized as follows;(1) The hydrogen blistering was observed in the case of hydrogen charging perpendicular to the rolling direction not only on low strength steels but also on high strength level steels having tensile strength up to 1200MPa. On the other hand, in the case of hydrogen charging parallel to the rolling direction, no hydrogen blistering appeared in all specimens.(2) It was found that the susceptibility to hydrogen embrittlement depended on the strength level of material and was affected by the hydrogen charging direction in the case of materials sensitive to hydrogen such as those tempered at 300°C and 400°C.(3) From the measurements of half-value breadth and residual stress by X-ray diffraction, it was estimated that the values of plastic deformation due to hydrogen dissolution for the specimens tempered at 500°C, 600°C and the annealed specimen were about 0.8%, 1.2% and 2.2%, respectively, while those of the specimens tempered at 300°C and 400°C were within 0.5%.(4) Hydrogen-induced cracking initiated around the nonmetallic inclusions (MnS) or micro-segregation bands and grew parallel to the rolling direction. Their fracture morphology was quasicleavage fracture such as river like pattern.

Features of the fracture surface for molybdenum alloys with different grain size and in the presence of secondary phase particles

1. It has been shown that the effect of the structural factor on the type of fracture surface for single-phase molybdenum alloy MChVP and two-phase alloy MTA apperars in the relationship of a single fracture surface element to original grain size taking account of the amount of specimen deformation (ψ). With shear this single element is a facet, with brittle intergranular failure it is the face of a grain, and with pitted failure it is a pit. 2. The effect of structural factor is also expressed in the difference in the temperature for the start and finish of known types of surface fracture; with increasing grain size these characteristics are reduced. The presence of particles in two-phase alloy has a stronger effect on the failure process than grain size, and in this respect two-phase alloy is similar to single-phase alloy with a grain size greater than 100 μm. 3. The start of lamination and pore formation in the alloys considered occurs on reaching a specific value of plastic deformation which increases with increasing grain size. 4. The temperature for the start of rapid pore formation in alloys and pits at the fracture surface corresponds to a reduction in relative elongation for the specimen neck in the temperature dependence for this characteristic. 5. The experimental results given establishing the effect of the structural factor on formation of different types of fracture surface may be satisfactorily explained by the difference in area of intergranular surface for metal with different grain size, the presence of grain boundaries elongated i the direction of the tensile axis, appearance of a radial component for tensile stresses during necking in the specimen, and also crack initiation primarily at grain boundaries.

Pulp testing : COOLEY R. L. and BARKMEIER W. W. Dent Abstr. 23 (1978) 416–417

Control of root torque is often achieved by introducing a twist in a rectangular archwire. The purpose of this study was to investigate third-order torque on different types of self-ligated brackets by analyzing the bracket’s elastic and plastic deformations in conjunction with the expressed torque at varying angles of twist.An orthodontic bracket was mounted to a load cell that measured forces and moments in all directions. The wire was twisted in the bracket via a stepper motor, controlled by custom software. Overhead images were taken by a camera through a microscope and processed by using optical correlation to measure deformation.At the maximum torquing angle of 63° with 0.019 × 0.025-in stainless steel wire, the total elastic and plastic deformation values were 0.063, 0.033, and 0.137 mm for Damon Q (Ormco, Orange, Calif), In-Ovation R (GAC, Bohemia, NY), and Speed (Strite Industries, Cambridge, Ontario, Canada), respectively. The total plastic deformation values were 0.015, 0.006, and 0.086 mm, respectively, measured at 0° of unloading.In-Ovation R had the least deformation due to torquing of the 3 investigated bracket types. Damon Q and Speed on average had approximately 2.5 and 14 times greater maximum plastic deformation, respectively, than did In-Ovation R.

Effect of the overloading frequency on the accumulation of plastic deformation in 1Kh18N9T steel at elevated temperatures

1. The research programs of the effect of the overload have been drawn up. Laws have been established making it possible to estimate quantitatively the effect of the overload frequency on the value of accumulation of plastic deformation. 2. An analytic formula has been obtained for the determination of the time needed for the plastic deformation to accumulated at any loading frequency and a known time needed for the same value of plastic deformation to accumulate in conditions of isothermal creep.

Effect of thermomechanical treatment on fine structure

1. Thermomechanical treatment improves the mechanical characteristics because of a) decrease of the size of grains of the original γ-phase in steel and the grains of the β-phase in titanium alloys as well as the size of the martensite platelets; b) the change in the ratio of the phase components (for average values of plastic deformation the plasticity becomes maximum when the maximum amount of the residual γ-phase or β-phase remains in the quenched alloy; c) the increase of the density of structural imperfections in the original phase remaining in martensite after deformation (added to those occurring in the martensite as the result of transformation). 2. We have shown the peculiar effect of the deformation of austenite on the fine structure of martensite: deformation of austenite resulting from thermomechanical treatment induces precipitation of carbon and increases the martensitic transformation point.