Showing papers on "Carbon steel published in 1981"
TL;DR: In this paper, a detailed qualitative and quantitative microstructural examination of four dual-phase steels has been carried out, and it has been found that during tensile deformation, martensite islands do not deform until strains well in excess of the maximum uniform strain have been reached.
Abstract: A detailed qualitative and quantitative microstructural examination of four dual-phase steels has been carried out. Dual-phase structures were produced in three of these steels by intercritical annealing; the other was in the as-rolled condition. Similar combinations of tensile properties were obtained with all four steels. In intercritically annealed material, greater austenite hardenability was encountered with the two steels containing strong carbide-forming elements (vanadium or titanium) than with a similar plain carbon steel. It has therefore been proposed that the carbonitride precipitates (which are present during the anneal) inhibit the movement of the austenite/ferrite interface during the post-anneal quench; strong metallographic evidence has been provided to support this view. It has been found that during tensile deformation, martensite islands do not deform until strains well in excess of the maximum uniform strain have been reached; this observation has enabled the successful applic...
223 citations
TL;DR: In this article, the formation of austenite from different microstructural conditions has been studied in a series of 1.5 pct Mn steels that had been heated in and above the intercritical (α+ γ) region of the phase diagram.
Abstract: The formation of austenite from different microstructural conditions has been studied in a series of 1.5 pct Mn steels that had been heated in and above the intercritical (α+ γ) region of the phase diagram. The influence of variables such as cementite morphology, initial structural state of the ferrite and the carbon content has been assessed in terms of their respective effects on the kinetics of austenite formation and final microstructure. Austenite was found to form preferentially on ferrite-ferrite grain boundaries for all initial structures. The results of this study have shown that the 1.5 pct Mn has lowered both the AC3 and AC1, lines causing large amounts of austenite to form in low carbon steel. The kinetics of austenite formation at 725 °C were not only very slow but also were approximately independent of the amount formed. Austenite appeared to form slightly more rapidly from cold rolled ferrite than from recrystallized ferrite or ferrite-pearlite structures.
145 citations
TL;DR: In this paper, the effects of hydrogen on ductile fracture were studied in two spheroidized plain carbon steels, containing 0.16 and 0.79 pct C. The results indicated that hydrogen primarily assists void growth during link-up in this steel.
Abstract: The effects of hydrogen on ductile fracture were studied in two spheroidized plain carbon steels, containing 0.16 and 0.79 pct C. A combination of fractography and quantitative metallography on sectioned, deformed specimens permitted separation of the effects of hydrogen on the initiation, growth, and link-up of voids. In both steels, hydrogen was found to have no significant effect on either the initiation of voids at carbides, or early growth of voids, prior to link-up. In the higher carbon steel the fracture surface dimple size increased after hydrogen exposure with no other evident change in the fracture surface appearance; it is therefore inferred that hydrogen primarily assists void growth during link-up in this steel. In the lower carbon steel the fracture appearance changed and a decrease in void size due to hydrogen was found fractographically; thus, both initiation and growth of voids are apparently enhanced during the link-up phase of fracture in this steel. It is hypothesized that these effects may be due largely to a void pressure mechanism if hydrogen is transported by mobile dislocations.
99 citations
01 Mar 1981-Metallurgical and Materials Transactions B-process Metallurgy and Materials Processing Science
TL;DR: In this article, a mathematical model incorporating both heat transfer and the transformation of austenite to pearlite in eutectoid carbon steel rods has been developed, which allows the temperature distribution and fraction of the transformed rod transformed to be predicted as a function of cooling conditions, rod diameter and transformation characteristics of the steel.
Abstract: A mathematical model incorporating both heat transfer and the transformation of austenite to pearlite in eutectoid carbon steel rods has been developed. A computer program based on the implicit finite-difference technique has been written which permits the temperature distribution and fraction of austenite transformed to be predicted as a function of cooling conditions, rod diameter and the transformation characteristics of the steel. The program takes into account the temperature-dependent heat transfer and thermophysical properties; and stresses the importance of the enthalpy of transformation. The model has been checked for internal consistency with theoretical equations, and model predictions have been compared to published industrial data for rod cooling in water at 100 °. The effect on the temperature distribution and fraction of austenite transformed of several variables,viz., rod diameter, starting temperature, heat transfer conditions, transformation characteristics and quenchant temperature, has been predicted using the model. The range of variables studied are typical of those found in industrial processes such as patenting and controlled cooling. Use of the model in the design of controlled cooling processes and in coping with problems such as segregation in wire rods is currently under study.
91 citations
TL;DR: In this paper, the possibilities of glow discharge spectroscopy for surface analysis of metals were discussed, and examples of results obtained were given concerning the control of sub-surface compositions after thermal or thermometric treatment of steels.
Abstract: This paper deals with the possibilities of glow discharge spectroscopy for surface analysis of metals. After a brief resume of the principles and characteristics of the technique, examples of results obtained are given concerning the control of sub-surface compositions after thermal or thermometric treatment of steels; surface analysis of low carbon steel strip at various stages of the production process; analysis of phosphate surface coatings; control of the surfaces of specimens for laboratory experiments; and laboratory studies of passivation phenomena.
83 citations
51 citations
TL;DR: In this paper, the authors carried out uniaxial push-pull fatigue tests with cylindrical specimens of low carbon steel with a carbon content of 0.1 percent.
Abstract: Stress-controlled uniaxial push-pull fatigue tests were carried out with cylindrical specimens of low carbon steel with a carbon content of 0.1 percent. Resistent heated grips provided testing temperatures up to 550°C. During all fatigue tests the time-dependent strain was measured. The strain at zero load, the plastic strain amplitude plotted against the number of cycles is known as the cyclic deformation curve. At room temperature, this curve depends on the applied stress amplitude. The shape of the cyclic deformation curve at the same stress amplitude is strongly temperature-dependent. In the temperature region of blue brittleness the endurance shows a maximum connected with a very low plastic strain amplitude. Also the cyclic stress strain curves have a different appearance within varied temperature ranges.
42 citations
TL;DR: In this paper, the formation mechanisms of both types were investigated on the basis of the experimental results with the effects of sulfur content and cooling rate on the morphology of sulfides, the relation between the solidification structure and the distribution of sulfide, and the observation of formation process of nonsmall sulfides in steels quenched from various temperatures.
Abstract: Manganese sulfides in low carbon steel were grouped into a colony type (type II according to Sims' classification) and non-colony type (type I, type III and type X). The formation mechanisms of both types were investigated on the basis of the experimental results with the effects of sulfur content and cooling rate on the morphology of sulfides, the relation between the solidification structure and the distribution of sulfides, and the observation of formation process of sulfides in steels quenched from various temperatures.Though the colony type sulfide was increased with the sulfur content and cooling rate, the non-colony type sulfide was hardly affected by the sulfur content but decreased with an increase of cooling rate. The former was observed mostly in interdendritic space and formed in contact with a melt at a final period of solidification, while the latter was observed mainly around a dendrite and increased remarkably after solidification.These results can rationally be explained by the mechanisms that the colony type sulfide is formed by the eutectic reaction and the non-colony type sulfide is formed as a precipitate from the solid steel.
41 citations
TL;DR: The surface hardness of nitrogen-implanted stainless-steel surfaces was measured with an abrasive wear technique capable of characterizing surface layers as thin as 25 nm as discussed by the authors, and the hardness decreased to the bulk value over a depth corresponding to the initial implantation depth.
Abstract: The hardnesses of nitrogen-implanted steel surfaces have been measured with an abrasive wear technique capable of characterizing surface layers as thin as 25 nm. Treated steel disks and reference disks were abraded with 1–5 μm diamond, and relative wear resistances were calculated from the mass losses. Surface hardness was obtained from a relationship between wear resistance and hardness. The surface of a hardened and tempered carbon steel implanted with nitrogen ions (1017/cm2) was significantly harder than with other treatments including quench hardening and nitriding. The hardness decreased to the bulk value over a depth corresponding to the initial implantation depth. Nitorgen-implanted stainless-steel surfaces wore faster than un-implanted ones, possibly due to interference with transformation hardening which normally occurs during wearing. This “softening” effect persisted to depths several times the depth of implantation, and may help to explain the reduction of sliding wear produced by the implant...
41 citations
Patent•
[...]
27 Nov 1981
TL;DR: In this article, the authors proposed to fill perforated holes thoroughly with molten metal and to prevent the formation of blowholes by subjecting iron and steel materials to be welded to laser welding by using shielding gases consisting of inert gases such as argon and helium mixed with suitable amts. of active gases according to the kinds of said materials.
Abstract: PURPOSE:To fill perforated holes thoroughly with molten metal and to prevent the formation of blowholes by subjecting iron and steel materials to be welded to laser welding by using shielding gases consisting of inert gases mixed with suitable amts. of active gases according to the kinds of said materials. CONSTITUTION:Iron and steel materials to be welded are subjected to laser welding by using shielding gases consisting of inert gases such as argon and helium mixed with suitable amts. of active gases such as oxygen, nitrogen and carbon dioxide according to the kinds of said materials. For example, if the materials to be welded are carbon steel, low alloy steel, high tensile steel, martensitic stainless steel and ferritic stainless steel, the shielding gases consisting of the compsns. of TableIare used. If the materials to be used are austenitic stainless steel, the shielding gases consisting of the compsns. of Table II are used. Thus the formation of babbles in molten metal is prevented in welding.
40 citations
TL;DR: In this paper, the effects of hydrogen on fracture of quenched and tempered 1045 steel were examined at room temperature on tensile, Charpy impact, and 4-point notched bend specimens.
Abstract: This work examined the effects of hydrogen on fracture of quenched and tempered 1045 steel Tests were made at room temperature on tensile, Charpy impact, and 4-point notched bend specimens This steel exhibits tempered martensite embrittlement (TME) for tempering temperatures between 300 and 375 °C Thus hydrogen in most cases affected fracture by increasing the amount of intergranular fracture In bend specimens, hydrogen also induced quasicleavage (QC) fracture at points of maximum normal stress below the notch root, points which appeared to be the locations of crack initiation Tear ridges on theseQC surfaces were at martensite lath packet boundaries Crack orientations were largely mode I in uncharged specimens, with mode II appearing at the notch root in most hydrogen-charged specimens These observations are in general agreement with earlier work on martensitic steel
TL;DR: In this article, it was shown that the forbidden spots observed in electron diffraction patterns from the precipitates can reasonably be interpreted on the basis of the characteristic growth nature of the carbide phases.
Abstract: Application of the lattice and structure imaging techniques in electron microscopy has shown that θ-Fe3C and χ-Fe5C2 intergrow microsyntactically in the precipitated particles at the early third stage of martensite tempering (520~670K). Also is found the microsyntactic intergrowth of higher Carbides, θn-Fe2n+1Cn, having structures closely related With those of θ-Fe3C and χ-Fe5C2. All the forbidden spots observed in electron diffraction patterns from the precipitates can reasonably be interpreted on the basis of the characteristic growth nature of the carbide phases. At the later stage of tempering (720-870K), the precipitates are θ-Fe3C containing various kinds of planar defect. Amechanism is presented for the transformation from χ-Fe5C2 to θ-Fe3C.
TL;DR: In this paper, the growth geometry of the Austenite-ferrite aggregates in a low carbon steel containing 0.15 wt pct C were studied in the temperature range of 800 to 870 °C.
Abstract: Austenitization kinetics of pearlite and ferrite aggregates, in a low carbon steel containing 0.15 wt pct C. were studied in the temperature range of 800 to 870 °C. The transformation was monitored by estimating the volume fraction of austenite and the surface area per unit volume of the austenite-ferrite interfaces by quantitative microscopy. It is concluded that the austenite growth geometry is two dimensional. Between 800 and 840 °C, the two dimensional radial growth of the austenite particles can be described by a simple parabolic law. This suggests a diffusion controlled growth mechanism. However, at 870 °C, the kinetics of the process are different from those at the lower temperatures studied, and the radial growth rate approaches a constant value at long times.
TL;DR: In this article, a translucent and polycrystalline h-BN film was grown at 1200 δC and the dc conductivity was 4.5 kJ/mol, which is the same as the one obtained in this paper.
Patent•
12 Jan 1981
TL;DR: In this paper, a high-strength, high-workability steel for cold plastic working, obtained by subjecting a hardenable carbon steel to rapid highfrequency induction heating, quenching it, rapidly heating it by high-frequency induction to a temperature of 300°-600° C., and rapidly cooling it.
Abstract: High-strength, high-workability steel for cold plastic working, obtained by subjecting a hardenable carbon steel to rapid high-frequency induction heating, quenching it, rapidly heating it by high-frequency induction to a temperature of 300°-600° C., and rapidly cooling it. This steel can be cold plastic worked, and then reheated at 300°-500° C. for 30-60 minutes, to obtain a steel having a high elastic limit.
TL;DR: In this article, the activation energies of carbon diffusion in low carbon steel and 304 stainless steel were measured under different experimental conditions using a metallographic technique and they were found to be 127.95 kJmol-1 and 205.57 kJ mol-1 respectively.
TL;DR: In this article, a series of FeMnC alloys was quenched from 760° and 820°C. This treatment produced dual-phase microstructures in which the carbon contents of the martensite and ferrite phases were held constant while the percent Martensite varied.
TL;DR: In this article, the Auger electron spectroscopy was used to investigate the cause of variations in susceptibility to intergranular stress corrosion between steel batches of apparently similar origin, history and operating conditions.
Abstract: A common cause of failure of large metallic components is stress corrosion, often in subtle combination with fatigue. In the case of carbon steel as used in pipelines, the problem of understanding the cause of variations in susceptibility to intergranular stress corrosion between steel batches of apparently similar origin, history and operating conditions has been researched for many years. We report here the results of investigations including Auger electron spectroscopy which show that the source of variable behaviour is probably the differences in the micro-chemical content of grain boundary paths, differences which may easily exist between one batch or another of apparently similar steel.
TL;DR: In this article, a neutral inhibitor of corrosion of a carbon steel in stirred 3% sodium chloride solutions was developed by using the combined action of a fatty polyamine of molecular weight greater than 320, oleylamino-propylene amine, and an amino-phosphonic acid, amino-tri [methyl-posphonic] acid.
Abstract: In this paper, we give an account of an attempt to develop a neutral inhibitor of corrosion of a carbon steel in stirred 3% sodium chloride solutions. For this purpose, we studied the combined action of a fatty polyamine of molecular weight greater than 320, oleylamino-propylene amine, and an amino-phosphonic acid, amino-tri [methyl-phosphonic] acid. The inhibitor efficiency was determined by two types of methods: indirect measurements of the electrochemical type, potentiostatic voltamperometry and determination of polarization resistance by means of a rotating disk electrode and direct measurements of the gravimetric type by means of a semi-pilot scale circuit simulating the conditions existing in a closed industrial circuit. For a product concentration of 1 g/l−1, the inhibitor efficiency determined by electrochemical tests is of the order of 80%, and 50% when determined by long term gravimetric tests (immersion times greater than 50 hours); examination of the condition of the surface in the la...
TL;DR: In this paper, the oxide-film breakdown was studied by observing changes, with time, of appearance, weight loss, and corrosion potential while varying the three components of the system: environment, substrate, and film.
Abstract: Breakdown of the thin air-formed oxide film is the first step in the corrosion of steel exposed to aqueous chloride environments. We studied oxide-film breakdown by observing changes, with time, of appearance, weight loss, and corrosion potential while varying the three components of the system: environment, substrate, and film. Environment was varied by changes in chloride and hydrogen peroxide concentrations. Low carbon steel, stainless steel, aluminum, and titanium substrates were studied. Various types of crystalline oxide film were applied to steel substrates by RF sputtering. The results of this work demonstrated that the chemical and electronic properties of the oxide film on steel are inconsequential in determining whether film-breakdown will occur. We interpret these results in terms of a film-breakdown mechanism in which substrate dissolution begins at film defects and spreads, thus causing removal of the film by undercutting. According to this model, the ability of the substrate to spo...
TL;DR: In this paper, low cycle fatigue studies have been carried out on 2 wt% Mn, 2wt% Si and 0.1 wt % C steels with dual-phase and tempered martensitic structures.
Abstract: Low cycle fatigue studies have been carried out on 2 wt% Mn, 2 wt% Si and 0.1 wt% C steels with dual-phase and tempered martensitic structures. Fatigue crack initiation and propagation were investigated using scanning electron microscopy as well as optical microscopy. In addition, taper-section and cross-section techniques were also performed for more detail studies on the correlation of crack initiation with the internal microstructures of the testing samples. Internal microstructures were also investigated on the dual-phase steel sample before and after fatigue fracture by transmission electron microscopy.
TL;DR: In this paper, the recovery and recrystallization behavior of ferrite in low carbon steel during and after intercritical rolling have been investigated using a laboratory mill, and the results obtained are as follows: dynamic recystallization of ferrites occurs in the intercritical rollings at a high reduction of about 80%.
Abstract: Recovery and recrystallization behavior of ferrite in low carbon steel during and after intercritical rolling have been investigated using a laboratory mill. The results obtained are as follows:(1) Dynamic recrystallization of ferrite occurs in the intercritical rolling at a high reduction of about 80%.(2) Dynamically recovered ferrite structure formed during intercritical rolling is very stable compared with that formed in the rolling below Ar1.(3) Fine ferrite-pearlite structure is obtained from austenite worked in the intercritical range.Making use of these beneficial effects of intercritical rolling, stronger and tougher steels can be produced by reheating steels at lower temperatures, followed by rolling both in the low temperature range of austenite and intercritical range where the fraction of transformed ferrite is less than that of non-transformed austenite. It is also necessary, for this purpose, that the rolled products be air-cooled or heat treated at a temperature below Ar1. If the total rolling reduction is the same, the properties of the steel obtained by intercritical multipass rolling are nearly equal to those obtained by single pass rolling.
TL;DR: In this article, the infrared and Raman spectra obtained from a weathering steel were compared to those obtained for carbon steel which had been exposed to the same environment, and the results showed that the two techniques are complementary and give structural information similar to that provided by X-ray and electron diffraction.
Abstract: Infrared and Raman spectroscopy are two analytical tools which have recently been applied to the study of corrosion products formed on metal surfaces. The two techniques are complementary and give structural information similar to that provided by X-ray and electron diffraction. However, they are unlike X-ray and electron diffraction in that they do not require crystalline solids to provide structural identification. Weathering steels are an important class of metals which form noncrystalline corrosion products. This report describes infrared and Raman spectra obtained from a weathering steel and compares the spectra to those obtained for carbon steel which had been exposed to the same environment.
Patent•
11 Dec 1981
TL;DR: In this paper, a steel sheet consisting of main structure of ferrite and having fine grains having ≤ 4.5mu mean grain diameter is obtained by heating, rolling and cooling a usual carbon steel under the specified condition so as to generate fine ferrite grains.
Abstract: PURPOSE:To manufacture with low cost a steel sheet of fine grain structure superior in ductility by heating, rolling and cooling a usual carbon steel under the specified condition so as to generate fine ferrite grains. CONSTITUTION:A rolling of the steel consisting basically of usual carbon steel constituents is started under the total reduction ratio higher than 80% in the temp. region at just above usual Ar3 transformation point (temp. at which ferrite tansformation is started on the way of slow cooling of the steel sheet after the rolling at austenite region) and below (Ar3+100 deg.C), and the rolling is finished at the temp. region at just below Ar3 point and above (Ar3-30 deg.C). This steel is air cooled after the rolling or cooled to = 20 deg.C/sec so as to obtain the finer grains. Thereby, the steel sheet consisting of main structure of ferrite and having fine grains having <=4.5mu mean grain diameter is obtained.
TL;DR: In this article, a study was made of the frictional properties of nickel and copper implanted steel plates, with doses of 1×1015-3×1017 ions/cm2 energies of 50-200 keV.
Abstract: A study has been made of the frictional properties of nickel and copper implanted steel plates. Ion implantation was performed with doses of 1×1015–3×1017 ions/cm2 energies of 50–200 keV. The friction coefficients of Ni and Cu implanted specimens, measured at atmospheric room temperature with a Bowden-Leben type friction testing machine, had a tendency to increase as the total dose increased and the acceleration energy decreased. Concentration profiles were measured by secondary ion mass analysis in order to investigate the element concentration which contributes to the frictional properties. The results suggest that the amount of implanted ions remaining in the surface layer (0–400 A) is of first importance in the frictional properties of Ni and Cu implanted steel plates.
Patent•
22 Dec 1981
TL;DR: In this paper, a super deep drawing steel sheet having high Lankford value with little anisotropic property was manufactured by continuously annealing the extremely low carbon steel containing Si, Mn, P, Al, N, Ti and Nb at the temperature under AC3 transformation point, after said sheet is hot rolled and cold rolled.
Abstract: PURPOSE:To manufacture super deep drawing steel sheet having r value with remarkably little anisotropic property, by continuously annealing the extremely low carbon steel containing Si, Mn, P, Al, N, Ti and Nb at the temperature under AC3 transformation point, after said sheet is hot rolled and cold rolled. CONSTITUTION:To the steel consisting of C 2.33C% and Nb%=0.003%-<0.025%. Thus, the steel to which Ti and Nb are added is continuously annealed at the temperature above 700 deg.C and under AC3 transformation point, after said steel is hot rolled and cold rolled, thereby super deep drawing steel sheet having high r value (Lankford value) with little anisotropic property may be manufactured.
TL;DR: In this article, the structural changes in a high-sulphur free-cutting steel and a lead-bearing HSC steel have been determined by compounding the results of tensile tests after cold rolling the steels for differing amounts up to 98% reduction.
Abstract: The overall property changes in a high-sulphur free-cutting steel and a lead-bearing high-sulphur free-cutting steel have been determined by compounding the results of tensile tests after cold rolling the steels for differing amounts up to 98% reduction. The structural changes have been determined by optical and thin-foil transmission electron metallography, while the tensile fractures found after cold rolling have been examined by scanning electron microscopy. The high-sulphur steel showed a lower work-hardening rate than the equivalent plain carbon steel at moderate strains, but at high strains a tensile strength of 1700 MN m−2 was obtained. The MnS particles were more plastic than the matrix (plasticity ratio >1) and a fibre-reinforcing effect could give rise to the high strength. For the lead-bearing steel the work-hardening rate was lower than with the lead-free steel. The lead caused the sulphides to fragment and, hence, the final strength level achieved was much lower, but still greater, t...