Showing papers on "Carbon steel published in 1976"

Hydrogen attack of carbon steel

Abstract: A model is developed for the kinetics of nucleation and growth of methane bubbles in the hydrogen attack of carbon steel. It is concluded that at high temperatures the time to incubate fissuring along grain boundaries is determined by the rate of iron diffusion away from microscopic growing bubbles. At lower temperatures and/or higher hydrogen pressures carbon supply is limiting. The equations fit the observed incubation times if the bubble density is high (~107/cm2) and essentially independent of temperature (T) and hydrogen pressure (P) over a wide range. It is postulated that the number of growing bubbles is limited at high nucleation rates (lowT and highP) by carbon starvation. At hiT and lowP chemisorption to lower the solid-vapor surface energy or fine inclusions are required to aid nucleation. A quantitative analysis of these processes leads to several predictions which can be checked experimentally.

Effect of Quenching and Tempering on Diffusion of Hydrogen in Carbon Steel

Abstract: The effect of quenching and tempering structure of various carbon steels on the diffusivity and solubility of hydrogen were studied at room temperature by using an electrochemical permeation technique. The minimum diffusion coefficient is obtained when the steels are in the as-quenched state; i.e, in a martensitic structure the diffusion coefficient increases with increasing tempering temperature. On the other hand, the solubility of hydrogen isa maximum for the quenched martensitic structure and decreases with increasing tempering temperature. An increase in carbon content reduces the diffusivity but increases the solubility of hydrogen. The variations in diffusivity and solubility can be explained in terms of hydrogen trapping process involving lattice imperfections such as dislocations, lattice vacancies and subgrain boundaries, etc, produced by martensitic transformation. (Received January 27, 1976)

Fatigue crack tip plastic zones in low carbon steel

Abstract: Microscopic plastic zone parameters at the tips of fatigue cracks in low carbon steel, as derived by the X-ray microbeam technique, have been correlated with measurement of some of the same parameters by the electron channeling contrast technique. Good correlation has been obtained for the parameters common to both techniques. The results for low carbon steel are found to correlate well with fatigue crack plasticity in other metals.

Strain aging kinetics of vanadium or titanium strengthened high-strength low-alloy steels

Abstract: The strain aging kinetics of two commercially available high-strength low-alloy (HSLA) steels were investigated. Strain aging was found to be caused by interstitial solutes and is thought to occur in two stages: Snoek rearrangement and “Cottrell atmosphere” formation. The latter phenomenon can be satisfactorily described by an Arrhenius relationship with an average activation energy of 34.5 kcal/mole. This high activation energy is believed to be the result of interactions between interstitial solutes and strain fields of the coherent precipitates which strengthen HSLA steels. Consequently, strain aging in HSLA steels is considerably slower than in plain carbon steel.

High strength, high ductility low carbon steel

Abstract: A high strength, high ductility low carbon steel consisting essentially of iron, 005-015 wt% carbon, and 1-3 wt% silicon Minor amounts of other constituents may be present The steel is characterized by a duplex ferrite-martensite microstructure in a fibrous morphology The microstructure is developed by heat treatment consisting of initial austenitizing treatment followed by annealing in the (α + γ) range with intermediate quenching

Rotor seal element with heat resistant alloy coating

Abstract: The disclosure relates to rotary machinery, including a wear ring seal member stationarily mounted in a holding member which extends generally coaxially about a rotatable cylindrical member in substantially sealing relationship with the surface of the rotatable member, the rotatable member being made of carbon steel. The improvement resides in providing the surface of the rotatable carbon steel member in sealing relationship with the ring seal with a fused alloy coating metallurgically bonded thereto, the coating being formed of a heat and corrosion resistant welding alloy composition containing about 10% to 30% by weight chromium and the balance at least about 60% nickel, such that the carbon steel member is protected against oxidation and ignition due to overheating.

Process for the controlled cooling of ferrous metal

Abstract: PROCESS FOR THE CONTROLLED COOLING OF FERROUS METAL ABSTRACT OF THE DISCLOSURE Austenitized ferrous metal. such as carbon steel, is quenched by means of an aqueous solution or a salt of poly-acrylic acid which develops an extremely stable and uniform water vapor envelope surrounding the steel. Rate of cooling is controlled by (1) the molecular weight of the salt, (2) con-centration of the salt in the solution, (3) solution temperature, and (4) the degree of agitation of the quenchant solution. In the case of carbon steel, by proper selection of the above variables, the austenitic structure of the hot steel may be directly transformed into non-martensitic structures of improved ductility, machinability and cold working properties, such as fine striped pearlite, without the necessity of further heat treatments, such as tempering, following quenching. The quenching solution may also be used to quench parts formed of alloy steel to obtain a martensitic structure without unwanted cracking and distortion. Non-ferrous metals may also be quenched using the polyacrylate quenching solution.

Thin walled steel cartridge case

Abstract: A thin walled steel cartridge case having a substantially larger internal volume than a conventional cartridge case. The cartridge case is fabricated from a high strength, heat treated carbon steel or boron steel and the wall contour in the head area is designed to avoid localized high stress. A low friction coating is applied to the outer surface of the cartridge case and serves to reduce stress concentrations in the head area and to reduce extraction force in the event of interference between the case and the chamber during extraction.

Surface segregation of manganese in low-carbon steel during annealing

Abstract: Techniques were developed for routine evaluation of the tendency for low-carbon steels to undergo surface segregation of manganese during annealing, and the gradients of manganese concentration near the surface were determined. In the analytical method developed, surface material is removed with a chemical polishing solution, which is then analyzed for iron and manganese by an atomic-absorption-spectrometry technique. The enrichment of the steel surface in manganese that occurs during annealing is consistent with a mechanism of selective oxidation for steel in contact with normally used commercial atmospheres. Detectable surface segregation in manganese did not occur when the oxygen potential of the atmosphere contacting the steel during annealing was sufficiently low. The degree of surface segregation that can occur during annealing was found to increase with an increase in the free manganese (uncombined, in solid solution) content of the steel.

Tin-electroplated steel sheets and method for making them

Abstract: A tin-electroplated steel sheet having an excellent sulfur resisting property and excellent smudge resisting property is disclosed. The tin-electroplated steel sheet comprises a cold rolled low carbon steel sheet substrate, a layer consisting of 1 to 15 g/m2 of electroplated tin, said layer being electroplated upon at least one side surface of said substrate and a layer consisting of 0.0071 to 0.71 g/m2 of zinc, said layer being plated upon the tin layer.

Fatigue behavior of a precipitation hardening Ni−Al−Cu medium carbon steel

Abstract: The fatigue behavior of an Fe-03 wt pet C-4 wt pet Ni-1 wt pet Al-1 wt pet Cu precipitation hardening steel was investigated in three different heat treated conditions which give similar tensile strengths but different microstructures One heat treatment produced a lightly tempered lath martensite having fine carbides and a high dislocation density The other two heat treatments produced highly tempered martensite with coarse carbides, fine intermetallic precipitates and a relatively low dislocation density The steel in the lightly tempered condition showed marked softening on strain cycling while the highly tempered conditions resulted in both hardening and softening The lightly tempered structure had better low cycle fatigue resistance but the two highly tempered structures had better high cycle resistance The dislocation substructure in the lightly tempered steel rearranges itself and accommodates plastic strain during cyclic deformation while the substructure in the highly tempered structures containing fine precipitates resists rearrangement This difference is suggested as the reason for the differences in behavior The three conditions show little variation in their resistance to fatigue crack propagation However, the highly tempered, precipitate containing structures were much more resistant to fatigue crack initiation in notched specimens

Method of nitride-strengthening low carbon steel articles

Abstract: A method for internal strengthening of articles formed from deep drawing quality low carbon steel strip or sheet containing about 002 to about 03% titanium in solution, up to about 03% columbium in solution, columbium when present being in an amount of at least 0025% in solution, with the sum total of titanium and columbium in solution not exceeding about 03%, comprising the steps of heating the articles at a temperature of about 570° to about 580° C in a nitriding fluid for a time sufficient to form a total nitrogen concentration adjacent the surfaces of the articles at least substantially equal to the amount theoretically required to combine completely with the nitride-forming elements in the steel; and diffusion annealing the articles in a non-nitriding fluid at a temperature of about 595° to about 815° C for a time sufficient to complete through-thickness strengthening by reaction of the nitrogen with the nitride-forming elements A preferred nitriding fluid is a fused cyanate salt bath

Effects of Strain, Strain Rate, and Temperature on the Hot Worked Structure of a 0.16% Carbon Steel

Abstract: Synopsis: The high temperature tensile deformation of a 0.16% carbon steel was studied over a wide range of strain rate from 18 sec-1 to 2.6 •~ 10-4 sec-1 in the austenite range. From the metallographic investigation of the specimens quenched by hydrogen gas instantaneously after deformation, it was observed that the structure rapidly deformed (ƒÃ=18 sec-1), which was very unstable at deformation temperature and underwent static recrystallization in less than 0.2 seconds, was retained to room temperature by the instantaneous

Magnetic pole construction

Abstract: PURPOSE:A high performance magnetic pole construction, obtaining by laminating those of the materials combined, thin plate consisting of a small iron loss material of silicon steel and a high flux density material of low carbon steel.

Process for strengthening of carbon steels

Abstract: A process for the strengthening of carbon steels wherein a hypoeutectoid carbon steel workpiece, preferably in the shape of a rod or a bar, is rapidly heated to a temperature completely within the austenite region at a rate sufficient to minimize grain growth of austenite grains, the resulting austenitized steel workpiece is quenched to transform the steel to a fine mixture of acicular proeutectoid ferrite and a finely divided eutectoid aggregate of ferrite and iron carbide, followed by working at a temperature ranging up to the critical lower temperature to strengthen the steel. The process of the invention provides a drastic increase in both strength and ductility as compared to untreated steels such as those obtained by hot rolling.

Method of producing silicon steel strip

Abstract: A slurry of ferrosilicon powder is applied to both sides of a low carbon steel strip. The particle size of the ferrosilicon powder is controlled so that, after the slurry coatings are dried, there exists on each side of the steel strip at least a single layer of closely packed particles. The coated strip is then compacted. It is next heated in a protective environment to cause uniform diffusion of silicon throughout the strip.

Resistance to Oxidation at Elevated Temperatures of a Number of Alloy Steels

Abstract: A wide range of steels, extending from a plain carbon steel to high chromium-nickel, austenitic types and some nickel-based alloys, have been subjected to a cyclic oxidation test in natural gas combustion products at various temperatures. Resistance to oxidation can be expressed in terms of a breakdown temperature which provides a convenient parameter by means of which the behaviour of steels and alloys may be compared. On this basis, the beneficial effects of additions of chromium of up to 30% are confirmed, as are additions of silicon and/or aluminium to chromium steels. Cobalt, copper, molybdenum, vanadium, tungsten, niobium, titanium and nitrogen have comparatively little effect. Manganese appears to be detrimental when added to chromium steels and carbon can be in some circumstances. Nickel can enhance oxidation resistance in some circumstances but is detrimental in others. The presence of sulphur in free-machining, stainless steels appears to counteract the effect of a higher-thannormal mang...

Production of medium or low carbn high tensile wire rod

Abstract: PURPOSE:To improve the strength, ductility, and cold forgibility of a medium or low carbon steel wire rod by hot working and cooling the wire rod under specified conditions to convert the structure to bainite.

Vibrational residual stress relief in a plain carbon steel weldment

Abstract: In the present work, attempts were made to reduce the residual stresses due to circumferential welding in a disc shaped test sample of a plain carbon steel (AISI 1018) through the application of resonant elastic vibrations. The magnitudes and the distribution of residual stresses in samples that were vibrated and not vibrated were determined by a modified Sachs boring-out technique. Results show that high strain amplitude vibrations do significantly lower the residual stresses in areas of high residual stress. In areas outside the areas of high residual stress, the residual stresses may be reduced or not affected. Implications for the use of vibrational stress relief are discussed.

Continuous casting method for the production of rolled low carbon steel products with improved formability

Abstract: The relatively poor formability and spot weld fracture appearance of hot-rolled and heavy gauge cold-rolled low carbon steels (in which silicon is the primary deoxidant) have been attributed to manganese silicate stringer-type inclusions, generally found in this product. The addition of at least about 1/8 pound magnesium, per ton of steel cast, is shown to modify this deleterious inclusion morphology, with a resultant improvement in the ductility and weldability of such hot-rolled and the heavy gauge cold-rolled products.

The determination of chromium in plain carbon steel and low-alloy iron and steel by atomic-absorption spectrophotometry

Abstract: Co-operative examination of published atomic-absorption procedures for several elements in steel showed good agreement between results apart from those for chromium. For this element the depressive effect of iron in the air-acetylene flame is eliminated when using the preferred nitrous oxide-acetylene flame. However, control of flame composition is essential as vanadium, molybdenum, aluminium and titanium in low-alloy synthetic test solutions and samples increasingly enhance the chromium absorbance with increased fuel richness. Copper, nickel and iron have no effect but, in any event, iron should be included in the calibration solutions. Hence a lean, oxidising flame must be used and the results for samples then agree closely with the certificate values.

Effect of copper, tin, nickel, and chromium on mechanical properties of low-carbon steel

Abstract: The effects of those impurities most commonly found in scrap steel on the mechanical properties of low-carbon steel were investigated. The yield and tensile strengths, uniform elongation, strain-hardening exponent, and normal anisotropy ratio were determined as afunction of copper, nickel, tin, and chromium content. Attempts to correlate the formability of steel sheet with changes in these properties are described. Emphasis is placed on the use of the normal anisotropy ratio and the strain-hardening exponentfor predicting to tal formability performance. The results of these tests indicate that tin is most detrimental to the formability of mild steel and that appreciable amounts of copper, nickel, and chromium can be tolerated with relatively few adverse effects.

Some Effects of Electrolyte Flow Rates on the Electrochemical Machining Process

Abstract: The characteristics of metal erosion are investigated under long flowpath conditions, when it is shown for a typical stainless steel that significant variations can occur in surface micro-finish in the electrolyte flow direction. Valency switches are also observed for this material, and it is demonstrated experimentally that the process is controlled by related electrolyte flow and erosion current density conditions. Similar effects are suggested during the machining of a low carbon steel. This paper reports part of a wider investigation into low flowpath ECM1.

Fatigue Of Structural Steel For Offshore Platforms

Abstract: Laboratory data for engineering fatigue design was obtained on cyclically strained cantilevered plates of carbon steel in air and flowing sea water. Some information on weld geometry and cathodic protection was gathered. The results were expressed as a "fatigue-life" prediction in terms of the total cyclic strain range (delta epsilon sub t) and the number of cycles N to grow a surface crack (1 sub 8) eight inches long. An alternate analysis in terms of fatigue crack growth rate (d1/dN) was developed for a portion of the results. Most data were collected in the low-to-medium cycle life regions (10 to the 3rd power - 10 to the 5th power cycles), but two specimens were tested where extended lives (10 to the 9th power cycles) and low strains (delta epsilon=200 mu inches/inch) prevailed. Precautions in corrosion fatigue tests of mild steel in sea water are highlighted.