Showing papers on "Carbon steel published in 1985"

Kinetics of austenite-ferrite and austenite-pearlite transformations in a 1025 carbon steel

Abstract: Isothermal and continuous-cooling transformation kinetics have been measured dilatometrically for the γ → α+ γ′ and γ′→ P reactions in a 1025 steel. The isothermal transformation of austenite for each reaction was found to fit the Avrami equation after the fraction transformed was normalized to unity at the completion of the reaction and a transformation-start time was determined. The transformation kinetics under isothermal conditions therefore were characterized in terms of then andb parameters from the Avrami equation together with the transformation-start times. The parametern was found to be independent of temperature over the range studied (645 to 760 ‡C) and to have values of 0.99 and 1.33 for the ferrite and pearlite reactions, respectively. This indicates that the nucleation condition is essentially constant and site saturation occurs early in the transformation process. The continuous-cooling experiments were conducted at cooling rates of 2 to 150 ‡C per second to determine the transformation-start times for the ferrite and pearlite reactions and the completion time for transformation to pearlite under CCT conditions. Both reactions were found to obey the Additivity Principle for continuous cooling provided that the incubation (pre-transformation) period was not included in the transformation time. The isothermal transformation data and CCT transformation-start times have been incorporated in a mathematical model to predict continuous-cooling transformation kinetics that agree closely with measurements made at three cooling rates.

Tensile stress-strain analysis of cold worked metals and steels and dual-phase steels

Abstract: A study has been made of the applicability of the differential Crussard-Jaoul (C-J) analysis that assumes the Ludwik power relation, the modified C-J analysis based on the Swift formula, and the Hollomon analysis to uniaxially prestrained metals and steels and high strength, formable, dual-phase steels. The pure aluminum and copper metals and a series of plain carbon steels with carbon ranging from 0.10 to 1.05 pct were uniaxially prestrained by a given amount of strain under ambient temperature. A plain carbon steel with carbon of 0.10 pct was utilized in manufacturing the dual-phase steels. An empirical analysis exhibited the limited applicability of the C-J analysis for the interpretation of the stress-strain relationship of uniaxially prestrained metals and steels. The C-J analysis was also less sensitive to changes in the deformation behavior of the dual-phase steels in which the ferrite matrix and the shape and distribution of the second phase martensite were altered by three heat treatments. The modified C-J analysis was most suitable for describing work-hardening of uniaxially prestrained metals and steels. This analysis revealed that the dual-phase steels deformed in two stages. The first stage was associated with deformation of the ferrite matrix, and the second stage was associated with uniform straining of ferrite and martensite. The more generally used Hollomon curves deviated from linearity over all the uniform strain range regardless of the uniaxially prestrained metals and steels and dual-phase steels. Thus, the Hollomon parameters could not be assigned to an entire curve.

Fatigue microcracks in a low carbon steel

Abstract: — The behaviour of a low carbon steel has been studied, in particular the initiation, growth and coalescence of fatigue microcracks on the surfaces of smooth specimens via surface replicas and photomicrographs. From the study, quantitative information on the initiation period, growth and coalescence of cracks, statistical distributions of crack length and crack depth, density of cracks, distribution pattern and characteristics of the major crack, were obtained. Knowledge of these parameters is critical for non-destructive inspection during service life and the application of fracture mechanics to life assessment.

Induction cooking utensils

Abstract: A cooking utensil for use with an induction range has a first layer including a magnetic metal which is capable of being inductively heated, and a second layer which includes a ply of aluminum and a ply of copper, this second layer being in intimate thermally conducting contact with the first layer and being located interiorly of the utensil with respect to the first layer. The first layer may have a ply of carbon steel located between two plies of stainless steel. A disclosed utensil has its bottom and side walls formed of a first layer with an inner ply of inductively heatable magnetic material, and an outer ply of copper or stainless steel; a second layer with a thermally conductive aluminum or copper ply which lies in direct contact with the magnetic material; and, a stainless steel layer at the interior of the utensil. A stainless steel ring encloses the perimetral edge of the utensil wall. To deter corrosion of the carbon steel at the edge of the utensil, the circumferential edge of the utensil has a stainless steel ring which encloses a metal which, in the galvanic series, is sacrificial with respect to the carbon steel.

Metallographic analysis of compound layers on ferritic nitrocarburized plain low carbon steel

Abstract: A simple method for the structural analysis of the compound layers on nitrocarburized steel is presented. The method involves light microscopical metallographic observation, and is supported by X-ray diffractometry data. The method has been used to examine the structure of compound layers on nitrocarburized plain low carbon steel.

Fretting fatigue in 0.55c spring steel and 0.45c carbon steel

Abstract: — Fretting fatigue strengths of high strength spring steel (JIS SUP9) and low strength medium carbon steel (JIS S45C) were examined by clamping the contact pads of the same individual materials. The pad contact pressures were kept constant at 60 MPa for SUP9 steel and at 45 MPa for S45C steel. The fretting reduced the fatigue strengths by a factor of about two in both the steels. Cyclic J-integral concepts were successfully employed to predict crack propagation lives using measured data on frictional forces between the fretting pads and the specimens.

Ultrahigh Carbon Steel.

Abstract: Recent studies and results on ultrahigh carbon (UHC) steels suggest that major development efforts on these steels are timely and that programs to evaluate prototype structural components should be initiated. These recent results include: the development of economical processing techniques incorporating a divorced eutectoid transformation, the improvement of room temperature strength and ductility by heat treatment, the enhancement of superplastic properties through dilute alloying with silicon, and the attainment of exceptional notch impact strength in laminated UHC steel composites manufactured through solid state bonding. The unique mechanical properties achieved in UHC steels are due to the presence of micron-size fer-rite grains and ultrafine spheroidized carbides.

Corrosion resisting steel pipe and method of manufacturing same

Abstract: This invention relates to a corrosion resisting steel pipe having a kind of double construction in which an outer carbon steel pipe member is lined with respect to its whole length with a corrosion resisting material consisting of Ti, and a method of manufacturing the same, and more particularly to a doubly-constructed corrosion resisting steel pipe of a unit length consisting of an outer pipe member composed of an end tube and a general tube joined to the end tube, a short tube of a Ti metal attached to an end portion of the end tube metallurgically by the diffusion welding, and an inner pipe member of a Ti metal attached to the whole of the inner surface of the outer pipe member including the inner surface of the short tube of a Ti metal joined to the end tube, the inner pipe member of a Ti metal being seal-welded with an Ti metal at the end portion of the end tube, a pipe of a predetermined length obtained by connecting the steel pipes of a unit length being sealed at its joint portion with a Ti metal so that the Ti metal overlaps the outer pipe members, the steel pipe according to the invention thus having reliably high sealability and corrosion resistance; and a method of manufacturing such a corrosion resisting steel pipe.

Stress corrosion cracking of carbon steel in caustic aluminate solutions—crack propagation studies

Abstract: Stress corrosion cracking of a commercial 0.19 pct C steel (SA-516 Grade 70) was studied in hot (92 ‡C) caustic solutions of NaOH and NaOH plus aluminate (AlO− 2) species. Potentiostatically controlled tests were conducted near the active-passive transition, using fracture mechanics testing techniques and fatigue precracked double cantilever beam specimens. Crack propagation rates (Ν) were determined for a range of stress intensities (K l). In simple NaOH solutions, Region I (K1-dependent) and Region II (K 1-independent) cracking behavior were observed. Increasing the concentration of NaOH from2m to8m decreasedK ISCC and displaced Region I and the onset of Region II to lowerK 1 levels. The presence of AlO− 2 produced a comparable effect, with Region II being extended to lowerK I -Ν levels relative to simple NaOH solutions of similar hydroxyl anion concentration. The overallK I -Νv behavior and fractography were consistent with a dissolution mechanism of crack advance based on the general principles of the film rupture-dissolution model. The effect of environment composition uponK I — Ν behavior was attributed to changes in repassivation kinetics.

The growth of short fatigue cracks in a medium carbon steel.

Abstract: Short crack growth behaviour was studied using a method of plastic replication on hour-glass shaped specimens of a medium carbon steel which were subjected to push-pull fatigue testing at ambient temperature. Crack lengths were measured from replicas using an optical microscope from which the growth rate could be calculated. A theory for short crack growth is presented which may be expressed mathematically by the equation:- = (for a < d) da dN where (a) is crack length, (d) is a characteristic dimension between adjacent microstructural obstacles to crack propagation, C1 is a function of stress or strain range and a is a constant. For the medium carbon steel used in this study (d) was equated to the ferrite band length which contained the growing crack. This theory was used to model short crack growth in an Aluminium alloy T6-7075 Al and for the medium carbon steel used in this project. iii By using a second equation to describe "long" crack growth of the form:- da dN = where C2 is a function of the applied strain range and 0 is a constant, it was then possible to describe the complete history of crack growth. By obtaining short crack growth data for different stress levels, quantitative expressions of these two equations were calculated from which fatigue lifetime predictions could be made by integration of the equations for any stress level. Using this method an estimate could also be made of the percentage of fatigue lifetime spent in the initiation and growth of short cracks.

Ultrahigh carbon steels containing aluminum

Abstract: An ultrahigh carbon steel having a composition of carbon in an amount of from about 0.8 weight percent up to the maximum solubility limit of carbon in austenite, aluminum in an amount of from about 0.5 to about 10 weight percent, an effective amount of a stabilizing element acting to stabilize iron carbide against graphitization, and the balance iron. Preferably, the aluminum is present in an amount of from about 0.5 to about 6.4 weight percent and the stabilizing element is chromium. The steel has excellent ductility and is readily hot, warm and cold worked without cracking. It is particularly useful in superplastic forming operations, and may be processed to a suitable microstructure by any technique which reduces its grain size to about 10 microns or less, and preferably to about 1 micron. Such a very fine grain size is readily acheived with the steel, and the aluminum and stabilizing additions act to retain the fine grain size during superplastic processing.

The Corrosion of Carbon Steel and Stainless Steel in Simulated Geothermal Media

Abstract: The corrosion rates of low-carbon steel, and 304, 316 and 410/420 stainless steels in simulated geothermal media containing hydrogen sulfide have been measured by means of the polarization resistance technique. Good agreement was found between weight-loss and polarization resistance measurements of the corrosion rate for all the metals tested. Carbon steel formed a non-adherent film of mackinawite (Fe1 + xS). The lack of protection afforded to the steel by the film resulted in an approximately constant corrosion rate. The stainless steels also exhibited corrosion rates that were independent of time. However, the 410 and 420 alloys formed an adherent film consisting mainly of troilite ( FeS ) which provided only limited passivity. In contrast, the 304 and 316 alloys appeared to be essentially protected by a passive film which did not seem to involve an iron sulfide phase. However, all the stainless steels, particularly the 410 and 420 alloys, showed pitting, which indicated that some breakdown of the passive films occurred.

Evaluation of the Localised Corrosion of Carbon Steel Overpacks for Nuclear Waste Disposal in Granite Environments

Abstract: The application of carbon steel corrosion allowance containers for the long term encapsulation of HLW or spent fuel requires data on the likely rates of corrosion attack so that the metal thickness needed to prevent penetration can be estimated. This paper describes a joint mathematical modelling and experimental approach to the evaluation of the rate of localised corrosion.

Austenitic stainless steels plate having high strength and high toughness at very low temperature

Abstract: PURPOSE:To manufacture an austenitic stainless steel plate having high toughness as well as high strength at very low temp. by adding specific elements to an Ni-Cr-Mn low carbon steel and carrying out hot rolling and heat treatment under specific conditions. CONSTITUTION:The steel has a composition containing, by weight, 0.01-0.15% C, 0.01-2.00% Si, 0.5-16.0% Mn, =2 elements among Al, Ca, Ce, and Zn or 0.01-3.00% Mo independently or in combination. The above steel is subjected to hot rolling, finish rolling at 850-1,050 deg.C, isothermal holding to >=800 deg.C, air cooling, and then water cooling which is started at >=800 deg.C and continued down to >=500 deg.C. In this way, the steel plate of austenite grain size No.3.0-9.0 having high toughness as well as high yield strength at a temp. as low as -269 deg.C can be manufactured.

Corrosion of carbon steel by concentrated sulfuric acid

Abstract: The corrosion rate of carbon steel in 50 to 99% sulfuric acid is controlled by the rate at which the ferrous sulfate corrosion product diffuses. The rate at which ferrous sulfate diffuses in sulfuric acid and, therefore, the corrosion rate of steel has been calculated for pipeline flow. The final expression for the corrosion rate in mm/y of carbon steel pipelines is CR = 1.42 x 10/sup -4/ T /sup 0.654/ v /sup 0.913/ /rho/ /sup 1.567/ ..mu.. /sup 1.221/ d /sup -0.087/ (w - 0.01). Corrosion rates calculated from this expression are in agreement with corrosion rates reported in the literature.

Effect of contact materials on fretting fatigue in a spring steel.

Abstract: Fretting fatigue strengths of high strength spring steel (JIS SUP9) were examined by clamping the contact pads of various materials ; the same steel, low strength carbon steel (SS41), plastics (POM) and ceramics (Si3N4). The fretting at a contact pressure of 60 MPa {6.1kgf/mm2} reduced the fatigue strength by a factor of 1.92 for SUP9 contact pad and 1.68 for SS41 contact pad. The ceramics contact pads were similar to SUP9 steel contact pad, whereas the plastics contact pads did not cause the fretting. The friction coefficients between the contact pads and the specimen increased in proportion to the appropriate relative slip amplitudes, but attained to a saturation dependent on the contact materials. The saturation values were 0.6 for SUP9 steel, 0.34 for SS41 steel and 0.13 for POM. Cyclic J-integral concepts were successfully employed to predict crack propagation lives using measured data on the frictional forces.

Corrosion Mechanism of Metals and Alloys in the Silicon-Hydrogen-Chlorosilane System at 500 C

Abstract: To determine suitable materials of construction for a high pressure fluidized-bed reactor and to develop a basic understanding of the corrosion mechanism of alloys and metals in a hydrochlorination reaction environment, selected materials were studied. The study included tests on nickel, copper, carbon steel, Alloy 400, AISI 304 stainless steel, Incoloy 800H, and Hastelloy B-2. Results showed that silicon diffusion into the base metal produced a silicide film that could resist HCI attack, although continuous diffusion of Si into the metal constitutes another form of corrosion. A process for selecting suitable base materials for the reactor is presented.