Showing papers by "Bethlehem Steel published in 1990"

A perspective on the morphology of bainite

Abstract: The morphology of continuously cooled bainite in steels is examined in this review and compared with that of isothermally transformed bainite. Some experimental observations of microstructures in continuously cooled commercial steels are also presented; these results demonstrate the presence of microstructures which are not easily defined in terms of any of the “classical” bainitic morphologies. The numerous terms created over the last 50 years to describe specific bainite morphologies have led to some confusion, and it is suggested that the commonly used terminologies do not adequately describe the full range of bainitic microstructures which are observed. A general definition for the bainite transformation is proposed. A classification system for bainitic microstructures is also developed, encompassing both isothermally transformed and continuously cooled bainites. It is suggested that primary bainite morphologies be classified as B1, B2, or B3, depending on whether the acicular ferrite is associated with (1) intralath precipitates, (2) interlath particles/films, or (3) discrete regions of retained austenite and/or secondary transformation product(e.g., martensite or pearlite), respectively. Possible ambiguities with the descriptions of autotempered martensite and Widmanstatten ferrite are also discussed, and a number of areas are identified where further work would be helpful.

The measurement and calculation of the X‐ray spatial resolution obtained in the analytical electron microscope

Abstract: SUMMARY The X-ray microanalytical spatial resolution is determined experimentally in various analytical electron microscopes by measuring the degradation of an atomically discrete composition profile across an interphase interface in a thin-foil of Ni-Cr-Fe. The experimental spatial resolutions are then compared with calculated values. The calculated spatial resolutions are obtained by the mathematical convolution of the electron probe size with an assumed beam-broadening distribution and the single-scattering model of beam broadening. The probe size is measured directly from an image of the probe in a TEM/STEM and indirectly from dark-field signal changes resulting from scanning the probe across the edge of an MgO crystal in a dedicated STEM. This study demonstrates the applicability of the convolution technique to the calculation of the microanalytical spatial resolution obtained in the analytical electron microscope. It is demonstrated that, contrary to popular opinion, the electron probe size has a major impact on the measured spatial resolution in foils < 150 nm thick.

The boron hardenability effect in thermomechanically processed, direct-quenched 0.2 Pct C steels

Abstract: The segregation and precipitation of boron have been studied in thermomechanically processed 0.2C-0.6Mn-0.5Mo steels containing nominally 0, 10, 20, 50, and 100 ppm B. These steels were hot-rolled in the laboratory (in simulation of production multipass rolling), and their transformation behavior during subsequent water quenching was examined for different finish-rolling temperatures (980 °C and 870 °C) and quenching temperatures (730 °C to 950 °C). The results showed that in general, a “free” boron content of 10 to 20 ppm (which is similar to the levels used for conventional quenched-and-tempered steels) will provide a boron hardenability increment similar to that for conventional quenched-and-tempered steels. The delay time prior to quenching (over the range of 10 to 100 seconds) did not have a significant effect on hardenability except in the steels containing 50 or more ppm B. In these higher B steels, precipitation of borocarbides occurred along austenite grain boundaries with a resultant decrease in hardenability.

The effects of both deviation from stoichiometry and boron on grain boundaries in Ni3Al

Abstract: X-ray spectra and Z-contrast images have been obtained from thin foils of off-stoichiometric Ni3Al both with and without boron. The results show that grain boundaries in nickel-rich Ni3Al are nickel-enriched and that the addition of boron increases this nickel enrichment. The nickel enrichment is present as a second phase along some boundaries in undoped material and along all boundaries in boron-doped material. The phase is shown, using convergent-beam electron diffraction, to be disordered and to have the same orientation as one of the adjacent grains. By comparison, grain boundaries in aluminium-rich Ni3Al, either with or without boron, have compositions that are similar to the matrix. Correspondingly, a second phase was not found along the grain boundaries of this alloy.

Composition and process for forming low permeability barriers for waste disposal sites

Abstract: A low-permeability barrier for waste disposal sites such as landfills and waste lagoons, and a method for constructing the same, includes a waste material. The waste material is stabilized to decrease the permeability characteristics of the waste material and may be further processed to improve the structural characteristics of the waste material and to prevent leaching of any leachable components. A method is provided for applying the waste material to the waste disposal site as a liner, interim cover, and/or final cover.

Method and apparatus for controlling the thickness of a hot-dip coating

Abstract: A method and apparatus for controlling the thickness of a hot-dip coating. The apparatus comprising a jet wipe nozzle having a gas discharge opening capable of changing the shape of both elongated, opposed edges, of the opening by inserting shims between the nozzle halves and sequentially engaging jacking means to produce a desired gas discharge opening gap profile.

Zinc-maganese alloy coated steel sheet

Abstract: Disclosed is a multi-layered zinc-manganese alloy coating electrodeposited on sheet steel. The alloy layer closest to the surface of the sheet steel has a composition of at least 50% manganese while the composition of the other alloy layers farther removed from the surface of the sheet steel have less than 50% manganese.

Zinc-iron phases formed on galvannealed steel

Abstract: Mossbauer spectroscopy has been used to identify the zinc-iron intermetallic phases present in the coating of three galvannealed steels, two of which were produced on commercial galvanizing lines and one in the laboratory. Both CEMS and XMS have been used in order to determine the depth dependence of each phase. Three main zinc-iron phases have been identified with the proportion of each dependent on the preparation conditions. In the commercially produced coatings, CEMS, probing near the top of the coating, indicates that the zinc rich χ-FeZn13 and δ-FeZn10 alloys are present. XMS indicates the presence of some Π-Fe3Zn10 closer to the steel. In contrast, the laboratory produced sample contains nearly pure χ-FeZn13 through the entire coating thickness. Subphases of the delta and gamma alloys were also identified. These subphases appear to be mixed with a preference for the higher zinc subphase of each to form closer to the surface of the coating.

Molten metal slide gate valve

Abstract: A molten metal slide gate valve for use on a ladle or tundish The slide gate valve uses a stationary upper plate having a groove formed in its lower face around the periphery of the plate The groove is connected to a source of a nonoxidizing gas under pressure to provide a gas seal around the molten metal orifices in the slide gate valve and prevent the aspiration of air into the molten metal orifices during discharge of the molten metal from the ladle or tundish

Corrosion of Stainless Steel Conductor Rolls in a Continuous Sheet Electrogalvanizing Line

Abstract: Conductor rolls carry electrical current from steel strip during plating on a continuous electrogalvanizing line. Wear of type 316L (UNS 31603) stainless steel (SS) sleeves on the conductor rolls can lead to increased line downtime and higher operating costs. We conducted laboratory tests to examine the hypothesis that some fraction of conductor roll wear is caused by corrosion that is accelerated by repeated cycles of coupling and uncoupling of the type 316L SS sleeve to zinc and exposure to a dilute sulfuric acid rinse solution. It was found that coupling to zinc causes reduction of the passive film on type 316L SS. Upon subsequent uncoupling, type 316L SS undergoes an interval of active corrosion prior to repassivation. When the time between uncoupling and recoupling is less than the time needed for repassivation, corrosion of type 316L SS is increased. We found that hydrogen peroxide accelerates the rate of repassivation and that it decreases corrosion of type 316L SS during cyclic coupling t...

Apparatus for the controlled cooling of hot rolled steel samples

Abstract: A method and apparatus for cooling samples of hot rolled steel sections. A programmable controller directs a predetermined sequence of air and cooling water sprays against the sample while held in a closed container. The controlled cooling of the sample prevents dimensional distortion of the sample so that accurate measurements of the finished hot rolled steel section can be determined.

Multiple-Attribute-Based Expert Support System for Customer/Order Evaluation

Abstract: Sales and marketing people routinely evaluate and rank their customers to develop a marketing strategy and plan of action for utilizing available sales resources. Performing this evaluation informally makes it difficult to take into account all the significant customer attributes in a consistent and objective manner. In this paper an approach based on multiple attributes is developed to assist in evaluating customer performance. This approach is coded primarily in an expert system shell, which is run on a personal computer. The expert system shell was chosen over other software by the marketing people because they preferred its user-friendly capabilities. This system is being used by the Tin Mill Products Marketing office of Bethlehem Steel and is being considered for use by other product-line marketing offices within Bethlehem.

Method and apparatus for continuous welded rail

Abstract: A method and apparatus for replacing old trackwork rail with new continuous welded rail including a temporary bridge for transferring rolling stock from the oil rail onto the new rail

Metallurgical tundish with filter

Abstract: Disclosed is a tundish apparatus for holding and filtering molten metal, such as steel, prior to the molten metal being continuously cast. An enclosure around the discharge orifice of the tundish accommodates a ceramic filter medium. The enclosure has a removable cover plate to allow continuous discharge of the molten metal in the event the filter medium becomes clogged and to allow access to the tundish nozzle.

Method for coiling twist free steel bars

Abstract: Disclosed is a method of coiling steel bars, especially hexagonal bars, with a twist free coil in a continuous rolling mill equipped with pouring reels Disclosed is the use of pinch rolls to prevent the twisting of the bar as it is being coiled

GRAIN BOUNDARY CHEMISTRY IN Ni3Al AND Ni3Si

Abstract: Measurements of the Ni/AI ratio at grain boundary regions in Ni3A1 have been performed, using x-ray microanalysis of thin foils in a scanning transmission electron microscope, as a function of both alloy stoichiometry and the addition of boron. It is shown that whilst grain boundaries of Al-rich and stoichiometric Ni3AI have a composition similar to the matrix composition, boundaries in Ni-rich Ni3A1 can be highly Ni-enriched. The addition of B to Ni3AI produces Ni enrichment in grain boundaries, the extent of which increases with increasing Ni content of the alloy. Also Auger electron spectrometry has been used to show that B segregates to the grain boundaries irrespective of the Ni:Al ratio. The chemistries of grain boundaries in Ni-rich Ni3Si (Ni3Si only exists on the Ni-rich side of stoichiometry), with and without B, have also been measured by AES. The results are similar to those from Ni3A1, that is, the grain boundaries are enriched in Ni and the addition of B further increases this Ni-enrichment. The implications of these results on the degree of grain boundary atomic order and on the ductility of polycrystals are discussed.

The effects of decarburization annealing on the microstructure and magnetic properties of semiprocessed motor lamination steels

Abstract: Epstein packs of five compositions of steel were decarburized in exothermic gas for various times at either of two temperatures and dewpoints. The rate controlling process for decarburization was identified. Moreover, the variables affecting and the values of the optimum magnetic properties were determined, as were the times for optimum annealing. In addition, the effects of Sb on optimum decarburization time and properties were noted and explained.

Two piece load cell pin

Abstract: A pivot pin including a hollow tubular sleeve having open ends for encircling a removable load cell having strain gauges attached thereto for measuring loads on a pivot joint. When loads are placed on a pivot joint the load cell will deflect and its deflections are detected by a strain gauge which measures the axial deflection of the load cell.

Zinc-manganese alloy coated steel sheet

Abstract: Disclosed is a multi-layered zinc-manganese alloy coating electrodeposited on sheet steel. The layered Zn-Mn alloy coating is presented in the Figure. The alloy layer closest to the surface of the sheet steel has a composition of at least 50 % manganese while the composition of the other alloy layers further removed from the surface of the sheet steel have less than 50 % manganese.