Directory of steel foundries in the United States, Canada, and Mexico, 1961-62.

"Producerh [i.e. Producers] of carbon, low and high alloy, heat and corrosion steel castings, high manganese castings, investment mold castings, shell mold castings, and tool steel castings are included."

Service performance of engineering materials

Corrosion research by Atrens and co-workers has made significant contributions to the understanding of the service performance of engineering materials. This includes: (1) elucidated corrosion mechanisms of Mg alloys, stainless steels and Cu alloys, (2) developed an improved understanding of passivity in stainless steels and binary alloys such as Fe-Cr, Ni-Cr, Co-Cr, Fe-Ti, and Fe-Si, (3) developed an improved understanding of the melt spinning of Cu alloys, and (4) elucidated mechanisms of environment assisted fracture (EAF) of steels and Zr alloys. This paper summarises contributions in the following: (1) intergranular stress corrosion cracking of pipeline steels, (2) atmospheric corrosion and patination of Cu, (3) corrosion of Mg alloys, and (4) transgranular stress corrosion cracking of rock bolts.

An evaluation of thermal plasmas in pyrometallurgy

The development of reliable, high powered plasma generators has resulted in many plasma processes being proposed as alternatives to existing pyrometallurgical technologies. This work evaluates the advantages and disadvantages of plasma systems by reviewing plasma generators, their integration with reactors and the process economics. Many plasma systems were shown to be technically and economically superior to existing technologies, but some of the plasma system advantages quoted in the literature were found to be impractical because of other system constraints. Process applications were limited by the power inputs available from plasma generators compared to AC electric furnaces. A series of trials were conducted where chromite and steelplant baghouse dusts were smelted in the Tetronics' 2.0 MW transferred arc/open bath reactor to confirm the operating characteristics of the plasma system and its economics. Chromite smelting was technical superior to submerged arc furnace technology, but the economics were unfavourable because of the limited power available from the water-cooled plasma torch and the high electrical energy consumption. A DC graphite electrode plasma furnace using preheated and prereduced chromite concentrates will compete economically with the submerged arc furnace. Ni, Cr and Mo were economically recovered from high alloy content steelplant dusts for recycling. Five Electric Arc Furnace dusts were smelted to produce a non-toxic residue and recover the contained zinc to an enriched zinc oxide product for recycling. It should be possible to condense the zinc vapour directly in a zinc splash condenser to increase the value of the product. Because of the limited power available from plasma generators, plasma processes will be most suitable for treating high and medium value materials such as Au, Pt, Mo, Ni, Ti, V, Cr etc at small production rates, heating metals in tundishes and ladles and remelting superalloy scrap. The treatment of environmentally hazardous waste materials is a particularly interesting application because of the additional financial incentives. Non-transferred arc plasma generators will be used for air and gas preheating in blast furnaces to reduce metallurgical coke consumptions.

Defects in steel investment castings

A general investigation was performed, in an industrial environment, of the major types of defect specific to investment castings in steel. As a result of this work three types of metallurgical defect were selected for further study. In the first of these, defects in austenitic stainless steel castings were found to result from deoxidation by-products. As a result of metallographic investigation and the statistical analysis of experimental data, evidence was found to support the hypothesis that the other two classes of defects - in martensite stainless and low alloy steels -both resulted from internal or grain boundary oxidation of the chromium alloy constituent This was often found to be followed by reaction between the metal oxides and the ceramic mould material. On the basis of this study, proposals are made for a more fundamental investigation of the mechanisms involved and interim suggestions are given for methods of ameliorating the effect in an industrial situation.

Laser-induced breakdown spectroscopy quantitative analysis method via adaptive analytical line selection and relevance vector machine regression model

Abstract A new LIBS quantitative analysis method based on analytical line adaptive selection and Relevance Vector Machine (RVM) regression model is proposed. First, a scheme of adaptively selecting analytical line is put forward in order to overcome the drawback of high dependency on a priori knowledge. The candidate analytical lines are automatically selected based on the built-in characteristics of spectral lines, such as spectral intensity, wavelength and width at half height. The analytical lines which will be used as input variables of regression model are determined adaptively according to the samples for both training and testing. Second, an LIBS quantitative analysis method based on RVM is presented. The intensities of analytical lines and the elemental concentrations of certified standard samples are used to train the RVM regression model. The predicted elemental concentration analysis results will be given with a form of confidence interval of probabilistic distribution, which is helpful for evaluating the uncertainness contained in the measured spectra. Chromium concentration analysis experiments of 23 certified standard high-alloy steel samples have been carried out. The multiple correlation coefficient of the prediction was up to 98.85%, and the average relative error of the prediction was 4.01%. The experiment results showed that the proposed LIBS quantitative analysis method achieved better prediction accuracy and better modeling robustness compared with the methods based on partial least squares regression, artificial neural network and standard support vector machine.

Influence of the cutting edge micro-geometry of PCBN tools on the flank wear in orthogonal quenched and tempered turning M2 steel

Quenched and tempered high-speed steels obtained by powder metallurgy are commonly used in automotive components, such as valve seats of combustion engines. In order to machine these components, tools with high wear resistance and appropriate cutting edge geometry are required. This work aims to investigate the influence of the edge preparation of polycrystalline cubic boron nitride (PCBN) tools on the wear behavior in the orthogonal longitudinal turning of quenched and tempered M2 high-speed steels obtained by powder metallurgy. For this research, PCBN tools with high and low-CBN content have been used. Two different cutting edge geometries with a honed radius were tested: with a ground land (S shape) and without it (E shape). Also, the cutting speed was varied from 100 to 220 m/min. A rigid CNC lathe was used. The results showed that the high-CBN, E-shaped tool presented the longest life for a cutting speed of 100 m/min. High-CBN tools with a ground land and honed edge radius (S shaped) showed edge damage and lower values of the tool’s life. Low-CBN, S-shaped tools showed similar results, but with an inferior performance when compared with tools with high CBN content in both forms of edge preparation.

Hitsin juurenpuolen kriittisyys suurlujuus teräksillä

Kandidaatintyön tarkoituksena oli selvittää pienahitsin juuren kriittisyyttä. Työ oli saanut aiheen rakenneputki kokeiden yhteydessä tehdyistä havainnoista. Työssä tutustuttiin millaiset ovat pienahitsin mitoitus menetelmät ja tausta tutkimusta kuinka sitä sovelletaan käytäntöön suurlujuusteräksille. Työssä esitellään käytetyt tutkimusmenetelmät kuinka menetelmätriangulaatio saavutettiin. Tutkimuskysymyksenä oli hitsien kestävyyden mitoituksen riittävyys. Tutkimukset suoritettiin tarkastellen staattisesti kuormitettuja pienahitsejä. Pienahitsi kappaleista tehtiin laboratoriokoekappale ja FEM-laskentamalli joista vertailtiin tuloksia. Laboratoriokokeessa mittaus menetelmänä käytettiin DIC-mittausta, jolle voitiin tehdä jälkikäsittelyjä ja sieltä määrittää haluttuja datapisteitä. Laskennassa suurimmat jännityskeskittymät syntyivät hitsin kohdalle mutta vetokokeessa koekappaleeseen syntyi vauriot sularajalle ja vetokorvakkeen kiinnityshitsin rajaviivalle. Tällä kohtaa todettiin materiaalimalli riittämättömäksi, koska siihen ei ollut määritelty muutosvyöhykkeen parametreja.

A study of the suppression of the high-temperature helium embrittlement in an oxide-particle dispersion strengthened alloy

In this paper, an investigation on the micro-structure of an Fe-base oxide-dispersion-strengthened (ODS) alloy irradiated with high-energy Ne-20 ions to different doses at a temperature around 0.5T(m) (T-m is the melting point of the alloy) is presented. Investigation with the transmission electron microscopy found that the accelerated growth of voids at grain-boundaries, which is usually a concern in conventional Fe-base alloys under conditions of inert-gas implantation, was not observed in the ODS alloy irradiated even to the highest dose (12000 at.ppm Ne). The reason is ascribed to the enhanced recombination of point defects and strong trapping of Ne atoms at the interfaces of the nano-scale oxide particles in grains. The study showed that ODS alloys have good resistance to the high-temperature inter-granular embrittlement due to inert-gas accumulation, exhibiting prominence of application in harsh situations of considerable helium production at elevated temperatures like in a fusion reactor.

A High-Resolution Transmission of the Precipitation Process in a Electron Microscopy Study Dilute Ti-N Alloy

The precipitation processes in dilute nitrogen alloys of titanium have been examined in detail by conventional transmission electron microscopy (CTEM) and high-resolution electron microscopy (HREM). The alloy Ti-2 at. pct N on quenching from its high-temperature beta phase field has been found to undergo early stages of decomposition. The supersaturated solid solution (alpha''-hcp) on decomposition gives rise to an intimately mixed, irresolvable product microstructure. The associated strong tweed contrast presents difficulties in understanding the characteristic features of the process. Therefore, HREM has been carried out with a view to getting a clear picture of the decomposition process. Studies on the quenched samples of the alloy suggest the formation of solute-rich zones of a few atom layers thick, randomly distributed throughout the matrix. On aging, these zones grow to a size beyond which the precipitate/matrix interfaces appear to become incoherent and the alpha' (tetragonal) product phase is seen distinctly. The structural details, the crystallography of the precipitation process, and the sequence of precipitation reaction in the system are illustrated.

Influence of Martensite Content and Morphology on Tensile and Impact Properties of High-Martensite Dual-Phase Steels

A series of dual-phase (DP) steels containing finely dispersed martensite with different volume fractions of martensite (V-m) were produced by intermediate quenching of a boron- and vanadium-containing microalloyed steel. The volume fraction of martensite was varied from 0.3 to 0.8 by changing the intercritical annealing temperature. The tensile and impact properties of these steels were studied and compared to those of step-quenched steels, which showed banded microstructures. The experimental results show that DP steels with finely dispersed microstructures have excellent mechanical properties, including high impact toughness values, with an optimum in properties obtained at similar to 0.55 V-m. A further increase in V-m was found to decrease the yield and tensile strengths as well as the impact properties. It was shown that models developed on the basis of a rule of mixtures are inadequate in capturing the tensile properties of DP steels with V-m > 0.55. Jaoul-Crussard analyses of the work-hardening behavior of the high-martensite volume fraction DP steels show three distinct stages of plastic deformation.

Electrical transport and crystallization studies of glassy semiconducting Si20Te80 alloy at high pressure

The effect of pressure on the electrical resistivity of bulk Si20Te80 glass is reported. Results of calorimetric, X-ray and transmission electron microscopy investigations at different stages of crystallization of bulk Si20Te80 glass are also presented. A pressure induced glass-to-crystal transition occurs at a pressure of 7 GPa. Pressure and temperature dependence of the electrical resistivity of Si20Te80 glass show the observed transition is a pressure induced glassy semiconductor to crystalline metal transition. The glass also exhibits a double Tg effect and double stage crystallization, under heating. The differences between the temperature induced crystallization (primary crystallization) and pressure induced congruent crystallization are discussed.

Metallization and crystallization of semiconducting amorphous Ga20Te80 alloy under high pressure

Pressure and temperature dependence of the electrical resistivity of amorphous Ga20Te80 alloy is reported for the first time. The alloy undergoes a pressure induced amorphous semiconductor-to-crystalline metal phase transition at 6.5 ± 0.5 GPa. The high pressure crystalline phase is a mixture of Te and GaTe3 phases.

A numerical investigation of ductile fracture initiation in a high-strength low-alloy steel

In this work, static and drop-weight impact experiments, which have been conducted using three-point bend fracture specimens of a high-strength low-alloy steel, are analysed by performing finite-element simulations. The Gurson constitutive model that accounts for the ductile failure mechanisms of microvoid nucleation, growth and is employed within the framework of a finite deformation plasticity theory. Two populations of second-phase particles are considered, including large inclusions which initiate voids at an early stage and small particles which require large strains to nucleate voids. The most important objective of the work is to assess quantitatively the effects of material inertia, strain rate sensitivity and local adiabatic temperature rise (due to conversion of plastic work into heat) on dynamic ductile crack initiation. This is accomplished by comparing the evolution histories of void volume fraction near the notch tip in the static analysis with the dynamic analyses. The results indicate that increased strain hardening caused by strain rate sensitivity, which becomes important under dynamic loading, plays a benign role in considerably slowing down the void growth rate near the notch tip. This is partially opposed by thermal softening caused by adiabatic heating near the notch tip.

Influence of grain size on high temperature fracture in a Mg AZ31 alloy

Tensile experiments at 673 K and grain sizes from similar to 8 to 17 mu m revealed large ductility at a low strain rate and a reduced ductility at a high strain rate, corresponding to a change from a high to a low value for the strain rate sensitivity. High strain rate deformation led to fracture by flow localization, whereas low strain rate deformation involved fracture by cavity nucleation and growth. Analysis revealed that grain boundary migration can assist significantly in reducing the stress concentrations caused by grain boundary sliding, thereby retarding cavity nucleation. Calculations demonstrate that the interlinkage of voids parallel and perpendicular to the tensile axis occurs significantly, so that it is not always possible to use the cavity shapes to distinguish between diffusion and plasticity controlled growth. Cavitation damage evolves slowly in materials with a coarser grain size because of reduced nucleation related to a reduction in the strain rate sensitivity and associated grain boundary sliding. (C) 2011 Elsevier B.V. All rights reserved.