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By W. John Rankin

Professionals, technical and non-technical, working in the mineral and metal commodity industries need to understand the concept of sustainability and its implications for the industry. Undergraduate courses have not done this well in the past. Much has been written in this field, and there have been great advances in understanding. However, much of what has been published is superficial and sometimes misleading, and there is as yet no coherent, single account that can serve as an introduction or overview for mineral industry graduates. This paper presents an outline which can guide readers in developing an understanding of the topic and its relevance to their work. Key references are provided, particularly those accessible on the internet, which will serve to introduce the reader to the important principles and understandings. The guide should also be useful to academics preparing students to work in the minerals and metal production sectors.

Jan 1, 2010

By Hai-Xing Fang, Chao Liu, Tao Zhang, Bing Xie, Hong-Yi Li, Cui Li

"Hongge Ore, a kind of vanadium-titanium magnetite ore containing high content of chromium, is valuable resource for extracting Fe, V and Cr in China. During present processing of the ore, vanadium and chromium were both concentrated in slag, leading to higher content of chromium in the vanadium slag than that of common one in Pan-Steel. Mineral phases and characteristics of spine! crystals, which influenced greatly subsequent roasting process, in the vanadium slag under different cooling conditions were investigated by using XRD and SEM/EDS. Results showed that vanadium slags containing various contents of chromium were composed of spine!, in which V and Cr were both concentrated, olivine and pyroxene. Growth rate of spine ls decreased sharply below 1350°C. The non-isothermal crystallization process could be described by modified Avrami equation and Ozawa equation. Avrami exponent and Ozawa index were calculated and growth mechanism of spine! crystals was discussed.IntroductionVanadium (V) as well as chromium (Cr) is important non-ferrous metal widely used in materials and chemical industries [1, 2]. Especially, both of them are important alloying elements for the production of high alloyed steels to achieve desired physical-chemical and mechanical properties. Vanadium-titanium magnetite ore in Panzhihua-Xichang area (China) is an important raw material for extracting vanadium. During the extracting process, vanadium is firstly reduced into hot metal and then concentrated in slag phase by blowing oxygen into the hot metal in converter [3]. This kind of slag containing 5~20 wt% V20 3 are usually roasted with sodium or calcium salts and then leached to obtain vanadium containing solution and final products. Current vanadium slag obtained from normal vanadium-titanium magnetite ore contains low content of Cr20 3 and chromium extraction is thus ignored. However, chromium content in the vanadium slag would be increased intensively when the Hongge Ore used, which is also important vanadium titanium magnetite in Panzhihua-Xichang area containing 0.2~0.8 wt% Cr203. Therefore, this kind of vanadium slag with high content of chromium would also be important sources for vanadium and chromium extraction. According to previous work [4], both vanadium and chromium could be extracted from vanadium slag with high content of chromium by salt roasting and leaching, which is illustrated in Fig.1."

Jan 1, 2013

By Tzu-Chien Lin, Jack Tsai, Ming-Yu Lin, Der-Ray Huang, Jiin-Sen Chen, Jing-Xuan Lin

"In this paper, some DVD-R discs have been selected for long time light exposure test and high temperature and humidity test. Generally, recordable media under long time light exposure maybe be defected seriously. If we use Jitter value 8% as a reference to determine the life time of DVD-R samples, some discs defect after 5 hours of light exposure while some discs can endure over 25 hours. Also if we use reflectivity 45% to determine the life time, some discs defect after 30 hours light exposure while some discs can endure over 40 hours. From our results, the good samples show good characteristics of PI error. The absorption spectrum of recordable media is a good reference to justify the quality of dye media. These results can be used to estimate the life time of recordable discs.IntroductionIn general, the life time of DVD-R with a layer of organic dye recording layer is required for preservation in decades. In addition to optical characteristics and thermal properties, we still need to consider the stability of the dye in recording media. The presentation of the color on organic dye is not only related to the material's property but also related to the light exposure. In this study, we focus on the absorption characteristics and reflectivity of organic dye in optical recording layer after light exposure. The optical properties of discs depend on the functional groups and molecular structure [1]. According to ""DVD Specifications for Recordable Disc (DVD- R)"", the reflectivity should higher than 40%. From measured reflectivity, we can confirm that the important issue is whether dye be affected by light exposure or not. Because each specific functional group absorbs the specific spectrum, we can check the characteristics of functional groups from their UV/Visible Spectra. We also use High-performance liquid chromatography (HPLC) to detect the different components of dye on the recording layer [2]. The jitter value test is to test the error cause by digital signal of recording media. If we use jitter value 8% as a reference to determine the life time of DVD-R samples, the purpose of this study is to investigate the jitter values of recording media after high light exposure and high temperature/humidity test. The results of these test will be helpful for the development of long-life optical storage media."

Jan 1, 2012

By D. F. Liub, Z. Y. Liu, W. Y. Xue, Y. F. Shenb, Y. D. Wang

"The microstructure characteristics and deformation behavior of ultrafme grained (UFO) 304SS fabricated by accumulative rolling and armealing have been investigated by means of tensile tests, electron-backscatter-diffraction (EBSD) and transmission electron microscopy (TEM) techniques. The volume fraction of martensite phase decreases with increasing armealing temperature. In the grain sizes ranging from 300 nm to 10 µm, the strength held Hall-Petch relationship. The sample with an average grain size of 300 nm exhibited extra high yield strength of 1700 MPa and a tensile strength of 1780 MPa, while the elongation retains 12%. The limited uniform elongation in the UFO materials could be explained in terms of plastic instability. Very interestingly, for the bulk material with an average grain size of 1.200 µm, the high yield strength and uniform elongation were simultaneously achieved to be as 1000 MPa and 18%, respectively.IntroductionUltra-high strengths have been achieved in elemental metals by employing heavy plastic deformation, or by creating ultra-fine-grained (UFO) structure. Here UFO materials are defined as polycrystalline solids with property-controlling microstructural features below the 1 µm level. Typical processing routes include severe plastic deformation (SPD) [1, 2], which decomposes the grains through dislocation accumulation and reorganization (polygonization). Several different kinds of SPD process for bulk materials are typically as equal-charmel angular pressing (ECAP) [3], high-pressure torsion (HPT) [4] and accumulative roll-bonding (ARB) [5]. One of the main motivations for such a push for the very small grain sizes stems from the expectation of unprecedented mechanical strength, as predicted by the well-known Hall-Petch relationship that projects a continuous rise of strength with decreasing grain size [6]. However, these ultra-high strength metals no longer have the high ductility typical of their conventional coarse-grained counterparts, because the undesirable inhomogeneous deformation on the microstructure level can lead to the early onset of failure, severely limiting the useful ductility [2]. Recently, the interesting strategies have been performed to increasing simultaneously the ductility and strength ofUFG pure copper and nanostructured alloys by Zhao et al [7, 8]. In a pure copper, a high ductility has been achieved without sacrificing strength by introducing a high density of pre-existing twins and a large fraction of high-angle grain boundaries. Their encouraging results trigger our motivation to obtain high strength and ductility from the commercially bulk material."

Jan 1, 2013

By Zhang Huaiwei, Shi Xiaoyan, Li Xinlin, Sun Fei, Hong Xin

"The control of the slag properties has become very essential in improving the separation between the slag and the matte in the copper slag cleaning process. The goal of the present work is to characterize the copper converting slag through chemical analysis (XRF), X-ray diffraction (XRD), scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy detection (EDS) and thermal analysis (DSC). The majority of the identified elements were Fe, Cu, Si and 0. The XRD has presented compounds such as Fe2Si04, Si02, CuFe204, Fe304, and Cu. The main existence of copper element was the metallic copper due to the entrainment loss. Slight amounts of copper were existed as the CuFe204 in the slag. The density, viscosity, electric conductivity and the thermodynamic property of the molten copper converting slag were also investigated in the study.IntroductionCopper slag, which is produced during pyrometallurgical production of copper from ores, contains materials like iron, alumina, calcium oxide, silica etc. For every tonne of metal production about 2.2 ton of slag is generated [l]. The slags of copper converting process contain about 5% of copper and about 20% magnetite. The copper are present in the slags either as physically entrapped or in chemically dissolved [2-3]. The traditional slag cleaning method is electric furnace process including two steps, intensive slag reduction and quiet sedimentation. Although the process is suitable for the various copper slags, it is also with the higher energy consumption [ 4-7]. The slag characterization studies are the fundamental step in the definition of an appropriate recycling process for saving the energy consumption."

Jan 1, 2013

By Ahmadzadegan. Arash, Anil Saigal, Michael A. Zimmerman

"In this study, the rheology of liquid crystalline polymer (LCP) melts through simplified 2-D and 3-D die geometries is simulated using Polyflow™. It is known that rheological properties of LCPs are close to long chain polymers and their directionality is close to those of small molecule liquid crystals (SMLCs). As a result, different rheological models (both viscoelastic and generalized Newtonian) for long chain polymers in Polyflow™ were investigated based on the available capillary rheometer data. By varying the parameters in these models, it is possible to adjust the effect of shear viscosity, normal stress differences and relaxations times on the rheology of the polymer. The free surface of the extrudate coming out of the die is simulated and the amount of die swell for different types of rheological models is compared. This study indicates that the Bird-Carreau model best applies to thermotropic LCP materials as quantified by die swell. Since the rheology of the LCPs affects the orientation of the crystals, the result of this simulation can be further used to predict the orientation of crystallines inside and outside the die.IntroductionAny rod like molecule or crystal tends to orient itself in the direction of shear as it moves within a flow. Since polymers consist of long chains of molecules, they experience the same phenomena when flowing in the melt condition. For most polymers, the molecules change direction and distribute uniformly in space during the solidification. However due to the higher inertia of the crystals in the liquid crystalline polymers, the oriented crystals will keep their order during the solidification and as a result the final product will show anisotropy in material properties."

Jan 1, 2012

By T. J. Weitz, J. E. Micheletti

"Pegasus Gold's Beal Mountain Mine is located near the Continental Divide, SW Montana. Conventional surface mining utilizes crushing, heap-leaching, carbon absorption/desorption, electrowinning and refining to produce approximately 60,000 oz gold annually. A leach pad sits at 2,300 meters (7,500 ft) elevation. Winters are long and cold with average snow accumulations ofl-2 meters; temperatures fall below minus 40'C and wind chill temperatures below 70°C. The Beal Mountain staff has developed special tools and procedures for burying drip emitter lines, and managing the heap and process solutions to allow for uninterrupted gold recovery during the winter season. Management of water balance and spring runoff is critical to the operations' success, due to mountainous terrain, high precipitation and proximity to a fishery and elk herd. The mine has an extensive network of land application disposal (LAD) and stormwater control systems to assure environmental protection and regulatory compliance.ABSTRACT ONLY"

Jan 1, 1997

By Ray D. Peterson, Garry G. Blagg

"Molten aluminum is routinely transported hundreds of miles to customers in large ""over-the-road"" crucibles. This is especially common for aluminum recycling organizations handling scrap and by-products. Receiving the aluminum in a molten form can save the customer time and money since in-house melting costs and capital equipment can be avoided. Additionally, the alloy can be on specification and nearly ready to use for the casting operation.A number of transport crucible designs are currently in use. The specifics of each design are based on the needs of the customer, the equipment used at both the producer and the consumer, and over-the-road transportation constraints. Crucibles are designed to maximize carrying capacity, and refractory life while minimizing heat flow and dead weight. These conflicting demands place difficult design criteria on the design engineer.This paper will review the basic advantages and disadvantages associated with molten metal transport, give examples of the design restrictions and examine several types design of crucibles currently in use."

Jan 1, 2000

By P. M. Rosário

The extraction performances exhibited by a phosphoric (D2EHPA), a phosphonic (Ionquest 801), a phosphinic (Cyanex 272) and a dithiophosphinic (Cyanex 301) acid derivative towards indium recovery from a diluted sulfuric solution are evaluated and compared. Equilibrium extraction isotherms were obtained. The chemical reactions involved and the approximate stoichiometry of the In(III) extracted species by the four ligands are presented and discussed. Stripping of In(III) from loaded D2EHPA and Ionquest 801 has been accomplished successfully, but has not been so effective from loaded Cyanex 301. Plots of %E vs. pH were established for D2EHPA, Ionquest 801 and Cyanex 301, denoting their behavior towards the extraction of similar mass concentrations of In(III), Fe(III), Fe(II) and Zn(II). Cyanex 301 is the least selective towards In(III), whereas D2EHPA and Ionquest 801, both for a pH = 0.5, do not extract Zn(II) at all.

Jan 1, 2003

By Marcel Sturzenegger

Though the extraction of copper is well established, generation of sulfur dioxide (S02) is still a troublesome issue. Conventional processes are further challenged by the increasing amount of impurities in the concentrates. Direct decomposition of the metal sulfides into the metal(s) and elemental sulfur under concentrated solar radiation offers a promising path to solve both problems. Thermogravimetric measurements under inert atmospheres have shown that synthetic chalcocite or chalcopyrite yield copper at temperatures as low as 1773 K. Even though optimum reaction temperatures might be somewhat higher, such temperatures are straightforwardly accessible in solar chemical reactors. The absence of oxygen will reduce the extent of slag forming reactions and thereby alter the evaporation characteristics of volatile impurities such as arsenic or antimony. Chemical equilibrium calculations for a chalcopyrite-enargite feed, e.g., have shown that under inert atmospheres arsenic compounds are completely evaporated at temperatures above 1000 K and an effective separation of arsenic from the matte is expected. An important step towards a solar production of copper is the design and testing of prototype solar chemical reactors for this reaction. Numerical modeling is a key tool supporting a rational design but it requires data of the high-temperature properties that prevail in these processes. Development of techniques for determining the essential quantities such as decomposition rates or radiative properties at temperatures up to 2000 K is therefore a main activity in our laboratory in order to control and optimize the process. Though developed in the frame of high-temperature solar technology, the experimental techniques are also suited to advance the understanding of conventional high-temperature processes. Keywords: Solar technology, Sulfur dioxide, Solar Radiation, Thermogravimetry, Chalcocite, Chalcopyrite, Numerical modeling.

Jan 1, 2003

By Alice Barreto Bevitori, Frederico Muylaert Margem, Noan Tonini SImonassi, Caroline Oliveyra, Sergio Neves Monteiro, Isabela Leão Amaral da Silva

"The mechanical behavior and the fracture characteristics of composites with DGEB/TETA epoxy matrix reinforced with up to 30% in volume of continuous and aligned ramie fibers were evaluated by tensile tests. Specimens with selected thin fibers aligned along the tensile axis were room temperature tested to rupture. The fracture surface was analyzed by scanning electron microscopy. The results showed significant increase in both the ultimate tensile strength and the elastic modulus. The fracture analysis indicated the possible mechanism for the fiber/matrix interaction, which could be responsible for the composite performance.IntroductionSince the middle of last century, polymer composites have substitute many conventional monolithic materials in applications ranging from aerospace to sport [l]. The main advantages of these composites are the low density and flexible properties specially using fiber as reinforcement to suit the mechanical performance requirements [2]. These are usually high strength and stiffuess requirements that could be reached with synthetic fibers such as gloss, carbon and aramid fibers. Its most commonly used example is ""fiberglass"", i.e., a thermoset polymer matrix composite reinforced with glass fiber. Indeed, ""fiberglass"" has a specific strength of the order of 500 MPa.cm3/g, which is the double of the strongest steels like the maraging. This motivated, at earlier times, ""fiberglass"" to replace many conventional materials including wood and natural fiber composites. Today, ""fiberglass"" has a wide range of uses from aerospace systems and appliances to sport and leisure components. However, its fabrication as well as those of any synthetic fiber such as carbon and aramid composites, requires a relatively large amount of energy. Presently, a growing concern exists regarding the consequences to the environmental by gases like C02 associated with both the energy consumption and the processing of synthetic fibers and their composites. These gases are well known responsible for global warming [3]."

Jan 1, 2013

By Jinqian Zhao, Jiarong Li, Shizhong Liu

"Creep cavitation of in single crystal (SX) superalloy was investigated. The constant load creep tests, in single crystal superalloys DD6, were conducted at the conditions of 800°C/700MPa, 850°C/550MPa and 900°C/450MPa, respectively. It was found that there were square facets on the stress fracture surface, and microscopic cavities in the ruptured specimens in the vicinity of the fracture surface. Both the square facets on the fracture surface and microscopic cavities in the section of the ruptured specimens show the morphology of the same thing at the different views, namely creep cavities, which are take the form of flatten cuboid. In fact, creep cavities are the longitudinally tensiled creep cracks slowly growing during the stress tensiling. The factors of creep cracks nucleation and growth conditions include: (a) enough high temperature to activate diffusion (b) casting pores as nucleation origination (c) high strains and strain rates. Eventually, the instantaneous fracture mechanism of creep specimen is cleavage fracture.IntroductionFor the materials used in elevated temperature service, creep behavior has to be accounted for. It is well recognized that creep rupture in polycrystalline materials at high temperature occurs principally by the nucleation and growth of microscopic cavities at grain boundaries, followed by microscopic cavities linkage to form micro- and eventually macro-intergranular cracks[l,2]. Without the usual grain boundaries, SX superalloys have superior capabilities at high temperatures to polycrystalline superalloys, and have become an established feature of gas turbine technology where they are commonly employed in the manufacture of high performance blades[3]. A considerable amount of work has been done over the past tens of years, and many models for nucleation and growth of creep cavities have been proposed, however, those are mainly for polycrystalline materials.In order to improve creep resistance that single crystal superalloys, in which grain boundaries are removed, have been developed. Because there don't exist grain boundaries in SX superalloy, the mechanism of nucleation and growth of creep cavities must be different from that in polycrystalline materials.Understanding the formation and characteristics of creep cavitation is crucial to model the lives of single crystal superalloys.M. Marchionni and L.G. Zhao et al. found that there were square facets on the stress fracture surface [4,5]. Roger C. Reed pointed out creep cavities lie in the necked region[6]. In this paper, the effects on the formation of creep cavities are discussed, as well as the morphology of creep cavities and fracture mechanism of SX superalloys."

Jan 1, 2013

By Joseph J. Poveromo

Technical progress in ironmaking will be discussed in three sectors: blast furnace ironmaking, direct reduction and alternative ironmaking to feed electric arc furnaces and ironmaking for waste oxide processing. The contributions of iron ore producer, Quebec Cartier Mining, in each sector will be outlined.

Jan 1, 2006

By Susumu Okabe

The Mitsubishi Continuous Copper Smelting/Converting Process employs an electric furnace for settling the slag/matte mixture formed in the smelting furnace. In order to improve the separation of slag and matte and to minimize power consumption, the design and the operating conditions of the electric furnace should be optimized. As the first step, numerical heat and fluid flow analysis of the melts was carried out based on the distribution of current density and Joule?'s heat obtained by the electric field calculation. For these calculations, 3-D body fitted coordinate system and a finite volume method were applied. Using the developed numerical model, the flow pattern analysis by pulse input of a tracer element was simulated. It was found that a strong thermal convection of the molten slag exists around the electrodes due to the concentrated Joule's heat generation in a small area just under the electrodes, and this strongly affects the flow pattern in the furnace. The calculation results were compared with the data obtained from 'a plant test.

Jan 1, 1998

By Ian Masters, Saul B. Davies, David T. Gethin

The purpose of this model is to simulate and analyze the energy flows within a rotary aluminum recycling furnace, using the global properties of its main components, the gas, metal and refractory walls. The model will simulate a series of operations such as loading, heating and stirring which will constitute the processing of a batch. Each main component of the furnace is treated as a one-dimensional heat transfer medium, the thickness and area of each medium being calculated from the actual geometry of the furnace. The physical properties are taken as the weighted average of those for the various layers forming the medium. Incorporated into the model are elements describing the radiative exchange within the furnace, melting of the charge, and forced convection in the melt due to the rotation of the furnace. This approach has produced a model with a reasonable computing time that can be used to run a whole series of simulations for the prediction and comparison of the furnace performance under different operating conditions.

Jan 1, 2000

By Partha Patra

Extracellular bacterial protein (EBP) from Paenibacillus polymyxa was isolated. Adsorption of bacterial cells of Paenibacillus polymyxa as well as EBP onto pyrite, galena and sphalerite was studied. Both bacterial cells and EBP was found to have different adsorption density for different minerals. Protein from mineral surfaces were extrated and examined through SDS PAGE electrophoresis. Specific group of protein was found to be adsorbing, specific to respective minerals. EBP was fractionated through FPLC. Adsorption studies were carried out with each fractions. Difference in adsorption density was observed for individual minerals. Flocculation and flotation experiment were carried out with these mineral specific EBP. Pyrite was selectively removed from ternary mixture of galena and spharite through flocculation anf flotation using pyrite specific EBP. Mineral specific EBP was found to selectively separated remove pyrite from the complex sulphide mixture.Zetapotential studies were carried out to examine the surface chemical changes of the minerals on interaction with EBP. Hydrophobicity of the minerals were carried out on interaction with bacterial cells as well as mineral specific EBP.

Jan 1, 2006

By D. J. Burkhardt

Newer copper SX/EW facilities often incorporate hot water heating for the cell feed electrolyte to obtain the necessary plating temperatures of 40 to 50°C. Heating is most necessary in oxide heap leaching, however it may also be required in bioleaching of secondary sulphides in colder climates or higher altitudes where most of the heat gain in the heap is lost to the environment. Given that the solution flows in the leach, organic circuit and electrolyte circuit are circular in nature, and the fact that the hot lean electrolyte is often exchanged with cooler rich electrolyte, it can be difficult to access the heating requirement for the cell feed. There are energy losses in piping, tankage, raffinate, and energy gains through the PLS and electrowinning process itself; some of these are significant and others are not. This paper discusses the overall heat balance, the relative significance of the various energy gains and losses, and describes a methodology to develop a heat balance to assist the engineer in sizing the heating equipment.

Jan 1, 2003

By Irsan Chandra

It is generally recognized that the gold thiosulfate leaching system requires the presence of copper and ammonia in order for acceptable leaching kinetics to be observed. However, the presence of copper and ammonia complicate the chemistry of the system as thiosulfate is rapidly oxidized by oxygen under these conditions. In addition, the environmental impact of ammonia would need to be considered before the adoption of this system. This paper describes fundamental studies into the thiosulfate oxygen system. The two reagents for this system are thiosulfate and oxygen, and leaching is carried out at pH < 7. It will be shown using electrochemical techniques that both the reduction of oxygen and the oxidation of gold-to-gold thiosulfate are hindered. Thus, if leaching is to work under these conditions, then both half reactions need to be improved. The use of additives, such as thiourea and lead have been shown to dramatically improve the oxidation of gold and the reduction of oxygen respectively. The leaching of gold in the presence of such additives is discussed.

Jan 1, 2003

By K. D. Peaslee

The 150 metal producers in Missouri generate approximately 8,000 tons of spent refractories each year, most of which is landfilled. Spent refractory samples were characterized and recycling / reuse techniques developed for some of the largest waste streams. Products using recycled materials are compared with products made from virgin materials.

Jan 1, 2000

By Che Xin, Liu Tianlong, Bi Hongyun, Chen Lijia

"High-cycle fatigue experiments were conducted at 800°C in laboratory air for three ferrite stainless steels including 15CrNbTi, 15CrMoNbTi and 18CrNbTi, where the stress ratio of 0.l was adopted. The experimental results show that at 800°C, the fatigue limit of the 15CrMoNbTi steel is the highest, the fatigue limit of the 15CrNbTi steel is slightly lower than that of the 15CrMoNbTi steel, and the fatigue limit of the 18CrNbTi steel is the lowest. At the same maximum stress, the 15CrMoNbTi steel has longer fatigue lives than the 15CrNbTi steel in the low stress area, while the 18CrNbTi steel has the shortest fatigue life. In addition, the observations on the fracture surfaces of fatigue specimens reveal that the fatigue cracks initiate transgranularly at the free surface of the specimens and propagate in a transgranular mode.IntroductionIn modem automotive industry, the manufacturers have paid great efforts to clean exhaust gas and to improve fuel economy. It is thought an effective way to increase the temperature of combustion chamber in automotive engine. And thus, the manifold closed to the engine in automotive exhaust system can suffer high temperature up to approximately 1000°C. Because of their relatively low thermal expansion coefficient, high yield strength at elevated temperature and good fatigue resistance, ferrite stainless steels, especially added with alloying elements such as Mo, Nb and Ti, are increasingly used for automotive exhaust systems [1-3]. In fact, exhaust manifold operated under high frequency vibration and exposed to high temperature exhausting gas also requires good fatigue resistance at elevated temperature. Some studies on the high temperature fatigue characteristics of stainless steel have been documented. It has beeen found that the fatigue limit of four ferrite stainless steels including 409L, 436L, 429EM and 444 (18Cr- 2Mo) reduces significantly with increasing temperature [4, 5]. In the research concerning the effect of a-phase embrittlement on fatigue behavior in a high-chromium ferrite stainless steel, it is noted that the precipitation of brittle a-phase will reduce the crack initiation and growth resistances and result in a decrease in fatigue limit [6]. In this investigation, the high-cycle fatigue behavior of three ferrite stainless steels including 18CrNbTi, 15CrNbTi and 15CrMoNbTi at 800°C have been studied to address the mechanical aspect of high-cycle fatigue behavior for ferrite stainless steels and to provide the theoretical reference for the safe design of automotive exhaust system."

Jan 1, 2013