Metallurgical Tests Research Articles

Study of properties of explanted implant with view to reuse

Introduction: Increasing number of implants is in use for treatment of fracture to get better results. Poor people are more prone to fractures but they are unable to afford these implants. On other hand, explants (removed implants) are not allowed to be reused by law. So why not to reuse suitable explants to alleviate the suffering, which will help these poor patients.Method: Implants were explanted from patients with clinical indication after voluntary consent. They were submitted to microbiological (in microbiology lab), mechanical and metallurgical (by Brinell hardness Machine and under Scanning Electronic Microscope) tests before and after minor modifications in vitro.Results: The properties of explants after minor modifications were compared with properties of new implants and were found to be same.Conclusion: As results are excellent in vitro, now it is high time to test the efficacy of explants in vivo so they can be reused in future patients if found good. This will help economically deprived patients and their families to a great deal. This will also reduce Bio Medical Waste (BMW). This research project is funded by Sumandeep Vidyapeeth, Piparia, Vadodara.

Application of Ferrite Ductile Iron on a Casting

In this paper, the ferrite ductile iron was used as the research object, the traditional 450-10 material production process of mechanical properties and metallographic test results can not meet the technical requirements of the problem, from requirements of component material standards, successful test of ferrite material of castings, stable performance can meet the requirements of metallurgical testing requirements, these have been mass production, and these have obtained good economic benefits.

Manufacturing Dies and Punches for Preparation of Powder Metallurgical Mechanical Test Specimens

A specific shape of the object made from the metal powders, is not new and confirmed from the practice of aged cultures and one such evidence is Ashoka Pillar in Delhi, India. For electric lamp filaments, tungsten powders strengthened with thoria which ensures the need of special manufacturing process i.e. Powder Metallurgy (P/M), which is as early as 19th century. Compaction plays a very important role in the entire P/M process, which has the intact relation with the object to be made. So the tools, dies in the compaction process are to be chosen with care which is scarce and costly in society. Hence, in the present work an attempt is made to select D2 steel and analyzed for chemical composition and mechanical properties according to ASTM standards. After confirmation of basic properties the die and punch for fabrication of tensile, flexural and impact powder metallurgical test specimens are machined according to ASTM B925–08 procedures on three-axis Computerized Numerically Controlled milling machine. Then the machined dies and punches dimensions are measured using line and end standard instruments and are confirmed with the values exist in the standard.

A geostatistical approach to measure the consistency between geological logs and quantitative covariates

Core logging is the geological study, recording and classification of petrophysical attributes of drill hole samples, such as lithology, alteration or mineralogical assemblage. The geological logging is qualitative and subject to errors because of its visual nature and other factors inherent to logging, such as low drill hole recoveries, difficulties in estimating the volumetric contents of minerals, or different logging criteria among geologists. To date, different tools for quality control and validation of geological logging have been elaborated, based on geological knowledge, statistics, geostatistics, image analysis, neural network and data mining. This paper presents an alternative approach based on geostatistical modeling for identifying and reclassifying potentially mislogged samples when quantitative covariates from geochemical analyses or metallurgical tests are available. The principle of this approach is to: (i) define geological domains for each quantitative variable by an adequate grouping of the log classes; (ii) transform the quantitative variables into normal scores, accounting for the previously defined domains, (iii) model the spatial correlation structure of the normal scores, (iv) perform leave-one-out cross validation and obtain predictions of the normal variables and the associated variance-covariance matrices of prediction errors; (v) calculate a measure of consistency for each sample and each possible logged class under a multivariate normal assumption; and (vi) compare these measures of consistency with the actual logged classes to detect suspicious logs. The methodology is demonstrated in a case study from an iron ore deposit, with data of rock type logged by geologists and seven quantitative variables (grades of elements of interest, loss on ignition and granulometry).

Development metallurgy guidelines for copper heap leach

This paper outlines a comprehensive, cost-effective testing program for the acid-ferric sulfate heap leaching of oxide, supergene and primary copper ores. It is based on extensive experience in copper heap leaching and uses the many technological advances in the field developed over the past several decades. The approach described requires firstly a detailed resource evaluation, then a hydrodynamic characterization of representative samples and, finally, a focused metallurgical testing program. The principles communicated here can be applied to other acid leachable minerals. The program varies considerably from conventional testing in its disciplined, orderly, step-by-step approach, its application of hydrological and chemical principles to leaching, and its reliance on fewer, more tightly controlled column tests. The purpose of the test program is to optimize the financial, time and other resources devoted to the program, while minimizing the financial risks to the development company or companies and the project funding providers.

Nano-surface-finishing of permanent mold punch using magnetorheological fluid-based finishing processes

ABSTRACTVarious plastic products such as bottles’ plastic caps are manufactured through casting using permanent molds. To obtain the smooth surface on plastic caps during manufacturing, the required permanent mold die punch surface should be defect free and its roughness values in nanometer range. Two different magnetorheological (MR) fluid-based finishing processes are used for nano-surface-finishing of die punch. The MR ball end with solid rotating tool core is used to finish the flat surface, and a turning type MR finishing process is used for external circular surface of the present mold die punch. The material of the present permanent mold punch is P20 tool steel with hardness of 431 VHN. The final roughness values of flat and external circular surfaces of the present die punch are obtained as 30 nm and 80 nm from the initial values of 1080 nm and 630 nm in 120 min of finishing. The change in topography of the surface is observed using metallurgical microscope and mirror image test. The reduction in surface roughness at the nanolevel and microscopic improvement on the die punch surface have demonstrated the feasibility of present finishing processes to be useful in industries for manufacturing the smooth surface of bottles’ plastic caps.

Treatment of Iron Tailings at the Forecariah Guinea Mine - Guinea Conakry

Forecariah Guinea Mine SA (FGMSA) in Guinea - Conakry mines and processes Iron ore. About 0.5 Mt of tailings material has already been generated with additional 4000 tons generated daily. This paper presents a re-treatment technology for the Iron tailings obtained from the processing plant of FGMSA. Metallurgical tests were carried out on the tailings to determine which process route gives the most satisfactory result in terms of recovery and cost. Two representative samples (FCOPD-01 and FCDOP-02), taking from the tailings, were investigated. Particle Size Distribution (PSD) and chemical composition of various size fractions of representative samples of the tailings were performed. Dense Medium Separation (DMS) and Magnetic Separation (WHIMS) were also performed on a number of size fractions. The initial chemical composition of the various size fractions shows that the highest Fe grades were present in the +1 mm fractions at 58.8% and 58.6% for FCOPD-01 and FCOPD-02 respectively. The PSD of the tailings also indicated a mass yield of 77.9% for the +1 mm fraction and 22.1% for the -1 mm fraction. Contaminant Oxides, such as Al2O3 and SiO2 tend to be higher in the finer size fractions (-1 mm) of both samples. Result from the DMS analysis performed on the (-4 +0.5) mm fraction shows an underflow mass yields of 45.98% with Fe grade of 65.55% and overflow mass yield of 53.08% with Fe grade of just 13.5%. Magnetic separation (WHIMS) results on the (-4 +0.5) mm samples also gave varied mass yield and Fe grade at different magnetic intensities (3000 Gauss, 6000 Gauss and 10,000 Gauss). However, the highest Fe mass yield and grade produced from the magnetic separation were 18.10% and 50.8% respectively. The results show that DMS technique has the potential to re-treat the tailings at FGMSA. Keywords: Treatment, Iron ore, Tailings, Magnetic separation, Dense Medium Separation

Treatment of Iron Tailings at the Forecariah Guinea Mine - Guinea Conakry

Forecariah Guinea Mine SA (FGMSA) in Guinea - Conakry mines and processes Iron ore. About 0.5 Mt of tailings material has already been generated with additional 4000 tons generated daily. This paper presents a re-treatment technology for the Iron tailings obtained from the processing plant of FGMSA. Metallurgical tests were carried out on the tailings to determine which process route gives the most satisfactory result in terms of recovery and cost. Two representative samples (FCOPD-01 and FCDOP-02), taking from the tailings, were investigated. Particle Size Distribution (PSD) and chemical composition of various size fractions of representative samples of the tailings were performed. Dense Medium Separation (DMS) and Magnetic Separation (WHIMS) were also performed on a number of size fractions. The initial chemical composition of the various size fractions shows that the highest Fe grades were present in the +1 mm fractions at 58.8% and 58.6% for FCOPD-01 and FCOPD-02 respectively. The PSD of the tailings also indicated a mass yield of 77.9% for the +1 mm fraction and 22.1% for the -1 mm fraction. Contaminant Oxides, such as Al 2 O 3 and SiO 2 tend to be higher in the finer size fractions (-1 mm) of both samples. Result from the DMS analysis performed on the (-4 +0.5) mm fraction shows an underflow mass yields of 45.98% with Fe grade of 65.55% and overflow mass yield of 53.08% with Fe grade of just 13.5%. Magnetic separation (WHIMS) results on the (-4 +0.5) mm samples also gave varied mass yield and Fe grade at different magnetic intensities (3000 Gauss, 6000 Gauss and 10,000 Gauss). However, the highest Fe mass yield and grade produced from the magnetic separation were 18.10% and 50.8% respectively. The results show that DMS technique has the potential to re-treat the tailings at FGMSA. Keywords : Treatment, Iron ore, Tailings, Magnetic separation, Dense Medium Separation

Mineralogical quantification of iron ore sinter

The mineralogy and microstructure of sinter play an important role in determining the physical and metallurgical properties of iron ore sinter. Characterisation of sinter phases is, therefore, a cost-effective and complementary tool to conventional physical and metallurgical testing of iron ore sinter in evaluating and predicting sinter quality. Over the years, CSIRO (Commonwealth Scientific and Industrial Research Organisation) has developed a scheme for characterising iron ore sinter which classifies primary sinter phases, such as un-reacted and partially reacted haematite, magnetite and remnant fluxes, and secondary phases including silico-ferrite of calcium and aluminium (SFCA), secondary haematite and magnetite, glass and larnite. Quantification of these phases has traditionally been carried out by manual point counting under a petrographic microscope. However, new technologies based on automated optical image analysis, quantitative X-ray diffraction and scanning electron microscopy are now available for evaluation. In this study, two sinter samples of varying chemistry were prepared and characterised using both point counting and automated optical image analysis. Quantification of sinter phases is a complementary tool for comparing the physical properties of sinter obtained from various sinter blends, and sinter phase quantification results can be used for comparing pot-grate sinter with different metallurgical properties.

Metallurgical failure analysis of a cracked aluminum 7075 wing internal angle

Internal angles are used to strengthen Aircrafts center box corners where the wing is attached to the airframe. There are 16 angles in Airbus A300s wing box. On the right side, rear spur, and lower flange area of the center wing box, one of these angles had been cracked with a length of 28mm. This crack has decreased residual strength of the part under allowed values and resulted to a rupture in the rear spur lower cap. Several reports of the same occurrences in other Airbus A300 air crafts, highlight the importance of finding the causes of this failure. Detailed optical and SEM, plus 4 other metallurgical tests were conducted on the failed angle. Finally, it was concluded that corrosion fatigue was the main reason which itself comes from manufacturing, maintenance, metallurgical, and geometric reasons as were discussed in this study.

Design and optimisation of charging ingredients and structure in an ironmaking system (Part II)

In order to maximise the reduction of pig iron cost in an ironmaking process, and at the same time ensure the output and quality of the pig iron, a design and optimisation system for the charging ingredients and structure in an ironmaking system was established using metallurgical theory. The system includes six modules, namely, sinter metallurgical performance testing and analysis, sintering burdening design, sinter component and property prediction, blast furnace burdening design, blast furnace batching calculation and ironmaking system burden optimisation. Based on actual production, testing and material balance theory, the system integrated these modules on VB and MATLAB using a series of intelligent algorithms, such as the BP neural network, multiple objective linear programming, genetic algorithms and so on. As a result, the optimum burden composition and structure of the sinter and blast furnace that satisfied all the constraint conditions could be obtained. Standing as a pinnacle of the global ironmaking production, the system can design and optimise not only the sintering burden, but also the blast furnace burden. Compared with the traditional production testing and hand calculation in the ironmaking system, the project can greatly reduce the production risk and greatly increase the calculation accuracy. Industrial application shows that the system is especially beneficial to reduce the ironmaking cost and at the same time ensure the output and quality.

Charging composition and structure optimisation in the sintering process (Part I)

In this paper, an optimisation system for charging composition and structure in the sintering process was established in order to reduce the sinter cost in the ironmaking process. The system comprised four modules: sinter metallurgical performance testing and analysis, sintering burdening design and optimisation, sintering matching calculation, and sinter component and property prediction. The data for the first module came from actual production values of a steelworks and from testing in the laboratory. Based on material balance theory, the second module used a linear programming method to optimise sinter cost, quality and quantity. The third module was built to predict the sintering production data. The fourth module can be used to predict some composition and properties of the sinter based on a Back-Propagation neural network. The system integrated all of these modules using Visual Basic and MATLAB. As the result, the optimum charging composition and structure of sinter which satisfies all constraint conditions can be obtained. Compared with traditional production testing and hand calculation in the sintering process the system can reduce the sinter cost and greatly decrease the production risk. Industrial application proves that the system is very useful and efficient in reducing sinter cost while ensuring output quantity and quality.

Comparing univariate and multivariate approaches for process variograms: A case study

The classical application of theory of sampling (TOS) is univariate. However, most practical situations address multi-analyte issues, in which the common belief is that one should focus a variographic study on the analyte with the most heterogeneous distribution. This paper introduces a multivariogram approach to process sampling and compares it with the classical univariate and multivariate approaches of variograms as applied to principal component analysis (PCA) scores. A case study of low-grade kaolin residue sampling for metallurgical testing is used to illustrate this methodology. A total of eight important properties are analysed, including chemical analytes, size distribution properties and pulp density. The results show that the classical univariate approach can underestimate the global sampling error if the sampling protocol is designed by using only the highest variance property. Variograms that are calculated from PCA scores highlight distinct spatial patterns through variable grouping in a reduced number of variograms. Multivariograms can be used to summarise time variations in multiple analytes and highlight the multivariate time autocorrelation aspects of these analytes. However, the resulting sampling variance is very high, and an alternative approach that applies multivariograms to PCA scores, filters noise from the data, and only keeps relevant data information, which reduces the global sampling variance, is proposed. This case study illustrates the usefulness of multivariate approaches to help multivariate variographic modelling in mineral processing and in many other fields within science and industry that deal with multi-analyte sampling issues.

A Geometallurgical Characterization of the Vaal Reef A-Facies at the Moab Khotsong Mine, Klerksdorp Goldfield, South Africa

A marked decline in the gold recovery factor of ore from the Moab Khotsong mine, treated through the Great Noligwa recovery plant, prompted a detailed geometallurgical characterisation of the Vaal Reef A-facies conglomerate at the Moab Khotsong mine. This paper serves to document the results of the investigation. Six samples of the Vaal Reef A-facies were collected in-situ from the underground operations at Moab Khotsong mine for mineralogical study and metallurgical tests. Laboratory scale leaching tests for gold (cyanide) and uranium (sulphuric acid) were carried out using dissolution conditions similar to that in use at the Great Noligwa treatment plant, followed by further diagnostic leaching in the case of gold. The gold in the ore is readily leachable with plant recoveries ranging between 89 and 93%. Additional recovery can be achieved through leaching at excess cyanide conditions, for a recovery of 92 to 97%. In addition to this, the recovery of gold can be further enhanced through the pre-treatment of the milled ore with acid prior to cyanidation i.e. the ‘reverse gold leach’ in which uranium is recovered first through acid leaching, followed by cyanidation for gold. The leach-based recovery of uranium varies between 30 and 64%. This is well correlated with the abundance of brannerite, which is known to be relatively refractory compared to uraninite. However a substantial amount of uranium is also contained in coffinite which leaches faster than brannerite (but more slowly than uraninite). Dissolution of coffinite and thus enhanced uranium recovery may be accelerated by increasing the oxidation-reduction potential of the leach, as well as raising the temperature at which the leaching is conducted.

The advantages and pitfalls of conventional heterogeneity tests and a suggested alternative

Author Summary: Heterogeneity Tests have been very popular for the last 30 years and there are several versions of them such as the method of choice used by François-Bongarçon to quantify and minimize QFE1 which is a combination of the Fundamental Sampling Error and the Grouping, Segregation Error and sometimes Analytical Error. A more recent version called “segregation free analysis for calibrating the constant K and x” is used by Minnitt, and an older, obsolete version using fragments collected one by one at random from several size fractions to calibrate the constant K was used a long time ago by Gy and Pitard. All these methods have their merits and pitfalls. The common pitfall is that they all depend on the collection of a representative composite sample consisting of about half a ton of material. In Mineral Processing it is well known how difficult it is for geologists to provide a representative sample from a given geological unit to perform reliable metallurgical testing; the same difficulties are encountered in performing Heterogeneity Tests. Furthermore, experience clearly shows that for trace constituents such as gold, many tons should be collected to obtain a reliable composite. Perhaps there is a more representative way to collect the information necessary to calculate the variance of the Fundamental Sampling Error FSE, which can support and complement the method of choice referred to earlier. This paper suggests that all the necessary information can be obtained by slightly modifying the logging practices of geologists. From such observations, reliable histograms of the size distribution of particles of the mineral of interest can be made representing the properties of an entire geological unit. Such information can be obtained at an early phase of exploration leading to an unmistakable definition of the sampling constant K, and possibly an accurate definition of the mathematical model of the liberation factor leading to the constant x; using modern microscopy the mineralogist can define the evolution of the liberation factor as a function of increasing comminution better than anyone else. Furthermore, this paper suggests that the determination of the liberation factor is no longer a critical factor, though most certainly useful, if using the information from modified logging practices and two old formulas suggested by Gy in the 50’s instead of his famous formula using the liberation factor.

Comparative Study of Ti Alloy and Stainless Steel 304L Friction Welded Joint with Different Interlayer Process Methods

Rotary Friction welding is a process of solid state joining, broadly in shaft and pipe weld, in the field of automobile, defence, aeronautical, chemical and nuclear environment assembly pipe lines. Due to its some distinctive advantages similar to ease of fabricate, environmentally sociable, high fabrication value and appropriate for similar, dissimilar metal joint. Now a day’s Titanium alloy and stainless steel materials are very popular material in industrial application due to its high mechanical potency, and non-corrosive in nature. In this study an attempt was made to join commercial rod of Ti-6Al-4V and Stainless steel304L with some methods and evaluates the joint strength. Different intermediate metals are taking on in this process and the outcomes are witnesses. From that study the best method of in-between metal was analyzed by carry out mechanical and metallurgical test.

Rare earth (La, Ce, Nd) and rare metals (Sn, Nb, W) as by-product of kaolin production, Cornwall: Part1: Selection and characterisation of the valuable stream

This paper analyses output streams of a kaolin plant to select the most valuable waste stream for metal recovery. The results indicate that rare metals (Sn, Nb, W) and Light Rare Earth Elements (LREEs) are pre-concentrated in the micaceous residue which contains a relatively high LREE (La, Ce, Nd) concentration of around 170ppm. This residue have been characterised using a two-stage gravity pre-concentration process involving a Falcon concentrator and a shaking table to obtain concentrates suitable for mineralogical study. A statistical analysis, combined with qualitative mineralogy, highlights the main mineralogical associations and identifies monazite, cassiterite, Nb-rutile and wolframite as the main metal-bearing minerals. Estimation formulas for Nb and LREE using only the TiO2 and SiO2 content of the wastes, obtained by binary and multiple linear regression, show very accurate results suggesting a possible on-line application. This will provide tools to select the most valuable waste streams or the associated tailing dams (using historical data) for metals recovery. These selected wastes will be used for metallurgical test works to assess the potential for by-product recovery of these metals.

Exploring the electrodes alignment and mushrooming effects on weld geometry of dissimilar steels during the spot welding process

The class two of RWMA electrode caps has very common application-purpose for the welding of steels and withstand for high thermal application on wrought cast. It has been experimentally used to weld carbon and stainless steels up to 900 weld attempts using AC waveform, C-type JPC 75 kVA, Japanese made spot welder. So the electrode alignments and resulting mushrooming effects are finally analysed in this research as well as the weld geometry of dissimilar (carbon and stainless) steels. When considering such weld joints, the heat imbalances are very interesting factors on spot welding research and therefore I have simulated the dissimilar weld joints using Ansys 14. Initially, it was simulated and later those results are compared with real welded samples. The common welded regions such as: fusion zones, heat affected zones, heat extended zones and base metals are all well-noticed for carbon steel sides but not for stainless steel sides. Besides, the electrode mushrooming effect on both sides of electrodes are not parallel deterioration and it has some demerits on internal structure indeed. Some of the dissimilar welded samples and electrode caps are eventually underwent metallurgical test to identify the improper alignment.

Material characterizations of mild steels, stainless steels, and both steel mixed joints under resistance spot welding (2-mm sheets)

Resistance spot welding is an essential welding mechanism for joining two or more metal sheets together in automotive industries. The mechanical assemblies are easily joined at discrete spots using high current flow through the area of concentration. It is easily achieved by compressing the base metals together to a certain pressure using copper electrode caps and allow the high current to flow through the concerned areas. The heat generation due to the current flow causes the metal sheets to be fused and consequently form bonds between base metals. The molten areas of base metals undergo solidification process by itself when the current flow is utterly stopped. Basically, the weld growth in any joint is determined by its process-controlling parameters, particularly the welding current, weld time, electrode force, and electrode tip. In these experiments, the welding current and weld time variations were carried out to characterize the weld growth for three types of joints mainly for stainless steel, mild steel, and both steel mixed joint. A pneumatically driven 75-kVA spot welder was used to accomplish the entire welding processes, and the welded samples were later subjected to tensile, hardness, and metallurgical tests to relate the diameter growth, loading force during tensile test, failure crack initiation, post-failure crack propagation direction, macro and microstructural changes, and also the hardness changes due to solidification process. Assessing the experimental results of 2-mm thickness of materials revealed that the welded areas’ characteristics have been varied from its original states to enriched states, in terms of shearing strength and hardness distribution as well as the microstructural orientation.

Failure analysis at deep drawing of low carbon steels

This paper presents a comparison in behaviour of two Zn coated, low carbon steels during deep drawing of bearing housing. The failures occurred during deep drawing process only for one steel. The experimental work consisted of a visual inspection, microscopic examination and chemical analysis of both materials. Metallurgical tests revealed the difference in microstructure and in carbon content. The anisotropy in behaviour was observed during deep drawing process. Metallography confirmed formation of longitudinal micro and macrocracks and elongated chains of cementite particles in matrix of ferrite. This study highlights the detrimental effect of the interface cementite particle/ferrite matrix as the main reason for the microcracks formation and reduction of steel capacity for deep drawing.