Cast Brass Research Articles

Increasing the Properties of Copper Alloys by Refining–Modifying Treatment with Melt Carbonates of Alkaline Earth Metals

The main tasks of treating a melt of brass are analyzed. A comparison of traditional treatment methods with the proposed method of improving the quality of the alloy is presented. The equilibrium conditions for the decomposition reactions of carbonates are considered when treating the melt in an open and closed ladle. The conditions for the reaction of carbonate decomposition are formulated. The possibility of the simultaneous flotation of the resulting gaseous product of the decomposition of carbonates in the process of refining the brass melt from dissolved gases and nonmetallic inclusions is considered. An analysis of the thermodynamic conditions of slagging impurities by introducing carbonates of alkali and alkaline earth metals through the interaction of their oxides with oxides of silicon and aluminum in the melts is presented. The possibilities of enhancing the physicomechanical properties of brass castings due to the modifying effect provided by the formation of oxides of calcium, strontium, barium, and sodium as a result of the dissociation of their carbonates are investigated. The applied technology of treating the melt of brass with alkaline earth metal carbonates in a pouring ladle and methods for studying the results from the point of view of microstructural analysis and values ​​of mechanical tests are described. The use of carbonates in the treatment of a brass melt created a more favorable microstructure, contributed to a decrease in the average nominal grain size, increased its uniformity, and reduce the likelihood of formation of an enlarged α phase. Extensive studies of the microstructure of samples with various treatment options for melts with carbonates are carried out. A study of the mechanical properties of brass samples before and after melt treatment with various combinations of alkaline earth metal carbonates is conducted. Compositions of carbonate mixtures that have the most favorable complex effect on the strength of brass with a simultaneous increase in the plasticity indices are determined. The optimum composition of the carbonate mixture is chosen experimentally. Efficiency of treatment is confirmed by industrial tests. The simplicity and other positive features of the proposed technology of refining–modifying treatment of a brass melt with mixtures of alkaline earth metal carbonates are noted.

Influence of Pulse Parameters on a b Cuzn Alloys Electrodeposited Coatings

Cu-Zn alloys is the most manufactured copper alloy in the word since it offers a wide range of properties depending on its zinc content. Although brass plating has been studied since 1841 by Ruoltz, and despite several studies devoted process improvement, CuZn coatings from non-cyanide baths shows low reproducibility, poor adhesion, inhomogeneous color and frequently cannot be deposited directly on steel. These problems are mainly attributed to an unusual crystalline phase distribution[1] [2]. Therefore, to obtain a higher quality of metallic electrodeposited alloy, it is mandatory to control the activity of the nobler ion in the solution, which is much more likely to be reduce. To that end, copper and zinc reduction potentials have to be bring closer by the use of a complexing agent of the copper ions. An electrolyte with a low citrate concentration has been developed and its electrochemical behavior extensively studied [3]. Varying Citrate concentrations will influence zinc electrodeposition and bath stability, giving the hand of the control of alloy element content. For the optimum conditions, CuZn coatings were obtained in a large range of Zn content (from 11% to 100%) as a function of Zn concentration and current density. Crystalline structures of the α β brass deposits were then identified in the range of 35% to 45% in Zn content, in order to be compared to commercial cast brass. The present study discusses the effect of pulse current for a selection of electrolytes, at the optimum of copper and citrate concentration. Wave modulation is investigated in order to compare Zn content and phase distribution for the same average current density. A particular focus was made on the quantification by XRD phase determination and its comparison with anodic dissolution. The best conditions have been tested on larger samples, to check adherence, homogeneity and to try to reach a maximum coating thickness and the right physical aspect than for the cast brass alloys. [1] J.C. Ballesteros, L.M. Torres-Martínez, I. Juárez-Ramírez, G. Trejo, Y. Meas, Study of the electrochemical co-reduction of Cu2+ and Zn2+ ions from an alkaline non-cyanide solution containing glycine, J. Electroanal. Chem. 727 (2014) 104–112. doi:10.1016/J.JELECHEM.2014.04.020. [2] T. Vagramyan, J.S.L. Leach, J.R. Moon, On the problems of electrodepositing brass from non-cyanide electrolytes, Electrochim. Acta. 24 (1979) 231–236. doi:10.1016/0013-4686(79)80030-4. [3] A. Dridi, L. Dhouibi, J.Y. Hihn, P. Berçot, W. Sassi, E.M. Rezrazi, Study of the influence of complexes stability on the kinetic of CuZn electroplating in a citrate bath, Submitted Electrochim. Acta. Figure 1

Maintenance of cast brass taps by pulsed Nd:YAG LASER welding

During solidification of melted metal in casting process, the volume decreases, resulting in cracks, voids and porosities. These defects, depending on the application and requirements, might result in rejection during quality control. For maintenance of cast brass taps, TIG welding is already employed. Thus, considering the several advantages of laser welding in comparison with conventional welding processes, in this work, the authors analyze the possibility of using laser welding in the maintenance of cast brass taps. A pulsed Nd:YAG laser welding machine was used to weld cast brass taps cracks. Additionally, a parametric study was carried in order to identify and determine the fundamental and best set of parameters to repair cast brass cracks and depressions with laser welding. The parameters are laser power and energy; pulse type and frequency; and laser beam diameter. Additionally, in order to analyze the repair and welding quality, metallographic (macro and micro) analyzes were carried. Both cracks and depressions were successfully repaired with laser welding technique. Therefore, in this work, it was verified the excellent applicability of pulsed Nd:YAG laser welding in repairing defects on cast brass taps. The best set of parameters was: 10 ms rectangular pulse with a frequency of 5 Hz; energy of 34.8 J; 1.2 mm laser beam; and Argon flow rate of 6 l/min.

On Consonance between a Mathematical Method for the CET Prediction and Constrained / Unconstrained Solidification

Abstract Some properties of the functions yielding from the temperature field have been employed as a tool to determine the structural zones’ localization in a large static steel ingot. Thus, a numerical simulation was performed to generate the temperature field converged subsequently into the thermal gradient field. As a result, the selection of a zone, in which a columnar into equiaxed structure transformation (CET) is expected, is possible. It is shown that the CET - zone is formed when the thermal gradient becomes temporarily constant. Moreover, the CET localization can be easily controlled / shifted by the mold thickness selection. Both temperature and thermal gradient fields were also calculated to predict mathematically the creation of some structural zones in the continuously solidifying brass ingot. The columnar structure resulting from the constrained growth seems dominant in these ingots. However, when the s/l interface rate and velocity of the liquidus isotherm movement are subjected to a separation then the birth of the equiaxed structure is to be expected. In the industrial practice, the following structural zones are evinced in a continuously cast brass ingot: chilled columnar grains-, (CC), fine columnar grains-, (FC), columnar grains-, (C), equiaxed grains zone, (E), and eventually the single crystal, (SC), situated axially. The current innovative method for the mathematical predictions of the CET appearance in the static ingot turns out also useful in the reproduction of the all mentioned structural zones’ localization. In particular, a study of the behavior of the velocity of the liquidus isotherm movement and thermal gradient changes versus solidification time delivers a precise information about these structural zones’ situation.

Microstructural Evolution and Mechanical Behavior of Lead-Free Silicon Brass Manufactured by Low-Pressure Die Casting

Low-pressure die casting (LPDC) has been widely used to process aluminum and magnesium alloys; however, it has yet to be applied to manufacture brass alloys. This study investigates the microstructural evolution and mechanical behavior of a lead-free CuZnSiAl silicon brass via a variable-controlling approach on the basis of a faucet casting by LPDC. The manufactured silicon brass castings are predominantly composed of bcc β-CuZn(Si, Al) and minor fcc α-Cu(Zn, Si) solid solutions. The silicon brass castings also predominantly exhibit short rod-like or granular α phases, which distinctly differ from the acicular α morphology obtained by conventional gravity casting. The manufactured silicon brass castings which contain finer β grains and short rod-like or granular α phase exhibit superior mechanical properties. Their optimal mechanical properties—elongation of 15.0%, yield strength of 359.8 MPa, and ultimate tensile strength of 598.9 MPa—are far superior to those of the typical lead brass HPb59-1. The results obtained in this study provide insight into the manufacture and design of lead-free silicon brass castings by LDPC.

Effect of Cryoforging on Mechanical Properties of Low SFE Cast Brass

Effect of Cryoforging on Mechanical Properties of Low SFE Cast Brass

Ultrasonic Inspection Techniques Possibilities for Centrifugal Cast Copper Alloy

Abstract The article deals with ultrasonic testing possibilities of the copper alloy centrifugal casts. It focused on the problems that arise when testing of castings is made of non-ferrous materials. Most common types of casting defects is dedicated in theoretical introduction of article. Ultrasonic testing technique by conventional ultrasound system is described in the theoretical part too. Practical ultrasonic testing of centrifugal copper alloy cast - brass is in experimental part. The experimental sample was part of centrifugally cast brass ring with dimensions of Ø1200x34 mm. The influence of microstructure on ultrasonic attenuation and limitations in testing due to attenuation is describes in experimental part. Conventional direct single element contact ultrasound probe with frequencies of 5 MHz, 3.5 MHz and 2 MHz were used for all experimental measurements. The results of experimental part of article are recommendations for selecting equipment and accessories for casting testing made of non-ferrous metals.

Role of the Structural and Thermal Peclet Numbers in the Brass Continuous Casting

AbstractThe Structural Peclet Number has been estimated experimentally by analyzing the morphology of the continuously cast brass ingots. It allowed to adapt a proper development of the Ivantsov’s series in order to formulate the Growth Law for the columnar structure formation in the brass ingots solidified in stationary condition. Simultaneously, the Thermal Peclet Number together with the Biot, Stefan, and Fourier Numbers is used in the model describing the heat transfer connected with the so-called contact layer (air gap between an ingot and crystallizer). It lead to define the shape and position of the s/l interface in the brass ingot subjected to the vertical continuous displacement within the crystallizer (in gravity). Particularly, a comparison of the shape of the simulated s/l interface at the axis of the continuously cast brass ingot with the real shape revealed at the ingot axis is delivered. Structural zones in the continuously cast brass ingot are revealed: FC - fine columnar grains, C - columnar grains, E - equiaxed grains, SC - single crystal situated axially.

Microstructural Investigation and Characterization of Bulk Brass Melted by Conventional and Microwave Processing Methods

Microwave processing of bulk metallic materials is an emerging area. In the present work, brass in bulk form is melted in a modified domestic microwave oven operating at 2.45 GHz frequency. As-received and the as-cast brass are subjected to metallurgical and mechanical characterization. Specimens’ surface morphology is studied under Scanning Electron Microscope (SEM). X-Ray Diffraction (XRD) pattern shows the presence of copper oxides phase in both cast brass. Average tensile strength of brass melted using microwave oven is found higher when compared with brass melted in muffle furnace. Hardness of the as-cast brass is found to be higher than the as-received brass. However, brass cast by microwave irradiation exhibits around 2 % higher hardness than the brass cast by conventional heating. Microwave melting of brass consumed nearly six times less time compared to conventional melting.

EXPORT PERFORMANCE IMPROVEMENT THROUGH MANAGEMENT AND TECHNOLOGY SUPPORT FOR SMES CRAFT

Specific targets of this activity are: (i) SMEs can increase turnover; (ii) SMEs can enhance variety of design products; (iii) SMEs have skilled human resources on product design; (iv) SMEs can prepare financial statements; (v) SMEs have a standard quality assurance; (vi) SMEs can improve product quality and speed up the production process; (vii) Obtaining copyrights products. Methods of implementation of this program include: training and assistance with activities such as: the manufacture of machinery and production equipment, supply of equipment, participation in exhibitions, arrangement of storage space and show room, cooperating with other parties as well as the processing of copyright products. The results obtained from these activities, first with the brass foundry furnace and molds made of firebrick resulted in increased speed of production processes as well as fuel efficiency and cost of production for SME-1 Whisnu. It took only three hours to the cooking process cast brass with a capacity of 120 kg previously take longer that 5 hours. Secondly, Machine Mixer Materials for Partners Java Fiber can shorten the process of mixing the fiber material to be faster, employees are not tired and product quality is getting better and there is no defective products. material mixing machine can stir 25 kg fiber material for 5 minutes, while the previous manual way takes 1 hour to stir 25 kg fiber. Thirdly, it has been conducted Partners Products Exhibition. Fourth, it generates three new product design by SME-1 Whisnu and 4 design new products by SME-2 Java Fiber. Fifth, the proposed copyright has begun to partner products to the Ministry of Justice and Human Rights. This activity resulted in increased revenue of SMEs 10% per year.

Aplikasi Cetakan Permanen untuk Meningkatkan Produksi dan Kualitas Produk IKM Pengecoran Logam Kuningan di Ngawen, Sidokarto, Godean, Yogyakarta

Small and Medium Enterprises (SME) brass foundry in Ngawen Sidokarto, District of Godean, Sleman, Yogyakarta mostly produced cow necklace accessories (klonthong) and jathilan accessories (klinthing). Te industry and business management are arranged within the scope of family. Te products are relatively low in quality and its market share is limited and tend to be traditional. Tis condition is caused by the weak knowledge of the management and the method of casting metals and metal science. Brass casting methode, that was used at IKM partner, is casting with mold of sand or soil. Tis process requires the making process of sand molds, that is removed afer the brass solidify. For large quantities products, this process is inefcient and takes a long time. It would require a more efcient and faster method in the production process. Method of sand casting and ceramics have been used by SMEs cast brass in Yogyakarta, however it has many disadvantages in terms of increased productivity and quality as well as the expansion of product applications. Te permanent mold casting of iron is a casting method which has many advantages over other methods, but the use for SMEs has not been applied in the SME of cast brass. Te permanen mold casting methods was introduced to SME partners. Tis replaces the sand mold materials and molding sand. It is expected the casting process is faster because the mold can be used for a large number of products. Te results show that the application of the technology results in products with precision and consistent in shape and size. Community Service of UGM with Appropriate Technology has also collaborated with Industry and Trade service of Yogyakarta donation of production machinery for making permanent mold. It can be concluded that the application of permanen mold in the brass foundry industry improve the product precision and the speed of produsction.

Development of Lead-Free Bronze with Sulfide Dispersion for Sliding Applications

Cu alloys such as bronze have long been used as bearing materials because of their good run-in properties for steels used as mating materials. These Cu alloys are also suitable for various applications: High-strength brass castings and phosphorus bronze castings are used for their ability to obtain higher strengths, whereas Pb–bronze castings are used for anti-seizure applications. To prevent scoring and seizure, base materials such as Cu alloys were often combined with a solid lubricant. In this study, the tribological properties of sulfide-dispersed bronze were investigated. Friction tests were conducted under dry conditions for bronze with/without sulfides. It was found that seizure was prevented in sulfide–bronze systems only under certain test conditions. It was estimated that the dispersed sulfide restricted the transfer of the Cu alloy elements to the mating steel surface. Moreover, the addition of Si to a Cu–Fe–S system and to sulfide-dispersed bronze resulted in crystallization of Fe–Si compounds. The hardness and anti-wear properties of the compounds were also improved.

Structural Zones in Large Static Ingot. Forecasts for Continuously Cast Brass Ingot

Abstract Some metallographic studies performed on the basis of the massive forging steel static ingot, on its cross-section, allowed to reveal the following morphological zones: a/ columnar grains (treated as the austenite single crystals), b/ columnar into equiaxed grains transformation, c/ equiaxed grains at the ingot axis. These zones are reproduced theoretically by the numerical simulation. The simulation was based on the calculation of both temperature field in the solidifying large steel ingot and thermal gradient field obtained for the same boundary conditions. The detailed analysis of the velocity of the liquidus isotherm movement shows that the zone of columnar grains begins to disappear at the first point of inflection and the equiaxed grains are formed exclusively at the second point of inflection of the analyzed curve. In the case of the continuously cast brass ingots three different morphologies are revealed: a/ columnar structure, b/ columnar and equiaxed structure with the CET, and c/ columnar structure with the single crystal formation at the ingot axis. Some forecasts of the temperature field are proposed for these three revealed morphologies. An analysis / forecast of the behavior of the operating point in the mold is delivered for the continuously cast ingot. A characteristic delay between some points of breakage of the temperature profile recorded at the operating point and analogous phenomena in the solidifying alloy is postulated.

Selling Authenticity in the Bamum Kingdom in 1929–1930

In February 1930, Eugene Pittard, the director of the ethnological museum in Geneva, sought to expand his museum’s collections in an unusual manner. Instead of sponsoring an expedition to Africa or acquiring objects from former missionaries, instead of buying from established dealers in ethnographic specimens or the newer galleries that specialized in l’art negre, Pittard wrote to an African man in Africa, a Bamum man named Mose Yeyap (Pittard 1930) (Fig. 1).1 Yeyap was the head of the relatively new artisanat in Foumban, a school and artists’ cooperative founded in 1927, and he was known as a key figure for collectors seeking to acquire works of art from the Bamum kingdom. Pittard’s letter explained that he “would like to assemble ... as true a picture as possible of the population of which you are a part, that is to say of the material life of this population. I am sending you by the same post [a list of] the kinds of things that would be the most interesting to have” (Pittard 1930). Pittard explained pointedly, “I insist on one point: Our intent is to have the oldest objects; those which have not been subjected to European influence.” He then listed for Yeyap the kinds of objects he had in mind: “sculpted wood masks, statues, sculpted horns, etc. ... sculpted drums with carved animals or other designs. Miss Debarge [a physician known both to Pittard and Yeyap] showed me drawings on paper that you made of sculptures. Is it possible to have these sculptures themselves?” (Pittard 1930). Pittard’s letter, of course, epitomizes how European arrogance and fantasy informed the collection of African art in the first decades of the twentieth century. Pittard condescendingly and absurdly schooled Yeyap about Yeyap’s own culture and, by privileging his desire for “the oldest objects,” those supposedly untouched by “European influence,” Pittard revealed his adherence to the chimerical “ideal” of African cultures as isolated in time and space. In a fascinating twist, however, we also have Yeyap’s response to Pittard. Yeyap answered back:

Fouling communities and degradation of archeological metals in the coastal sea of the Southwestern Gulf of Mexico

Corrosion and biofouling phenomena of cast iron and brass were evaluated under natural conditions to determine the degradation process of archeological artifacts. Field exposure studies of experimental materials were conducted over 15 months at an offshore position in the sea of Campeche in the Gulf of Mexico. Corrosion was determined by gravimetric measurements. The community structure of the benthic assemblage inhabiting the surfaces of both materials was evaluated. A total of 53 species was identified. The community in both cases was composed of a small number of species. Encrusting, attached and erect life forms were dominant on iron. Attached life forms were dominant on brass. Biofouling produced a decrease in the weight loss measurements of cast iron samples. Biofouling provided a beneficial factor for in situ preservation of iron archeological artifacts in wreck sites.

Fundamentals of ductile cast iron scuffing at the boundary lubrication regime

The friction regime of partially lubricated and highly loaded contact when the oil does not entirely separate the rubbing surfaces and its thickness is comparable to the roughness of the surfaces poses, in some cases, risk of scuffing and catastrophic wear.The present study, on life prediction of tribological systems from ductile cast iron, steel and brass, is shown by an analysis of the fundamental mechanisms of scuffing. Ductile cast iron according to DIN EN 1563 with nodular graphite standard EN ISO 945 is submitted to systematic tribological tests of scuffing and analysed in the context of quasi-conventional tribometry lubricated with reference and reclaimed naphthenic oils.The 3D morphologies of the rubbing surfaces are characterised and the fundamental conditions of the scuffing process are investigated. The results are elucidated in order to propose a phenomenological description of the analysed wear process and its invariants. Therefore, the role of solid materials as well as the nature of lubricants is both taken into consideration.

The Effect of Tin and Heat Treatment in Brass on Microstructure and Mechanical Properties for Solving the Cracking of Nut and Bolt

This work studied the effect of tin (1%Sn) addition in brass 60%Cu+40%Zn (commercial grade) by casting process conducted poured melt metals inside a sand mould and heat treatment in cast brass on microstructure and mechanical properties for solving the cracking of nut and bolt. Three conditions of brass sample for experiment viz.- brass 60%Cu + 40%Zn (commercial grade), brass 60%Cu + 39%Zn+1%Sn (as-cast) and brass 60%Cu+39% Zn+1%Sn (precipitation hardening). The microstructure of specimens all condition, it was found that consists of α phase and β phase. Which brass addition 1% Sn, the β phase content in α phase matrix structure more than brass commercial grade. For microstructure of brass produce by precipitation hardening, shape of α phase are slender and long which have slight distributed in β-phase. The mechanicals properties, that is hardness, ultimate tensile strength and compressive strength. It was found that the brass 60%Cu+39% Zn+1%Sn (precipitation hardening), all test mechanical properties it was higher than the all samples condition. This results can be explain incharacterization of microstructure to gives deformation of copper alloy.

History in 3-D

This article discusses how kinematic mechanisms created by Franz Reuleaux are now being made available by Cornell University for students and researchers. The university’s Sibley School of Mechanical and Aerospace Engineering owns the largest set of cast iron and brass models of machines designed by Reuleaux more than 130 years ago. Cornell librarians have helped develop the Kinematic Models for Design Digital Library, or K-MODDL, to allow Internet users to view the models close up. The Cornell Reuleaux Collection contains numerous kinematic mechanisms for rotary and reciprocating engines using both steam and internal combustion. It also includes a dozen working clock escapement mechanisms, from the early verge and foliot escapement to the gravity escapement employed in London’s famous Big Ben. K-MODDL will make the collection available to educators, researchers, and students well beyond the Cornell campus. Those with access to a 3-D printer will be able to build a reproduction of the real thing to see up close how the mechanism works.

Pin-On-Disc Characterization of Brass/Ferritic and Pearlitic Ductile Iron Rubbing Pair

Wear behaviour of special brass produced through two different methods (centrifugal and sand casting) was investigated. The wear tests were carried out at sliding velocities of 0.2 ms–1, 0.3 ms–1, 0.4 ms–1 and 0.5 ms–1 and under 10 N, 20 N, and 40 N variable loads. The sliding distance was 600 m for all the tests. A pin-on-disc device with round specimen inserts was used to conduct friction and wear tests in which the friction coefficient, the contact temperature and the linear wear of the tribo-pairs were continuously recorded against sliding distance. Two different materials were used as the counterparts, namely ferritic ductile iron equivalent to GGG40 and pearlitic ductile iron equivalent to GGG60. The microstructures and wear scars of the brass specimens were examined by optical, scanning electron microscopy (SEM) and X-ray microanalyses by EDAX. A correlation between hardness and wear volume rate was established for the investigated centrifugally cast and sand cast brass specimens. The volume rate of specimens produced by sand casting method was generally found to be higher than those of centrifugally cast specimens. Ferritic ductile counterpart led to higher wear volume rate than pearlitic ductile counterpart for the both specimens. Severe abrasive wear scars were observed for the sand cast specimens/ferritic ductile iron pair. However, severe adhesive wear took place for the centrifugally cast specimen/pearlitic ductile iron pair.

Characteristics and machinability of lead-free P/M Cu60–Zn40 brass alloys dispersed with graphite

The aim of this paper was to produce a lead-free machinable brass dispersed with graphite particles by powder metallurgy process. The weight of brass powder decreased with increasing the heat treatment temperature over 873 K by vaporized zinc. The voids were also observed according to Kirkendall effect by the difference of diffusion velocity between Cu and Zn at the brass powder surface. In the case of spark plasma sintering, however, zinc vaporization has not occurred because of sealing pressurization and pressure forming. A specimen of brass without graphite particle, sintered at 1053 K by SPS, had a large elongation similar to that of the cast brass alloy. Using the blended brass powder with graphite particles, graphite particles were dispersed in extruded material by applying the SPSed billet. P/M extruded brass alloys with 1 mass% graphite particle was significantly effective to improve their machinability as well as the conventional brass alloys with lead.