Metal Mold Casting Research Articles

Microstructure phase analysis and process optimization of ZL205A metal mold casting

In this paper, we take an elastomeric transmission structure part made of ZL205A alloy as the research object, and use the metal type gravity casting technology for casting trial production, analyze the quality and mechanical properties of the molded parts of ZL205A alloy parts under different process parameters, optimize the casting process parameters, get the optimal combination of process parameters, and obtain large ZL205A castings with less internal quality defects and high mechanical properties.

Microstructural and mechanical characteristics of AlSi5Cu3 aluminum alloy cast in metal mold and sand mold

In this effort, the impact of mold material on the microscopic behavior and mechanical performance of AlSi5Cu3 alloy was investigated. The AlSi5Cu3 alloy was cast in the metal and sand molds with equal cavity size and the characteristics of castings were evaluated. The metallographic analysis revealed that, due to the rapid solidification, the number of grains is 2.17% higher and the grain area is 3.71% less compared to sand mold casting. Moreover, due to the formation of more refined grain structures, metal mold casting has greater mechanical properties compared to sand mold casting. The findings revealed that the hardness, ultimate tensile strength (UTS), and impact strength of metal mold casting samples were improved by 8.82%, 10.74%, and 12.5% compared to sand mold casting samples.

Influence of the mold type on the mechanical properties of the piston alloy with nano alumina in casting and metal mold

This research is an experimental comparison study to show the influence of mold type casting on mechanical properties. The study considers the aluminum alloy of a gasoline engine piston with nanoparticles alumina Al2O3 size 25 nm manufactured in two types of molds. Sand mold and cast-iron mold were selected to cast the aluminum composite components. A systematic comparative study of tensile strength and hardness properties of cast aluminum components is made on sand and metal molds production. The nano powder can add to enhance the mechanical properties must not exceed 4 % for metal and sand mold casting. According to data for hardness, adding nano alumina powder has minimal impact on metal mold casting, but it significantly improves sand casting. From a financial standpoint, metal casting provides higher economic values for making piston aluminum castings. The hardness rises as the alumina content does in two molds as compared to the obtained specimen. It demonstrates that the highest hardness occurs at 4 % alumina in the sand-casting mold and at 6 % alumina in the metal. When the compositions of the casting materials are the same, a comparison of the fracture morphology between sand and mold casting reveals more ductile fractures for metal molds compared to brittle fractures in sand cast by large silicon separation grains because of higher grain growth in sand casting by longer solidification time. The same is seen in mold casting, which exhibits reduced ductility due to the alumina nanoparticles' dispersion strengthening process in the aluminum matrix. This arises as a result of nano alumina dispersion acting as barriers to dislocation motions in the aluminum matrix, enhancing strength but reducing ductility.

Effect of Sc on microstructure and properties of A357 alloy under different casting conditions

The effect of Sc on microstructure and mechanical properties of A357 alloy was investigated using sand molds and metal molds. The results showed that the eutectic Si in A357-0.5Sc alloy showed finer fibrous structure and smaller secondary dendrite spacing than that of A357 alloy in metal mold casting; a significant degeneration of secondary and tertiary dendrites has happened during solidification in A357-0.5Sc alloy using sand molds. UTS and YS of A357-0.5Sc alloy were higher than those of A357 Alloy in both metal molds and sand molds. In metal mold casting, the elongation of A357-0.5Sc alloy was higher than that of A357 alloy. In sand casting, the elongation of A357 and A357-0.5Sc alloys is almost equal. The YS of A357-0.5Sc alloy in sand mold is 7.5% higher than that of A357 alloy in metal mold, and the UTS and EI are almost equal. Taken together, the mechanical properties of A357-0.5Sc using in sand molds shows better than that of A357 using metal molds, which can improve mechanical properties in sand molds to meet the requirements of casting of complex parts in sand molds.The secondary dendrite of A357 and A357-0.5Sc alloys was obvious in metal mold casting. The main factor affecting the mechanical properties of the metal mold alloy was the secondary dendrite spacing. The addition of Sc would degrade the secondary and tertiary dendrites of A357 alloy in sand-casting. Moreover, the main factor affecting the mechanical properties of the sand-casting alloy was grain size.

Effect of the Type of Inorganic Binder on the Microstructure and Properties of AlSi7Mg Alloy Castings Made by Ablation Casting Technology.

The results of studies on the effect that the type of binder and casting technology exert on the microstructure and properties of AlSi7Mg alloy castings are discussed in this paper. Comparative tests were carried out on three casting manufacturing technologies, i.e., conventional sand mould casting and cooling process, metal mould (die) casting, and sand mould casting with ablation breakdown of mould and cooling of castings. Moulds were made from four different sand mixtures with inorganic binders hardened by various technologies. The microstructure of test castings was examined at three different levels, i.e., in the upper part, central part, and lower part of each casting. The tensile test at room temperature was carried out in accordance with standards. The experimental results showed differences in the microstructure of castings. The differences resulted from changes in the crystallisation path due to the use of three different casting technologies, ensuring different rates of heat dissipation from castings; they were also due to the shape of castings. It has been shown that castings made by ablation technology are characterised by a high degree of the microstructure refinement (SDAS reduced by 18–30%), which gives higher strength properties than the properties of castings made in conventional sand moulds. Samples taken from castings made by the ablation technology in moulds with phosphate binder and microwave-hardened geopolymer binder were characterised by the mechanical properties comparable to gravity die castings.

Microstructure evolution and mechanical properties of the Mg-Sm-Gd-Zn-Zr alloy during extrusion

Mg-2.6Sm-1.3Gd-0.6Zn-0.5Zr (wt.%) alloy is prepared with metal mold casting and followed hot extruded at 400°C with the extrusion ratio of 25:1. Microstructure and mechanical properties of the as-extruded alloy are investigated using optical microscope (OM), scanning electron microscope (SEM) with electron backscatter diffraction (EBSD), X-ray diffraction (XRD) and transmission electron microscope (TEM). The results show that the as-extruded alloy is fully dynamically recrystallized, which develops rare earth (RE) texture component. The as-extruded alloy shows an age-hardening response at 200°C, in which there are numerous nano-scale plate strengthening phase β′ precipitated in the matrix. The as-extruded alloy in the peak-aged condition exhibits ultimate tensile strength, yield strength, and elongation of 332 MPa, 220 MPa and 22.7% at room temperature, respectively. The dominant strengthening mechanisms of the investigated alloy are fine-grain strengthening, solid solution strengthening and precipitate strengthening.

Design of metal casting mold for ADC 12 aluminium alloy with assistance of 20 kHz ultrasonic vibration

Metal mold casting is widely used in industry because of higher accuracy than sand casting and lower cost than diecasting. Metal mold casting can yield products with complex shapes and adjustable cooling rate. In this work, designing and fabrication of 20 kHz ultrasonic assisted mold casting using 20Cr steel are studied. Some major components such as motor, heater power, melting chamber are selected and calculated. Model for heating and pouring the ADC 12 alloy is designed. Samples with and without ultrasonic vibration are investigated using 3D laser scan.

Effect of cooling rate on C92900 bronze microstructure and properties

In the mechanical engineering, antifriction tin bronzes are used for the manufacture of friction parts. For example, the C92900 bronze has found use in aircraft braking system components. One of the ways to improve the properties of leaded tin bronzes is to increase the cooling rate during solidification. This paper studies the effect of the cooling rate and changes in the content of alloying elements within the limits established by the C92900 bronze industry standard OST 1 90054-72. In order to provide different cooling rates, the prepared alloys were casted into molds made of resin-bonded sand, steel and graphite with cooling rates 0.4, 5.0, and 14.6 °C/s, respectively. The influence of the cooling rate and the bronze composition on the freezing range, macrostructure, microstructure, thermal conductivity, mechanical, and tribological properties were investigated. Differential thermal analysis demonstrated that the upper-limit alloying of C92900 bronze leads to a decrease of the solidus temperature by 40 °C, which should be considered during deformation processing and heat treatment. An increase in the cooling rate during C92900 bronze ingot solidification provides a significant grain refinement and changes the amount, size and morphology of phases. For example, in case of metallic and graphite mold casting, the size of lead particles decreases, and its circularity increases. The change in the Sn content within the range established by the industrial standard has a significant effect on the γ-(Cu,Ni)3Sn intermetallic phase fraction. The increase in the cooling rate has no significant effect on the C92900 bronze thermal conductivity but increases hardness by 30 HB as well as cooling rate and yield strength and ultimate tensile strength. Wear tests carried out in accordance with the «shaft – partial insert» scheme in a kerosene medium using a steel counterbody showed that an increase in the cooling rate during solidification leads to an increase in the bronze wear rate from ~0.4·10–8 to ~1.2·10–8. The change in the bronze composition within the industrial standard range has practically no effect on the wear rate but leads to a slight increase of the coefficient of friction.

Effect of Mg content on microstructure and properties of Zn-Al-Cu Alloy

Zn-Cu-Al-xMg (x=0,0.25,0.5) zinc alloy was prepared by metal mould casting. The effects of Mg addition on the structure, electrical conductivity and mechanical properties of Zn-Al-Cu alloy were studied. The results show that without Mg addition, the alloy consists of Zn solid solution(ƞ phase) containing of Cu and Al and layered α+η eutectic structure. With the addition of Mg, the η phase grains were refined, the layered eutectic structure disappeared, and the intermetallic compound Mg2Zn11 appeared, and its content increased with the increase of Mg content. The hardness of the alloy increases with the increase of Mg content. When the content of Mg is 0.5wt.%, the hardness reaches the maximum value of 151HV. Tensile strength and electrical conductivity first increase and then decrease. When the addition of Mg is 0.25wt.%, the maximum tensile strength and electrical conductivity are 270 MPa and 26.4% IACS, respectively. The wear mechanism of zinc alloy is a mixture of adhesive wear and abrasive wear, and the adhesive wear is dominant.

High temperature creep behavior and creep microstructure evolution of T6 state Mg–15Gd alloy

The creep properties of Mg alloys are critical for their high temperature applications. But for Mg–Gd alloys, there is a lack of systematic research on the creep behavior and microstructure evolution above 250 °C. In this study, the high temperature tensile creep behavior and microstructure evolution of the T6 state Mg-15Gd (wt.%) metal mold casting alloy were investigated at temperatures from 235 to 300 °C and stresses from 50 to 90 MPa. The experimental alloy was composed of α-Mg matrix, elliptic shape β′ precipitates, cuboid-shaped GdH2 phase and a small amount of M5Gd phase. It was found that the creep strain and creep rate of the experimental alloy increased but the creep life decreased with increasing the creep temperature and the applied stress. At a fixed creep temperature of 260 °C, the calculated stress exponent n value was about 2.8 in the applied stress range of 50–90 MPa, suggesting that the creep deformation may be controlled by dislocation slip. Meanwhile, under a defined creep stress of 50 MPa, the calculated activation energy Q value of the alloy was about 108 kJ mol−1 in the temperature range of 235–300 °C, indicating that the pipe diffusion may be a dominant affecting factor. During the creep process, the α(Mg) grain size coarsened and the quantity, size and type of the precipitated phases changed with three-stage: β′ (cbco) →β1 (fcc) →β (fcc). Observation of creep microstructure evolution under 50 MPa and 260 °C confirmed that the creep mechanism was dislocation glide and the creep fracture mechanism was brittle transgranular cleavage fracture.

Effect of Al Content on Microstructure and Properties of Zn-Cu-Al Alloy

Zn-Cu-Al zinc alloy was prepared by metal mould casting. The effects of Al addition on the microstructure, electrical conductivity and wear resistance of Zn-Cu-Al alloy were studied. The results show that the structure of Zn-Cu-Al alloy is composed of Zn solid solution containing Cu and Al (η phase), eutectic phase (α+η) and CuZn5 (ε phase); Al0.4Zn0.6 phase appeared when Al addition content exceeded 2.0wt.%; With the increase of Al addition content, eutectic phase (α+η) content increased and η phase grain refined. Meanwhile, the hardness and electrical conductivity of the alloy increase with the increase of Al addition content. When the addition of Al is 5.0 wt.%, the hardness and electrical conductivity of the alloy reach the maximum, 151HV and 26.4% IACS, respectively. The wear mechanism of the alloy is mainly plastic deformation with a mixture mode of plastic deformation and adhesion.

Alloy design and fabrication of ingots in Cu-Zn-Mn-Ni-Sn high-entropy and Cu-Zn-Mn-Ni medium-entropy brasses

Cu-Zn-Mn-Ni-Sn high-entropy (HE) and Cu-Zn-Mn-Ni medium-entropy (ME) brasses were designed and the ingots were fabricated by conventional casting process via metallic mold casting. The ingots of the equiatomic CuZnMnNi ME brass showed dendrite structures composed of body-centered-cubic (BCC) and face-centered-cubic (FCC) phases. A single FCC phase was obtained in the ingots of non-equiatomic CuxZnMnNi (x = 2, 3, and 4) ME brasses. The addition of Sn to CuxZnMnNi (x = 1, and 2) ME brasses significantly affected the solidification microstructure and the constituent phases. The ingots of the CuZnMnNiSn0.2 HE brass showed only sharp peaks corresponding to BCC phase in XRD patterns. The Sn addition to CuxZnMnNi (x = 1, and 2) ME brasses led to superior mechanical strength in the ingots.

Effects of trace Cr on as-cast microstructure and microstructural evolution of semi-solid isothermal heat treatment ZC61 magnesium alloy

The content and kind of trace elements in magnesium alloys have important effects on their ascast and semi-solid microstructures. In this research work, effects of trace Cr on as-cast and semi-solid microstructures of ZC61 magnesium alloy were investigated by metal mold casting and semi-solid isothermal heat treatment. The results show that the addition of Cr can refine the α-Mg phase without generating a new phase, noticeably change the eutectic phase, and decrease the average size of solid particles at the same isothermal heat treatment conditions. Non-dendritic microstructures of all alloys are constituted of α1-Mg phases, α2-Mg phases and eutectic phases after water quenching. With isothermal temperature increased or holding time prolonged, the eutectic microstructure (α-Mg+MgZn2+CuMgZn) at the grain boundaries in as-cast alloy is melted preferentially and then turned into semi-solid non-dendritic microstructure by processes of initial coarsening, microstructure separation, spheroidizing and final coarsening. Especially when the ZC61-0.1Cr alloy was treated at 585 °C for 30 min, the ideal non-dendritic microstructure can be obtained, and the corresponding solid particle size and shape factor were 37.5 μm and 1.33, respectively. The coarsening process of solid α-Mg phase at higher temperature or longer time, which is affected by both combining growth and Ostwald ripening mechanism, is refrained when Cr is added to the ZC61 alloy.

The inorganic bond preparation for the coldhardening mixtures

The sodium silicate solution (liquid glass) was prepared to be used as the inorganic bond for the cold-hardening refractory mixtures for the metal mould casting. The source of the silicon oxide was the rice production wastes namely the rice hulls. Several methods were regarded for the liquid glass synthesis and the characteristics of the obtained liquid glasses are presented.

Microstructure and Tribological Characteristics of Strain-Induced Melt Activation (SIMA)-Processed Al–10Cu–Fe alloy

In the present study, the influence of synthesis methods, namely the conventional metal mould casting (MMC) and strain-induced melt activation (SIMA) processes, on the microstructure and tribological characteristics of Al–10Cu–Fe alloy has been studied. The alloy was prepared by melting the commercial purity aluminium and copper. The effect of holding time in semi-solid region on the microstructure of the alloy subjected to SIMA was studied. Microstructural characterization was performed using optical and scanning electron microscopy, while chemical segregation is investigated using energy-dispersive spectroscopy. Hardness and strength of the resulting alloy are measured using macroindentation and tensile testing, respectively. Near-spherical grains were achieved in the SIMA process with an average grain diameter varying from 44 to 67 µm for holding times ranging from 30 to 55 min. The wear properties of stirred MMC alloy which was subjected to SIMA process are considerably better than those of either conventional MMCs or unstirred MMC subjected to SIMA process. The 50% pre-deformation followed by intercritical annealing at 580 °C and 30 min holding time is the optimum parameters to obtain the wear properties of Al–10Cu–Fe alloy. The improved wear and mechanical properties of the alloy are discussed in the light of the microstructural features of SIMA-processed alloy and the nature of the worn surfaces.

STRUKTUR MIKRO DAN SIFAT MEKANIS ALUMINIUM PADUAN SERI 6063 HASIL COR DARI CETAKAN LOGAM, PASIR RESIN FURAN DAN PASIR KOMOSSA

Abstract: Material developments in Indonesia is already very advanced rapidly certainly need high level of violence but has a mass of light. Aluminum should be developed because it possesses a lightweight and available in the land of our country that is rich in agricultural products. As an alternative to strengthen aluminum alloy that is with Si and Mg, as well as the rapid cooling process when smelting. This study was conducted to observe the microstructure and mechanical properties of the raw material of aluminum alloy series 6063. Tests conducted with metal mold, furan resin sand mold, commossa sand mold, the cooling rate of each mold will affect the hardness of the material which can be seen microstructure with microstructural observations. The survey results revealed that the aluminum with a metal mold casting has a hardness of 54 HRB, furan resin sand has a hardness of 40 HRB, sand commossa has a hardness of 33 HRB. Metal mold has a shock force of 0,316 J/mm2, particularly a furan resin sand shock force of 0,265 J/mm2, commossa sand has a shock force of 0.206 J/mm2. Metal mold has a high hardness compared with furan resin sand rated second, while the sand was rated commossa end but increasingly harsh mean tenacity of a material value will increase. According to the test micro structure, the aluminum is brittle, the distance or the distribution of grain will be a meeting or a lot.

Microstructure and mechanical properties of Mg–3.0Y–2.5Nd–1.0Gd–xZn–0.5Zr alloys produced by metallic and sand mold casting

Abstract

Age Hardening Behavior of Al-Li Alloys Produced by Sand Mold Process

Al-Li alloys have higher mechanical properties and more lightweight than other conventional aluminum alloys. Therefore , it is focused as a good material for weight reduction of industrial fields. However, since the Al-Li alloy are highly active and hard to cast, there has been limited research on casting. In this study, age-hardening behavior of Al-2.5mass%Li alloys cast into sand and metal mold were investigated. All alloys cast into Y-block shape sand mold, and then artificial aged after solution treated at 743K for 36ks. Because of difference in quantity of precipitation by metastable δ’(Al3Li) phase, peak hardness of metal mold casting is higher than that of sand molds castings.

Analysis of wear properties of aluminium based journal bearing alloys with and without lubrication.

Apart from classical bearing materials, Aluminium alloys are used as bearing materials these days because of their superior quality. In this analysis, new Aluminium based bearing materials, with filler metals Si, Ni, and Cr are prepared by metal mould casting in burnout furnace machine, and tribological properties of these alloys with and without lubrication were tested. The experiments for wear with lubrication are conducted on multiple specimen tester and experiments without lubrication is conducted on Pin on disk tribometer. The disc material used was SAE 1050 steel. Wear tests were conducted at a sliding speed of 0.785 m/s and at a normal load of 20 N. Coefficient of friction values, temperature changes and wear of the specimens were plotted on graph according to the above mentioned working conditions. Hardness and weight losses of the specimens were calculated. The obtained results demonstrate how the friction and wear properties of these samples have changed with the % addition of Silicon, Chromium and Nickel to the base metal aluminium.

Formation mechanism of spheroidal carbide in ultra-low carbon ductile cast iron

The formation mechanism of the spheroidal carbide in the ultra-low carbon ductile cast iron fabricated by the metal mold casting technique was systematically investigated. The results demonstrated that the spheroidal carbide belonged to eutectic carbide and crystallized in the isolated eutectic liquid phase area. The formation process of the spheroidal carbide was related to the contact and the intersection between the primary dendrite and the secondary dendrite of austenite. The oxides of magnesium, rare earths and other elements can act as heterogeneous nucleation sites for the spheroidal carbide. It was also found that the amount of the spheroidal carbide would increase with an increase in carbon content. The cooling rate has an important influence on the spheroidal carbide under the same chemical composition condition.