Effects of the Parameters of Sloping Plate Process on Microstructures of A2017 Alloy

2012 ◽  
Vol 503-504 ◽  
pp. 342-345
Author(s):  
Ren Guo Guan ◽  
Zhan Yong Zhao ◽  
Chao Lian ◽  
Run Ze Chao ◽  
Chun Ming Liu
Keyword(s):  
Grain Size ◽  
Nucleation Rate ◽  
Casting Temperature ◽  
Plate Length ◽  
Preheating Temperature ◽  
Semisolid Forming ◽  
Coarse Microstructure ◽  
Sloping Plate

In this paper, effects of the parameters of sloping plate process on microstructures of A2017 alloy were investigated, and semisolid ingot of A2017 alloy was prepared. The grain size of the ingot prepared by the wavelike sloping plate is much smaller than that prepared by the flat sloping plate. The primary grain becomes rounder and smaller with the increment of the sloping plate length. High preheating temperature of the plate reduces the nucleation rate of the melt and leads to coarse microstructure. When the casting temperature is 720°C, the sloping angle is 45°, and the wavelike plate length is between 400mm and 500mm, semisolid ingot of A2017 alloy with fine and homogeneous microstructures can be obtained. The reheated microstructure of semisolid ingot is mainly composed of spherical solid grains and the melted liquids and is suitable for semisolid forming.

Grain Refinement of LC9 Alloy by Low-Power Ultrasonic Vibration Melt Treatment

2012 ◽  
Vol 538-541 ◽  
pp. 1267-1271
Author(s):  
Le Ping Chen ◽  
Yan Yan Han ◽  
Quan Zhou
Keyword(s):  
Grain Size ◽  
Low Power ◽  
Grain Refinement ◽  
Ultrasonic Vibration ◽  
Turning Point ◽  
Treatment Temperature ◽  
Melt Treatment ◽  
Preheating Temperature ◽  
Power Ultrasonic ◽  
Treatment Changes

The influences of different preheating temperature of mold and treatment temperature on solidified structure of LC9 alloy were studied by low-power ultrasonic vibration melt-treatment. The results show that grain of LC9 alloy can be refined greatly by low-power ultrasonic vibration melt-treatment. The dendrite growth is restrained and the microstructure is changed from larger dendrite grains to dominant fine none-dendritic and globular grains. With the decrease of preheating temperature of mold, grain size decreases. The efficiency of grain refinement is better at low preheating temperature. With the increase of ultrasonic vibration temperature, grain size decreases firstly, then increases, and the turning point is 660 °C. At 640 °C, grain size of the alloy with US vibration treatment changes slightly compared with non US-treated alloy.

scholarly journals The Effect of Shell Thickness, Insulation and Casting Temperature on Defects Formation During Investment Casting of Ni-base Turbine Blades

2015 ◽  
Vol 15 (4) ◽  
pp. 115-123 ◽  
Author(s):  
M. Raza ◽  
M. Irwin ◽  
B. Fagerström
Keyword(s):  
Grain Size ◽  
Investment Casting ◽  
Shell Thickness ◽  
Turbine Blades ◽  
Shrinkage Porosity ◽  
Grain Structure ◽  
Casting Temperature ◽  
Free Form ◽  
Thin Sections ◽  
Tip Shroud

Abstract Turbine blades have complex geometries with free form surface. Blades have different thickness at the trailing and leading edges as well as sharp bends at the chord-tip shroud junction and sharp fins at the tip shroud. In investment casting of blades, shrinkage at the tip-shroud and cord junction is a common casting problem. Because of high temperature applications, grain structure is also critical in these castings in order to avoid creep. The aim of this work is to evaluate the effect of different process parameters, such as, shell thickness, insulation and casting temperature on shrinkage porosity and grain size. The test geometry used in this study was a thin-walled air-foil structure which is representative of a typical hot-gas-path rotating turbine component. It was observed that, in thin sections, increased shell thickness helps to increase the feeding distance and thus avoid interdendritic shrinkage. It was also observed that grain size is not significantly affected by shell thickness in thin sections. Slower cooling rate due to the added insulation and steeper thermal gradient at metal mold interface induced by the thicker shell not only helps to avoid shrinkage porosity but also increases fill-ability in thinner sections.

Preparing Semisolid Light Alloys by Vibrating Wavelike Sloping Plate Process and Thixoforming

2007 ◽  
Vol 561-565 ◽  
pp. 865-868 ◽  
Author(s):  
Ren Guo Guan ◽  
Zhen Huan Xing ◽  
Lu Shi ◽  
Chao Wang ◽  
Yi Wang
Keyword(s):  
Continuous Casting ◽  
Holding Time ◽  
Casting Temperature ◽  
Az91d Alloy ◽  
Plate Surface ◽  
Experimental Conditions ◽  
Light Alloys ◽  
Forging Process ◽  
Temperature Ranges ◽  
Sloping Plate

By using self-made vibrating wavelike sloping plate setup, semisolid billets with fine spherical or rosette grains have be prepared by semi-continuous casting, and the solidified shell on the sloping plate surface can be effectively avoided. Burst nucleation in the whole melt and dendrite fracture causes the formation of fine spherical microstructures. Under the current experimental conditions, proper casting temperature ranges of 660°C~680°C and the amplitude value of under 2mm proper are suggested. When the reheating temperature is 575°C and the holding time is 60min for AZ91D alloy, 597°C and 90min for Al-6Si-2Mg (wt-%) alloy, semisolid forging process can be successfully implemented. Thixo-forming products of two alloys are fine with smooth appearance, good microstructures and properties.

Numerical Simulation and Optimization in Solidification of Zinc Alloy

2011 ◽  
Vol 287-290 ◽  
pp. 2902-2905 ◽  
Author(s):  
Ying Zhang ◽  
Guo Rui Jia ◽  
Xian Jiao Xie ◽  
Shui Sheng Xie ◽  
Jin Yu He ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Aluminum Alloy ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Shrinkage Porosity ◽  
Casting Temperature ◽  
Zinc Alloy ◽  
Simulation And Optimization ◽  
Preheating Temperature ◽  
The Heat Transfer Coefficient

Numerical method was used to simulate the solidification process of zinc-aluminum alloy Zamak 5, shrinkage porosity of the zinc-aluminum alloy ingot with big diameter (114mm) was simulated using the shrinkage criterion, orthogonal test was designed to analysis the influence of different casting parameters as casting temperature, preheating temperature of the mold and the heat transfer coefficient between the mold and the environment. The result shows that the shrinkage value was minimal when the casting temperature was 480, the preheating temperature was 200 and the heat transfer coefficient was 200.

The Effect of Preheating Temperature on the Microstructure and Properties of Copper by the Liquid Die Forging Technology

2011 ◽  
Vol 418-420 ◽  
pp. 1213-1217
Author(s):  
Gui Rong Yang ◽  
Wen Ming Song ◽  
Ying Ma ◽  
Yuan Hao
Keyword(s):  
Electrical Conductivity ◽  
Grain Size ◽  
Tensile Strength ◽  
Metal Mold ◽  
Obvious Effect ◽  
Microstructure And Properties ◽  
Copper Specimen ◽  
Die Forging ◽  
Preheating Temperature ◽  
Microstructure Density

The copper specimen was fabricated through liquid die forging under different preheating temperature of mold condition. The effect of preheating temperature of mold on the microstructure, density, hardness, tensile strength and electrical conductivity were investigated. The results show that the crystal grain size was deceased firstly and then increased with the increasing of preheating temperature. Crystal grain was uniform and fine when the preheating temperature was 250 °C. The density of copper fabricated through liquid die forging was improved by about 5% comparing with that through static casting in metal mold. The hardness of copper fabricated through liquid die forging was HBS 85.2 when the preheating temperature was 250°C, which was higher than that at the rest preheating temperature conditions. The tensile strength was 288 MPa when the preheating temperature was 250°C. There was no obvious effect on the electrical conductivity under different preheating temperature.

scholarly journals The effect of particles on dynamic recrystallization and fabric development of granular ice during creep

2005 ◽  
Vol 51 (174) ◽  
pp. 377-382 ◽  
Author(s):  
Min Song ◽  
Ian Baker ◽  
David M. Cole
Keyword(s):  
Grain Size ◽  
Dynamic Recrystallization ◽  
Mechanical Behavior ◽  
Grain Boundaries ◽  
Microstructural Evolution ◽  
Nucleation Rate ◽  
Random Orientation ◽  
Water Ice ◽  
Average Grain Size ◽  
Prepared Particle

AbstractThe mechanical behavior and microstructural evolution of laboratory-prepared, particle-free fresh-water ice and ice with 1 wt.% (~0.43 vol.%) silt-sized particles were investigated under creep with a stress level of 1.45 MPa at −10°C. The particles were present both within the grains and along the grain boundaries. The creep rates of specimens with particles were always higher than those of particle-free ice. Dynamic recrystallization occurred for both sets of specimens, with new grains nucleating along grain boundaries in the early stages of creep. The ice with particles showed a higher nucleation rate. This resulted in a smaller average grain-size for the ice with particles after a given creep strain. Fabric studies indicated that ice with particles showed a more random orientation of c axes after creep to ~10% strain than the particle-free ice.

A Compound Process Preparing Semi-Solid A356 Alloy Slurry

2010 ◽  
Vol 97-101 ◽  
pp. 1003-1007 ◽  
Author(s):  
Zheng Liu ◽  
Wei Min Mao
Keyword(s):  
Grain Size ◽  
Nucleation Rate ◽  
A356 Alloy ◽  
Electromagnetic Stirring ◽  
Structure Morphology ◽  
Compound Process ◽  
Semi Solid ◽  
Low Superheat

The semi-solid A356 alloy slurry is prepared by compound process, and the effect of the compound process on morphology and size of primary α-Al in A356 alloy is researched. The results indicate that the compound process remarkably affects the morphology and the size of primary α-Al. Primary α-Al with particle-like is distributed uniformly in A356 alloy, and there is no the transient area of change in structure morphology. Compared with the samples prepared by low superheat pouring and slightly electromagnetic stirring, the nucleation rate, morphology and grain size of primary α-Al in A356 alloy are markedly improved by the compound process. The mechanism of refining grain in the compound process is probed.

Effect of Liquid-Die-Forging Pressure on Microstructure and Mechanical Properties of A390 Sloping Swash-Plate

2012 ◽  
Vol 538-541 ◽  
pp. 1356-1359
Author(s):  
Guang An Zhang ◽  
Feng Jiang ◽  
Qi Zhou ◽  
Fu Fa Wu
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Eutectic Silicon ◽  
Applied Pressure ◽  
Primary Silicon ◽  
Specific Pressure ◽  
Die Forging ◽  
Microstructure And Mechanical Properties ◽  
Swash Plate ◽  
Preheating Temperature

The effect of liquid-die-forging pressure on the microstructure and mechanical properties of A390 sloping swash-plate forming was investigated. It was found that the microstructure and comprehensive mechanical properties of the alloy were effectively improved by the liquid-die-forging pressure applied on the A390 aluminum melt. With continuous increasing of the specific pressure, the grain size of primary silicon gradually decreased, the fraction of eutectic silicon obviously decreased, and its morphology was granular mainly. When the applied pressure was 181 MPa, the size of primary silicon was reduced to about 20 μm. When the casting temperature of the alloy was 820 °C, the mould preheating temperature was 240 °C and the forging casting specific pressure reached 181 MPa, the sloping swash plate without macro-defects, and with the internal compact-gain structure and excellent mechanical properties can be obtained.

Numerical Simulation and Process Optimization of Investment Casting of the Blades for High Nb Containing TiAl Alloy

2013 ◽  
Vol 747-748 ◽  
pp. 105-110 ◽  
Author(s):  
Liang Yang ◽  
Li Hua Chai ◽  
Lai Qi Zhang ◽  
Jun Pin Lin
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Investment Casting ◽  
Casting Temperature ◽  
Interface Heat Transfer Coefficient ◽  
Preheating Temperature ◽  
Interface Heat Transfer ◽  
Porosity Defects ◽  
Interface Heat

Low pressure turbine blades (LPT) made by investment casting from intermetallic titanium aluminide alloys for aero-engine applications have about 50% weight saving compared with that from nickel-based counterparts. Investment casting process of the low pressure turbine blades for high Nb containing TiAl alloy was simulated by Procast. The height of the blade is about 125mm and the thinnest part of it is about 6mm. Compositions of the cast and mould are Ti-45.5Al-8Nb (at %) and Zircon sand, respectively. The simulation result showed that there were porosities appearing in the centre of blades, which may be due to the formation of isolated liquid. In this work, the simulation, analysis and comparison of different casting ways were carried out. The result showed that compared with top and bottom casting, blades made by side casting have less porosity defects. And then the casting temperature, casting velocity, mould preheating temperature and interface heat transfer coefficient were optimized based on orthogonal design. The result also indicated that the influence of process parameters to porosity defects of blades can be ranked from strong to weak as follow: casting temperature>shell mould preheating temperature>casting velocity>interface heat transfer coefficient. When the casting temperature was 1700, the mould preheating temperature was 500, the casting velocity was 0.5 m·s-1, and the interface heat transfer coefficient was 500 W·m-2·K-1, the volume of porosity defects was the smallest.

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