Effects of Mold Temperature and Pouring Temperature on the Hot Tearing of Cast Al-Cu Alloys

Hot tearing is one of metal casting defects and often found in the casting products such as cracks on the surface. Solidifaction metal causes a thermal contraction and shrinkage, when the contraction and shrinkage occurs if a metal alloy is restrained by mold design, it will effect hot tearing. Hot tearing is influenced by several factors, including the chemical composition of the alloy, the casting temperature, mold temperature, mold constraint, fast or slow solidifaction, non uniform solidifaction, and so on. This study aimed to obtain a certain temperature that cause the maximum of hot tearing defects, so it can be recommended to the metal casting industry in aluminum-silicon material to avoid the casting temperature. Three variations of the casting temperature used in this study including 710 oC, 760 oC and 810 oC. The material used in this study is an alloy of Al-1.19% Si (percent by weight). The method used is a visual method using mold CRCM (Constrain Casting Rod Modified) Horizontal used for the index analysis of HTS (Hot tearing Susceptibility). The results gotten include the hot tearing increases with the increasing of casting temperature, and it decreases with the decreasing the casting pouring. The maximum of hot tearing index is 45 HTS at 760 oC for casting temperature. Tear formed on products from smooth categories (hairline cracks) to the complete categories (broken specimen).

Download Full-text

Mechanical Properties Simulation of Squeeze Cast Magnesium Alloy

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.306-307.1464 ◽

2011 ◽

Vol 306-307 ◽

pp. 1464-1467

Author(s):

Zhi Hong Guo ◽

Hua Hou ◽

Shu Wei Qu

Keyword(s):

Mechanical Properties ◽

Squeeze Casting ◽

Tensile Elongation ◽

Mold Temperature ◽

Processing Parameters ◽

Mould Temperature ◽

Pouring Temperature ◽

Squeeze Pressure ◽

Squeeze Cast ◽

Cast Magnesium

A research program was simulated to study the effects of pouring temperature, squeeze pressure and die temperature on the tensile, elongation and hardness properties of AZ91D magnesium alloys using anycasting software. The curves with different processing parameters on mechanical properties have been painted. The results indicated that mechanical properties increased firstly, then decreased when the pouring temperature increased to 670°C, and gradually increased with the increasing of squeeze pressure. The affect laws of mould temperature are similar as ones of pouring temperature. Eventually found that the squeeze casting got better mechanical properties(σb= 225MPa, δ= 3.6%, Vickers hardness=62) on the pouring temperature 670°C, mold temperature 180°C, holding pressure 120Mpa, pressure duration 25s.

Download Full-text

Numerical Simulation of Casting Deformation and Stress of A356 Aluminum Alloy Thin-Walled Frame Casting

Materials Science Forum ◽

10.4028/www.scientific.net/msf.1033.24 ◽

2021 ◽

Vol 1033 ◽

pp. 24-30

Author(s):

Yi Dan Zeng ◽

Li Tong He ◽

Jin Zhang

Keyword(s):

Aluminum Alloy ◽

Casting Process ◽

Mold Temperature ◽

Hot Cracking ◽

Thin Wall ◽

A356 Aluminum Alloy ◽

Pouring Temperature ◽

Thin Walled ◽

Alloy Castings ◽

A356 Aluminum

One of the main reasons for the scrap of cast thin-wall frame aluminum alloy castings is deformation and cracking. It is an effective method for solving the problem by predicting the distribution of casting stress, clarifying the size of the deformation and the location of the crack, and taking necessary measures in the process. This paper uses the ProCAST software to simulate the thermal stress coupling of A356 thin-walled frame castings, analyzes the influence of pouring temperature, pouring speed and mold temperature on the stress field distribution of castings, predicts the hot cracking trend and deformation, and optimizes Casting process..

Download Full-text

Slurry Preparation and Hot Tearing Susceptibility of A201 Aluminum Alloy in Rheological Die Casting

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.285.311 ◽

2019 ◽

Vol 285 ◽

pp. 311-317 ◽

Cited By ~ 1

Author(s):

Jun Zhen Gao ◽

Qiang Zhu ◽

Da Quan Li ◽

Xiao Gang Hu ◽

Min Luo ◽

...

Keyword(s):

Aluminum Alloy ◽

Die Casting ◽

Mold Temperature ◽

Hot Tearing ◽

Cast Aluminum Alloy ◽

Cast Aluminum ◽

Intensification Pressure ◽

Semi Solid ◽

Index Value ◽

Hot Tearing Susceptibility

A201 alloy is the strongest cast aluminum alloy, but it is considered one of the most difficult aluminum alloys to cast due to its susceptibility to hot tearing during solidification. Semi-solid casting, which characterizes fine near-globular or non-dendritic grains and relatively narrow solidification range, is potential to reduce hot cracking tendency of alloys. In this present work, semi-solid slurries of A201 alloy were prepared using Swirled Enthalpy Equilibrium Device (SEED) technique and then injected into a self-designed high pressure hot tearing mold. The microstructures of A201 semi-solid slurries with different pouring temperatures were examined. Effects of different casting pressures on the hot tearing sensitivity of A201 have been investigated. This study finds that SEED is capable of producing satisfying A201 semi-solid slurries. Lower pouring temperatures produce A201 semi-solid slurries with finer and rounder grains as well as more uniform microstructure distribution. Increasing the intensification pressure significantly decreases the hot treating tendency of A201 alloy. When the pressure reaches to 90 MPa and the mold temperature of about 250 °C, the hot tearing susceptibility (HTS) index value is nearly zero, which means almost no surface cracks are found in the semi-solid A201 die casting parts.

Download Full-text

Tensile properties and hot tearing susceptibility of cast Al-Cu alloys containing excess Fe and Si

International Journal of Minerals Metallurgy and Materials ◽

10.1007/s12613-020-2039-7 ◽

2020 ◽

Author(s):

Khalil Ganjehfard ◽

Reza Taghiabadi ◽

Mohammad Talafi Noghani ◽

Mohammad Hossein Ghoncheh

Keyword(s):

Tensile Properties ◽

Hot Tearing ◽

Cu Alloys ◽

Excess Fe ◽

Hot Tearing Susceptibility

Download Full-text

Numerical Simulation of Filling for 7075 Alloy and TiB2/7075 Composites Wheel Prepared by Low Pressure Die Casting

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.904.173 ◽

2014 ◽

Vol 904 ◽

pp. 173-179

Author(s):

Qian Gao ◽

Bin Yang ◽

Gui Sheng Gan ◽

Huan Chun Wu

Keyword(s):

Numerical Simulation ◽

Die Casting ◽

Mold Temperature ◽

Low Pressure ◽

Shrinkage Porosity ◽

Physical Parameters ◽

Pouring Temperature ◽

Low Pressure Die Casting ◽

7075 Alloy ◽

Pressure Die Casting

Based on the experimental and calculation results between the reinforcing particles content and thermal physical parameters, low pressure die casting of wheels was taken as an example to study the casting property of the 7075 alloy and TiB2/7075 composites. The influences of die temperature, pouring pressure, pouring temperature and TiB2 content on the filling of 7075 alloy and TiB2/7075 composites wheels are studied by numerical simulation. Shrinkage porosity appears both in the spoke and rim of the wheel. The shrinkage porosity of the 7075 alloy decreases from 2.089% to 1.622% with mold temperature increasing from 100°C to 400°C. The shrinkage porosity of wheel decreases from 1.630% to 1.598% and 1.583% in the composite with 3 and 6wt.% TiB2 particles. Besides, shrinkage porosities decrease with increasing pouring temperature.

Download Full-text

Effects of Compound Treatment of Pulsed Magnetic Field and Mechanical Vibration on Solidified Structure of Mg97Y2Cu1 Alloy

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1061-1062.17 ◽

2014 ◽

Vol 1061-1062 ◽

pp. 17-22

Author(s):

Hao Zhang ◽

Quan Zhou ◽

Sen Zhang

Keyword(s):

Magnetic Field ◽

Grain Size ◽

Volume Fraction ◽

Mechanical Vibration ◽

Mold Temperature ◽

Pulse Frequency ◽

Pulse Voltage ◽

Pulsed Magnetic Field ◽

Second Phase ◽

Pouring Temperature

The influences of different pulse voltage, pulse frequency, pouring temperature and mold temperature on solidified structure of Mg97Y2Cu1alloy reinforced by long-period ordered structure with compound treatment of pulsed magnetic field and mechanical vibration were studied. The results show that grains of the alloy can be refined greatly with compound treatment. Primary phase degrades from developed dendrites into rosette-shaped crystal. Distribution of second phase is more uniform and continuous, and its volume fraction increases. When the pulse voltage is at 0-280V or the pulse frequency is at 1-10Hz, grain size of the alloy decreases dramatically as pulse voltage or pulse frequency increases. When the pouring temperature is at 660-750°C or the mold temperature is at 20-600oC, grain size of the alloy with compound treatment decreases grossly with the increase of the pouring temperature or the mold temperature.

Download Full-text

Thermal Contraction during Solidification of Aluminium Alloys

Materials Science Forum ◽

10.4028/www.scientific.net/msf.519-521.1681 ◽

2006 ◽

Vol 519-521 ◽

pp. 1681-1686 ◽

Cited By ~ 6

Author(s):

Dmitry G. Eskin ◽

Laurens Katgerman

Keyword(s):

Aluminium Alloys ◽

Hot Tearing ◽

Thermal Contraction ◽

Solidification Shrinkage ◽

Solidification Range ◽

Cu Alloys ◽

Solid Density ◽

Two Stages ◽

Liquid And Solid Phases ◽

Hot Tearing Susceptibility

Aluminium alloys during solidification change their density. This process can be conditionally divided into two stages: solidification shrinkage due to the density difference between liquid and solid phases and thermal contraction due to the temperature dependence of the solid density. Solidification shrinkage is the main cause of porosity in castings and also plays an essential role in the development of macrosegregation, whereas thermal contraction is important for the development of hot and cold cracks and is responsible for shape distortions during casting. An experimental technique has been developed and applied to binary Al–Cu alloys in order to quantify the thermal contraction in the solidification range and at subsolidus temperatures. It is shown that thermal contraction of aluminium alloys starts at rather high fractions of solid, between 80 and 95%. The experimentally determined temperature of contraction onset agrees well with the temperature at which the mushy material acquires the ability to transfer stresses. The magnitude of contraction accumulated in the solidification range corresponds well to hot tearing susceptibility of the alloy. Factors that decrease the temperature of contraction onset and the magnitude of contraction, e.g. grain refinement, are also known to decrease hot tearing. The data on the temperature at which the thermal contraction starts, on the magnitude of the contraction, and on the thermal contraction coefficient are used to model hot tearing and shape distortions during casting.

Download Full-text