scholarly journals Investigation of the Quench Sensitivity of an AlSi10Mg Alloy in Permanent Mold and High-Pressure Vacuum Die Castings

Materials ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 1876 ◽  
Author(s):  
Mengyun Liu ◽  
Zhan Zhang ◽  
Francis Breton ◽  
X.-Grant Chen
Keyword(s):  
High Pressure ◽  
Cooling Rate ◽  
Aluminum Matrix ◽  
Critical Time ◽  
Permanent Mold ◽  
Temperature Property ◽  
Critical Cooling Rate ◽  
Quench Sensitivity ◽  
Die Castings ◽  
Nose Temperature

The quench sensitivities of an AlSi10Mg alloy in permanent mold (PM) and high-pressure vacuum die (HPVD) castings were investigated with time–temperature–transformation and time–temperature–property diagrams using an interrupted quench technique. The quench-sensitive temperature range of the HPVD casting sample is 275–450 °C, and its nose temperature is 375 °C. The quench-sensitive range of the PM casting sample is 255–430 °C, and the nose temperature is 350 °C. The mechanical strength versus the cooling rate in both casting samples were predicted via a quench factor analysis and verified experimentally. The critical cooling rate of the HPVD casting sample is 20 °C/s whereas it is 17 °C/s for the PM casting sample. With a shorter critical time, higher nose temperature, and higher critical cooling rate, the HPVD casting sample exhibits a higher quench sensitivity than the PM casting sample. The differences in the quench sensitivities of the AlSi10Mg alloy due to the different casting processes is explained via the different precipitation behavior. At the nose temperature, coarse β-Mg2Si precipitates mainly precipitate along the grain boundaries in the HPVD casting sample, whereas rod-like β-Mg2Si precipitates distribute in the aluminum matrix in the PM casting.

scholarly journals Quench Sensitivity and Phase Transformation Kinetics of AlSi7MnMg High Pressure Vacuum Die Casting

2020 ◽  
Vol 326 ◽  
pp. 02001
Author(s):  
Mengyun Liu ◽  
Zhan Zhang ◽  
Francis Breton ◽  
X.-Grant Chen
Keyword(s):  
High Pressure ◽  
Phase Transformation ◽  
Mechanical Strength ◽  
Isothermal Treatment ◽  
Transformation Rate ◽  
Temperature Property ◽  
Quench Sensitivity ◽  
Transformation Diagrams ◽  
Nose Temperature ◽  
Kinetics Of

The quench sensitivity of an AlSi7MnMg alloy in high-pressure vacuum die (HPVD) casting was investigated by time-temperature-transformation and time-temperature-property diagrams with an interrupted quench technique. The quench sensitive temperature range of the alloy is from 260 to 430 °C and its nose temperature is 350 °C. The mechanical strength versus cooling rates of the HPVD casting was predicted using quench factor analysis method and verified by experimental results. The critical cooling rate is 6 °C/s to remain 95% of the maximal mechanical strength. The coefficients k2 - k5, related to the nucleation and precipitation kinetics of TTP curves, and phase transformation diagrams were determined. The precipitation of Mg2Si phase in the castings was observed during isothermal treatment using transmission electron microscope. Moreover, the quench sensitivity and kinetics of the phase transformation of AlSi7MnMg alloy and AlSi10MnMg alloys were compared. It reveals that the quench sensitivity and phase transformation rate of the former are lower than that of the latter.

Investigation of Quench Sensitivity of an Al-7.5Zn-1.7Mg-1.4Cu-0.12Zr Alloy

2012 ◽  
Vol 706-709 ◽  
pp. 431-435 ◽  
Author(s):  
Bai Qing Xiong ◽  
Xi Wu Li ◽  
Yon Gan Zhang ◽  
Zhi Hui Li ◽  
Bao Hong Zhu ◽  
...  
Keyword(s):  
Incubation Period ◽  
Critical Time ◽  
Tem Analysis ◽  
Quench Sensitivity ◽  
Time Property ◽  
Nose Temperature ◽  
Temperature Time

In the present work, quench sensitivity of an Al-7.5Zn-1.7Mg-1.4Cu-0.12Zr alloy is investigated by temperature-time-property (TTP) curve and TEM analysis, comparing with traditional AA 7B04 and AA 7150. The results indicate that the nose temperature of TTP curve and the corresponding incubation period of the alloy, AA 7150 and AA 7B04 are about 290°C/4.5s, 320°C/2.6s and 335°C/0.1s, respectively, The nose temperature of the alloy is the lowest among three alloys and the critical time at the nose temperature is the longest for the alloy, which is obvious that the alloy has lower quench sensitivity. Further TEM analysis shows that, with the prolongation of keeping time at the nose temperature, quench-induced precipitation phenomenon becomes obvious.

Effects of RE on Critical Cooling Rate of Bearing-B Steel

2012 ◽  
Vol 535-537 ◽  
pp. 761-763 ◽  
Author(s):  
Yi Sheng Zhao ◽  
Xin Ming Zhang ◽  
Zhi Guo Gao
Keyword(s):  
Phase Change ◽  
Cooling Rate ◽  
Experimental Results ◽  
Cooling Rates ◽  
Critical Cooling Rate ◽  
The Law

The law of phase change of bearing-B steel during continual cooling was studied by adopting dilatometer. The CCT curves of bearing-B steel were drawn, and the effects of RE on critical cooling rates were studied. The experimental results show that the start temperatures of martensite TM was decreased from 438 to 404°C. The critical cooling rate was simultaneously decreased from 33 to 15°C/s.

Effects of Rare Earths on Structural Transformation of Heavy Rail Steel

2011 ◽  
Vol 194-196 ◽  
pp. 237-242
Author(s):  
Cheng Jun Liu ◽  
Ya He Huang ◽  
Mao Fa Jiang
Keyword(s):  
Cooling Rate ◽  
Incubation Period ◽  
Rare Earths ◽  
Rail Steel ◽  
Vacuum Induction Furnace ◽  
Critical Cooling Rate ◽  
The Stability ◽  
Heavy Rail ◽  
Electronic Microscope ◽  
Heavy Rail Steel

Clean heavy rail steel was prepared by the process of vacuum induction furnace smelting, forge work and rolling. Effects of Rare earths (RE) on phase transformation and microstructure of heavy rail steel were investigated by thermal simulation machine, metallographic microscope and scanning electronic microscope. Thermal simulate tests indicate that, RE can move the C curve of pearlite transformation to lower right, prolong the incubation period of pearlite and improve the stability of undercooled austenite. The minimum incubation period of pearlite transformation is increased from 24s to 30s by RE. Furthermore, RE can decrease the critical cooling rate of pearlite transformation from 1°C•s-1to 0.5°C•s-1and the critical cooling rate of quenching from 15°C•s-1to 13°C•s-1. Additionally, RE can fine the annealing and anormalizing pearlite notably. The pearlite laminae distance of heavy rail steel added RE is decreased by 12.9% (annealing) and 13.3% (normalizing), respectively.

Microstructure and Hardness of Gray Cast Iron as a Product of Solidification in Permanent Mold

2020 ◽  
Vol 991 ◽  
pp. 37-43
Author(s):  
Agus Yulianto ◽  
Rudy Soenoko ◽  
Wahyono Suprapto ◽  
As’ad Sonief ◽  
Agung Setyo Darmawan ◽  
...  
Keyword(s):  
Cast Iron ◽  
Cooling Rate ◽  
Induction Furnace ◽  
Gray Cast Iron ◽  
Casting Process ◽  
Melting Process ◽  
Gray Cast ◽  
Outer Side ◽  
Permanent Mold ◽  
Test Results

Molds of metal are widely used in the casting process. The cooling rate in solidification of castings product with metal molds on the outer side and inner side is different. Therefore, sizes and types of phase will be also different. This study aims to investigate the microstructure andhardness of gray cast iron. To realize this research, the gray cast iron melting process was carried out in an induction furnace. Melted gray cast iron was poured into a Ferro Casting Ductile mold that has been through a preheating process at a temperature of 300 o C. The gray cast iron is then tested for composition, microstructure and hardness. The test results show that the part containing morecementite phase will be harder.

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