The Influence of Cooling Rate on Macrosegregation in Bi-Sn Alloy

Macrosegregation occurs in casting the most case is as a result of slow interdendritic flow due to shrinkage geometry, solid deformation or gravity. In some cases could be the result of solid movement in the early stages of solidification[1]. The problem is that the observation of macrosegregation in steel material is not easy because of high temperature condition. This recent work uses low melting temperature material alloy to simulate the actual condition as a model material. Various efforts to prevent macrosegregation are aimed to control liquid flow and movement of solid, one of them is by cooling rate controling. In this experiment the mold is cooled in three types of cooling medias to represent three different cooling conditions in order to observe the influence of cooling rate on macrosegregation during solidification of the alloy. The outer part close to the mold wall and the bottom of casting contains less solute than inner location. This occurs in all cooling conditions but cooling rate can cause the solute in casting distributed differently. At high cooling rate condition, distribution of Bi rich grain is more uniform. It is mean that macrosegregation is reduced. Bi-richer grains accumulate at the bottom of the ingot. It could be caused by those grains settle due to their relative density to surrounding liquid during solidification.

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Microstructure and Properties of a Non-Quenched Prehardened Steel at Different Cooling Rate

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.524-527.1976 ◽

2012 ◽

Vol 524-527 ◽

pp. 1976-1979

Author(s):

Yi Luo ◽

Jin Ming Peng

Keyword(s):

Mechanical Properties ◽

Fine Structure ◽

Optical Microscopy ◽

Cooling Rate ◽

Retained Austenite ◽

Transformation Products ◽

Electronic Microscopy ◽

Transmission Electronic Microscopy ◽

Microstructure And Properties ◽

Cooling Conditions

Mechanical properties of non-quenched prehardened (NQP) steel air cooled and sand cooled after forged were tested and their microstructure was investigated by optical microscopy and transmission electronic microscopy(TEM). The results show that mechanical properties of the NQP steel are similar at both cooling conditions, and their microstructure is bainite, whose fine structure is main bainite ferrite laths, retained austenite films, retained austenite islands and their transformation products. Bainite ferrite laths of the NQP steel air cooled are narrower than that sand cooled, while more retained austenite islands exist in latter.

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Correlation of Processing, Inner Structure, and Part Properties of Injection Moulded Thin-Wall Parts on Example of Polyamide 66

International Journal of Polymer Science ◽

10.1155/2014/718926 ◽

2014 ◽

Vol 2014 ◽

pp. 1-8 ◽

Cited By ~ 6

Author(s):

Dietmar Drummer ◽

Steve Meister

Keyword(s):

Cooling Rate ◽

Injection Moulding ◽

Degree Of Crystallinity ◽

Process Conditions ◽

Thin Wall ◽

Polyamide 66 ◽

Slow Cooling ◽

Cooling Conditions ◽

Internal Structures ◽

Wall Injection

In micro- and thin-wall injection moulding the process conditions affect the developed internal structures and thus the resulting part properties. This paper investigates exemplarily on polyamide 66 the interactions of different cooling conditions on the morphological and crystalline structures. The investigations reveal that a slow cooling rate of the melt results in a homogeneous morphology and a higher degree of crystallinity and also a favoured crystalline structure. Consequently, the dielectric behaviour and light transmitting part properties are affected.

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Ferritic Microstructures

10.31399/asm.tb.spsp2.t54410113 ◽

2015 ◽

pp. 113-131

Keyword(s):

Carbon Atom ◽

Cooling Rate ◽

Classification System ◽

Acicular Ferrite ◽

Carbon Steels ◽

Atom Diffusion ◽

Continuous Cooling ◽

Cooling Conditions ◽

Induced Changes

This chapter describes the ferritic microstructures that form in carbon steels under continuous cooling conditions. It begins with a review of the Dubé classification system for crystal morphologies. It then explains how cooling-rate-induced changes involving carbon atom diffusion and the associated rearrangement of iron atoms produce the wide variety of morphologies and microstructures observed in ferrite. The chapter also describes a classification system developed specifically for ferritic microstructures and uses it to compare common forms of ferrite, including polygonal or equiaxed ferrite, Widmanstatten ferrite, quasi-polygonal or massive ferrite, acicular ferrite, and granular ferrite.

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The Precipitation Behavior of γ' Phase in Superalloy FGH96 during Continuous Solution Cooling Conditions

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.652-654.1092 ◽

2013 ◽

Vol 652-654 ◽

pp. 1092-1095

Author(s):

H.S. Liu ◽

Lin Zhang ◽

Xin Bo He ◽

Xuan Hui Qu ◽

Zhou Li ◽

...

Keyword(s):

Cooling Rate ◽

Continuous Solution ◽

Water Cooling ◽

Precipitation Behavior ◽

Cooling Conditions ◽

Mean Diameter ◽

The Mean ◽

Shape Changes

The precipitation behavior of γ' phase after continuous solution cooling tests was examined in superalloy FGH96. The results indicate that, with the increase of cooling rate, the mean diameter of secondary γ' precipitates decreases as well as the shape changes from cuboid to spherical. Either under water cooling or cooling at 10 °C/min and 25 °C/min, the highest strength can not be obtained.

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Influence of Al and N Content and Cooling Rate on the Characteristics of Complex MnS Inclusions in AHSS

Crystals ◽

10.3390/cryst10111054 ◽

2020 ◽

Vol 10 (11) ◽

pp. 1054

Author(s):

Muhammad Nabeel ◽

Michelia Alba ◽

Neslihan Dogan

Keyword(s):

Cooling Rate ◽

High Strength Steels ◽

High Strength ◽

Slow Cooling ◽

N Content ◽

Al Content ◽

Advanced High Strength Steels ◽

Cooling Conditions ◽

Mns Precipitation ◽

Precipitation Ratio

This study focused on the characteristics of complex MnS inclusions in advanced high strength steels. The effect of metal chemistry (Al and N) and the cooling rate of steel were evaluated by analyzing the inclusions present in five laboratory produced steels. The observed complex MnS inclusions contained Al2O3-MnS, AlN-MnS, and AlON-MnS. An increase in Al content from 0.5% to 6% increased the number of complex MnS inclusions by ~4 times. In comparison, a decrease of ~80% was observed due to the increased N content of steel from <10 ppm to ~50 ppm. MnS precipitation ratio was used to determine the potency of different inclusions forming complex MnS inclusions due to heterogeneous nucleation. It was found that the MnS precipitation ratio of the observed inclusions was related to their misfit with MnS, and it decreased in the order of AlN > AlON > Al2O3. Moreover, it was determined that AlN particles could be easily engulfed at the solidification front relative to Al2O3, which resulted in a higher MnS precipitation ratio for Al2O3 under slow cooling conditions.

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Experimental Investigation on Determinant of Steel Specimen Transformation Temperature under Air Cooling Conditions

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.148-149.223 ◽

2010 ◽

Vol 148-149 ◽

pp. 223-226

Author(s):

Lian Sheng Chen ◽

Tao Wang ◽

Jin Ying Song ◽

Yi Liu ◽

Zhen Yu Liu ◽

...

Keyword(s):

Phase Transition ◽

Experimental Investigation ◽

Transition Temperature ◽

Cooling Rate ◽

Phase Transition Temperature ◽

Transformation Temperature ◽

Steel Specimen ◽

Air Cooling ◽

Cooling Conditions ◽

Metal Phase Transition

In order to get rid of thermal interferences, the experiment was conducted to test the temperature drops of 40Cr by embedding thermocouple in central part of the steel specimen under the air cooling conditions. The cooling rate of the center was obtained and the phase transition temperature at the start and end points were determined. By comparing with 40Cr CCT curves, obvious effects of the metal phase transition latent heat on cooling rate were shown. The results should be revised when CCT curves which obtained form constant-speed cooling rate conditions were used to determined phase transition start and end temperature in non-constant cooling rate conditions.

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The Effect of Cooling Rate During the Hydrothermal Growth on the Tip Geometry of ZnO Nanorods

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.602-604.144 ◽

2012 ◽

Vol 602-604 ◽

pp. 144-147

Author(s):

He Qiu Zhang ◽

Xiu Ming Ren ◽

Li Zhong Hu ◽

Jiu Yu Ji ◽

Yang Li ◽

...

Keyword(s):

Cooling Rate ◽

Hexagonal Phase ◽

Zno Nanorods ◽

Critical Factor ◽

Hydrothermal Growth ◽

Water Cooling ◽

X Ray Diffraction ◽

X Ray ◽

Cooling Conditions ◽

Structural Characterizations

The ZnO nanorods with sharp tip have been fabricated via water cooling treatment during the hydrothermal growth. The morphology and crystal structure of the zinc oxide nanostructure were examined by field-emission scanning electron microscopy and x-ray diffraction, respectively. The structural characterizations revealed that the as-synthesized nanorods were single crystalline, with a hexagonal phase. It has been demonstrated that the cooling rate is the critical factor of the synthesis of the sharp tip ZnO nanorods by comparing the different cooling conditions. The growth mechanism for the sharp tip ZnO nanorods has been proposed on the basis of the different crystallographic habits of wurtzite hexagonal ZnO crystals.

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Optimal Precipitation Hardening Conditions in Lead Base Anodes for Copper Electrowinning

Materials Science Forum ◽

10.4028/www.scientific.net/msf.638-642.1091 ◽

2010 ◽

Vol 638-642 ◽

pp. 1091-1097

Author(s):

Carlos Camurri ◽

Claudia Carrasco ◽

Antonio Pagliero ◽

Rafael Colás

Keyword(s):

Cooling Rate ◽

Yield Stress ◽

Hot Rolling ◽

Precipitation Hardening ◽

Working Life ◽

Cooling Conditions ◽

Roll Temperature ◽

Copper Electrowinning ◽

Stable Conditions ◽

Useful Life

The suitable yield stress of Pb-0.07%Ca-1.3%Sn anodes of 6 mm thickness for copper electrowinning is achieved by means of deformation and precipitation hardening processes, being its useful life dependant of this yield stress. In such sense the objective of the present work is to optimize the precipitation hardening, finding for this purpose the best cooling conditions of the anodes in the molds and of the hot rolling temperature. The results show that increasing cooling rate of ingots from natural cooling the precipitation hardening is enhanced, with increases of 10% and 12.5 % on the yield stress and working life of the anodes respectively, and that a minimum of 45 days of ageing is necessary to reach stable conditions for the precipitation hardening, with precipitates formation as CaSn3. The hot roll temperature as not significant effect on the precipitation hardening of the anodes.

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Influence of Copper Additions in Fe-10Ni (mass %) Alloys on Cooling Microstructures

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.172-174.505 ◽

2011 ◽

Vol 172-174 ◽

pp. 505-510

Author(s):

Coraline Crozet ◽

Annie Antoni Zdziobek ◽

Sabine Lay ◽

Stéphane Coindeau

Keyword(s):

Cooling Rate ◽

Metastable Phase ◽

High Temperature Phase ◽

Temperature Phase ◽

Slow Cooling ◽

Ni Alloys ◽

Copper Addition ◽

Cu Alloys ◽

Cooling Conditions ◽

Metastable Phase Formation

Austenite/ferrite phase transformations in Fe-xCu-10Ni alloys, 0<x<15 (mass%), are studied under two different cooling conditions, ice-brined quenching or slow cooling in the dilatometer. The influence of copper addition and cooling rate on the microstructure of the alloys is studied. Metallographic examinations of quenched samples show that metastable transformations occur during cooling. As for Fe-Ni alloys, it is impossible to stabilize the high temperature phase (γFeNi) in the Fe-Ni-Cu alloys. Dilatometry measurements of the γ → α transformation temperature with a cooling rate of 2°C/min also indicate a metastable phase formation despite the low cooling rate. For all alloys, a mixture of massive and lath ferrite is observed, one being predominant depending on the cooling conditions and composition. It is shown that the cooling rate has nearly no influence on the microstructure of alloys with a small amount of Cu unlike the alloys containing more Cu. In all alloys containing Cu, nanometric γCu precipitates, much finer in the quenched samples, are detected in the ferrite grains.

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