scholarly journals RESEARCH OF THE INFLUENCE OF SLOW-DOWN COOLING SPEED IN THE INTERVAL OF EUTEKTIC TRANSFORMATION ON THE STRUCTURE AND MECHANICAL PROPERTIES OF CAST IRON CASTINGS

2020 ◽  
pp. 51-55
Author(s):  
N. I. Gabelchenko ◽  
N. A. Kidalov ◽  
A. A. Belov ◽  
M. D. Bezmogorychnyy ◽  
A. I. Gabelchenko
Keyword(s):  
Mechanical Properties ◽  
Cast Iron ◽  
Cooling Rate ◽  
Quality Index ◽  
Fuel Oil ◽  
Controlled Cooling ◽  
Slowing Down ◽  
Eutectic Transformation ◽  
Iron Castings ◽  
Cooling Speed

The work is devoted to the study of the effect of slowing down the cooling rate in the interval of eutectic transformation on the structure and mechanical properties of castings from gray doeutectic iron. To slow down the cooling rate in the interval of eutectic transformation, an exothermic carbon-containing additive, fuel oil M-100, was used. It is shown that the use of controlled cooling can significantly increase the quality index of cast iron without introducing additional alloying elements into the composition of cast iron.

scholarly journals Improvement of mechanical properties of iron castings via adjusting of solidification rate

2020 ◽  
pp. 17-20
Author(s):  
N. I. Gabelchenko ◽  
A. A. Belov ◽  
N. A. Kidalov ◽  
A. I. Gabelchenko
Keyword(s):  
Mechanical Properties ◽  
Cooling Rate ◽  
Solidification Rate ◽  
Crystallization Rate ◽  
Heat Extraction ◽  
Eutectic Transformation ◽  
Primary Austenite ◽  
Iron Castings ◽  
Alloying Additives ◽  
Air Blowing

The work is devoted to improvement of mechanical properties of iron castings via adjusting of the cooling rate without introduction of alloying additives. The new technological solution is suggested; it can be easily adapted to a casting technology. This solution is based on variation of the cooling rate of iron castings within structurally sensitive solidification intervals. For this purpose, the casting mould was initially cooled after pouring, then heated and cooled again. Cooling of the mould during the period of primary austenite crystal forming led to increase of dendrite crystallization rate and was executed using compressed air. Retarding of the cooling rate during the period of eutectic transformation was provided by the mould heating via burning of exothermic carbon-containing additives introduced in a facing layer of sand-clay moulding mix. Burning reaction is accompanied by heat extraction, what steeply retarded the cooling rate within the interval of eutectic transformation. Consequent acceleration of castings cooling within the interval of eutectoid transformation was achieved via repeated air blowing through a worked reaction layer. Adjusted cooling of iron castings allowed to provide the most favourable solidification conditions, taking into account strictly individual requirements for each structurally sensitive temperature intervals. It led to increase of a volumetric part of primary austenite dendrite crystals, to decrease of eutectic transformation overcooling degree, to forming of graphite eutectics and enlargement of dispersity of pearlite component in iron. Consequently, lowering of widespread iron castings rejects takes place, among them chilling, with simultaneous improvement of metal mechanical properties. As a result, the primary and real structures were varied, what had a positive effect on mechanical properties of casting metal. It is shown that use of solidification rate adjustment led to essential increase of metal tensile strength for the experimental casting.

scholarly journals Cast Iron Cooling Rate Variation Using Cooling Channels: A Numerical Approach

2021 ◽  
pp. 29-35
Author(s):  
Olumide Adewole Towoju
Keyword(s):  
Mechanical Properties ◽  
Cast Iron ◽  
Cooling Rate ◽  
Flow Rate ◽  
Numerical Approach ◽  
Cooling Curve ◽  
Rate Variation ◽  
Cooling Fluid ◽  
Cooling Channels ◽  
The Impact

The cooling rate of molten cast iron can make or mar it. The cooling rate plays a significant role in the resulting mechanical properties of cast iron. It determines the grain growth and size. The mechanical properties of cast iron variation along its length are achieved either with the use of different mold materials or by sectioning to ensure varied cooling rates. Mechanical properties can, however, also be varied along its length without any of these adopted methods by the incorporation of cooling channels in the mould. This study seeks to expand the frontier of this concept with the use of different cooling fluids and fluid flow rate, and numerically investigate the impact on the cooling rate of gray cast iron (class 40). The cooling curve for the cast iron was impacted by the use of different cooling fluids with the attainment of the desired mechanical properties with the selection of an appropriate cooling fluid. Also, the flow rate of the cooling fluid has an impact on the cast iron cooling rate.

Influence of Charge Composition on EN-GJS-500-7 Ductile Iron Properties in Foundry Operating Conditions

2020 ◽  
Vol 998 ◽  
pp. 42-47
Author(s):  
Alena Pribulová ◽  
Peter Futaš ◽  
Marcela Pokusova
Keyword(s):  
Mechanical Properties ◽  
Cast Iron ◽  
Ductile Iron ◽  
Ductile Cast Iron ◽  
Operating Conditions ◽  
Production Costs ◽  
Steel Scrap ◽  
Charge Composition ◽  
Iron Castings ◽  
Worldwide Production

Worldwide production of ductile iron castings reached in year 2017 26,428,148 metric tons, which is 34% of the total weight of all castings made from cast iron. The most significant increase in ductile iron castings was recorded in Slovakia, up to 78.6%. Castings from ductile iron have a very huge utilization thanks their very good foundry and mechanical properties. The current economic situation in all industries forces entrepreneurs and producers to rationalize production and reduce production costs, with a worldwide trend to increase the share of steel scrap, a technology for the production of ductile cast iron. The paper describes the results of research focused on the effect of charge composition, mainly the share of scrap steel on the final properties and structure of ductile iron EN-GJS-500-7 under the operating conditions of foundry. Six melts with different charge composition were made. The samples from all melts were taken and chemical analysis, microstructure analysis and testing on mechanical properties were made on them. The mechanical properties of produced globular cast irons were according with the relevant standard. It is important to mention that there has been a significant increase in strength characteristics in melts in which the carbon content exceeded 4% (CE = 4.7 and 4.8%, respectively).

scholarly journals A rapid approach to estimate the mechanical properties of grey cast iron castings

2018 ◽  
Vol 24 (3) ◽  
pp. 213 ◽  
Author(s):  
Paolo Ferro ◽  
Thomas Borsato ◽  
Franco Bonollo ◽  
Stefano Padovan
Keyword(s):  
Mechanical Properties ◽  
Cast Iron ◽  
Master Curve ◽  
Mechanical Characterization ◽  
Grey Cast Iron ◽  
Iron Castings ◽  
Solidification Kinetics ◽  
Grey Cast ◽  
Microstructure Morphology

<p>Grey cast iron is a brittle or quasi-brittle material very sensitive to the microstructure morphology deriving from its solidification kinetics. This is the reason why different zones of a casting, even with the same thickness, may be characterized by different mechanical properties according to the solidification time. The mechanical characterization of the alloy made by following the Standards that refer to values obtained from separately casted samples is insufficient for a designer who needs to know the specific properties of the material in each zone of interest of the casting. In this work a method is described to predict the mechanical properties of castings made of GH 190 cast iron that correlates the solidification times with the ultimate tensile strength through a master curve, supposed to depend only on alloy chemical composition. This predictive approach was successfully validated with experimental mechanical characterization of a real industrial casting.</p>

Effect of Ar Purification on Microstructure and Properties of High Strength Gray Cast Iron

2011 ◽  
Vol 266 ◽  
pp. 241-245
Author(s):  
Juan Yang ◽  
Sheng Xin Liu ◽  
Qi Fei Hou ◽  
Hua Wei Sun ◽  
Yu Fu Sun ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cast Iron ◽  
Optical Microscopy ◽  
Gray Cast Iron ◽  
High Strength ◽  
Gray Cast ◽  
Metallographic Examination ◽  
Iron Castings ◽  
Graphite Morphology ◽  
Quality Indexes

The effects of Ar purification on the impurity characteristic, graphite morphology and quality indexes of high strength gray cast iron were investigated by microstructures analysis and mechanical properties examination. The results show that there are a large amount of particles and floccule impurities in the specimens without Ar purification. The granular impurities usually have been incorrectly considered as “C-type” graphite observed by optical microscopy in the metallographic examination in the practical production of small and medium high strength gray cast iron castings. The amount of impurities is greatly decreased and the quality indexes of high strength gray cast iron with Ar purification are markedly improved.

Numerical Simulation of the I-Beam during Cooling Process

2013 ◽  
Vol 712-715 ◽  
pp. 1634-1637
Author(s):  
Jian Liu ◽  
Fu Zeng Hou ◽  
Xiao Guang Yu
Keyword(s):  
Mechanical Properties ◽  
Numerical Simulation ◽  
Heat Treatment ◽  
Cooling Rate ◽  
Theoretical Basis ◽  
Treatment Process ◽  
Residual Austenite ◽  
Heat Treatment Process ◽  
Cooling Process ◽  
Controlled Cooling

In order to improve the comprehensive mechanical properties of the steel, the heat treatment software COSMAP is used to simulate the rolling and controlled cooling of I-beam. The numerical simulation shows that: when the cooling rate is controlled at 10 °C/s around, the mechanical properties of controlled cooling can be obviously improved. The strength and hardness can be improved on the condition of ductility and toughness ensured, while the amount of residual austenite can be reduced significantly, which provide a theoretical basis for further optimization of the heat treatment process.

The Influence of the Cooler Material on the Structure and Hardeness Gradient of a Grey Pearlitic Cast Iron

2015 ◽  
Vol 1128 ◽  
pp. 18-25 ◽  
Author(s):  
Sorin Ion Munteanu ◽  
Ioan Ciobanu ◽  
Aurel Crisan ◽  
Tibor Bedo ◽  
Daniel Feraru
Keyword(s):  
Cast Iron ◽  
Cooling Rate ◽  
Hardened Layer ◽  
Superficial Layer ◽  
Physical Characteristics ◽  
Grey Cast Iron ◽  
Industrial Practice ◽  
Iron Castings ◽  
Iron Sample ◽  
Grey Cast

The structure and properties of grey cast iron castings are considerably influenced by the cooling rate during solidification. In order to obtain grey cast iron parts with a hard superficial layer (wear resistant), external metallic coolers are placed on those surfaces during casting. This is the case of cam pushers, camshafts, driving shafts, metalworking rolls, etc. Cast iron coolers or steel coolers are mostly used in practice. The cooling rate during solidification is influenced by the thermo-physical characteristics of the coolers. This paper presents the results obtained by simulation and experimental research on coolers material influence on the structure and hardness of the surface layer of a pearlitic cast iron sample. It was studied the solidification of samples with dimensions 20 x 20 x 60 mm, cast of pearlitic cast iron in six variants: without a cooler and in the presence of some metallic coolers of different thermo-physical characteristics (iron, steel, copper, titanium and aluminum coated with a thin layer of steel). It was studied the influence of cooler material on structure of the superficial layer, on thickness of the hardened layer, on superficial hardness, on the temperature field and cooling rates. Conclusions are drawn regarding these influences and the possibility of using external coolers in industrial practice.

Effect of Cooling Speed on the Microstructure and Mechanical Properties of Sn-0.7Cu-0.05Ni Solder Alloy

2018 ◽  
Vol 934 ◽  
pp. 73-78
Author(s):  
Phairote Sungkhaphaitoon
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Melting Point ◽  
Cooling Rate ◽  
Solder Alloy ◽  
Testing Machine ◽  
Solder Alloys ◽  
Scanning Calorimetry ◽  
Microstructure And Mechanical Properties ◽  
Cooling Speed

To study the effect of cooling speed on the microstructure and mechanical properties of Sn-0.7Cu-0.05Ni solder alloy, molten alloys were cooled at two different rates, using water-cooling and mold-cooling. The mechanical properties of the obtained alloys were analyzed with a universal testing machine (UTM) and by Vickers microhardness testing (HV). The microstructures were characterized using an optical microscope (OM) and energy dispersive X-ray spectroscopy (EDX).The melting point was ascertained by differential scanning calorimetry (DSC). The cooling rate of the water-cooled system (0.28 o C/s) was faster than the cooling rate of the mold-cooled system (0.05 °C/s). The grain size of the alloy produced by the faster cooling rate was finer than that of the alloy obtained from the slower cooling rate. This finer grain size gave the alloy superior ultimate tensile strength (UTS) and hardness but inferior ductility (%EL). The microstructure of both Sn-0.7Cu-0.05Ni solder alloys exhibited three phases of β-Sn, Cu6Sn5 and (Cu,Ni)6Sn5 intermetallic compounds. The melting point and undercooling of the solder alloys was 233.8 °C and 35.7 °C, respectively.

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