Formation of Spinel Phases in Oxidized BOF Slag under Different Cooling Conditions

2017 ◽  
Vol 88 (11) ◽  
pp. 1700066 ◽  
Author(s):  
Liang Jiang ◽  
Yiwang Bao ◽  
Qixing Yang ◽  
Yuhong Chen ◽  
Guiqun Liu ◽  
...  
Keyword(s):  
Cooling Conditions ◽  
Spinel Phases ◽  
Bof Slag

BOF Slag: Turning Waste Into Value

2019 ◽  
Author(s):  
S. Chatterjee ◽  
K. Konar ◽  
B. Senguttuvan ◽  
A. Maity ◽  
R. N ◽  
...  
Keyword(s):  
Bof Slag

Effects of Cooling Conditions on Thermal Crack Initiation of Brittle Cutting Tools during Intermittent Cutting

2015 ◽  
Vol 656-657 ◽  
pp. 237-242
Author(s):  
Kenji Yamaguchi ◽  
Tsuyoshi Fujita ◽  
Yasuo Kondo ◽  
Satoshi Sakamoto ◽  
Mitsugu Yamaguchi ◽  
...  
Keyword(s):  
Crack Initiation ◽  
Thermal Shock ◽  
High Speed ◽  
Cutting Tools ◽  
Cutting Speed ◽  
Cutting Condition ◽  
Thermal Crack ◽  
Cooling Conditions ◽  
Cutting Operation ◽  
Intermittent Cutting

It is well known that a series of cracks running perpendicular to the cutting edge are sometimes formed on the rake face of brittle cutting tools during intermittent cutting. The cutting tool is exposed to elevated temperatures during the periods of cutting and is cooled quickly during noncutting times. It has been suggested that repeated thermal shocks to the tool during intermittent cutting generate thermal fatigue and result in the observed thermal cracks. Recently, a high speed machining technique has attracted attention. The tool temperature during the period of cutting corresponds to the cutting speed. In addition, the cooling and lubricating conditions affect the tool temperature during noncutting times. The thermal shock applied to the tool increases with increasing cutting speed and cooling conditions. Therefore, to achieve high-speed cutting, the evaluation of the thermal shock and thermal crack resistance of the cutting tool is important. In this study, as a basis for improving the thermal shock resistance of brittle cutting tools during high-speed intermittent cutting from the viewpoint of cutting conditions, we focused on the cooling conditions of the cutting operation. An experimental study was conducted to examine the effects of noncutting time on thermal crack initiation. Thermal crack initiation was found to be restrained by reducing the noncutting time. In the turning experiments, when the noncutting time was less than 10 ms, thermal crack initiation was remarkably decreased even for a cutting speed of 500 m/min. In the milling operation, the number of cutting cycles before thermal crack initiation decreased with increasing cutting speed under conditions where the cutting speed was less than 500 m/min. However, when the cutting speed was greater than 600 m/min, thermal crack initiation was restrained. We applied the minimal quantity lubrication (MQL) coolant supply to the intermittent cutting operation. The experimental results showed that the MQL diminished tool wear compared with that under the dry cutting condition and inhibited thermal crack initiation compared with that under the wet cutting condition.

scholarly journals Time-Dependent Strength Behavior, Expansion, Microstructural Properties, and Environmental Impact of Basic Oxygen Furnace Slag-Treated Marine-Dredged Clay in South Korea

2021 ◽  
Vol 13 (9) ◽  
pp. 5026
Author(s):  
Gyeong-o Kang ◽  
Jung-goo Kang ◽  
Jin-young Kim ◽  
Young-sang Kim
Keyword(s):  
Particle Size ◽  
Environmental Impact ◽  
South Korea ◽  
Mechanical Characteristics ◽  
Basic Oxygen Furnace ◽  
Microstructural Properties ◽  
Compression Tests ◽  
Basic Oxygen ◽  
Strength Behavior ◽  
Bof Slag

The aim of this study was to investigate the mechanical characteristics, microstructural properties, and environmental impact of basic oxygen furnace (BOF) slag-treated clay in South Korea. Mechanical characteristics were determined via the expansion, vane shear, and unconfined compression tests according to various curing times. Scanning electron microscopy was conducted to analyze microstructural properties. Furthermore, environmental impacts were evaluated by the leaching test and pH measurements. According to the results, at the early curing stage (within 15 h), the free lime (F-CaO) content of the BOF slag is a significant factor for developing the strength of the adopted sample. However, the particle size of the BOF slag influences the increase in the strength at subsequent curing times. It was inferred that the strength behavior of the sample exhibits three phases depending on various incremental strength ratios. The expansion magnitude of the adopted samples is influenced by the F-CaO content and also the particle size of the BOF slag. Regarding the microstructural properties, the presence of reticulation structures in the amorphous gels with intergrowths of rod-like ettringite formation was verified inside the sample. Finally, the pH values and heavy metal leachates of the samples were determined within the compatible ranges of the threshold effect levels in the marine sediments of the marine environment standard of the Republic of Korea.

scholarly journals Component Modification of Basic Oxygen Furnace Slag with C4AF as Target Mineral and Application

2021 ◽  
Vol 13 (12) ◽  
pp. 6536
Author(s):  
Yanrong Zhao ◽  
Pengliang Sun ◽  
Ping Chen ◽  
Xiaomin Guan ◽  
Yuanhao Wang ◽  
...  
Keyword(s):  
Intermediate Phase ◽  
Raw Materials ◽  
Activity Index ◽  
Basic Oxygen Furnace ◽  
Hydration Products ◽  
Basic Oxygen ◽  
Bof Slag ◽  
Mineral Compositions ◽  
Slag Component ◽  
Basic Oxygen Furnace Slag

In this paper, a new method of basic oxygen furnace (BOF) slag component modification with a regulator was studied. The main mineral was designed as C4AF, C2S and C3S in modified BOF slag, and the batching method, mineral compositions, hydration rate, activation index and capability of resisting sulfate corrode also were studied. XRD, BEI and EDS were used to characterize the mineral formation, and SEM was used to study the morphology of hydration products. The results show that most inert phase in BOF slag can be converted into active minerals of C4AF and C2S through reasonable batching calculation and the amount of regulating agent. The formation of C4AF and C2S in modified BOF slag is better, and a small amount of MgO is embedded in the white intermediate phase, but C3S is not detected. With the increase in the CaO/SiO2 ratio in raw materials, the CaO/SiO2 ratio of calcium silicate minerals in modified BOF slag increases, the contents of f-CaO are less than 1.0%, and the activity index improves. Compared with the BOF slag, the activity index and exothermic rate of modified BOF slag improved obviously, and the activity index of 90 days is close to 100%. With the increase in modified BOF slag B cement, the flexural strength decrease; however, the capability of resisting sulfate corrode is improved due to the constant formation of a short rod-like shape ettringite in Na2SO4 solution and the improvement of the structure densification of the hydration products.

Machinability investigations on CFRP composites: a comparison between sustainable cooling conditions

2021 ◽  
Author(s):  
Mohd Danish ◽  
Munish Kumar Gupta ◽  
Saeed Rubaiee ◽  
Anas Ahmed ◽  
A. Mahfouz ◽  
...  
Keyword(s):  
Cooling Conditions ◽  
Cfrp Composites
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