Tribological Studies on Deep Cryogenic Treated Aisi T42 High Speed Steel Using Response Surface Methodology
D. Candane,
N. Alagumurthi,
K. Palaniradja
Issue:
Volume 2, Issue 2, April 2013
Pages:
12-22
Received:
20 April 2013
Accepted:
Published:
2 April 2013
Abstract: High – speed steels are the most widely used tool material in small and medium scale industries, owing to their excellent toughness and economic price over their competitors. But the wear resistance and hot hardness of high-speed steels are poor compared to tools made out of carbides. Recent investigations, on the effect of cryogenic treatment have proved to be an alternative option to enhance the hardness and wear resistance of high-speed tool materials. But so far only a limited number of investigations have been made into the effect of cryogenic treatment on different grades of high-speed steels. The present research reports the effect of deep cryogenic treatment on AISI T42 grade high – speed steel, with specific emphasis on mode and mechanism of wear. Wear behavior has been studied using pin-on-disc tribo-meter under dry condition. Response surface methodology was adopted in designing the experiments for two factors with five levels. Mathematical model has been developed incorporating the effect of sliding velocity and load on the wear behavior. Sliding velocity was found to be dominant factor than normal load. Morphology of worn surface and the wear debris was studied using SEM to identify the mode and mechanism of wear. Mild oxidative wear was the dominant mode of wear throughout the range of variables used in this study. Deep cryogenically treated specimens exhibited significant improvement in wear resistance than conventionally heat treated specimens, especially at higher sliding velocities. The wear rate of conventionally heat treated specimen was found to be 3.138 to 2.493 times higher than that of deep cryogenically treated specimens. There was an increase in hardness value form 66.8-67.2 HRC at the end of conventional heat treatment to 69.5-70.2 HRC at the end of deep cryogenic treatment.
Abstract: High – speed steels are the most widely used tool material in small and medium scale industries, owing to their excellent toughness and economic price over their competitors. But the wear resistance and hot hardness of high-speed steels are poor compared to tools made out of carbides. Recent investigations, on the effect of cryogenic treatment have...
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Minimization of Variation in Clinker Quality
Fasil Alemayehu,
Omprakash Sahu
Issue:
Volume 2, Issue 2, April 2013
Pages:
23-28
Received:
1 May 2013
Accepted:
Published:
30 May 2013
Abstract: Cement quality is typically assessed by its compressive strength development in mortar and concrete. The basis for this property is a well-burned clinker with consistent chemical composition and free lime. The main reason for the clinker free lime to change in situation with stable kiln operation is variation in the chemical composition of the kiln feed. This variation in chemical composition is related to raw mix control and the homogenization process. To ensure a constant quality of the product and maintain a stable and continuous operation of the kiln, the attention must be paid to storage and homogenization of raw materials and kiln feed. Due to variations in the kiln feed chemical compositions that affect its burnability and the fuel consumption. The raw materials for Portland cement production are the mixture (as fine powder in the 'Dry process') of minerals containing calcium oxide, silicon oxide, aluminum oxide, ferric oxide, and magnesium oxide. The homogeneity of feed chemical composition has an important relationship to fuel consumption, kiln operation, clinker formation and cement performance. In this regard an attempt made to deals with the mixing of raw materials process and estimation of composition of raw mill feed, kiln feed, as well as formed clinker, which were done successfully through various results obtained experimentally and various steps have been taken to reduce these variations in clinker quality.
Abstract: Cement quality is typically assessed by its compressive strength development in mortar and concrete. The basis for this property is a well-burned clinker with consistent chemical composition and free lime. The main reason for the clinker free lime to change in situation with stable kiln operation is variation in the chemical composition of the kiln...
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