Study of Microstructure and Mechanical Property Degradation of SA210 A1 Boiler Tube

The comprehension of the microstructure change and mechanical property degradation are of particular importance for assessing the integrity of aging boiler tubes.This paper describes the investigation of microstructure evolution and mechanical property degradation of SA210 A1 steel used in an actual boiler condition. The investigation deals with visual inspection, chemical composition analysis, micrograph study using Energy Dispersive Spectroscopy-Scanning Electron Microscopy (EDS-SEM), tensile test and hardness test. The result showed that the prolonged operating period in the high temperature condition resulted in the reduction of the mechanical properties of the SA 210 A1 steel tube. The study also indicated the presence of the onset of the pearlite disintegration and coagulation, resulted from the microstructure degradation of the aged steel tube after the elevated temperature service in a boiler

Evolution of Microstructure and Wear Resistance of Carburized Low Carbon Steel

The main aims of this present work were to investigate the microstructure and wear resistance of AISI 1020 during the pack carburization. The samples were prepared in a rectangular shape with a dimension of 5 mm X 25 mm X 2 mm for microstructure and hardness studies. Another set of samples with a dimension of 4.0 cm x 2.5 cm x 0.5 cm was prepared for the wear resistance performance. Both sets of samples were packed in the steel container which was tightly sealed. The carburizing atmosphere in the container was prepared by using mixtures of powdered charcoal and tamarind catalysts. The carburizing temperature of 950 °C with a fixed carburizing time of 2 hours was controlled for the pack carburizing treatment. The results exhibited that in the fresh condition, AISI 1020 mostly contained ferrite. Nevertheless, after carburization, quenching, and tempering process were carried out, the microstructures of the samples were changed from ferrite to pearlite and then martensite. An increase in the carbon content after carburization plays a major role in the evolution of the high hardness layers which subsequently enhanced the hardness and the wear resistance performance of AISI1020 after quenching and tempering

An Economic Consideration Guideline for the Selection of Corrosion - Control Strategies

ABSTRACT Corrosion has an enormous economic impact on our industries. Hence, it is very important for engineers to apply the appropriate corrosion prevention techniques to protect the metallic process equipment from corrosion.  Usually, engineers spend their effort seeking for the corrosion control strategies. In fact, the effective corrosion prevention projects should be technically and economically evaluated.  Engineers can assess the corrosion prevention strategies in terms of technical validity. Nevertheless, the economic consideration of the anti-corrosion strategies seems to be one of their problems. The purpose of this article is to present the economic techniques which can be employed as a quick guide to make decision of their corrosion prevention projects. The other purpose is to review the corrosion mitigation methods and the economic considerations of the financial investment in the corrosion prevention strategies.  The application of these techniques is also illustrated in a selected practical example. Keyword: Corrosion, Engineering Economy, Corrosion Mitigation Approaches, Economic Consideratio

An Economic Consideration Guideline for the Selection of Corrosion - Control Strategies

ABSTRACT Corrosion has an enormous economic impact on our industries. Hence, it is very important for engineers to apply the appropriate corrosion prevention techniques to protect the metallic process equipment from corrosion.  Usually, engineers spend their effort seeking for the corrosion control strategies. In fact, the effective corrosion prevention projects should be technically and economically evaluated.  Engineers can assess the corrosion prevention strategies in terms of technical validity. Nevertheless, the economic consideration of the anti-corrosion strategies seems to be one of their problems. The purpose of this article is to present the economic techniques which can be employed as a quick guide to make decision of their corrosion prevention projects. The other purpose is to review the corrosion mitigation methods and the economic considerations of the financial investment in the corrosion prevention strategies.  The application of these techniques is also illustrated in a selected practical example. Keyword: Corrosion, Engineering Economy, Corrosion Mitigation Approaches, Economic Consideratio

The study on high temperature degradation of AISI 1020 low carbon steel in the carburization state

วารสารวิชาการและวิจัย มทร.พระนคร, 10 (2) : 22-29This research was aimed to study the high temperature degradation of AISI 1020 carbon steel pipe under the carburizing atmosphere. This environment was prepared by a mix of powdered charcoal and CaCO3 catalysts and then simulated at temperature of 1000C for 1, 2 and 4 hours. The variation in the weight of the aged steel specimens was obtained by the measured metal loss at various working periods. The light optical microscope was used to observe the microstructural changes of aged steel samples. The results revealed that the prolonged operating period decreases the weight of samples and the degradation occurs on the outer surface of the pipes. The study also indicated the microstructural difference between the inner and outer wall of the steel pipe, which is resulted from the changes in chemical compositions during the carburizing process.Rajamangala University of Technology Phra Nakho

Grain Refining Effect of Al-5Ti-1B Master Alloy on Microstructures and Mechanical Properties of A356 Alloy

In this study, the structures of Al-5Ti-1B master alloy and its influence on microstructures and mechanical properties of A356 alloy were investigated. The results show that Al-5Ti-1B master alloy consisted of the uniform distribution of lump-like TiB2 and network of TiAl3 on α-Al matrix. The addition of the Al-5Ti-1B master alloy can significantly reduce the grain size of A356 alloy. The mechanical properties of A356 alloy, i.e. ultimate tensile strength, yield strength and elongation were also improved. The use of Al-5Ti-1B master alloy as a grain refiner in the casting process of A356 alloy can effectively enhance the grain refinement and thus improve the mechanical performance of A356 alloy.</jats:p

Evolution of Microstructure and Wear Resistance of Carburized Low Carbon Steel

The main aims of this present work were to investigate the microstructure and wear resistance of AISI 1020 during the pack carburization. The samples were prepared in a rectangular shape with a dimension of 5 mm X 25 mm X 2 mm for microstructure and hardness studies. Another set of samples with a dimension of 4.0 cm x 2.5 cm x 0.5 cm was prepared for the wear resistance performance. Both sets of samples were packed in the steel container which was tightly sealed. The carburizing atmosphere in the container was prepared by using mixtures of powdered charcoal and tamarind catalysts. The carburizing temperature of 950 °C with a fixed carburizing time of 2 hours was controlled for the pack carburizing treatment. The results exhibited that in the fresh condition, AISI 1020 mostly contained ferrite. Nevertheless, after carburization, quenching, and tempering process were carried out, the microstructures of the samples were changed from ferrite to pearlite and then martensite. An increase in the carbon content after carburization plays a major role in the evolution of the high hardness layers which subsequently enhanced the hardness and the wear resistance performance of AISI1020 after quenching and tempering

Study on carburized steel used in maritime industry: The influences of carburizing temperature

This paper aims to examine the influence of carburizing temperature on carburized mild steel. Carburizing treatment was carried out at carburizing temperatures of 800 and 900 °C with fixed carburizing time of 1 h. The results indicated that carburization treatment could improve the hardness of the samples. However, it was found that the hardness profile of mild steel was almost unchanged after treatment at the carburizing temperature of 800 °C. Carburization treatment carried out at the carburizing temperature of 900 °C could significantly enhance the hardness conditions and also increase the case depth of carburized mild steel. Carburized steel can provide a tough and durable surface to protect against severe degradations, such as marine erosion, wear, and cavitation in maritime applications.</jats:p

Cryogenic treatment of tool steels: A brief review and a case report

Tool steels used in marine industries demand for the effective approach to enhance their properties. Normally, conventional heat treatment is widely used to increase the performance of tool steels. However, this method cannot fully enhance the tool steel performance. On the other hand, cryogenic treatment is a supplementary process to the conventional heat treatment, which can promote the conversion of retained austenite to martensite and accelerate the precipitation of fine carbides. In this paper, a systematic review of cryogenic treatment of tool steels was presented. A wide range of useful investigations was reviewed, particularly in the details of the transformation of retained austenite to martensite and the precipitation of the fine carbides. A case study on a tool steel subjected to conventional heat treatment, conventional cold treatment, and deep cryogenic treatment was also given and discussed to give an insight in the cryogenic treatment of tool steels.</jats:p

Evolution of Microstructure and Wear Resistance of Carburized Low Carbon Steel

The main aims of this present work were to investigate the microstructure and wear resistance of AISI 1020 during the pack carburization. The samples were prepared in a rectangular shape with a dimension of 5 mm X 25 mm X 2 mm for microstructure and hardness studies. Another set of samples with a dimension of 4.0 cm x 2.5 cm x 0.5 cm was prepared for the wear resistance performance. Both sets of samples were packed in the steel container which was tightly sealed. The carburizing atmosphere in the container was prepared by using mixtures of powdered charcoal and tamarind catalysts. The carburizing temperature of 950 °C with a fixed carburizing time of 2 hours was controlled for the pack carburizing treatment. The results exhibited that in the fresh condition, AISI 1020 mostly contained ferrite. Nevertheless, after carburization, quenching, and tempering process were carried out, the microstructures of the samples were changed from ferrite to pearlite and then martensite. An increase in the carbon content after carburization plays a major role in the evolution of the high hardness layers which subsequently enhanced the hardness and the wear resistance performance of AISI1020 after quenching and tempering.</jats:p