The important supporting component in a gas turbine is the casing,which has the characteristics of large size,complex structure,and thin wall.In the context of existing 3DP sand casting processes,casting crack defects...The important supporting component in a gas turbine is the casing,which has the characteristics of large size,complex structure,and thin wall.In the context of existing 3DP sand casting processes,casting crack defects are prone to occur.This leads to an increase in the scrap rate of casings,causing significant resource wastage.Additionally,the presence of cracks poses a significant safety hazard after the casings are put into service.The generation of different types of crack defects in stainless steel casings is closely related to casting stress and the high-temperature concession of the sand mold.Therefore,the types and causes of cracks in stainless steel casing products,based on their structural characteristics,were systematically analyzed.Various sand molds with different internal topology designs were printed using the 3DP technology to investigate the impact of sand mold structures on high-temperature concession.The optimal sand mold structure was used to cast casings,and the crack suppression effect was verified by analyzing its eddy current testing results.The experimental results indicate that the skeleton structure has an excellent effect on suppressing cracks in the casing.This research holds important theoretical and engineering significance in improving the quality of casing castings and reducing production costs.展开更多
Since the USA patent of electroslag remelting(ESR) metallurgy was held by P. K. Hopkins in 1940, the ESR technology has now entered a relatively mature stage after a 70-year history of development. At present, the ann...Since the USA patent of electroslag remelting(ESR) metallurgy was held by P. K. Hopkins in 1940, the ESR technology has now entered a relatively mature stage after a 70-year history of development. At present, the annual capacity of ESR steels around the world is approximately 2 million tonnes. ESR metallurgy emerged in China in 1958. Since then, electroslag furnaces were gradually installed in Chinese special steel plants. At present, there are more than 200 electroslag remelting furnaces in the metallurgical workshops of these steel plants with an annual production capacity of about 500,000 tonnes of ingots and components made of about 200 varieties of steels, including high quality steels and superalloys. This ESR technology is used as a special remelting and refining method for producing high quality steels and superalloys. However, traditional ESR technology has the disadvantages of environmental pollution and extremely high specific power consumption. High power consumption restricts, to a certain degree, the competitiveness of ESR steels in the marketplace. The measures of power saving in ESR have been researched in recent years. In this paper, some factors influencing power consumption, such as filling ratio, slag system, slag amount, melting rate and furnace structure are reviewed, and several new ESR technologies for power saving are proposed.展开更多
The vibrating electrode method was proposed in the electro-slag remelting （ESR） process in this paper, and the effect of vibrating electrode on the solidification structure of ingot was studied. A transient three- d...The vibrating electrode method was proposed in the electro-slag remelting （ESR） process in this paper, and the effect of vibrating electrode on the solidification structure of ingot was studied. A transient three- dimensional （3D） coupled mathematical model was established to simulate the electromagnetic phenomenon, fluid flow as well as pool shape in the ESIR process with the vibrating electrode. The finite element volume method is developed to solve the electromagnetic field using ANSYS mechanical APDL software. Moreover, the electromagnetic force and Joule heating are interpolated as the source term of the momentum and energy equations. The multi-physical fields have been investigated and compared between the traditional electrode and the vibrating electrode in the ESR process. The results show that the drop process of metal droplets with the traditional electrode is scattered randomly. However, the drop process of metal droplets with the vibrating electrode is periodic. The highest temperature of slag layer with the vibrating electrode is higher than that with the traditional electrode, which can increase the melting rate due to the enhanced heat transfer in the vicinity of the electrode tip. The results also show that when the amplitude and frequency of the vibrating electrode increase, the cycle of drop process of metal droplets decreases significantly.展开更多
基金financially supported by the National Natural Science Foundation of China(No.52175352)the Xing Liao Ying Cai Project of Liaoning Province(No.XLYC2008036)the Shenyang Youth Innovation Talent Support Program(No.RC220429)。
文摘The important supporting component in a gas turbine is the casing,which has the characteristics of large size,complex structure,and thin wall.In the context of existing 3DP sand casting processes,casting crack defects are prone to occur.This leads to an increase in the scrap rate of casings,causing significant resource wastage.Additionally,the presence of cracks poses a significant safety hazard after the casings are put into service.The generation of different types of crack defects in stainless steel casings is closely related to casting stress and the high-temperature concession of the sand mold.Therefore,the types and causes of cracks in stainless steel casing products,based on their structural characteristics,were systematically analyzed.Various sand molds with different internal topology designs were printed using the 3DP technology to investigate the impact of sand mold structures on high-temperature concession.The optimal sand mold structure was used to cast casings,and the crack suppression effect was verified by analyzing its eddy current testing results.The experimental results indicate that the skeleton structure has an excellent effect on suppressing cracks in the casing.This research holds important theoretical and engineering significance in improving the quality of casing castings and reducing production costs.
基金financially supported by the National Natural Science Foundation of China(Grant No.51475313)
文摘Since the USA patent of electroslag remelting(ESR) metallurgy was held by P. K. Hopkins in 1940, the ESR technology has now entered a relatively mature stage after a 70-year history of development. At present, the annual capacity of ESR steels around the world is approximately 2 million tonnes. ESR metallurgy emerged in China in 1958. Since then, electroslag furnaces were gradually installed in Chinese special steel plants. At present, there are more than 200 electroslag remelting furnaces in the metallurgical workshops of these steel plants with an annual production capacity of about 500,000 tonnes of ingots and components made of about 200 varieties of steels, including high quality steels and superalloys. This ESR technology is used as a special remelting and refining method for producing high quality steels and superalloys. However, traditional ESR technology has the disadvantages of environmental pollution and extremely high specific power consumption. High power consumption restricts, to a certain degree, the competitiveness of ESR steels in the marketplace. The measures of power saving in ESR have been researched in recent years. In this paper, some factors influencing power consumption, such as filling ratio, slag system, slag amount, melting rate and furnace structure are reviewed, and several new ESR technologies for power saving are proposed.
基金financially supported by the National Natural Science Foundation of China(No.51275320)
文摘The vibrating electrode method was proposed in the electro-slag remelting （ESR） process in this paper, and the effect of vibrating electrode on the solidification structure of ingot was studied. A transient three- dimensional （3D） coupled mathematical model was established to simulate the electromagnetic phenomenon, fluid flow as well as pool shape in the ESIR process with the vibrating electrode. The finite element volume method is developed to solve the electromagnetic field using ANSYS mechanical APDL software. Moreover, the electromagnetic force and Joule heating are interpolated as the source term of the momentum and energy equations. The multi-physical fields have been investigated and compared between the traditional electrode and the vibrating electrode in the ESR process. The results show that the drop process of metal droplets with the traditional electrode is scattered randomly. However, the drop process of metal droplets with the vibrating electrode is periodic. The highest temperature of slag layer with the vibrating electrode is higher than that with the traditional electrode, which can increase the melting rate due to the enhanced heat transfer in the vicinity of the electrode tip. The results also show that when the amplitude and frequency of the vibrating electrode increase, the cycle of drop process of metal droplets decreases significantly.
