| The rapid development of hi-tech industry (such as medical equipment manufacturing industry, aerospace industry and photology, etc.) on the work piece surface finish quality put forward higher and higher requirements, the machining quality of stainless steel pipe’s surface is also face the challenge. Stainless steel pipe with high heat resistance, high corrosion resistance, high strength, nonmagnetic, good toughness is widely applied in many important areas (such as precision instruments, environmental protection industry and transport machinery, etc.), but stainless steel belongs to easy passivated metal materials, so in the molding process, it’s easy to generate oxide skins which have compact structure and matrix adhesion to the base metal, compared with ordinary steel, it is more difficult to remove oxide skin for stainless steel tube. Especially, some stainless steel tubes which have special structure or special shape (such as slim, oversized or abnormal shaped, etc.) are difficult to move during processing, which makes it more difficult to process the inner surface, sometimes the inner surface even cannot be processed.There are three common methods to clean the inner surface of stainless steel tube:pickling method、shot peening and electrochemical method. However, pickling and electrochemical method can generate waste acid, rinse water, toxic gas and heavy metal ions, which not only seriously polluted the environment for human survival, but also can cause serious harm to the employees; Shot peening is easy to make the processed work piece’s surface to generate defects, and it is difficult to guarantee the sheet parts to maintain the original form. So, we rely on various forms of energy and make use of a variety of ways to find a new process method. Magnetic honing as a new technology make magnetic field to use in industrial areas. Magnetic honing technology utilizes electromagnetic interaction to rotate and axially translate a rotor abrasive on the inner surface of work piece, so as to effectively solve the practical issue that the inner surface of the long stainless steel pipes are hardly polished since they are too long and not suitably rotated at high speed. No one has proposed the concept of magnetic honing at present, both in China and abroad. It is put forward for the first time in2008, the participants are Ya Gang professor and Yao Xingai associate professor who work in Taiyuan University of Technology.Liu Wei, who has been graduated from Taiyuan University of Technology two years ago, developed a rotor grinding tool with high magnetic conductivity and strong grinding force under the guidance of Ya Gang professor and Yao Xingai associate professor. While in the process of operation, we found that the rotor grinding tool was very heavy and had serious vibrate problems. At the same time, the magnetic honing system got hot too fast while its heat dissipation was too slow. In order to make sure that the insulation structure can work normally, the surrounding temperature must to be under its prescribed limit working temperature, that’s the limit that the normally ongoing processing time of the stainless steel pipe is within10min once a time. These problems blocked the magnetic honing technique’s promotion and application in actual production. For this reasons, a kind of magnetic abrasive has been designed, which had larger magnetic conductivity, enough grinding ability, light weight and small vibration on the basis of the previous research. Meanwhile, cooling circulatory system has also been added for magnetic honing system. Electromagnetic field and temperature field of magnetic honing system are key factors that influenced the processing results. In this paper, parametric analysis and optimization design for magnetic honing system has carried out with the help of the finite element analysis software:Ansoft Maxwell. In the finite element analysis software ANSYS Workbench, we import the Ansoft Maxwell electromagnetic field analysis file and make it associated with the transient temperature field analysis module settings, so as to realize the direct coupling of electromagnetic field and temperature field, which will make the temperature field simulation of magnetic honing system more accurately. Processing experiments also have been carried out in this paper, so as to verify the electromagnetic field and temperature field simulation conclusion. The experimental results show that:1. When we use different material (microlite corundum, zirconium corundum and white corundum) to grind stainless steel pipe wetly at the same speed, feed and time, microlite corundum’s processing effect is best.2. When we use microlite corundum to grind stainless steel pipe wetly at the different speed and the same feed and time, the results showed that:within a certain range, the higher speed can get the better machining effect.3. After adding the cooling circulation system, the heat issue of the magnetic honing system has been solved, the ongoing process time has been improved from10min to40min.4. Wet grinding has preliminarily reached the goal of this project, that is the inner surface’s roughness value of workpiece should be reduced more than two levels.Magnetic honing processing experiment provides a powerful experimental data and technical basis for subsequent research and improvement on magnetic honing system. |
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