بررسی آزمایشگاهی و شبیه‌سازی تاثیر دما در فرآیند تیگزوفورجینگ، مطالعه موردی: تولید درپوش گیربکس حلزونی مدل 62

نویسندگان

باشگاه پژوهشگران جوان و نخبگان دانشگاه آزاد اسلامی، واحد خمینی شهر

چکیده

برای تولید قطعاتی که دارای خواصی مناسب و در نزدیک­ترین حالت تولید به­شکل نهایی باشند می­توان از انواع فرآیند­های شکل­دهی نیمه­جامد استفاده نمود. تیگزوفورجینگ به مجموعه­ای از فرآیندهای نیمه­جامد گفته می­­شود که در آن عملیات شکل­دهی برای موادی با کسر جامد کمتر از 55% صورت بگیرد. هدف از این مقاله بررسی تاثیر دما (یعنی دمای قالب و قطعه خام) برای تولید قطعه­ای نسبتاً پیچیده است. خروجی­های مورد بررسی نیز ریزساختار و مشخصات مکانیکی قطعه تولیدی در نظر گرفته شده است. برای این منظور یک­سری آزمایشات عملی صورت گرفته است. همچنین داده­های حاصل در این آزمایشات با مقادیر استخراجی از شبیه­سازی مورد ارزیابی قرار گرفته است. نتایج نشان می­دهد که با افزایش دمای قالب، ریزساختار درشت­تر می­شود. همچنین در این حالت ساختار غیر همگنی به­وجود می­آید. نتیجه این اتفاق کاهش سختی به مقدار 5/12% است. البته نیروی شکل­دهی نیز کاهش یافته که مقدار 6/20% گزارش شده است. همچنین رشد دانه­ها با افزایش دمای قطعه و مدت زمان نگه­داری نشان داده شده است. می­توان گفت برای مدت زمان نگه­داری min5 دقیقه، چنانچه دما از ºC570 به ºC600 افزایش یابد، مقدار اندازه دانه 3/5% افزایش می­یابد. یا برای دمای ºC570 افزایش زمان نگه­داری از min5 به min30 موجب افزایش 9/73% در اندازه دانه می­گردد. در ادامه برای بهبود سختی نمونه­ها از عملیات T6 استفاده شده است. با استفاده از این عملیات، میزان سختی 3/17% افزایش یافت. دلیل این امر   شکسته­شدن فاز یوتکتیک و تبدیل آن به ساختار همگن و کروی است.

کلیدواژه‌ها


عنوان مقاله [English]

Experimental Study and Simulation of the Effect of Temperature in Thixoforging Process, Case Study: Producing of the 62 Model Helical Gearbox Cap

نویسندگان [English]

  • amin kolahduz
  • sasan aminian
azad , khomeini shahr
چکیده [English]

Semi-solid metal (SSM) processing has been used to produce of the engineering components with the suitable properties and at the closet form of the final part. Thixoforging is one of SSM processes that in this process the forming operation is performed on materials with the solid fraction of less than 55%. The purpose of this paper is to discuss on the temperature (mold and specimen temperature and holding time) for the producing of a relatively complex piece. The characteristics of the microstructures and mechanical properties of thixoforged Al-A356 alloy were studied. For this aim, some experimental tests were done. Also the results of these tests are compared with the results of simulations. The results showed that by increasing mold temperature, causes more inhomogeneous microstructure and therefore the hardness and forming force decreased %12.5 and %20.6 respectively. Also the results showed that increasing the specimen temperature and holding time, the grain size of primary α–al phase increased. For example in holding time of 5 min, by increasing the temperature from 570°C to 600°C, the grain size of primary α–al increased 3.5 percent. Also in the temperature from 570°C, by increasing holding time of 5 min to 30 min, the grain size of primary α–al increased 73.9 percent. In this work, the T6 heat treatment process was used for improving the hardness. The hardness was increased %17.3, because of changing in primary α–al phase and produced the homogeneous microstructure.

کلیدواژه‌ها [English]

  • Thixoforging
  • non-isothermal forging
  • mold temperature
  • slug temperature
  • holding time
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