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تحلیل ریزساختار و خواص مکانیکی گریدهای فولادی تصفیه شده به روش RH قبل و بعد از نورد

نوع مقاله : مقاله پژوهشی (کاربردی)

نویسندگان
1 گروه مهندسی مکانیک، دانشگاه ملی مهارت، تهران، ایران.
2 گروه علوم مهندسی، دانشگاه ملی مهارت، تهران، ایران.
چکیده
در این مقاله تحلیل ریزساختار و خواص مکانیکی گریدهای فولادی تصفیه شده به روش RH قبل و بعد از نورد انجام شده است. در فرآیند RH که تحت شرایط خلاء انجام می‌گیرد عموما واکنش کربن با گاز اکسیژن صورت گرفته و منجر به کاهش کربن و اکسیژن مذاب به ترتیب کمتر از10و 15 PPM می‌گردد، علاوه برکربن‌زدایی و اکسیژن‌زدایی می‌توان هیدروژن و نیتروژن مذاب را به واسطه ایجاد خلا به حداقل ممکن کاهش داد. پس از گاززدایی و بهبود کیفیت مذاب از 6 گرید فولاد نمونه‌گیری و جهت مقایسه ریزساختار و بررسی خواص مکانیکی روی نمونه‌ها آزمون‌های مکانیکی شامل کشش و سختی انجام گرفت. نتایج نشان داد که نورد بر ساختار و خواص فولادها در تمامی گریدها تأثیر زیادی دارد. طبق نتایج بدست ‌آمده، فاز مارتنزیتی تیغه‌ای پس از نورد تقریباً 2 درصد افزایش می‌یابد و به دلیل بزرگ‌تر و پهن‌تر شدن دانه‌ها تیغه‌های مارتنزیتی نیز شکسته شده و پهن‌تر می‌شود. نتایج آزمون‌های مکانیکی نشان داد که سختی و استحکام نهایی نمونه نورد شده به ترتیب به 95 HB و 325 MPa رسید که نشان می‌دهد علاوه بر اینکه ناخالصی درمحصول نهایی کاهش داشته ساختار مارتنزیتی نیز تاثیرگذار بوده است، همچنین برای از بین بردن اکسیژن به افزودن آلومینیوم که باعث ایجاد ناخالصی می‌شود نیاز نیست، بلکه با حذف گاز هیدروژن کیفیت بالا رفته و استحکام ورق نیز در محدوده بسیار مطلوبی قرار می‌گیرد.
کلیدواژه‌ها
موضوعات

عنوان مقاله English

Analysis of microstructure and mechanical properties of refined steel grades by RH method before and after rolling

نویسندگان English

Abbas Abbasian 1
Mohammad Ali Etminani Esfahani 2
1 Department of Mechanical Engineering, Technical and Vocational University (TVU), Tehran, Iran.
2 Department of Engineering Sciences, Technical and Vocational University (TVU), Tehran, Iran.
چکیده English

In this article, the analysis of microstructure and mechanical properties of refined steel grades by RH method before and after rolling has been done. In the RH process, which is carried out under vacuum conditions, the reaction of carbon with oxygen gas generally takes place and leads to the reduction of dissolved carbon and oxygen below 10 and 15 PPM, respectively. reduced After degassing and improving the melt quality, samples were taken from 6 grades of steel, and in order to compare the microstructure and check the mechanical properties, mechanical tests including tensile and hardness were performed on the samples. The results showed that rolling has a great effect on the structure and properties of steels in all grades. According to the obtained results, the martensitic phase of the blade increases by approximately 2% after rolling, and due to the larger and wider grains, the martensitic blades are also broken and become wider. The results of the mechanical tests showed that the final hardness and strength of the rolled sample reached 95 HB and 325 MPa, respectively, which shows that in addition to the reduction of impurities in the final product, the martensitic structure was also effective, as well as adding aluminum to eliminate oxygen. It does not cause impurity, but with the removal of hydrogen gas, the quality is increased and the strength of the sheet is in a very favorable range.

کلیدواژه‌ها English

Steel
Decarburization
Degassing
RH
Rolling
Mechanical Properties
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دوره 22، شماره 3
فنی و مهندسی
پاییز 1404
صفحه 449-465

  • تاریخ دریافت 23 مهر 1403
  • تاریخ بازنگری 18 آذر 1403
  • تاریخ پذیرش 18 فروردین 1404