Development of Valve Steel containing of a Blend of Hard Phases for High-Temperature Applications | ||
| Journal of Ultrafine Grained and Nanostructured Materials | ||
| مقاله 8، دوره 58، شماره 2، اسفند 2025، صفحه 228-241 اصل مقاله (1.46 M) | ||
| نوع مقاله: Research Paper | ||
| شناسه دیجیتال (DOI): 10.22059/jufgnsm.2025.02.08 | ||
| نویسندگان | ||
| taher El-Bitar1؛ Maha ElMeligy* 1؛ Mohammed Gamil2 | ||
| 1Plastic Deformation Department, Central Metallurgical R&D Institute (CMRDI), Cairo 11422, Egypt | ||
| 2Department of Mechanical Engineering, Faculty of Engineering at Shoubra, Benha University, Cairo | ||
| چکیده | ||
| The steel contains carbon, silicon, chrome, and molybdenum. Multi-directional hot forging was implemented on 5 successive steps, for matrix grains refinement with homogeneously distributed embedded Cr/Mo carbides. Forging at the 1st step was carried out at 1150 oC and finished at 1000 oC, while the final 5th deformation step was finished at 890 oC, where the cross-section area reduction was reachin to 64.03 %. The Z-parameter was then evaluated for each forging step. It is found that the Z-parameter increases continuously, which is resulting in successive decrease of expected γ-grain size, and consequently the generated microstructure is subjected to repeated grain refinements. The forged steel rods were then heat treated at 930 oC and soaked for 15 min. and followed by a salt bath 1st quenching at 400 oC for 15 min. And followed by oil (2nd) quenching. After the 2 quenching cycles, the generated microstructure contains bainite islands interspersing across freckled ferrite matrix with scattered Cr/Mo carbides. The generated bainite is featured with a low carbon content. Thermodynamically, Cr/ Mo carbides are the most stable carbides within the working temperature range. The bainitic aggregates are found surrounded by thin retained austenite films. Quenching in water after salt bath treatment creates platelet late martensite integrated with the widespread Cr/Mo carbides, that existing between the ferrite matrix grains. | ||
| کلیدواژهها | ||
| Valve steel؛ Multi-directional hot forging؛ Bainite generation؛ Late martensite؛ Salt bath؛ Oil and water quenching | ||
| مراجع | ||
|
| ||
|
آمار تعداد مشاهده مقاله: 466 تعداد دریافت فایل اصل مقاله: 286 |
||