تحليل وتحديد آلية الفشل في قوالب الطرق المغلق
Analysis and Identification of the Failure Mechanism in Closed Dies Forging
- الباحث
- منير احمد علو
- المشرف
- عدنان ابراهيم محمد - ابراهيم عبد الكريم احمد
- الجامعة
- الجامعة التكنولوجية
- الكلية / القسم
- قسم هندسة الانتاج والمعادن / هندسة الانتاج والمعادن
- الشهادة
- ماجستير
- السنة
- 2021
- لغة الرسالة
- انكليزي
- الكلمات المفتاحية
- Closed die forging;Failure mechanism;Die wear;Finite element
Abstract
The closed die forging is used in various industries requires high mechanical characteristics. They are involved in the production of engines, electrical transmission systems and several other components. During the closed die forging processes, the life of the tools is the main factor that is affected by thermomechanical stresses, so this study concerned with the analysis of the causes of rapid failure at an early stage of hot forging tools. Failure of dies in hot forging process depends on the causes of dies failure, such as plastic deformation, wear and thermomechanical fatigue. The billet material was alloy steel Ck45, and tool material was 56 NiCrMoV 7. The forging process carried out at 950 °C - 1150 °C by 800-ton horizontal mechanical press. The finite element software MSC Simufact forming 16.0 were used to simulate the process. With the use of the finite element method, much information was supplied, such as temperature and distribution of stresses on the tools, etc. which can be helpful in interpreting the mechanism of failure of forging tools. The results showed that the plastic deformation occurred in the upper and lower dies is due to that the Equivalent stresses and Maximum principle stresses exceed the die material yield point, and the dies temperature increase progressively reduces the hardness; softening effects during the forging process. The optimization process that was done depicted that the best forming process was at a temperature of 1050°C, and the maximum die productivity before failure was found at this temperature for the critical edge areas of the die (p1, p2) and it’s amounted to 365 pieces. The equivalent stresses at these points were 630.65 and 618.32 MPa, respectively, which are less than the yield stress of the die material. The hardness at these points was 41.85 HRC 41.82 HRC, which is higher than the critical hardness of the die’s material, this interpreting that no plastic deformation occurs in the dies at these critical points with this forming temperature, in addition to high productivity. This improvement by reducing the forging temperature leads to minimizing the production time required and cost, which is an important factor for manufacturers. The use of FEM method was efficient to enhance the prediction of die life before failure.
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