Current failure mechanisms and treatment methods of hot forging tools (dies) - a review

Emamverdian, Ali Akbar; Sun, Yu; Cao, Chunping; Pruncu, Catalin I.; Yu, Wang

doi:10.1016/j.engfailanal.2021.105678

Cited by 40 publications

(17 citation statements)

References 102 publications

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“…Furthermore, the dies suffer dry wear and heating impact when directly contacting hot metals in an unlubricated environment. Therefore, dry wear is one of the failure mechanisms in the hot-working die industry [5,6]. Based on previous studies, abrasive wear, adhesive wear and oxidative wear are the reasons for degradation in hot-working dies [7,8].…”

Section: Introductionmentioning

confidence: 99%

Wear characteristics of austenitic steel and martensitic steel at high temperature

Bai

Yang

et al. 2022

Mater. Res. Express

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The wear under high-temperature condition is one of the die failure patterns. Therefore, the wear resistance at high temperature is an important parameter for selecting die materials. In this work, the wear resistance of SDHA steel and 4Cr5Mo2V steel at 400 - 700°C were evaluated by a friction and wear tester. The wear behaviors and oxide types were investigated through a scanning electron microscope (SEM) and X-ray diffraction (XRD). The results show that the oxides on the worn surface are Fe2O3 and Fe3O4 at the test temperatures. The wear volume of two steels first decreases and then increases, reached the minimum value at 500 ℃. Besides, SDHA steel has better wear resistance compared with 4Cr5Mo2V steel, which is attributed to the excellent hardness stability at high temperature. The coarse M7C3 carbides in 4Cr5Mo2V steel cause the peeling and delamination of oxide layer to damage wear resistance at 700 ℃.

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Section: Introductionmentioning

confidence: 99%

Wear characteristics of austenitic steel and martensitic steel at high temperature

Bai

Yang

et al. 2022

Mater. Res. Express

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“…This results from the difficulty in shaping steel with a high content of nickel and a poor selection of the process parameters [16,17]. As a result of high pressures at high temperatures as well as a long path of friction, in the case of the punch used in the second forging operation, we observe wear [18] (mainly abrasive wear as well as material tempering causing plastic deformation) of the so-called "calotte" on the head surface in the tool axis. This is the main cause of removing the punches from further operation (after they reach the critical dimensions of depth and calotte radius).…”

Section: Introductionmentioning

confidence: 98%

Wear Analysis of Forging Tools Used in an Industrial Production Process—Hot Forging in Closed Dies of the “Head-Disk” of an Engine Valve Forging

et al. 2021

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The article performs an analysis of the durability of punches applied in the process of producing a valve forging from chromium-nickel steel. A forging of this type is made in two operations: coextrusion of a long shank, followed by finishing forging in closed dies of the valve head. The product obtained in this way (after other additional finishing procedures) constitutes the key element of the combustion engine (resistant to high pressures and temperatures) in motor trucks. Unfortunately, a significant problem in this production process is a relatively low durability of the forging tools, especially the punch used in the second forging operation. The key element at this stage, deciding about the punch’s further operation, is the area of the so-called “calotte”. The short-term life of the tools results from very hard performance conditions present during the forging process (periodical high mechanical and thermal loads, long path of friction). The latter cause intensive abrasive wear as well as high adhesion of the forging material to the tool surface. Based on the performed studies, including the following: technology analysis, numerical modelling, macro analyses combined with 3D scanning of tool sections as well as microstructural tests and hardness measurements, it was established that it is crucial to properly select the process parameters (charge and tool temperature, tribological conditions), as even slight changes introduced into them significantly affect the operation time of the forging tools. Mastering and proper implementation of the analyzed forging technology requires numerous further studies and tests, which will enable its perfection and thus increase the durability of the tools as well as the quality of the produced items.

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“…The main damage mechanisms leading to die failure in hot forging processes are abrasive and adhesive wear, mechanical and thermomechanical fatigue, plastic deformation and oxidation [3]. According to the statistics provided by many authors, 70 % of forging dies are taken out of service due to wear, 25% due to mechanical fatigue, and only 3-5% of the forging dies failed due to thermal cracking and plastic deformation [4]. All of the mechanisms occur simultaneously from the very beginning of the IOP Publishing doi:10.1088/1757-899X/1238/1/012025 2 press hardening process, and they can be more or less intensive depending on factors as the design of the die, lack of hardness at elevated temperature, contact time, sliding distance, inadequate die material, work piece temperature and lubrication [3].…”

Section: Introductionmentioning

confidence: 99%

A case study of mechanical and thermal fatigue of press hardening dies

Chantziara

Kalahroudi

Bergström

et al. 2022

IOP Conf. Ser.: Mater. Sci. Eng.

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Press hardening provides ultra-high strength steel components, typically boron steels, of complex geometries. In the process, the steel sheet is heated in a furnace to the austenitization temperature, transferred to the press, then simultaneously formed at high temperature and cooled in the die. Life limiting factors for the press hardening dies are mechanical fatigue, thermal fatigue, and wear. In the present case study two die segments were selected where critical damages were mechanical and thermal fatigue, respectively. The dies were made of a H13 type premium hot-work tool steel with complex heated die technology, die design integrating an advanced cooling system, for pressing automotive frame parts. The first die failed due to mechanical loading with a crack initiated from the ejector pin area. The die design, the mechanical loads, the elevated temperature, and the tool steel crack resistance are main factors to consider. In the second die cracks initiated from an ejector pin hole, as well, due to thermal cycles causing alternating compressive and tensile stresses at the surface, which led to crack nucleation because of the accumulation of local plastic strain in the surface.

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Current failure mechanisms and treatment methods of hot forging tools (dies) - a review

Cited by 40 publications

References 102 publications

Wear characteristics of austenitic steel and martensitic steel at high temperature

Wear characteristics of austenitic steel and martensitic steel at high temperature

Wear Analysis of Forging Tools Used in an Industrial Production Process—Hot Forging in Closed Dies of the “Head-Disk” of an Engine Valve Forging

A case study of mechanical and thermal fatigue of press hardening dies

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