A new method for manufacturing hollow valves via cross wedge rolling and forging: Numerical analysis and experiment validation

Ji, Hongchao; Liu, Jinping; Wang, Baoyu; Fu, Xiao‐An; Xiao, Wenchao; Zheng-huan, HU

doi:10.1016/j.jmatprotec.2016.09.004

Cited by 58 publications

(17 citation statements)

References 21 publications

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“…The valve microstructure is a main factor in future engine applications [6][7][8]. Austenitic 21-4N stainless steel is widely used for valves because of its good balance between strength and toughness and good wear resistance in an extreme working environment [9]. However, austenitic 21-4N stainless steel has poor plasticity and a narrow range of processing temperature.…”

Section: Introductionmentioning

confidence: 99%

Predicting the Microstructure of a Valve Head during the Hot Forging of Steel 21-4N

Huang

et al. 2018

Metals

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Abstract:Valve microstructure is important during hot forging. Austenitic 21-4N steel is often used in exhaust valves. In this study, the microstructure evolution of the forging valve process was predicted using the internal state variables (i.e., average grain size, recrystallized fraction, and dislocation density) modus for 21-4N. First, 21-4N was subjected to hot compression tests on a Gleeble-1500D and static grain growth tests in a heating furnace. A set of uniform viscoplastic constitutive equations was established based on experimental data. Next, the determined unified constitutive equations were conducted in DEFORM-3D, and the microstructure evolution of 21-4N during forging was calculated. Finally, the simulation results of grain size evolution were validated via experiments. Results showed good consistency between the simulations and experiments. Thus, the models adequately predicted the microstructure evolution.

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Section: Introductionmentioning

confidence: 99%

Predicting the Microstructure of a Valve Head during the Hot Forging of Steel 21-4N

Huang

et al. 2018

Metals

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“…CWR is usually applied in the metal forming industry for the manufacture of elongated products, such as stepped shafts [6][7][8][9], balls [10], and preforms of forging [11][12][13][14][15][16][17].…”

Section: Working Principle Of Cross Wedge Rollingmentioning

confidence: 99%

Research and industrialization of near-net rolling technology used in shaft parts

2018

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Shaft part rolling is an efficient and green nearnet shaping technology offering many advantages, including high production efficiency, high material utilization rate, high product quality, and excellent production environment. In this paper, the features of shaft part rolling are introduced along with the working principles of two main shaft part rolling technologies, namely, cross wedge rolling (CWR) and skew rolling (SR). In relation to this technology, some R&D achievements gained by the University of Science and Technology Beijing are summarized. Finally, the latest developments in shaft part rolling are presented, including SR steel balls, precise forming of camshaft blank by CWR, SR phosphorous copper balls at room temperature, and CWR hollow axle sleeve. Although the shaft part rolling technology has been widely used in China, it only accounts for about 15% of applicable parts at present. Nevertheless, this technology has broad application prospects.

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“…But some defects can easily occur during electric upsetting such as coarse grain, overheating, overlap and cracking [2,3]. In recent years, a team in the University of Science and Technology Beijing (USTB) proposed a new method to produce the preform of valves by cross wedge rolling (CWR), which has higher production efficiency and better control of product quality [4][5][6].…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on Cross Wedge Rolling of 21-4N Heat Resistant Steel

Zheng

2019

Metals

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21-4N is a typical heat resistant steel used as the material of exhaust valves. The application of cross wedge rolling to manufacture preform for valves has the advantages of higher efficiency and better quality. In this study, cross wedge rolling of 21-4N with an area reduction ratio of 65% was experimentally studied. Twelve groups of different tool parameters of cross wedge rolling tests were carried out. It is found that a larger stretching angle or a smaller forming angle is better for surface quality. When the stretching angle is 7° and the forming angle is less than 25°, a smooth surface can be obtained. Furthermore, the influence of stretching angle on central quality is not obvious, but a greater forming angle is prone to get a better central quality. When the forming angle is larger than 30°, no central damage was found in the workpieces. Considering the balance of surface quality and central quality, a stretching angle of 7° and a forming angle of 30° is a suitable combination for cross wedge rolling of 21-4N with an area reduction ratio of 65%.

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A new method for manufacturing hollow valves via cross wedge rolling and forging: Numerical analysis and experiment validation

Cited by 58 publications

References 21 publications

Predicting the Microstructure of a Valve Head during the Hot Forging of Steel 21-4N

Predicting the Microstructure of a Valve Head during the Hot Forging of Steel 21-4N

Research and industrialization of near-net rolling technology used in shaft parts

Experimental Study on Cross Wedge Rolling of 21-4N Heat Resistant Steel

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