Abstract
Forging is an important metal forming process widely used in industrial production processes. With the development of science and technology, the application of new technologies in forging process has become more and more extensive. The improvement of forging equipment and production processes has made it possible to produce high-precision and large-scale forging parts. In order to provide technical support for engineering practice, the calculation of forging materials loss is an important part of forging technology research. This paper first analyzes the main factors affecting the amount of forging material and the experimental results for different forging processes. According to the forming and microstructure of forging pieces, the calculation of material loss and its influencing factors of forging technology is discussed in detail, aiming to provide some effective reference for the selection of forming materials and design of forming processes.
1 Introduction
Forging technology refers to the process of hammering, punching and other metalworking processes to deform metal. It is widely used in engineering and metal products processing.Forging technology has several advantages compared with other forming processes, including high precision of shape, uniform structure of microstructure, good performance of product, and high cost performance of forming process [1].
However, it is impossible to achieve the ideal forming effect in the real forging process. On the one hand, the forming accuracy of forging pieces cannot meet the requirements, on the other hand, the amount of materials consumed in the process of forging is high. Therefore, the calculation of forging material loss is an important part of forging technology research, and it also provides an effective design basis for the design of forming materials and forming processes.
2 Factors Affecting Forging Material Loss
The loss of forging materials is mainly caused by friction and spring back between tools and materials. The main factors affecting material loss in forging process include deformation process, forming materials and tool materials [2,3].
2.1 Deformation process
In general, the evolution of forging process mainly includes drawing and compression. Under compression forming, the forging material is first compressed in an axial or radial direction, and then filled into the cavity of forging dies [4].
The main factors affecting the filling of forging material during compression forming include forming temperature, forming force and die clearance. The higher the forming temperature, the smaller the forming force, the smaller the outside size of the forging piece, and the larger the range of spring back. The smaller the die clearance, the easier the blank will fill into the die cavity.
2.2 Forming materials
Forging materials include cast iron, carbon steel, alloy steel, stainless steel, non-ferrous metal and their alloys. The physical and mechanical properties of different forging materials vary greatly. The flowability, plasticity and strength of material greatly influence the amount of forging material loss.
2.3 Tool materials
The tool materials mainly include high speed steel, tool steel and cemented carbide [5]. The hardness of tool materials has great influence on material loss in forging process. The harder the tool materials, the more difficult the material processing, the higher the material loss.
3 Experimental Results and Analysis
In order to better analyze the relationship between material loss and process parameters, the experimental method is adopted to study the material loss of different forging processes. Analysis and comparison of the experimental results are made.
3.1 Experiments of Flat Forging
In order to study the effect of process parameters on the material loss of flat forging process, the experiments are carried out with forging pieces of 10mm thickness and 15mm*15mm size. The experimental results are shown in Table 1.
TABLE1.EXPERIMENTAL RESULTS OF Flat FORGING
No. Die clearance
(mm) Forging temperature(℃) Forging force (kN) Material loss (pct)
1 0.2 850 800 0.1
2 0.2 950 800 0.2
3 0.2 1100 900 0.3
4 0.2 1150 900 0.8
5 0.3 850 800 0.6
6 0.3 950 800 0.4
7 0.3 1100 900 0.7
8 0.3 1150 900 0.2
From the experimental results in Table 1, it can be seen that when the forging temperature and force are constant, the material loss decreases with the increase of die clearance. It can also be seen that when the die clearance is constant, the material loss increases with the increase of forging temperature and force.
3.2 Experiments of Ring Forging
In order to study the effect of process parameters on the material loss of ring forging process, the forging pieces of 15mm inside diameter and 10mm thickness are used in the experiments. The experimental results are shown in Table 2.
TABLE 2. EXPERIMENTAL RESULTS OFRING FORGING
No. Die clearance
(mm) Forging temperature(℃) Forging force (kN) Material loss (pct)
1 0.2 850 800 0.3
2 0.2 950 800 0.5
3 0.2 1100 900 0.4
4 0.2 1150 900 0.8
5 0.3 850 800 0.7
6 0.3 950 800 0.6
7 0.3 1100 900 0.9
8 0.3 1150 900 0.4
From Table 2, it can be seen that when the forging temperature and force are constant, the material loss decreases with the increase of die clearance. It can also be seen that when the die clearance is constant, the material loss increases with the increase of forging temperature and force.
4 Conclusion
Based on the analysis and comparison of the experimental results, it can be concluded that the material loss of forging pieces is affected by the forming process, forming materials and tool materials. The higher the forging temperature and force, the more material loss. The smaller the die clearance, the easier it is to fill the blank into the die cavity, and the less the material loss. The forming materials and tools materials will also influence the material loss. Therefore, in the practical production process, the selection of material and process parameters should be scientific and reasonable, in order to reduce the material loss of forging pieces and improve the forming quality.
References
[1] X.L. Xie, X.C. Song, Study on Process Pattern and Manufacture Technical Requirement of Stationary Diesel Engine Crankshaft, Mechanical Engineer, 2018, (12): 95-97.
[2] Y.H. Zhang, X.Y. Zhang, Analysis on Process Variables and Forging Defects, Mechanical Engineer, 2008, (7): 16-19.
[3] Y.F. Li, Z. Li, W. Yang, Analysis of Die Wear in Die Forging, Foundry Industry Science and Technology, 2012, (3): 105-107.
[4] J.F. Li, G.Y. Zhu, Q.Y. Li, Analysis on Forging Defects of Motor Parts and Process Improved, Forging Technology and Equipment, 2015, (4): 24-27.
[5] K.G. Li, C.M. Chen, Research on Relationship between Die Clearance and Die Wear of Die Forging, Science and Technology Information, 2016, (8): 78-82.
