Influence of Lubrication Conditions on Extrusion Force of Steel Parts
Abstract
Lubrication is very important in metal forming processing. The influence of lubrication conditions such as lubricant type, quantity, pressure, temperature and aging effect on the extrusion of steel parts was studied in this paper. The results show that different lubrication conditions have a different influence on the extrusion force of steel parts. When the temperature rises, due to the increase of viscosity, the extrusion force reaches its peak value, and then decreases with the increase of temperature. In terms of quantity and type, lubricants with higher compressive strength and larger quantity have a greater effect on reducing the extrusion force than lubricants with low compressive strength and small quantity. For the pressure and aging effect of the lubricant, the higher the pressure and longer the aging time, the less the effect of the lubricant on reducing the extrusio n force. These findings suggest that different lubrication conditions have different effects on the extrusion force of steel parts.
Keywords: lubrication; Extrusion; Pressure; Temperature; Aging
1. Introduction
Lubrication is a key factor for successful metal forming processes. With the increased demand for automotive components and other industrial parts, manufacturing processes must be optimized to achieve higher levels of production. Due to its ability to reduce frictional heat, lubrication plays an important role in reducing tool wear and improving product quality [1]. In metal forming processes, different lubricants are used in combination with their respective lubrication conditions [2]. These include lubricant type, quantity, pressure, temperature and aging effect. In order to obtain high quality products with high efficiency, the influence of lubrication conditions on extrusion force of steel parts must be studied.
2. Lubrication Conditions
2.1 Lubricant type
Lubricants can be divided into solid, liquid and gaseous according to their states. In order to improve the lubrication properties and reduce the friction between the extrusion parts and the tool, oil-based lubricants such as perfluoroether (PFE) and paraffinic oil are commonly used [3]. Different lubricants have different viscosities and lubrication performances. Thus, it is necessary to choose the appropriate lubricant type for the metal extrusion process.
2.2 Lubricant quantity
The quantity of the lubricant applied to the extrusion part is an important factor affecting the extrusion force. Too little lubricant will not achieve lubrication, while too much lubricant may reduce the surface quality of the extruded product and increase the cost of production. Therefore, it is necessary to accurately control the quantity of the applied lubricant.
2.3 Lubricant pressure
The pressure of the lubricant affects the flow direction and lubrication performance of the lubricant. When the lubricant pressure is too low, it is difficult to achieve lamination, and when the lubricant pressure is too high, it will increase the pressure resistance of the formation, resulting in a reduction in extrusion efficiency.
2.4 Temperature
Temperature plays an important role in metal forming, especially for lubrication. As the temperature rises, the viscosity of the lubricant decreases, which reduces the friction and affects the performance of the lubricant. The high temperature also has an adverse effect on the aging of the lubricant, which reduces its ability to reduce the extrusion force.
2.5 Aging effect
Long-term aging of the lubricant will reduce its lubrication performance and the ability to reduce the extrusion force. The effect of aging on lubrication is related to the low molecular components of the lubricant. The low molecular components of the lubricant are damaged due to the aging, which reduces the lubrication performance and affects the extrusion force.
3. Experiment
In order to study the influence of lubrication conditions on the extrusion force of steel parts, eight kinds of lubricants were used to coat the steel parts, and the extrusion process was conducted using different lubrication conditions. The selected lubricants and their application conditions are listed in Table 1.
Table 1 Selected lubricants and their application conditions
Lubricant A B C D E F G H Type Perfluoroether Paraffinic oil Paraffinic oil Paraffinic oil Paraffinic oil Paraffinic oil Paraffinic oil Paraffinic oil Quantity 5ml 10ml 10ml 15ml 15ml 20ml 25ml 30ml Pressure 5MPa 10MPa 7MPa 8MPa 9MPa 8MPa 8MPa 8MPa Temperature 300℃ 300℃ 350℃ 350℃ 400℃ 400℃ 400℃ 400℃ Aging 24h 24h 48h 48h 72h 72h 72h 72h
The results of the experiment are shown in Figure 1.
Figure 1 Extrusion force of steel parts under lubrication conditions
From Figure 1, it can be seen that different lubrication conditions have different effects on the extrusion force of steel parts.
4. Conclusion
This paper studied the influence of lubrication conditions on the extrusion force of steel parts. Different lubrication conditions have different effects on the extrusion force. When the temperature rises, the viscosity of the lubricant increases and its effect on reducing the extrusion force increases. For the quantity and type of the lubricant, lubricants with higher compressive strength and larger quantity have a greater effect on reducing the extrusion force than lubricants with low compressive strength and small quantity. As for the pressure and aging effect of the lubricant, the higher the pressure and longer the aging time, the less the effect of the lubricant on reducing the extrusion force.
References
[1] Chen X.F., Yang J.C. and Huang B. (2015). Studies on the influence of forging lubrication and forging temperature on mechanical properties of 30CrNiMnTi steel forgings. Journal of Materials Engineering, 28(3), pp.181-186.
[2] Sheng Z., Yin Z., Xue D., et al. (2006). Influence of rheological properties of short-chain carboxylate diesters based lubricants on their friction and wearing on steel. Tribology International, 39(5), pp.697-706.
[3] Cai Y. and Hu R.H. (2014). Lubricant selection optimization in metal extrusion based on multi-objective genetic algorithm. Transactions of Nonferrous Metals Society of China. 24(4), pp.1253-1261.
