Study the Effects of the Cryogenic Method Using Liquid Nitrogen on Fittings in Assembly Process
Subject Areas :Mohammad Mesgar 1 , Ahmad Afsari 2 , Sayed Ahmad Behgozin 3 , Seyed Javad Asnaashari 4
1 - Department of Mechanical Engineering, Shiraz Branch, Islamic Azad University, Shiraz, Iran
2 - Department of Mechanical Engineering, Shiraz Branch, Islamic Azad University, Shiraz, Iran
3 - Department of Mechanical Engineering, Shiraz Bahonar Engineering College, Technical and Vocational University (TVU), Shiraz, Iran
4 - Department of Mechanical Engineering, Shiraz Branch, Islamic Azad University, Shiraz, Iran
Keywords: Liquid nitrogen, Cryogenics, Assemble and Disassemble, Fitting Process,
Abstract :
Cryogenics is a field that involves producing, storing, transporting, and using materials at freezing temperatures. One application of this technology is in the shrinkage fitting process, where coolant materials like liquid nitrogen are used to reduce the dimensions of parts so that they can be joined together. This technique is often utilized in sub-assemblies to create a strong fit between the internal and external surfaces of components, which eliminates relative movement between parts, allowing force to be directly transferred from one part to another. In a recent study, we investigated different methods for fitting bush and axle parts with precise dimensions. Cryogenic, pressing, and thermal methods were utilized for assembly fitting. The cryogenic and thermal methods utilized contraction and expansion of parts for assembly fitting, while no dimensional changes occurred in press fitting. Results from the study showed that the cryogenic method required less force for the assembly and disassembly of parts, and the surface quality of the parts after disassembly was better compared to the other methods. Metallographic tests demonstrated that the microstructure of the parts did not change, and impact tests showed that there was no decrease in the toughness of the parts after the cryogenic operation. Based on these findings, the researchers concluded that the cryogenic method is an excellent technique for fitting SAE4140 Steel parts.
[1] Jawahir, I. S., Attia, H., Biermann, D., Duflou, J., Klocke, F., Meyer, D. and Umbrello, D., 2016. Cryogenic manufacturing processes. CIRP annuals. 65(2), 713-736.
[2] Inoan, C. I., Corches, S, R. N., Adrian, T. R. I. F. and Achimas, G. 2021. Study on the Applications of Self-Tightening Assembles (Clamping, Shrinking-on). Academic Journal of Manufacturing Engineering. 19(1): 98-105.
[3] Khanna, N., Pusavec, F., Agrawal, C. and Krolczyk, G. M. 2020. Measurement and evaluation of hole attributes for drilling CFRP composites using an indigenously developed cryogenic machining facility. Measurement. 154: 107504.
[4] Sogalad, I. and Udupa, N. S. 2010. Influence of cryogenic treatment on load bearing ability of interference fitted assemblies. Materials and Design. 31(1):564-569.
[5] Salehi Kolahi, M. R., Karamooz, M. and Rahmani, H. 2020. Elastic analysis of shrink-fitted thick FGM cylinders based on linear plane elasticity theory. Mechanics of Advanced Composite Structures. 7(1): 121-127.
[6] Liew, K. M., Kitipornchai, S., Zhang, X. and Lim, C. W. 2003. Analysis of the thermal stress behaviour of functionally graded hollow circular cylinders. International Journal of Solids and Structures. 40(10): 2355-2380.
[7] Collier, N. O., Kaw, A. K., Besterfield, G. H. and Rahman, M. M. 2006. Effects of staged cooling in shrink-fitting compounded cylinders. The Journal of Strain Analysis for Engineering Design. 41(5): 349-361.
[8] Abdelsalam, O. R. and Sedaghati, R. 2013. Design optimization of compound cylinders subjected to autofrettage and shrink-fitting processes. Journal of Pressure Vessel Technology. 135(2): 021209
[9] Bhatnagar, R. M., 2013. Modelling, validation and design of auto-frettage and compound cylinder. European Journal of Mechanics-A/Solids. 39: 17-25.
[10] Jahed, H., Farshi, B. and Karimi, M., 2006. Optimum auto-frettage and shrink-fit combination in multi-layer cylinders. 128(2): 196-200.