2 nd Austrian-Indian-Symposium on Materials Science and Tribology Wiener Neustadt, 26 th – 29 th May 2014 MaTri'14 Static and Dynamic Friction of Sphero- graphite Cast Iron with Sn Microalloy Mara Kandeva 1, Boryana Ivanova 2, Dimitar Karastoyanov 3, Emilia Assenova 4 1 Tribology Center, Technical University - Sofia, 2 Dept. Material Science and Technology, Technical University – Sofia 3 Institute for Information and Communication Technologies, Bulgarian Academy of Sciences, Sofia 4 Society of Bulgarian Tribologists, Sofia

2 nd Austrian-Indian-Symposium on Materials Science and Tribology Wiener Neustadt, 26 th – 29 th May 2014 MaTri'14 Introduction Sphero-graphite cast iron is a composite construction material with good mechanical characteristics. Sn microalloying improves of strength, hardness, etc., but also tribological characteristics friction and wear. Aim: study of the influence of Sn quantity in sphero-graphite cast iron during : preliminary displacement (static friction) and motion (dynamic friction). Tasks: 1. Development of procedures and devices for static and dynamic dry friction study at various normal loads and sliding velocity; 2. Study of friction force and coefficient at static friction and dynamic friction.

2 nd Austrian-Indian-Symposium on Materials Science and Tribology Wiener Neustadt, 26 th – 29 th May 2014 MaTri'14 Materials, procedures and devices Fig.1. Scheme of the device for static friction study Fig.2. Scheme of the device for dynamic friction study Specimen №01234 Sn, %00,0180,0200,0320,051 НВ Table 1: Specimens’ Sn content and hardness HB

2 nd Austrian-Indian-Symposium on Materials Science and Tribology Wiener Neustadt, 26 th – 29 th May 2014 MaTri'14 Materials, procedures and devices Fig.3 Microstructure of the specimens: (a) 0% Sn, (b) 0,018 % Sn, (c) 0,020 % Sn, (d) 0,032% Sn, (e) 0,051% Sn

2 nd Austrian-Indian-Symposium on Materials Science and Tribology Wiener Neustadt, 26 th – 29 th May 2014 MaTri'14 Experimental: Static Friction 1 Sphero-graphite non-heated cast iron specimens, Sn content: 0%, 0.018%, 0.020%, 0.032%, 0.051% Counterbody: Steel alloy, НВ 450 ; roughness Ra = 0,432 µm Normal loads Р 1 = 98,1 N; Р 2 = 196,2 N; Р 3 = 245,25 N; Р 4 = 294,3 N Fig.5. Static COF µ о vs normal load P Fig.6. Static COF µ о vs Sn content

2 nd Austrian-Indian-Symposium on Materials Science and Tribology Wiener Neustadt, 26 th – 29 th May 2014 MaTri'14 Static Friction 2 Fig. 7. COF jump Δµ vs load P Fig. 8. COF jump Δµ vs Sn content Fig. 9. Static friction force Т о vs static contact duration Fig.10. Static friction force Т о vs static contact duration for specimen without Sn for specimen with 0,051% Sn content

2 nd Austrian-Indian-Symposium on Materials Science and Tribology Wiener Neustadt, 26 th – 29 th May 2014 MaTri'14 Static friction conclusion …..

2 nd Austrian-Indian-Symposium on Materials Science and Tribology Wiener Neustadt, 26 th – 29 th May 2014 MaTri'14 Dynamic friction 1 Fig. 2 Device for dynamic friction study: one way translation at various loads and sliding speeds Fig.11.COF vs load P, sliding speed V = 7,2 cm/min Fig.12 COF vs Sn content P, sliding speed V = 7,2 cm/min for specimen without Sn for specimen with 0,051% Sn content

2 nd Austrian-Indian-Symposium on Materials Science and Tribology Wiener Neustadt, 26 th – 29 th May 2014 MaTri'14 Dynamic friction 2 Fig.13. COF vs sliding speed at Р = 98 N load Fig.14. COF vs sliding speed at Р = 294 N load Conclusion Dynamic friction

2 nd Austrian-Indian-Symposium on Materials Science and Tribology Wiener Neustadt, 26 th – 29 th May 2014 MaTri'14 Conclusion 1. Results are obtained for the variation of static and dynamic friction coefficient in function of load and Sn content in the cast iron. 2. Increasing of Sn leads to nonlinear decrease in static COF and friction jump passing through a minimum. 3. A minimum is also observed in the variation of the dynamic COF at small sliding speeds.

2 nd Austrian-Indian-Symposium on Materials Science and Tribology Wiener Neustadt, 26 th – 29 th May 2014 MaTri'14 Acknowledgements Part of the study is related to the 7 FP Project „Acom In (Advanced Computing Innovations)” coordinated by the Institute of Information and Communication Technologies at the Bulgarian Academy of Science and the project No BG051PO “Development support of PhD students, postdoctoral researchers and young scientists in the field of virtual engineering and industrial technologies”. The project is realized with the financial support of the Operational Program Human Resources Development, co-financed by the European Union through the European Social Fund.

2 nd Austrian-Indian-Symposium on Materials Science and Tribology Wiener Neustadt, 26 th – 29 th May 2014 MaTri'14 THANK YOU FOR YOUR ATTENTION Mara Kandeva, Tribology Center, Dept., Technical University-Sofia, Boryana Ivanova, Dept. Material Science and Technology, Technical University-Sofia Dimitar Karastoyanov, Institute for Information and Communication Technologies, Bulgarian Academy of Sciences, Sofia, Emilia Assenova, Society of Bulgarian Tribologists,

2 nd Austrian-Indian-Symposium on Materials Science and Tribology Wiener Neustadt, 26 th – 29 th May 2014 MaTri'14 Slide 13

2 nd Austrian-Indian-Symposium on Materials Science and Tribology Wiener Neustadt, 26 th – 29 th May 2014 MaTri'14 Slide 14

2 nd Austrian-Indian-Symposium on Materials Science and Tribology Wiener Neustadt, 26 th – 29 th May 2014 MaTri'14 Slide 15, proba

2 nd Austrian-Indian-Symposium on Materials Science and Tribology Wiener Neustadt, 26 th – 29 th May 2014 MaTri'14 THANK YOU FOR YOUR ATTENTION