Reducing production loss by prolonging service life of rolling mill shear pin with ultrasonic nanocrystal surface modification technology

• Published in: International journal of precision engineering and manufacturing Vol. 14; no. 11; pp. 2027 - 2032
• Main Authors: Pyun, Young Sik, Cho, In Ho, Suh, Chang Min, Park, Jin, Rogers, Josh, Kayumov, Ravil, Murakami, Riichi
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.11.2013
• Subjects: Engineering; Industrial and Production Engineering; Materials Science; Service life; Fatigue; Ultrasonic nanocrystal surface modification (UNSM); Compressive residual stress; AISI1045
• ISSN: 2234-7593; 2005-4602
• DOI: 10.1007/s12541-013-0276-7

Premature failure at the shear pin of stainless hot rolling mill caused by increasing productivity and fluctuation of roll torque raises significant downtime cost. To reduce downtime cost, UNSM (Ultrasonic Nanocrystal Surface Modification) treatment is applied to the neck groove of shear pin as the alternative to existing solutions. This treatment prevents premature failure, increases service life and reduces the number of replacements. Proper process variables of UNSM technology which give the strongest fatigue strength are determined by comparing with S-N curve of rotary bending test result. Surface roughness, hardness and compressive residual stress on three kinds of test specimens are analyzed together with SEM analysis of fracture surface. Real shear pins are produced by the property of highest fatigue strength and installed to the hot mill stand for validation. They come to pass as twice as the original operation cycle.