Backup rolls are the main tool in a four-high rolling mill; the rolling forces applied in load cells promote the fatigue of the material due to mechanical contact between backup rolls and work rolls. This work investigated the causes of recurrent failures in backup rolls, with cracking always initiated on the surface of the roll body and finishing in the main radius between neck and roll body. Aiming to find the causes of failure, visual inspection and morphology of the fracture were performed, complemented with mechanical tests of hardness on the stress concentration area, in addition to validating the results by applying the finite element method, using ANSYS Mechanical Static Structural Software. It was concluded that the fatigue crack initiated on the surface of BUR due to work hardening continued growing up over the fatigued material, creating beach marks, and finally, a fracture occurred in the main radius of BUR due to stress concentration. The work hardening is the main cause of spalling on BURs and other mechanical components exposed to mechanical contact.
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http://dx.doi.org/10.3390/ma15103524 | DOI Listing |
Materials (Basel)
May 2024
Provincial Key Lab of Advanced Welding Technology, School of Materials Science and Engineering, Jiangsu University of Science and Technology, 666 Changhui Road, Zhenjiang 212100, China.
Hot-rolled backup rolls are widely used in steel rolling and usually need to be repaired by arc hardfacing after becoming worn. However, a corrugated-groove defect commonly occurs on the roll surface due to the uneven hardness distribution in the hardfacing layers, affecting the proper usage of the roll. Accordingly, a new swing-arc submerged arc welding (SA-SAW) process is proposed to attempt to solve this drawback.
View Article and Find Full Text PDFHeliyon
June 2023
Research Institute of Electronic Science and Technology, University of Electronic Science and Technology of China, No. 2006, Xi Yuan Ave., West High-Tech Zone, Chengdu, 611731, Sichuan, China.
As the core of Internet of Things (IoT), embedded processors are being used more and more extensive. However, embedded processors face various hardware security issues such as hardware trojans (HT) and code tamper attacks. In this paper, a cycle-level recovery method for embedded processor against HT tamper is proposed, which builds two hardware-implementation units, a General-Purpose Register (GPRs) backup unit and a PC rollback unit.
View Article and Find Full Text PDFClin Orthop Relat Res
September 2023
Royal College of Surgeons in Ireland, Dublin, Ireland.
Background: On May 14, 2021, a criminal cyberattack was launched against the Irish public healthcare system, the Health Service Executive, resulting in a complete shutdown of all national healthcare computer systems, including the Irish National Orthopaedic Register (INOR). Cyberattacks of this kind occur sporadically, and postevent analyses can inform future preparedness efforts, but few such analyses have been published.
Question/purpose: What was the impact of the cyberattack in terms of (1) registry downtime, (2) harms to patients, and (3) costs to the INOR for data contingency and reconciliation?
Methods: All nine hospitals using the INOR were included for data collection.
Materials (Basel)
June 2022
School of Mechanical and Electrical Engineering, Jiangxi University of Science and Technology, Ganzhou 341000, China.
4.5 wt% Si steel sheets with four different yttrium (Y) contents (0, 0.006, 0.
View Article and Find Full Text PDFMaterials (Basel)
May 2022
Facultad de Ingenieria Mecanica y Electrica, Universidad Autónoma de Coahuila, Unidad Torreon, Torreon Coahuila 27410, Mexico.
Backup rolls are the main tool in a four-high rolling mill; the rolling forces applied in load cells promote the fatigue of the material due to mechanical contact between backup rolls and work rolls. This work investigated the causes of recurrent failures in backup rolls, with cracking always initiated on the surface of the roll body and finishing in the main radius between neck and roll body. Aiming to find the causes of failure, visual inspection and morphology of the fracture were performed, complemented with mechanical tests of hardness on the stress concentration area, in addition to validating the results by applying the finite element method, using ANSYS Mechanical Static Structural Software.
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