Abstract
Flow drilling process produces bushes for removable joints that can be threaded by forming tapping process, reducing stages in production of components of automobile industry and in construction sheds. High strength and low alloy steels (HSLA) are employed on several applications in the processing industry. Benefits provided by these materials make them an efficient solution, since their high cold resistance allows reducing weight on structures, as well as maintaining the required mechanical properties. The present study evaluated the conventional and friction drilling processes in HSLA steel sheets with a thickness of 4.25 mm. Specimens were subjected to cyclic loadings, with no rework after holemaking, so the resultant characteristics of each process were maintained. Fractured surfaces were analyzed with a scanning electron microscope (SEM) to identify the fracture mechanism in different drilling processes. Fractographies obtained on both processes indicated that the failure mechanism occurred due to ductile fracture resulting from the nucleation, growth and coalescence of micro cavities. Keywords: High strength low alloy steel, conventional drilling, flow drilling, ductile fracture.
Highlights
High strength low alloy steels (HSLA) are composed of microstructures formed by hard martensite particles distributed in the ductile ferrite matrix [1]
Contribute to stiffness and weight reduction, being preferred in automotive industry. As their formability characteristics are good, they play an effective role in the production of parts in vehicles such as suspension systems, support elements, longitudinal beams, transverse components and chassis [3]
When these materials are exposed to high temperatures, there is a recrystallization of the microstructure in the heat-affected zone, which directly influences the resistance limit of the material [4]
Summary
High strength low alloy steels (HSLA) are composed of microstructures formed by hard martensite particles distributed in the ductile ferrite matrix [1]. Contribute to stiffness and weight reduction, being preferred in automotive industry As their formability characteristics are good, they play an effective role in the production of parts in vehicles such as suspension systems, support elements, longitudinal beams, transverse components and chassis [3]. The continuity of material removal is ensured by the relative movement of feed between workpiece and tool, which occurs along a path coincident or parallel to the longitudinal axis of tool [7] This drilling process leaves burrs on the entry and exit surfaces of the piece. Burr material is hardened and brittle and can initiate a cracking triggering a failure due to fatigue, as well as compromising safety of workers during handling To avoid these problems, an additional burr removal (deburring) operation is required, which is the last activity during manufacturing [8]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
