Forgeability of ultra-fine grained aluminum alloy for bolt forming

• Published in: International journal of mechanical sciences Vol. 52; no. 10; pp. 1269 - 1276
• Main Authors: Choi, J.S., Nawaz, S., Hwang, S.K., Lee, H.C., Im, Y.T.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01-10-2010; Elsevier
• Subjects: Aluminum base alloys; Applied sciences; Bolt forming; Bolting; Bolts; Compression tests; Drawing and wire drawing; Equal channel angular extrusion; Exact sciences and technology; Formability; Forming; Fundamental areas of phenomenology (including applications); High strength; Homogeneity; Inelasticity (thermoplasticity, viscoplasticity...); Manufacturing costs; Metals. Metallurgy; Physics; Production techniques; Solid mechanics; Structural and continuum mechanics; Ultra-fine grain; Formability; Bolt forming; Equal channel angular extrusion; Ultra-fine grain; Bolted joint; Die; Forming; Bolt; Nanostructure; Aluminium alloy; Fastener; Compression test; ECAP; Microhardness; Tension test; Weight; Forging; Fine grain structure; Room temperature
• ISSN: 0020-7403; 1879-2162
• DOI: 10.1016/j.ijmecsci.2010.06.002

In the present investigation, an equal channel angular extrusion (ECAE) was used to make bulk nanostructure of the commercially available aluminum alloy AA1050 at room temperature. In order to investigate the effect of the ECAE routes on formability, three different routes A, Bc, and C were applied up to three passes by employing a split die set-up, which required less extrusion load compared with the conventional dies. Formability of the conventional and ultra-fine grained specimens was measured by applying a compression test. Considering the formability obtained from the compression test, bolt forming sequences were developed into three stages and applied to manufacture a high strength bolt using a cylindrical ultra-fine grained specimen at room temperature. The effects of processing routes and number of passes in the ECAE on strength increase and its homogeneity in the manufactured bolts were investigated by the tension and microhardness test, respectively. According to this investigation, a novel approach to utilize the ECAE to manufacture high strength bolt using the conventional material is demonstrated. This approach can be extended to other manufacturing parts that require high strength and lesser weight at a competitive manufacturing cost.