Experimental Study On Split-extrusion Law Of Dovetail Slot

Splitting extrusion, a newly named local continuous plastic forming method, is still on the way of research and exploration.In this paper, by taking the dovetail slot as the research object, the slot depth is 10mm and the slot bottom width is 12mm in the study. The splitting extrusion deformation process of the dovetail slot was researched and forming laws was concluded preliminary in the article, using numerical simulation and physical simulation.The main research work and results are as follows:(1)The research scheme of dovetail slot splitting extrusion forming was proposed. The main factors including splitter broadening angle, splitter tilt angle, and dovetail angle were determined, and the main indicators including the stable deformation maximum force P, slot-side swelling height H and its influence width B, sunk angle of wedging A, unstable swelling length L, relative section length of the waste△L were determined. The 16 tests were arranged reasonably using orthogonal test method after verifying no interaction betweenαandβby interactive test.(2) Using finite element simulation software Deform-3D, the dovetail slot splitting extrusion forming process was simulated and researched. The process of splitting extrusion stroke-load curve of stress-effective and strain-effective distribu-tion, the displacement curve of tracking points were analyzed in detail. Splitting extrusion forming process were divided into 3 stages, the first is dedicated to wedging into, the second concentrates on steady deformation and the third is waste material extruded, by combining stroke-load curve and simulation graph. The research results show that forming area includes four aspects:a) sunk angle of wedging; b) front metal accumulation; c) slot-side swelling and d) pressure of slot bottom.(3)Using orthogonal design software(orthogonal design assistantⅡV3.1), variance analysis of simulation results show that, the primary and secondary relationship among every factors on indicator P isθ,αandβ;and on H and B isβ,θandα; and on L and B isθ,βandα; the main factor on indicator A isβ, and on△L isθ. Meanwhile, relationship curves between factors and indicators were drawn.6 tests dies were designed and made, and physical tests were finished by Lead, and numerical tests also were added, the compared analysis results show that the two coincides basically.(4) The reasons of forming defects (such as slot opening and slot-side swelling, etc.) of dovetail slot splitting extrusion were analyzed. Two improving schemes on slot opening phenomenon were proposed:a) setting a fixed notch lag angleβ0 and b) automatically generating a variable Po.Reverse design thought about slot-side swelling phenomenon was put forward, and a kind of blank performing shape was designed. All were verified by numerical simulation.