Numerical Simulation And Experimental Study Of A390Aluminum Alloy Tube Extrusion Process

Modern car industry is moving towards lightweight、high-speed and energy saving. This paper chooses the A390aluminum alloy as the research object. Using the DC casting hollow billet and extrusion technology roadmap to manufacture aluminum automobile engine cylinder liner. Combine the technique of numerical simulation with experimental research method to focus on the DC casting tube extrusion process and crafts, and reached the following conclusions:(1) By comparing the simulation results of different extrusion method, die angle and extrusion ratio, compared with direct extrusion, indirect extrusion has small temperature rise, uniform transformation, low extrusion force and energy consumption. However, when the extrusion modular angle was65°dead zone disappear and the metal from superficial layer flew to the external surface. As the extrusion ratio increases, the metal flow zone and the deformation distribution tends to uniformity.(2) Summing up the temperature field, the stress-strain field, surface quality and production equipment, flat-die mould backward extrusion was selected in the billets in size of Φ160mm/Φ70mm, and tapered surface mould forward extrusion of65°die angle was chosen in size of Φ200mm/Φ70mm in the billets during the extrusion process.(3) By comparing the results of different extrusion temperature and speed, the effect of extrusion temperature and speed on the pipe deformation was not so far; the temperature rise of the ingot caused by ingot deformation was principally decided by extrusion speed; the load and energy consumption of the extruder was mainly decided by extrusion temperature.(4) The range of different sizes pipe extrusion process was obtained by analyzing the calculation results:the range of extrusion temperature is380℃～490℃, the range of extrusion speed is0.8～2.2mm/s during extruding the pipe in size of Φ160mm/Φ70mm by indirect extrusion; the range of extrusion temperature is400℃～470℃, the range of extrusion speed is0.8～1.6mm/s during extruding the pipe in size of Φ160mm/Φ70mm by forward extrusion.(5) The results of different extrusion process show that continuous surface wrinkling occurs when the extrusion temperature is below420℃during indirect extrusion of Φ160mm/Φ70mm hollow billet, surface quality becomes better when the extrusion temperature exceed420℃. As to the direct extrusion of Φ200mm/Φ70mm, when the temperature above470℃, the surface delaminated or even crack.(6) With hot extrusion of A390alloy, the morphology of eutectic Si changed from needle-like to granular or short rod. Primary Si can be broken with hot extrusion when coarse in the as-cast structure. But fine Primary Si particles rarely affected by the extrusion. The a-Al dendrites are able to reduce and even eliminate with hot extrusion. As the size and distribution of primary Si doesn’t change apparently with the process of extrusion, the as-cast structure of A390alloy that plays a vital role on the size and distribution of primary Si.(7) The tubes made by backward extrusion meet the technical requirements of the engine cylinder liner.