Effect of Manganese and Magnesium Content and Conditions of Annealing on Mechanical Properties and Cracking Formation during Bending of Aluminum Alloy AA3005

摘要

The study reveals the effect of Mn and Mg content on mechanical and technological properties during the bending of thin sheets of aluminum alloy 3005. For experimental research the ingots were cast through an out-of-furnace refining unit, homogenized at a temperature of 590°C, during 6 hours. Further ingots were hot rolled to a thickness of 3.5 mm and subsequently cold rolled into sheets of thickness 0.33 and 0.25 mm. Annealing of rolls was provided at temperatures 230...285°C for 1.5 hour in air-circulation annealing furnaces with a protective atmosphere and on a continuous heat treatment line. The change in the tensile strength, yield stress, elongation as a dependence on the content of alloying elements and annealing modes was shown. Technological properties were evaluated by performing bend tests. It has been established that an increased content of magnesium and manganese in the AA3005 alloy results in lower values of the elongation for all annealing temperatures. Annealing in the air-circulation annealing furnaces resulted to higher plasticity values and lower values of strength compared to annealing at continuous heat treatment line for all annealing temperatures and magnesium and manganese temperatures. The plasticity of samples 0.25 mm thick raises evenly throughout the annealing temperature range. For specimens 0.33 mm thick, the effect of the magnesium and manganese content, as well as the type of heat-treatment equipment on the samples' plasticity during annealing is more pronounced than for samples 0.25 mm thick. In sheet samples from the AA3005 alloy annealed on continuous heat treatment line, with an increased content of magnesium and manganese, cracks are observed at the inflection point for both thicknesses. When annealing in air-circulation annealing furnaces, cracks are not observed for both increased and reduced magnesium and manganese content.