Research On Flow Spinning Method Of 1J50 Soft Magnetic Alloy Tube

Magnetic shield case is the important component to prevent electromagnetic radiation, information leakage, etc., and widely used in aerospace, military, medical treatment, communication and other fields. Soft magnetic alloy is the main material used for preparing magnetic shield with high property because of its excellent ability to resist magnetic interference and is usually made into tube-shape for good magnetic shielding property. The traditional preparing process for soft magnetic alloy is mainly welding, stamping and turning but will cause problems like being out of shape, low finished product ratio, magnetic leakage, low forming limit and material waste, etc. Flow spinning is considered one of the most efficient methods to manufacture tubular parts and has the advantages like high utilization rate, high forming property, easy process equipment etc. Furthermore, spinning is one kind of continue plastic forming technology and will avoid forming shortage above.1J50 soft magnetic alloy tube blank was treated as research object. Flow spinning after recrystallization annealing was used to prepare soft magnetic alloy tubular parts for the poor plasticity of original tubular workpiece. Based on good plastic property, research on finite-element simulations and experiments of three-roller tagger flow spinning were carried out; high-heat treatment was carried out to improve magnetic property after flow spinning and corresponding heat treatment process program was obtained. Main research comment and results are as followed:(1) The parameters of 1J50 soft magnetic alloy tube blank mechanical property was obtained via tensile test. The result showed that the plasticity of original 1J50 soft magnetic alloy tube blank was too poor to be used for flow spinning. The reason why the mechanical property of 1J50 soft magnetic alloy tube blank was bad was analyzed and recrystallization annealing was put forward to improve the mechanical property. The range of annealing temperature was determined through theoretical analysis. Annealing treatment scheme namely, preservation at 700℃ for 30 min, that can guarantee both good plastic property and high annealing efficiency was obtained through further annealing treatment, mechanical experiment and microstructure observation, namely. The annealing treatment laid the foundation of flow spinning for 1J50 soft magnetic alloy tube blank.(2) Three-roller stagger flow spinning finite-element model was established via MARC The simulation and analysis for recrystallization annealed1J50 soft magnetic alloy tube blank was carried out. Two process schemes that thinning ratios were relatively 60% and 80% are designed and the process parameters were determined via theoretical analysis and calculation. Pre-state technology was used to accomplish full-pass simulation for the process scheme of 60% thinning ratio. Results of stress and strain distribution, thickness deviation and spinning force were analyzed. It provided reference basis for the following flow spinning experiments.(3) Flow spinning experiment research for recrystallization annealed J50 soft magnetic alloy tube blank that thinning ratios were relatively 60% and 80% was carried out and spun parts with overall good forming was obtained. The influence of the feed rate and spinning pass on the forming quality were analyzed by taking the wall thickness deviation, ovality, straightness and roughness as the evaluating index of forming quality. The feed rate that can guarantee both forming quality and production efficiency was obtained, as well as the influence law of spinning pass to forming quality.(4) Magnetic property improving heat treatment process research for 1J50 soft magnetic alloy spun parts was carried out. Magnetization principle of soft material, magnetic index, the influence factors and test principle of magnetic property was introduced. Magnetic property test equipment was chosen and the magnetic property improving treatment scheme was determined. The magnetic properties before and after treatment were tested and analyzed. The change rule of the magnetic properties at different temperatures for different time was analyzed. The coercivity was taken as the intermediate quantity to determine the relationship between grain size and magnetic property and it will be of great significance for the production practice of 1J50 soft magnetic alloy products.