Soft magnetic structural-steel-plate with excellent toughness under low temperature and method for making same

Abstract

A soft magnetic structured steel sheet of fine low-temperature flexibility, the constituent (mass ratio) of which is: C 0.010 to 0.040 percent, Si 0.50 to 1.00 percent, Mn 1.00 to 1.50 percent, P equal to or less than 0.005 percent, Al 0.50 to 1.00 percent, Cr 0.20 to 0.50 percent, Cu 0.20 to 0.60 percent, Ti 0.005 to 0.02 percent, N 0.001 to 0.008 percent, Ni 0.30 to 0.80 percent, Ca 10 to 60 ppm, and the rest Fe and inescapable inclusion, Pcm equal to or less than 0.20 percent. The invention realizes the unification of high intensity, high flexibility, fine welding performance and fine electromechanical property of the soft magnetic structured steel sheet, which is in particular to the side guide absorbing bearing force, guiding force and driving force of the magnetic levitation vehicle.

Description

technical field [0001] The invention relates to a soft magnetic structural steel plate and a manufacturing method, in particular to a soft magnetic structural steel plate for a magnetic levitation track beam. Background technique [0002] Ordinary soft magnetic structural steel plates for magnetic levitation first appeared in Germany. In 1999, German Thyssen Steel AG applied for US 6287395 "High-energy weldable soft magnetic steel and its application on magnetic levitation rail components" which revealed the soft magnetic In the process of the invention of structural steel plates, US Patent 6287395 describes the effects of various alloy elements in steel, but the actual impact toughness is low, especially at low temperatures below 0°C. Operation brings hidden dangers; at the same time, the magnetic induction is not high, B40 is only about 1.60T, especially under low magnetic field, B3 is only 0.60T, the electromagnetic conversion efficiency is low, the invalid loss is large,...

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Problems solved by technology

[0002] Ordinary soft magnetic structural steel plates for magnetic levitation first appeared in Germany. In 1999, German Thyssen Steel AG applied for US 6287395 "High-energy weldable soft magnetic steel and its application on magnetic levitation rail components" which revealed the soft magnetic In the process of the invention of structural steel plates, US Patent 6287395 describes the effects of various alloy elements in steel, but the actual impact toughness is low, especially at low temperatures below 0°C. Operation brings hidden dangers; at the same time, the magnetic induction is not high, B40 is only about 1.60T, especially under low magnetic field, B3 is only 0.60T, the electromagnetic conversion efficiency is low, the invalid loss is large, and the power loss is large, which cannot adapt to the increasingly strict environment. protection requirements

[0003] Chinese patent application No. 01126937.5 "High-performance soft magnetic steel for maglev trains", the performance of the soft magnetic structural steel plate used for maglev track beams has been greatly improved compared with the German invention, but its magnetic flux density, resistivity and low-temperature impact toughness are still not enough High (B40 is about 1.60T~1.61T, B3 is about 0.9T~1.00T, resistivity ρ is about 0.39~0.40μΩm, 0℃Akv≥140J), especially when the impact toughness is lower than -10℃, it cannot guarantee ≥27J, The weldability is also poor, and the welding line energy can only be controlled at ≤12kJ / cm to ensure that the heat-affected zone (HAZ) is Akv≥27J at 0°C. Therefore, there are still major safety hazards in the use of this kind of soft magnetic structural steel plate in the colder north.

[0004] Chinese Patent Application No. 02136192.4 "Soft Magnetic Structural Steel Plates for Magnetic Suspension Track Beams" has greatly improved the performance of the previous patent 01126937.5, and its magnetic flux density and resistivity have been greatly improved (B40 is about 1.65T ~ 1.68T, B3 is about 1.15T~1.30T, the resistivity ρ is about 0.42~0.45μΩm), although the low-temperature impact toughness has been greatly improved, Akv (-20℃)>150J, the weldability has also been greatly improved, and larger input energy can be used for welding. Simulation Welding heat-affected zone (HAZ) -20°C Akv>27J (simulation parameters: peak temperature is 1350°C, t 8 / 5 50 seconds, single cycle), but the impact toughness Akv of the base metal and the welded joint below -20°C fluctuates greatly, especially the local brittle zone (LBZ) in the welding heat-affected zone, and the Akv below -20°C cannot satisfy ≥ 27J, at the same time, the process is relatively complicated, and the production cost is also high, which requires off-line normalization heat treatment

[0005] Chinese patent application No. 03116097.2, not only the manufacturing process is simple, but also the production cost is low, no off-line normalization heat treatment is required, and the performance of the steel plate is greatly improved, especially the low-temperature impact toughness is greatly improved, Akv (-30 ° C) ≥ 100J , the weldability has also been greatly improved, and larger heat input welding can be used to simulate the welding heat-affected zone (HAZ) -30°C Akv≥21J (simulation parameters: peak temperature is 1350°C, t 8 / 5 50 seconds, single cycle), but the impact toughness Akv of the base metal and the welded joint below -30°C fluctuates greatly, especially the local brittle zone (LBZ) in the welding heat-affected zone, and the Akv below -30°C cannot always be Satisfy ≥27J, especially the study found that the alloy system with high Si content determines that the low-temperature toughness of the soft magnetic structural steel plate cannot stably meet the safety of use in cold regions below -30°C

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