A heat treatment method for iron-based nanocrystalline transformer core with low loss and high frequency

Abstract

The invention discloses a heat treatment method for low-loss and medium and high-frequency iron-based nanocrystalline transformer iron cores. The heat treatment method is characterized by winding iron-based nanocrystalline tapes to obtain iron cores with a duty factor of not less than 75%, and performing first heat treatment on the iron cores in a nitrogen or argon protective atmosphere or a vacuum environment, wherein the first heat treatment adopts a three-stage heat preservation method; performing iron core loss testing on the iron cores after the first heat treatment under conditions of 20kHz and 0.5T, wherein the iron cores with the loss of not more than 22W / kg are first-class iron cores and the iron cores with the loss of more than 22W / kg are second-class iron cores; and performing second heat treatment on the two types of iron cores respectively, wherein the iron cores after the second heat treatment are the low-loss and medium and high-frequency iron-based nanocrystalline transformer iron cores. By adopting the heat treatment method, the medium and high-frequency transformer magnetic cores meeting user requirements can also be prepared by using the relatively thick ordinary iron-based nanocrystalline tapes produced in batches and the qualification rate is greatly improved in comparison with that of the existing methods.

Description

technical field [0001] The invention relates to a heat treatment method, in particular to a heat treatment method for a low-loss medium-high frequency iron-based nanocrystalline transformer core. Background technique [0002] Traditional medium and high frequency transformer cores are generally made of silicon steel sheets or ferrite, generally in the intermediate frequency range of 1-8kHz, silicon steel sheet cores are mostly used, which can exert their high saturation magnetic induction intensity, relatively high magnetic permeability, and rank High temperature, good temperature stability and insensitivity to stress. In the high frequency range of 8-50kHz, ferrite cores are often used, which can play its characteristics of low high-frequency loss, higher magnetic permeability than silicon steel sheets at high frequencies, and insensitivity to stress. Suitable for mass production. However, the loss of silicon steel sheet increases sharply after the frequency increases. I...

AI Technical Summary

Problems solved by technology

[0005] When a strip with a thickness of 27±4μm is subjected to transverse magnetic field heat treatment under a protective atmosphere such as vacuum or nitrogen and argon, due to the relatively large fluctuation range of strip thickness, the heat release and temperature fluctuations during heat treatment are relatively large. As a result, the fluctuation range of the magnetic performance index of the iron core after heat treatment is very large, the qualified rate of the iron core is unstable, and the average value is not high

At the same time, because the strip thickness fluctuation is not obvious, it is impossible to screen and classify the iron core before heat treatment.

This has led to problems such as unstable magnetic performance indicators of iron core products after heat treatment, low pass rate of iron core products, and poor economic indicators.

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