磁性材料.第12部分:电工钢带和薄板表面绝缘涂层耐热性评定的试验方法

[中文适用范围]： 本部分IEC 60404适用于IEC 60404-1-1中分类的电工钢带和钢片上的表面绝缘涂层。 本文件定义了评估电工钢带和钢片表面绝缘涂层耐热性的测试的一般原则和技术细节。 评估是通过评估表面绝缘涂层的指定特性由于在指定温度（最高850°C）下进行指定时间（最长2500小时）的热处理而发生的变化。该指定特性在（23±5）°C的环境温度下测量，无论是否经过热处理。 本文件适用于表面绝缘涂层的以下特性： - 附着力； - 表面绝缘电阻； - 堆叠系数。 本文件不适用于表面绝缘涂层的其他特性，例如焊接性能，或其他效果，例如变色和脱气，这些可能由暴露在高温下引起。 注意：某些测试需要很长时间才能完成，因此它们通常不适合用于特定订单材料的验收测试。 [外文原描述]： IEC 60404-12:2023 is applicable to surface insulation coatings on electrical steel strip and sheet classified in IEC 60404-1-1. This document defines the general principles and technical details of the tests for the assessment of the thermal endurance of surface insulation coatings on electrical steel strip and sheet. The assessment is made by evaluating the change of a specified property of the surface insulation coating due to a heat treatment at a specified temperature up to 850 °C for a specified duration time up to 2 500 h. The specified property is measured at an ambient temperature of (23 ± 5) °C both without heat treatment and after heat treatment. This edition includes the following significant technical changes with respect to the previous edition: the method of test for adhesion has been modified to match to the method of bend test specified in ISO 1519 using a cylindrical mandrel of 32 mm in diameter instead of the 30 mm diameter mandrel specified in the first edition; the method of test for interlaminar insulation resistance has been modified to match to the method specified in IEC 60404-11 and the modified Franklin test has been removed; the method of test for compressibility has been modified to match to the method of test for stacking factor specified in IEC 60404-13; the concept of "resistance grades" has been removed; the clamping pressure to be used at temperature ratings above 500 °C has been reduced to (0,01 ± 0,001) N/mm2; the testing for continuous exposure has been made a subject to an agreement between the manufacturer and the purchaser and the procedure has been moved to an informative Annex A.