Blue break attempt

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The blue break test is a standardized method of materials testing for testing steels for macroscopic, non-metallic inclusions.

The unnotched specimen to be tested is broken at about 300 ° C-400 ° C. At this temperature the steel turns blue, but not the non-metallic inclusions . These can now be seen with the naked eye or at low magnification. According to the series of guidelines in the steel-iron test sheet 1584, the result can be divided into 10 classes.

Another standardized method for determining the macroscopic degree of purity is the step rotation test . The procedure was seldom used because of the complex sample preparation. The corresponding standard was therefore deleted in 2001 without replacement.

In addition, the macroscopic degree of purity is often determined by means of ultrasonic testing. The advantage is that a complete volume of the sample is checked using ultrasound, while the other methods can only check surfaces.

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