Mẫu chuẩn thử từ tính No. 1, EN ISO 9934-2, ASTM E1444

Reference block for magnetic particle testing, for fluorescent powder

Test Body type1 according to EN ISO 9934-2 appendix B for the traceability of magnetic powder

The test body is a disk with two types of natural cracks, as shown in the picture below. The big cracks are sanding cracks while the little cracks are tension cracks.

The test body has been permanently magnetized by use of the hole in the middle of the test body. The rating of the test body is made by comparison of the picture with the results of the test body while using fluorescent magnetic powder and a UV lamp.

The test body is used in these aspects: a) for quality comparison of different magnetic powders b) for quality assurance of magnetic powders while working with the testing bench and c) to assure the same dose of magnetic powder in automatic testing apparatus.

Production

Material preparation: 90MnCrV8; surfaces plane grinded on 9,7 ± 0,05 mm

Hardening: 860oC to 2 h; in oil rinsed; hardness 63 to 70 HRC

Grinding cracks: speediness 35 m/s; grain 46J7; delivery 0,05 mm cross feed 2,0 mm

Stress-corrosion cracks: black heated at 145oC to 150oC for 1,5 h

Magnetization: central conductor, direct current I = 1 kA (peek)

Check of the cracks: it must be used a fluorescent magnetic powder test material