BS EN 10247 is a safety standard on micrographic examination of the non-metallic inclusion content of steels using standard pictures.
BS EN 10247 defines a method of microscopic non-metallic endogenous inclusion assessment using picture charts. If defined by a product standard or agreement between the involved parties for certain special products, inclusions with a width below 2,0 μm can be evaluated by length alone. Inclusions with dimensions exceeding the upper limits in Table 2 are evaluated as belonging to the maximum class and noted separately with their true dimensions.
If particles are elongated or if there are stringers of particles, they are parallel to each other. BS EN 10247 applies to samples with microscopic precipitation approaching random distribution. From the data of measurements obtained by this method, evaluation according to other standards can be established.
Note 1: The method does not apply to particles of a length or diameter less than 3,0 μm or width smaller than 2,0 μm.
Note 2: BS EN 10247 does not apply to free-cutting steels.
Note 3: The basic principle of BS EN 10247 allows the determination of non-metallic inclusion content by image analysis techniques.
BS EN 10247 on micrographic examination of the non-metallic inclusion content of steels using standard pictures is relevant to:
BS EN 10247 establishes procedures for the assessment of inclusions in steels, based on their morphology using standard pictures.
BS EN 10247 includes principles that yield results coherent with consolidated individual inclusion measurements and expressed in physical units. The chart of standard pictures is derived from mathematical principles. In distinction to other inclusion rating standards, in BS EN 10247 the order of the classification begins with the length. The results are directly computed from field assessments. The same precision level is achieved by using the same method in the manual evaluation and computer-controlled measurements. The results are in physical units: length in μm/mm2, number/mm2, areas in μm2/mm2. BS EN 10247 consists of a comparison between inclusions observed in a field of view and chart pictures. The chart classifies inclusions into four distinct types according to their shape. The minimum requirements for applying this method are a square measuring frame of 0,71 mm x 0,71 mm overlaid on the viewfield at a magnification of 100:1, along with the chart – or alternatively a measuring scale.
Overall, BS EN 10247 is helpful as it consists of a single particle, a stringer of particles, or an agglomeration of stringers. All inclusions are treated as ellipses with special rules for agglomerations of stringers. Inclusions are classified according to shape, arrangement, and size.
EN 10247:2017