Sample preparation
The sampe should be cutted in order to obtain testing surface. The mosaic approach and fixture method can be applied to fix the sample avoiding the round polished edge and make sure the smoothness of the testing surface.
The most important thing when polishing is to avoid the falling and deformation of the folders or the dirted polished surface. These measures make sure the testing surface clean and the inclusion form stastic.
When inclusions are tiny, the above operations are particularly important.At this time the Diamond abrasive polishing is appropriate. In some cases, in order to obtain the highest possible sample hardness, the sample can be heat-treated before the polishing.
5.4 Surface Quality
5.41 No bubbles, cracks, scarring, folding, inclusion and end-layering is allowed in the surface of the cold steel. But the minor pit not more than 10 percent of nominal thickness, convex, indentation, fat stripes, abrasions and the in-pressed oxided iron is allowed.
5.42 the surface defects in the cold steel allows grinding mending method , but the depth can not be more than 10% of the nominal thickness.
5.43 In terms of stainless steel or high quality surface requirements of cold-formed steel, their surface quality requirements determined by consultation between the two sides of supply and demand.