Abrasive particle shape, particle size classification and macrostructure and density

　　1 Abrasive particle shape

　　The shape of abrasive particles can be divided into three basic shapes: round, angular and cylindrical. Round ones include mortar white cast iron shot, decarburized annealed cast iron shot, and cast steel shot; angular ones include white cast iron sand and cast steel sand; cylindrical ones include steel wire cut shot. The round white cast iron shot and cast steel shot can be crushed by the crusher to obtain angular white cast iron sand and cast steel sand respectively. Owen's main products are: cast steel shot, cast steel sand, cylindrical wire cut shot, stainless steel shot and other products.

　　When cleaning and derusting steel pretreatment, it is best to use angular abrasives with slightly higher hardness, or mixed abrasives of circular and angular or angular and cylindrical shapes. The new cylindrical and angular abrasives have sharp corners that gradually become rounded after repeated wear and tear. However, the high-hardness cast steel grit (53-57HRC or HRC≥64.5) is constantly broken during use, which can always maintain sharp edges and corners, and can be used for rapid cleaning of the black thin oxide layer with strong adhesion.

　　2 Grain size classification of abrasives

　　During use, the diameter of the abrasive decreases continuously due to wear, which is conducive to taking care of the cleaning, rust removal, etching and surface strengthening of small inner fillets.

　　Macrostructure and Density of Abrasives

　　The lower density of white cast iron shot (sand) and decarburized annealed cast iron shot is due to more pores, shrinkage porosity, crack defects and more graphite; Loose, high density. Therefore, white cast iron shot (sand) and decarburized annealed cast iron shot have high porosity and short life; while cast steel shot (sand) and steel wire cut shot have low porosity and long life.

　　3. Simple method to judge the quality of abrasive and correct selection of abrasive

　　Simple method for judging the quality of abrasives

　　The standards for judging the quality of abrasives can refer to "Metallurgical Standard" (YB/T5149-93), (YB/T5150-93), the American Society of Automotive Engineers Standards SAE-J827, SAE-J1993.

　　One of the simple methods to judge the quality of cast steel shot (sand) abrasive is to use a static pressure test on a strength testing machine. A certain diameter of abrasive is qualified when it does not break under the pressure limit that can be tolerated; the second method is The hammer test is performed empirically.