Bending Test Method to Detect Coating Bond Strength

       Bending test is the main means of thermal spraying field inspection, which is used to determine the spraying critical thickness and optimal spraying parameters of spraying materials. The sample material is A3 steel or 40 steel, the thickness is 1.2mm, and the size is 100mmx50mm. If the bent coating has slight cracks, it is qualified; if the coating is cracked, it is the lower limit of qualified; if the coating is peeled off, it is not qualified. The bending samples are sprayed with the best parameters of the spray powder, and the bending samples are grouped in groups of three and sprayed in groups with different thicknesses. For example, the coating thickness of the first group is 0.10mm~0.15mm; the second group is sprayed 0.16mm~0.20mm; the third group is 0.21mm~0.25mm; the fourth group is 0.26mm~0.25mm. 30mm.



After the sample is sprayed, perform a bending test with a bender, carefully check the cracking of the coating, and especially carefully identify the lower limit of qualification. The thickness of the sprayed coating is the critical thickness of the material under the process conditions.