ASTM B916:01(R2021) pdf free download – Standard Test Method for Adherence of Porcelain Enamel Coatings to Sheet Metal.
6. Procedure
6.1 Specimen Deformation—The hammer weight of the suggested drop weight device is 5 lb (2268 g). which requires a 16 in. (4()6.4 mm) drop distance to yield the specified 80 iniib (9.03 J)energy at impact. The hammer weight of the drop weight device may range from 2 to 8 lb N)7 to 3629 g). If the hammer weight is within this range. but n 5 lb. calculate the drop distancc to yield 80 in.Ilbf of cncrgy at impact. The ccntcr of the area to be deformed shall he at least 1½ in. (38.1 mm) from the edge of the specimen. If two or more deformations are made on a single specimen. place them at least 3 in. (76.2 mm) between centers and average and treat the measurements on theni as a single measurement. Raise and secure the hammer to obtain the required drop distance. [bid the specimen firmly against and parallel to the top surface of the die with the enameled side up and release the hammer.
6.2 The specified drop weight device is provided with a spring to limit the indenter to a single impact blow against the specimen. If the device to he used is not designed in this way. use another means or procedure to avoid a restrike of the indenter.
6.3 A visual examination of the impact area is then made. Evaluation of the degree of adherence obtained is judged by the amount of glass retained in the impact area.
7. Rating of .dherence
7.1 Examine the impacted area and compare to the following reference standards (see Figs. 3 and 4):
0 • No adhrence—only shiny metal sSowing, and enam& may be flaking 0* beyond the impact area
1 = Pocw adherence—very hills ass adhering, less then 10%. and iy *1 me outer edges o me impact area
2 = Fair adherence—glass pailicles adheeng in at least 25 to 30% o the impact area
3- Good adherenCe—glass particles adh.nng in at least SOlo 60% Cl the impact area
4- Very good adhereece—gless particles adheflng ii at least 70 to
80% of the impact area,
5 = Excelent adherence—glass pandas covering almost al of the impact area—at least 90 %.
7.2 Report adherence rating. estimated to thc nearest 0.5.
X. Referee Method
S. I Since adherence depends on factors other than the enamel, that is. steel, firing, and metal preparation, in cases of disputed results, a direct comparison should be made between the test enamel known to have acceptable adherence by coating.
10 one-half of a panel with each of the enamels and comparing results as in 7.1.
9. Precision and Bias
9.1 The precision and bias of this test method is being established.