Standard Test Method for Adhesion Between Steel Tire Cords and Rubber

Abstract

5.1 This test method is considered satisfactory for the acceptance testing of commercial shipments of steel tire cord because current estimates of between-laboratory precision for single materials are considered acceptable and the method has been used extensively in the trade for acceptance testing. 5.1.1 If there are differences or practical significances between reported test results for two laboratories (or more), comparative tests should be performed to determine if there is a statistical bias between them, using competent statistical assistance. As a minimum, the test samples should be used that are as homogenous as possible, that are drawn from the material from which the disparate test results were obtained, and that are randomly assigned in equal numbers to each laboratory for testing. Other materials with established test values may be used for this purpose. The test results from the two laboratories should be compared using a statistical test for unpaired data, at a probability level chosen prior to the testing series. If a bias is found, either its cause must be found and corrected, or future test results must be adjusted in consideration of the known bias. 5.2 The mold described in this test method is primarily designed for quality acceptance testing for steel cord where the sample size for each cord is 4 or a multiple thereof, but any mold/cavity combination which will provide the required test block dimensions (Figs. 1 and 2) is acceptable. Except where noted Note 1: All dimensions in millimetres except where noted. Note 2: Material—Mild steel. Note 3: Mold should be coated permanently with a polytetrafluoro-ethylene, such as Teflon®, or preferably, with a stainless steel reinforced polytetrafluoro-ethylene with a polyamid binder, such as Excalibur®.4 Note 4: Dimensions with “*” may be altered to accommodate test grips.