Standard Test Method for Bend Testing of Metallic-Coated Steel Sheet to Evaluate Coating Adhesion

Importancia y uso:

4.1 This test method provides a standard method to bend the product to verify good coating, adhesion free of delamination, on metallic-coated steel sheet products under the jurisdiction of ASTM Committee A05 and its subcommittees as designated by a purchaser in a purchase order or contract.

4.1.1 Metallic coated coupons are bent 180° around progressively more thicknesses of metal, the end point being when failures no longer occur. The bend area is examined without magnification after each bend in order to determine coating fracture and loss of adhesion.

4.1.2 If desired, further examination of loss of adhesion or pickoff can be determined by performing a tape pull-off test subsequent to bending.

4.1.3 The material condition at the time of testing, sampling frequency, specimen location and orientation, minimum t-bend rating exhibiting no delamination or pick-off, reporting requirements, and other test parameters are contained in the pertinent material specification or in a general requirement specification for the particular product form. References are provided to the appropriate ASTM standards.

4.2 For this test method to successfully evaluate coating adhesion, the metal substrate must be capable of withstanding the bending operation without fracturing.

4.3 Coating adhesion is a significant quality characteristic of metallic coated steel sheet products. This test method employs the relevant t-bend rating specified in the referenced product standards to quickly determine if the metallic coating is free of delamination on the outside of a bend specimen. This is critical in ascertaining product conformance to specifications.

4.4 This test method is similar to, and uses some of the same apparatus as, Test Method D4145, which determines a t-bend rating for flexibility and adhesion of organic coatings (paints) on metallic substrates.

4.5 This test method may be used by other ASTM Committees and other standards writing bodies for the purpose of conformance testing.

Subcomité:

A05.07

Referida por:

A0924_A0924M-22A, A0653_A0653M-23, A0792_A0792M-23, A0875_A0875M-23, A0792_A0792M-23, A1046_A1046M-24, A0463_A0463M-22, A1063_A1063M-22, A0653_A0653M-23, A0924_A0924M-22A

Volúmen:

01.06

Número ICS:

25.220.40 (Metallic coatings)

Palabras clave:

coating adhesion; delamination; steel sheet; steel sheet – metallic-coated;