Impact Test Astm D2794 [ OFFICIAL ]

This test is critical for industries where coated metal parts are exposed to mechanical abuse during manufacturing, assembly, transportation, or end-use (e.g., automotive body panels, appliances, coil-coated siding, drum coatings).

A weighted, hemispherical-tipped indenter (diameter: 0.625 in or 15.9 mm) is dropped from a specific height onto the coated side (or reverse side) of a test panel, causing rapid indentation. The coating is then evaluated for cracking or loss of adhesion. impact test astm d2794

is the closest direct replacement. However, results between D2794 and ISO 6272-1 are not directly interchangeable due to differences in indenter/die geometry and panel clamping. 11. Practical Applications & Typical Values | Coating type | Typical reverse impact (in·lb) | Notes | |--------------|-------------------------------|-------| | General industrial enamel | 20–40 | Often fails at lower end | | Automotive clearcoat | 40–80 | Requires very flexible chemistry | | Polyester coil coating | 80–160 | High flexibility for post-forming | | Epoxy powder coating | 80–120 | Thicker films (2–4 mils) | | High-build polyurethane | 100–160 | Impact modifiers added | | PVDF (Kynar) | 120–180 | Extremely flexible | This test is critical for industries where coated

1. Overview and Scope ASTM D2794 is a standardized test method used to determine the resistance of a dry, cured organic coating (paint, lacquer, varnish, or related product) to cracking or detachment from a metal substrate when subjected to sudden, rapid deformation (impact). is the closest direct replacement

statement because no absolute reference material exists for impact resistance. 10. Comparison with Other Impact Standards | Standard | Key differences | Status | |----------|----------------|--------| | ASTM D2794 | Hemispherical tip 0.625 in, support die 0.64 in opening, weight 2 or 4 lb, manual drop tube. | Withdrawn 2019 | | ISO 6272-1 | Similar geometry (20 mm tip, 27 mm die opening) but requires calibrated drop height, allows pneumatic or automatic release. Includes precision data. | Active | | ASTM D5420 (Gardner impact) | For rigid plastics, not coatings on metal. Different tip/support sizes. | Active | | ASTM G14 | For pipeline coatings (larger indenter, heavier weight). | Active | | NCCA II-12 | Coil coating industry method, based on D2794 but with stricter panel specs. | Active |