AASHTO M 246:15(2019) Standard Specification for Steel Sheet, Metallic-Coated and Pol lymer-Precoated, for Corrugated Steel Pipe.
5.2.4. Corrugation size, if corrugated (Section 6.3);
5.2.5. Substrate dimensions (specified thickness; width, either flat or overall corrugated: and length, if cut length);
5.2.6. Grade of polymer coating (Section 3) indicating thickness on each side;
5.2.7. Coil size requirements (specify maximum outside diameter (OD), acceptable inside diameter (ID),
and maximum mass);
5.2.8. Certification, if required (Section 11.1); and
5.2.9. Special requirements.
Note 1—Typical ordering descriptions are as follows: Polymer-precoated steel sheet, aluminum- zinc alloy coated for CSP, conforming to M 246- , 2.77 by 700 mm by coil, with Grade 250 polymer coating (0.25 mm); coil 1200 mm max OD, 600 mm ID, 10 000 kg max coil mass. [Polymer-precoated steel sheet, zinc-coated for CSP, conforming to M 246- .1
6.1. The metallic-coated steel substrate shall conform to all applicable requirements of the specification listed below lbr the kind of metallic coating specified. If the type of metallic coating is not stated in the order, zinc-coated sheet as described in Section 6.1.1 shall be furnished.
6.1.1. Zinc Coating—Zinc-coated steel sheet shall conform to the requirements of M 218.
6.1.2. Aluminum-Zinc Alloy ‘oating 55—Aluminum-zinc alloy coated steel sheet shall conform to the requirements of M 289 and zinc-5 aluminum-MM alloy coated steel sheets shall conform to the requirements of ASTM A929/A929M.
6.1.3. The steel sheet shall be thoroughly cleaned of any chromate pretreatment or other passivation using a multi-brush cleaning process. All traces of the caustic cleaning solution shall be immediately rinsed from the sheet following caustic cleaning. After drying. the steel sheet shall be treated with chrornic acid solution and heat-cured prior to application of the polymer film. The deposited chromium content shall range from 135 to 190 mg/rn2.
6.2. The polymer coating shall be a film coating composed of at least 85 percent ethylene acrylic acid (EAA) copolyrner or at least 25 percent Maleic Anhydride (MAlI) Grafted Polymer, which is partially hydrolyzed. The polymer coating shall be capable of being applied to the sheet specified in Section 6.1. After application, the polymer coating shall be free of holes, tears, and discontinuities, and shall be sufficiently flexible so that it will withstand the corrugating. forming, and lock-seaming operations as well as the punching of holes for rivets or perforations. Note 2 -The MAIl grafted polymer coating is only applied over zinc-coated steel conforming to the requirements of Section 6.1.1.
6.3. If the polymer-coated sheet is to be furnished with corrugations, the corrugations shall conform to the requirements stated in the appropriate specification listed in Section 6.1.AASHTO M 246 pdf download.