AWS C2.18:93R2001

This guide presents an industrial process for the application of thermal spray coatings (TSC) on steel. It covers safety, job/contract description, background and requirements, selection of TSCs, TSC operator qualification, materials and equipment, application-process method with quality-control check points, Job Control Record, maintenance and repair of TSCs, records, debris containment and control, and warranty.
Scope : 1.1 Scope. This guide covers the application of thermalspray coatings (TSC) for the protection of steel with aluminum, zinc and their alloys, mixtures, and composites. This scope of this guide includes the major elements of an industrial process instruction covering job description, safety, consumable materials, surface-preparation and thermal spray equipment, quality control (QC) equipment, TSC operator training and qualification, a step-by step surface preparation and thermal spraying application method with quality control checkpoints, maintenance and repair of thermal spray coatings, and a job control record. Nominal TSC feedstock spray rates and coverage information for a common planning base are presented for purchasers and contractors. A TSC selection guide for various service environments and the operator qualification requirements are presented in appendices. This guide is modelled on the thermal spray method of MILSTD- 2138A(SH), Metal Sprayed Coating Systems for Corrosion Protection Aboard Naval Ships.1 1.2 Definitions. The following define abrasive blast cleaning methods for various surface finishes. Abrasive Blast Cleaning: NACE No. 1: White-Metal Blast-Cleaned Surface Finish. Defined as a grey-white (uniform metallic) color, slightly roughened to form a suitable pattern for coatings. This surface is free of all oil, grease, dirt, mill scale, rust, corrosion products, oxides, paint, and other foreign matter. (NACE No. 1 is comparable to SSPC-SP 5, White Metal Blast Cleaning.) SSPC-SP 5: White-Metal Blast Cleaning. These blastcleaned surfaces must have a uniform, grey-white metallic color and must be free of all oil, grease, dirt, mill scale, rust, corrosion products, oxides, old paint, stains, streaks, or any other foreign matter.3 NACE No. 2: Near-White Blast Finish. This is defined as a surface from which all oil, grease, dirt, rust scale, and foreign matter have been completely removed except for slight shadows, streaks, or discolorations (of oxides bonded with metal). At least 95% of any given surface area has the appearance of NACE No. 1, and the remainder of the area is limited to slight discolorations. (NACE No. 2 is comparable to SSPC-SP 10 Near-White- Metal Blast Cleaning.) SSPC-SP 10: Near-White-Metal Blast Cleaning. A near-white metal blast-cleaned surface, when viewed without magnification, shall be free of all visible oil, grease, dirt, dust, mill scale, rust, paint, oxides, corrosion products, and other foreign matter, except for staining as noted. Staining shall be limited to no more than 5% of each square inch of surface area and may consist of light shadows, slight streaks, or minor discolorations caused by stains of mill scale or stains of previously applied paint.