1 Aug In order to ensure strict adherence to the specification ASTM A when performing repairs at the galvanizing plant, the galvanizer should be. ASTM A Practice for Repair of Damaged and Uncoated Areas of Hot-Dip Galvanized Coatings details how to repair a damaged hot-dip galvanized coating . 2. Referenced Documents. ASTM Standards: A Terminology Relating to Metallic Coated Steel Prod- ucts2. D Specification for Zinc Dust Pigment3.
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Therefore, once in-field, any size of repairable coating defect can be touched up. Ensure a blotter test is performed prior to using a compressed air source in accordance with Astm a780 D This practice can also be used to repair hot-dip galvanized coatings damaged astm a780 excessively rough handling during shipping or erection. There is no ASTM specification which specifies a maximum allowable repair size for galvanized items already accepted and delivered.
Surface profiling for abrasive blast cleaned surfaces may be performed using any method listed within ASTM D visual comparator, surface profile depth micrometer, or replica tape.
Zinc-rich paint is applied to a clean, dry steel surface by either a brush or spray. For all surface preparation methods, cleaning must extend into astm a780 surrounding, undamaged galvanized astm a780. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
Topics include proper materials to use while performing the process, as well as specifications to follow and proper application of the astm a780 materials. The touch-up and repair of hot-dip galvanized steel coatings is important to maintain uniform barrier and cathodic protection as well as ensure longevity.
Brite Zinc meets astm a780 exceeds this percent.
Historical Version s – view previous versions of standard. For less critical field exposure conditions, blast clean the surface to near-white metal, in accordance with SSPC-SP10 1 to 2 mil 25 to 50 m anchor patternas a minimum. The zinc coating is difficult to damage, and field fabrication that requires removal of the coating should be minimized as much as possible.
As noted before, the cathodic protection of the coating will provide some protection to uncoated areas, but the best practice for longevity is to touch-up any bare areas. Zinc-based solder products closely match astm a780 surrounding zinc and blend in well with the existing coating appearance. Always check for visible contaminants on the surface of the repair area just prior to mechanical cleaning. Inorganic binders are particularly suitable for paints applied in touch-up applications of undamaged hot-dip galvanized areas.
The method and extent of surface preparation shall be mutually agreeable to the contracting parties. A listing of various manufacturers and products for the maintenance and repair of hot-dip galvanized structures is available for download.
Inch-pound units and SI units are not necessarily exact equivalents. Requirements concerning the renovation of uncoated areas remaining after initial hot-dip galvanizing are contained within the applicable material specification. This practice describes the use of three types astm a780 material that possess the required properties for repair of damaged galvanized coatings, namely: The six-part video series will provide astm a780 beneficial astm a780 aids to those needing assistance with meeting astm a780 requirements of ASTM Astm a780 Maximum Allowable Repair Size The practice for repairing the galvanized coating in-field is the same as the practice for repair at the galvanizing facility, but there are more astm a780 to the allowable repair size while at the galvanizing facility.
ASTM does not give any warranty express or implied or make any representation that the contents of this abstract are accurate, complete or up to date. The damage may be the result of welding or cutting flamein which case the coating will be astm a780 predominantly by burning. Paints containing zinc dust are classified as organic or inorganic, depending on the binder they contain.
Ensuring Conformance to ASTM A | American Galvanizer’s Association
Topics will include proper equipment and materials to use while performing the process, explanation of the specifications to follow, and examples astm a780 best practice during application astm a780 the repair materials. To ensure that a smooth reconditioned coating can be effected, surface preparation shall extend into the undamaged galvanized coating. If replica tape is utilized, two readings awtm to be taken over each location and averaged to get one “measurement” of the profile of the surface.
Within the astm a780 of this specification and where appropriate, SI units are shown in brackets. Touch-up materials are required to meet a coating thickness of at least 2.
Most organic zinc-rich paints are not critical of climatic or atmospheric conditions for curing. Appropriate grinding tools include reciprocating sanders, orbital sanders, or grinding devices that utilize abrasive cloths, discs, wheels or astm a780.
Finally, a visual inspection to confirm the level of cleanliness must be carried out to ensure the standard is met. The zinc used is nominally This abstract is a brief summary of the referenced standard. The practice for repairing the galvanized coating in-field is the same as the practice for repair at the galvanizing facility, but there are more restrictions to the allowable repair astm a780 while at the galvanizing facility.
Where circumstances do not astm a780 blast astm a780, it is permissible to power disk sand areas to be repaired to bright metal.
Each system shall be used independently of the other without combining values in any way. Hand tool cleaning with a stiff-bristle or nylon brush does not meet specification. Galv Touch-Up and Repair Dr. Effective May 1st astm a780 When it comes to repairing galvanized steel in the field, there is no limitation to the size that can be astm a780.
At the galvanizing facility, the maximum allowable repair size for iron astm a780 steel products per ASTM A is no more than 1 inch [2.
astm a780 Galv Astm a780 does the cold galvanizing process consist of? The practice is the same, but there are more restrictions to the allowable repairs on a new product than one that has been in service. Where blast or power tool cleaning cannot be performed, hand tool cleaning aztm SSPC-SP2 Hand Tool Cleaning allows the use of wire brushing, scraping, chipping and sanding. However, do not clean excessively beyond the area of repair. This astm a780 describes methods that may be used to repair damaged hot-dip galvanized coatings on hardware, structural shapes, and other products fabricated prior to hot-dip galvanizing, and uncoated areas remaining after initial astm a780 galvanizing.
Repairing HDG Steel
The videos provide highly beneficial a7780 aids to those needing assistance with touch-up and repair, whether in the plant or the field. After surface preparation, the standards refer to points of inspection astm a780 to ensure proper adhesion of the repair material.
Experience astn that in general organic zinc-rich systems are more astm a780 of surface preparation. Call for more information. Touch-up and repair of galvanized steel is simple whether newly galvanized or in service for years.
Apply the paint as recommended by the paint manufacturer in a single application employing multiple spray passes to achieve a dry film thickness to be astm a780 upon between the contracting parties.