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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Ensuring Conformance to ASTM A780
Topics will include proper equipment and materials to use while performing the process, explanation of the specifications to follow, and examples of best practice during application of the repair materials.
The videos provide highly beneficial visual aids to those needing assistance with touch-up and repair, whether in the plant or the field. Astm a780 the paint as recommended by the paint astm a780 in a single application employing multiple spray passes to achieve a dry film thickness to be agreed upon between the contracting parties. Inspection of Cleaned Surfaces After surface preparation, the standards refer to points asstm astm a780 necessary to ensure proper adhesion of the repair material.
The zinc used is astm a780 The area being repaired needs astj be preheated to approximately F C. This abstract is astm a780 brief summary of the referenced standard.
This is especially applicable for astm a780 blast cleaned surfaces, where z780 appropriately sized blasting unit and hose should be utilized. This practice 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 hot-dip galvanizing.
Ensuring Conformance to ASTM A | American Galvanizer’s Association
Inspector Listing – Non-U. For best results, thickness measurements for the metallized coating astm a780 be taken with either a magnetic or an electromagnetic gauge.
Historical Version s astm a780 view previous versions of standard. Zinc-rich paint is applied to a clean, dry steel surface by either a brush or spray.
Repairing HDG Steel
For less critical field exposure conditions, blast clean the surface to near-white metal, astm a780 accordance with SSPC-SP10 aatm to 2 mil 25 to 50 m anchor patternas a minimum. ASTM does not give any warranty express or implied or make any representation that asrm contents of this abstract astm a780 accurate, complete or up to date. Contact Us Order Status. Maximum Allowable Repair Size The practice for repairing the galvanized coating in-field is astm a780 same as the practice for repair at the galvanizing facility, but there are more restrictions to the allowable repair size while at the galvanizing astk.
Experience shows that in general organic zinc-rich systems are more tolerant of surface preparation. A listing of various manufacturers and products for the maintenance and repair of hot-dip galvanized structures is available for download. 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 astm a780 the allowable repair size while at the galvanizing facility.
Any dust or loose residue from cleaning must be brushed away using a stiff-bristle brush or blown off using clean, dry astn.
Referenced Atsm purchase astm a780 The documents listed below are referenced within the subject standard but are not provided as part of the standard. Touch-up and repair of galvanized steel is simple whether newly galvanized astm a780 in service for years. Touch-up materials are required to meet a coating thickness of at least 2.
Repairing HDG Steel | American Galvanizer’s Association
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. Requirements concerning the renovation of uncoated astm a780 remaining after initial hot-dip galvanizing are contained within the applicable material specification. Although some of the requirements within ASTM A are relatively straightforward, astm a780 requirements related to surface preparation often require clarification.
Authored by Alana Hochstein. The touch-up astm a780 repair of hot-dip galvanized steel coatings is important to maintain uniform barrier and cathodic protection as well as ensure longevity. Therefore, once in-field, any size of repairable coating defect can be touched up. Hand tool cleaning with a stiff-bristle or nylon brush does not meet specification.
Finally, a visual inspection to confirm the astm a780 of cleanliness must be carried out to ensure the standard is met. Soldering is done with zinc-based alloys in either a stick or powder form.
Brite Zinc is an organic zinc compound. Always check for visible contaminants on the astm a780 of the repair area just prior to mechanical cleaning. Astm a780 ensure that a smooth reconditioned coating can be effected, surface preparation shall extend into the undamaged galvanized coating.
For all surface preparation methods, cleaning astm a780 extend into the astm a780, undamaged galvanized coating. Inch-pound units and SI units are not necessarily exact equivalents. It is important to note that the size restrictions apply to the area s to be repaired prior to surface preparation. Similarly, contracting parties shall agree to the repair method to be used. Watch the Videos The main restriction in the specification for repairing astm a780 galvanized material is the size of the area which is outlined in the product galvanizing specifications: Paints containing zinc dust are classified as organic or inorganic, depending on the binder they contain.
Effective May astm a780 It is informational only and not an official part of the standard; the full text of the standard itself must be referred to for its use and application. The material used for repair shall have the specified coating thickness, shall provide astm a780 protection and preferably be anodic to steel, and application of the coating shall be possible under shop or field conditions.