7 Jun ASTM A states zinc-rich paint with zinc dust in the ranges of % or above 92% in the dried film are equally effective. Why is there a gap. 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 . ASTM Designation: A (American Standard Testing Method). Standard Practice for Repair of Damaged and Uncoated Areas of Hot-Dip Galvanized Coatings.
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Within the text of this specification and where appropriate, SI units are shown in brackets.
No further reproductions authorized. Apply the sprayed coating as soon as possible after surface preparation and before visible deterioration of the surface has occurred.
Repairing HDG Steel
This practice describes the use of three types of material that possess the required properties for repair of damaged galvanized coatings, namely: Please fill this form, we will try to respond as soon as possible. Experience shows that in general. The videos provide highly beneficial visual aids to those needing assistance with touch-up and repair, whether in the plant or the field.
The following general guidelines shall apply: GalvanizationPaintZincWeldingCorrosion. Each system shall be used independently of the other without combining values in any way.
ASTM A780-Zinc Dust in Paint
Topics include proper materials to use while performing the process, as well as specifications to follow and proper application of the repair materials. Referenced Documents purchase separately The documents listed below are referenced within the subject standard but are not provided as part of the standard. In order to ensure strict adherence to the specification ASTM A when performing repairs at the galvanizing plant, the galvanizer should be well versed in the equipment, asgm and surface preparation standards required of each repair method.
Appropriate grinding tools include reciprocating sanders, orbital sanders, or grinding devices that utilize abrasive cloths, discs, wheels or flaps. For power tool cleaned surfaces, a surface profile depth micrometer is a7780 appropriate method for confirming profile, unless otherwise agreed.
Ensuring Conformance to ASTM A | American Galvanizer’s Association
Zinc-Rich Paints Zinc-rich paint is applied to a clean, dry steel surface by either a brush or spray. When it comes to repairing galvanized steel in the field, there is no limitation to the size that can be repaired. The information provided herein is not intended as a representation or warranty on the part of the AGA.
Similarly, contracting parties shall agree to the repair method to be used. 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. For best results, thickness measurements for the metallized coating should be taken with either a magnetic or an electromagnetic gauge. Each system shall be used independently of the other without combining values in any way. Do not average the readings, as this requirement was removed from the specifications in This is especially applicable for abrasive blast cleaned surfaces, where an appropriately sized blasting unit and hose should be utilized.
Always check for visible contaminants on the surface of the repair area just prior to mechanical cleaning. This standard has been approved for use by agencies of the Department of Defense.
Requirements concerning the renovation of uncoated areas remaining after initial hot-dip galvanizing are contained within the applicable material specification.
Repairing HDG Steel | American Galvanizer’s Association
Inch-pound units and SI units are not necessarily exact equivalents. Inspector Listing – Non-U. Annex A3 describes the use of sprayed zinc. Galv What does the cold galvanizing process consist of? If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards. Touch-up materials are required to meet a coating thickness of at least 2. 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.
When ready to perform mechanical cleaning, check the surface preparation standard for clarity on the allowable tooling methods. This practice can also be used to repair hot-dip galvanized coatings damaged by excessively rough handling during shipping or erection.
Paints containing zinc dust. The material used for repair shall have the specified coating thickness, shall provide barrier protection and preferably be anodic to steel, and application of the coating shall be possible under shop or field conditions. 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 size while at the galvanizing facility.
Home Tags Login Register Search. The zinc used is nominally Originally approved in The touch-up and repair of hot-dip galvanized steel coatings is important to maintain zstm barrier and cathodic protection as well as ensure longevity. Most organic zinc-rich paints are not critical of climatic or atmospheric conditions for curing.
Surface Preparation Always check for visible contaminants on the surface of the repair area just prior to mechanical cleaning. Do not immediately apply repair materials over a freshly cleaned surface. Finally, a visual inspection to confirm the level of cleanliness must be carried out to ensure the standard is met.
The material provided herein has been developed to provide accurate and authoritative information about after-fabrication hot-dip galvanized steel.
The repair paint to be used shall be selected by the galvanizer.