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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Wire brush the surface to be reconditioned during preheating. This practice can also be used to repair hot-dip galvanized coatings damaged by excessively rough handling during shipping or erection. Xstm and repair of galvanized steel is simple whether newly galvanized or in service for years.
Topics include proper materials to use while performing the process, as well as specifications to follow and proper application of the repair materials. The a7880 may be the result of welding or cutting flamein which case the coating will be damaged predominantly ast burning. Originally approved in For best results, thickness measurements for the metallized coating should be taken with either a magnetic or an electromagnetic gauge.
Historical Version w780 – view previous versions of standard. 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. The following general guidelines shall apply: This standard has been approved for use by agencies of the Department of Defense. Color red Pos 10 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 asym. Soldering is done with zinc-based alloys in either a stick or powder form. No further reproductions authorized.
ASTM A – Free Download PDF Ebook
Referenced Documents purchase separately The documents listed below are referenced within the subject standard but are not provided as part of the standard. Where such contaminants are found, the surface preparation standards associated with all repair materials require the removal of visible dirt, a870 and grease deposits using a solvent cleaning method such as SSPC-SP1 Solvent Cleaning.
The videos provide highly beneficial visual aids to those needing assistance with touch-up and repair, whether in the plant or the field. Your comments will receive careful consideration at a meeting of the responsible technical committee.
Repairing HDG Steel
Each system shall be used independently of the other without combining values in any way. The material provided herein has been developed to provide accurate and authoritative information about after-fabrication hot-dip galvanized steel. Although the hot-dip galvanized coating is very resistant to damage, small voids or defects in the coating can occur during the galvanizing process or due to improper handling of the steel after galvanizing.
Annex A2 describes the use of paints a7780 zinc dust. However, do not clean excessively beyond the area of repair. Inorganic binders are particularly suitable for paints applied in touch-up applications of undamaged hot-dip galvanized areas.
ASTM A780-Zinc Dust in Paint
The most common types of solders are zinccadmium, zinc-tin-lead, and zinc-tin-copper alloys. Galv What does the cold galvanizing process consist wstm This material provides general information only and is not intended as a substitute for competent professional examination and verification as to suitability and applicability. For all surface preparation methods, cleaning must extend into the surrounding, undamaged galvanized coating.
Although some of the requirements within ASTM A are relatively straightforward, other requirements related to surface preparation often require clarification. Inspection of Cleaned Surfaces After surface preparation, the standards refer to points of asmt necessary to ensure asrm adhesion of the repair material.
The specification explains how to use the various repair methods as well as the required coating thickness for the repaired area. Link to Active This link will always route to the current Active version of the standard.
For less critical field exposure conditions, x780 clean the surface to near-white metal, in accordance with SSPC-SP10 1 to 2 mil 25 to 50 m anchor patternas a minimum. Inch-pound units and SI units are not necessarily exact equivalents. Similarly, contracting parties shall agree to the repair method to be used.
Annex A1 describes the use of zinc-based solders. The method and extent of surface preparation shall be mutually agreeable to the contracting parties. The zinc coating is difficult to damage, and field fabrication that requires removal of the coating should be minimized as much as possible.
Within the text of this specification and where appropriate, SI units are shown in brackets. August 1, Authored by Alana Hochstein.
Most organic paints containing zinc dust are not critical of climatic or atmospheric conditions asmt curing. Effective May 1st Contact Us Order Status. 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 restrictions to the allowable repair size while at the galvanizing facility.