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. 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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The six-part video series will provide highly beneficial visual aids to those needing assistance with meeting the requirements of ASTM A The a7880 restriction in the specification for repairing newly galvanized material is the size of the area which is aa780 in the product galvanizing specifications:.
Referenced Documents purchase separately The documents listed below are referenced within the subject standard but are not provided as part of the standard.
Aetm damage may be the result of welding or cutting flamein which case the coating will be damaged predominantly by burning. Topics include proper materials to use while performing the process, as well as specifications to follow and proper application of the repair materials.
Inch-pound units and SI units are not necessarily exact equivalents. It is asm to note that the size restrictions apply to the area s to be repaired prior to surface preparation. 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 astn. For all surface preparation methods, cleaning must extend into the surrounding, undamaged galvanized coating.
Do not immediately apply repair materials over a freshly cleaned surface. Touch-up materials are required to meet a coating thickness of at least 2. Contact Us Order Status.
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, materials and surface preparation standards required of each repair method. Effective Astk 1st Galv What does the cold galvanizing process consist of?
There is no ASTM specification which specifies a maximum allowable repair size for galvanized items already accepted and delivered. Although some of the requirements within ASTM A are relatively straightforward, other requirements related to surface preparation often require clarification.
Ensuring Conformance to ASTM A | American Galvanizer’s Association
Surface A708 Always check for visible contaminants on the surface of the repair area just prior to mechanical cleaning. Zinc Spray Metallizing Zinc spray, or metallizing, is done by melting zinc powder or zinc wire in a flame or electric arc and projecting the molten zinc droplets by air or gas onto a78 surface to be coated.
Do not average the readings, as this requirement was removed from the specifications in aztm 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.
This abstract is a870 brief summary of the referenced standard. Any dust or loose residue from cleaning must be brushed away using a stiff-bristle brush or blown off using clean, dry air.
Authored by Alana Hochstein. The videos provide highly beneficial visual aids to those needing assistance with touch-up and repair, whether in the plant or the field.
A listing of various manufacturers and products for the maintenance and repair of hot-dip galvanized structures is available for download.
When it comes to repairing galvanized steel in the field, there is no limitation to the size that can be repaired. Where circumstances do not allow blast cleaning, it is permissible to power disk sand areas to be repaired to bright metal.
Although the hot-dip galvanized coating is very resistant to damage, z780 voids or defects in the coating can occur during the galvanizing process or due to improper handling of the steel after galvanizing. Each system shall be used independently of the other without combining values in any way. This practice can also be used to repair hot-dip galvanized coatings damaged by excessively rough handling during shipping or erection.
ASTM does not give any warranty express or implied sstm make any representation that the contents aa780 this abstract are accurate, complete or up to date. Link to Active This link will always route to the current Active version of the standard. The information provided herein is not intended as a representation or warranty on the part of the AGA. Soldering is done with zinc-based alloys in either a stick or powder form.
The zinc used is nominally Galv Touch-Up and Repair Dr.
Ensuring Conformance to 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. The specification explains how to use the various repair methods as well as the required coating thickness for the repaired area. Call for more information. This material provides general information only and is not intended as a substitute for competent professional examination and verification as to suitability and applicability.
The repair coating thickness must meet the specification requirement for the material category of the part with a maximum thickness w780 4 mils ? Ensure a blotter test is performed prior to using a compressed air source in accordance with ASTM D Inspector Listing – Non-U.
Corrosion resistance and service performance are very dependent on the properties of the paint system, the extent of surface preparation, and skills of individual applicators.
Historical Version s – view previous versions of standard. Watch the A7880 The main restriction in the specification for repairing newly galvanized material is the size of the area which is outlined in the product galvanizing specifications: Touch-up and repair of galvanized steel is simple whether newly galvanized or in service for years.
Most organic zinc-rich paints are not critical of climatic or atmospheric conditions for curing. At the galvanizing facility, the maximum allowable repair size for iron and steel products per ASTM A is no more than 1 inch [2. For s780 results, thickness measurements for the metallized coating should be taken with either a magnetic or an electromagnetic gauge.
When ready to perform mechanical cleaning, check the surface preparation standard for clarity on the allowable tooling methods.
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 area being repaired needs to be preheated to approximately F C. Brite Zinc meets and exceeds this percent.