ASTM-A › Zinc Coating (Hot-Dip), Assembled Steel Products. ASTM-A – EDITION – SUPERSEDED — See the following: ASTM-. in Specifications A and A This ASTM Standards A47/ A47M 1 This specification is under the jurisdiction of ASTM Committee A05 on. ASTM AAM Standard Specification for Zinc – Standard A and A shall be done using the metric equivalent of the test.
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ASTM B standard spe Q386 number in parentheses indicates the year of last reapproval. A superscript epsilon e indicates an editorial change since the last revision or reapproval. This standard has been approved for use by agencies of the Department of Defense. In the case of orders in SI units, such shall be stated to the galvanizer when the order is placed.
The axtm of separate reinforcing steel bars shall be in accordance with Speci? Inchpound units and SI units are not necessarily exact equivalents. Within the text of this speci?
ASTM Standard List: Coated Steels
Each system shall be used independently of the other without combining values in any way. In the case of orders in SI units, all testing and inspection 1 This speci? Current edition approved October 10, Originally published as A — 28 Satm. Last previous edition A — 01a.
Terminology A contains other terms and de? For purposes of this speci? These inclusions are raised surfaces and are easily knocked off FIG. For thickness testing purposes, articles whose surface area is greater than in. In the case of any such local section containing more than one material category or steel thickness range as delineated ast Table 1, that section will 3a86 more than one specimen see Fig.
If a sample is taken as representing the lot for acceptance, the atm shall be taken at random from the lot without regard to the perceived quality or appearance of any individual unit in the lot being sampled. The sample consists of one or more test articles. For thickness testing purposes, the entire surface area of each unit of product constitutes a specimen.
In the case of any such article containing more than one material category or steel thickness range as delineated in Table 1, that article will contain more than one specimen see Fig. For magnetic thickness measurements, specimen excludes any area of the surface which is subject to processes such as?
The minimum average coating thickness grade for any specimen shall be one coating grade below that required for the appropriate material category and thickness in Table 1. For a unit of product whose surface area is equal to or less than in. In the case of an article containing more than one material category or steel thickness range as delineated in Table 1, that article will contain more than one specimen, as appropriate see Fig.
Materials and Manufacture 5. NOTE 2—The presence in steels and weld metal, in certain percentages, of some elements such as silicon, carbon, and phosphorus tends to accelerate the growth of the zinc-iron alloy layer so that the coating may have a matte? The galvanizer has only limited control over this condition. The mass, shape, and amount of cold working of the product being galvanized may also affect this condition. Practice A provides guidance on steel selection and discusses the effects of various elements in steel compositions for example, siliconthat in?
Practices AAand A provide guidance for steel fabrication for optimum hot dip galvanizing and shall be complied with in both design and fabrication. Consultation between the designer, fabricator, and galvanizer at appropriate stages in the design and fabrication process will reduce future problems.
It is the responsibility of the purchaser to heat treat or otherwise allow for the possibility of such embrittling phenomena. The requirements for malleable iron castings to be galvanized shall be as stated in Speci? If a zinc alloy is used as the primary feed to the galvanizing bath, then the base material used to make that alloy shall conform to Speci?
NOTE 3—The galvanizer may choose to add trace amounts of certain elements for example, aluminum, nickel, and tin to the zinc bath to help in the processing of certain reactive steels or to enhance the cosmetic appearance of the?
The use of these trace elements is permitted provided that the bulk chemistry of the galvanizing bath is at least The elements can be added to the galvanizing bath as part of a pre-alloyed zinc feed, or they can be added to the bath by the galvanizer using a master feed alloy.
NOTE 1—Each specimen comprises nominally one third of the total surface area of the article.
Minimum average thickness of coating for any individual specimen is one coating grade less than that required in Table 1. Where s386 consisting of various material thicknesses or categories are galvanized, the coating thickness grades for each thickness range and material category of material shall be as shown in Table 1.
In the case of orders in SI units, the values in Table 1, shall be applicable as metric units in micrometres. In the case of orders in inch-pound units, the measured value shall be converted to coating grade units by the use of Table 2.
ASTM AAM Standard Specification for Zinc_百度文库
NOTE 4—The coating thickness grades in Table 1 represent q386 minimum value obtainable with a high level of con? While most coating thicknesses will be in excess of those values, some materials in each category may be less reactive for example, because of chemistry or surface condition than other materials of the steel category spectrum. Therefore, some articles may have a coating grade at or close to the minimum requirement shown in Table 1.
In such cases, the precision and accuracy of the coating thickness measuring technique should be astn into consideration when rejecting such articles for coating thickness below that required by this speci? Purchasers desiring a guarantee of heavier coatings than the minimum thicknesses shown herein should use the special requirements see 4.
The other values are based on conversions using the following formulas: Surface conditions related to de? The zinc coating on threaded components of articles galvanized under this speci? Surfaces that remain uncoated after galvanizing a86 be renovated in accordance with w386 methods in Practice A86 unless directed by the purchaser to leave the uncoated areas untreated for subsequent renovation by the purchaser. NOTE 5—Inaccessible surface areas are those which cannot be reached for appropriate surface preparation and application of repair materials as described in Practice A Such inaccessible areas, for example, would be the internal surfaces of certain tanks, poles, pipes, tubes, and so forth.
NOTE 6—The requirements for the? They do not address the matter of measured coating thickness variations that can be encountered because of different steels or different thicknesses of a given steel being used in an assembly. NOTE 7—Items which are prepared for galvanizing by abrasive cleaning will generally develop a thicker coating with a moderately rougher surface.
ASTM Standard List: Coated Steels :: Total Materia Article
In addition, the purchaser should anticipate the need for test batches or extra preparation steps, or both, such as blasting before galvanizing or other methods, to attempt to reach the higher requirements with consistency.
Some higher-than-standard thicknesses may be impractical or unattainable. Except for local excess coating thickness which would interfere with the use of the product, or make it dangerous to handle edge tears or spikesrejection for nonuniform coating shall be made only for plainly visible excess coating not related to design factors such as holes, joints, or special drainage problems see Note 6.
Since surface smoothness is a relative term, minor roughness that does not interfere with the intended use of the product, or roughness that is related to the as-received un-galvanized surface condition, steel chemistry, or steel reactivity to zinc 5 6. Internal threads are not prohibited from being tapped or retapped after galvanizing. Coatings shall conform to the requirements of Speci? Lumps, projections, globules, or heavy deposits of zinc which will interfere with the intended use of the material will not be permitted.
Plain holes of 1? Marks in the zinc coating caused by tongs or other items used in handling the article during the galvanizing operation shall not be cause for rejection unless such marks have exposed the base metal and the bare metal areas exceed allowable maximums from 6. The pieces shall be handled so that after galvanizing they will not freeze together on cooling. NOTE 8—Depending upon product design or material thickness, or both,? NOTE 9—Although some material may be formed after galvanizing, in general the zinc coating on the articles covered by this speci?
Unless otherwise agreed upon between the galvanizer and the purchaser, or established within this speci? For test by the purchaser after delivery, the lot consists of the single order or the single delivery load, whichever is the smaller, unless the lot identity, established in accordance with the above, is maintained and clearly indicated in the shipment by the galvanizer.
Otherwise, the test specimens shall be selected at random from each lot. In this case, the minimum number of specimens from each lot shall be as follows: Number of Pieces in Lot 3 or less 4 to to 1 1 to 3 3 to 10 10 and over Number of Specimens all 3 5 8 13 20 NOTE 10—Where a number of identical items are to be galvanized, a statistical sampling plan may be desired.
Such a plan is contained in Test Method B which addresses sampling procedures for the inspection of electrodeposited metallic coatings and related? If Test Method B is used, the level of sampling shall be agreed upon between the galvanizer and the purchaser at the time the coating order is placed. The specifying of tests for adhesion and embrittlement shall be subject to mutual agreement between the galvanizer and purchaser.
Visual inspection of the coating shall be made for compliance with the requirements. For each specimen as described in 3. The average of the? A specimen must be evaluated for each steel category and material thickness within the requirements for each specimen of the test article.
The weight of coating per unit area thus determined is converted to equivalent coating thickness values in accordance with Table 2 rounding up or down as appropriate.
The thickness of coating thus obtained is the test article coating thickness, or in the case of a specimen removed from a test article, is the specimen average coating thickness.
The weight of coating per unit area thus determined is converted to equivalent coating thickness values according to Table 2 rounding up or down as appropriate. The thickness of coating thus obtained is the test article coating thickness. The accuracy of both methods will be in? These tests shall not be required unless strong evidence of embrittlement is present.
Inspection, Rejection, and Retest 9. This shall be achieved by an in-plant inspection program designed to maintain the coating thickness,?
The galvanizer shall afford the inspector all reasonable facilities to satisfy him that the zinc coating is being furnished in accordance with this speci? However, by agreement the purchaser is not prohibited from making tests which govern the acceptance or rejection of the materials in his own laboratory or elsewhere.
By mutual agreement, the galvanizer is not prohibited from submitting the lot remaining after sorting and removing nonconforming articles without replacement of the nonconforming articles.
In such case, the now-smaller lot shall be treated as a new lot for purposes of inspection and acceptance. The thickness thus determined is a point value. The average of no less than? If the lot size is such that the sample size cannot be doubled, then the sample size shall be as previous, but the number of widely dispersed sites at which measurements were made shall be doubled, and these sites will constitute the new sample.
This new sample shall be measured using magnetic thickness gages which have been calibrated for accuracy against reference material thickness standards. If the lot is found to be nonconforming by the new sample, the galvanizer has the right to sort the lot for conforming articles by individual test, to re-galvanize non-conforming articles, or to renovate the nonconforming articles in accordance with 6.