Find the most up-to-date version of ASTM E at Engineering Macroetching, also known as deep etching, involves etching specimens prepared with a suitable acid or reagent for macrostructural examination. Contact us. Purchase your copy of ASTM E – 17 as a PDF download or hard copy directly from the official BSI Shop. All BSI British Standards available.
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A number in parentheses indicates the year of last reapproval. This standard has been approved for use by agencies of the Department of Defense. The method is limited in application to bars, billets, blooms, and forgings of carbon and low alloy steels.
Steels react differently to etching reagents because of variations in asym composition, method of manufacture, heat treatment and many other variables. Establishment of general standards for acceptance or rejection for all conditions is impractical as some conditions axtm be considered relative to the part in which it occurs.
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. Photographs for Rating Macroetched Steel 3 plates 3 3. Splash is normally associated with molten steel which solidi?
Current edition approved Oct. Originally approved in Last previous edition approved in as E — In wstm cast product, it is sometimes called ingotism or ingot pattern. Dark center is solid material and should not be confused with center unsoundness. They are asttm found in continuously cast or bottom poured products. In an etched transverse section, they appear as short, tight discontinuities which are usually located in the midway to center location of the section.
They are also known as shatter cracks or hairline cracks. These may be located anywhere from the near surface region of the product to the center of the product, depending on the source and severity of the condition. Compositional differences also in? The method employs the action of an acid or other corrosive e81 to develop the macrostructural characteristics of a suitably prepared specimen. The name implies that the etched surface is examined visually, or at low magni? Sulfur printing shall be performed in accordance with Practice E Examination and rating of specimens shall be in accordance with Sections 10 and 11 of this E standard.
Asm cast steel blooms and billets, in the as cast condition, shall be examined according to the procedures described in Sections 10 and With reductions over a 3: The hydrochloric acid need not be reagent grade.
Commercial quality hydrochloric acid also known as muriatic acid is satisfactory. The etching solution should be clear and free from scum.
The reagent should be used under a fume hood, or some other means of carrying off the corrosive fumes must be provided. The solution may be heated without serious change in concentration.
The etching solution may be reused if it has not become excessively contaminated or weakened. NOTE 1—The addition of asym peroxide H2O2 may be necessary in order to provide sufficient reaction to properly etch some types of product.
This should be added to an etching bath that is operating at room temperature. E — 01 5. The acids are strong and they can cause serious chemical burns. Add acid slowly to water with stirring.
This is especially true for sulfuric acid. Mix solutions and macroetch under a fume hood. A freshly made solution is necessary for best results.
ASTM E381 – 17
The solution should be swabbed on the? Inspection is most effective when done while the piece is still wet. The use of this reagent necessitates a smooth surface. The reagent is used at room temperature by immersion or swabbing. When the use of a reagent other than those described in 5. See Test Method E for other etching solutions. For ingot cast product, the specimen is usually taken after ingot breakdown.
Billets or blooms going into small sizes are sampled after the initial breakdown. Sampling of continuously cast product is usually done in the as-cast condition, or after intermediate or? Random sampling of the? Torch cutting or other hot cutting will materially affect the structure of the specimen and may be used only when necessary to remove a larger piece prior to cutting to size by cold methods.
Sufficient torch cut material should be removed by cold cutting to eliminate the thermal effects of torch cutting. Disks or specimens are usually cut to reveal a transverse surface, but the requirements of the speci? In the case of forgings, depending upon prior agreement, this may be accomplished by adding excess metal for discard on the ends or ends of the forging; or, by forging in multiple lengths and removing the test disk between individual pieces when cutting up the multiple forging.
Any method of preparing smooth surfaces with a minimum amount of cold work should be satisfactory. Disks may be faced on a lathe or a shaper. The usual procedure is to take a roughing cut, then a? This will generate a smooth surface and remove cold work from prior operations. Sharp tools are necessary to produce a good specimen. Grinding, which also may be used, is usually conducted in the same manner, using free-cutting wheels and light feeds. Any grease, oil, or other residue will produce an uneven attack and must be removed.
It may be necessary to use solvents to clean the surface. Once cleaned, care should be taken to avoid touching or otherwise contaminating the surface.
The sectioning of the large specimens should be done so as not to disturb the central portion of the section. Small pieces may be etched in glass or porcelain vessels of the types commonly available in laboratories. Larger disks are etched in e318 alloy vessels, various types of ceramic pots, rubberlined kettles or wooden tanks. If metal tanks are used, lead is most common for containing sulfuric acid solutions while high-nickel sstm or high-silicon iron are preferred to contain hydrochloric acid solutions.
A nickel-molybdenum alloy can be used for containing solutions of sulfuric or hydrochloric acid, or both. If the tank is metallic, the disks being etched should not be in contact with each other or with the vessel. Such contact will set up electrolytic galvanic couples and will produce an uneven and misleading etch attack.
Resins in wood used to make tanks sometimes act as uncertain and uneven inhibitors resulting in unsatisfactorily etched disks. Do not place specimens in a cold solution and then heat it to the desired temperature.
The specimens may be placed directly into the solution, but the best practice is to place the specimen in corrosion-resistant baskets or on corrosion-resistant supports, such as glass rods underneath the specimen to raise it off the bottom of the dish. Maintain a sufficient volume of solution in the vessel to cover the specimen with a layer of at least 25 mm 1 in.
When etching is completed, remove the specimen from the solution, taking care not to mar the specimen surface. Remove the smut that forms on the specimen surface by scrubbing the surface with a stiff brush under hot running water. This brush may have natural vegetable or synthetic?
After the smut is removed, rinse the specimen under hot running water and blow it dry with compressed air. The specimen should not be blotted dry. The best time for examination is immediately after drying. Dried surfaces may be protected with oil or a transparent lacquer. Etch the specimens to reveal the structure clearly and then remove it from the etch bath. Overetching can lead to misinterpretation. In most cases, 15 to 30 min will be sufficient for hot-acid etching.
Etching times with cold solutions see 5. Examination of Ingot Cast Product Specimens 9. Also report the presence asym any of the conditions in Plate II. Examination of Continuously Cast Product Specimens The type of condition present may be identi?
Rating of each condition is accomplished by measurement. Some conditions related to the cast structure for example, chill zone and columnar structure may not be discernible in product which has been reduced by rolling and forging while pattern is only discernible in a wrought specimen.
Some of the conditions are represented by sketches drawn on the photomacrographs. Plate III is used to identify the type of condition observed on the macroetch specimens. Conditions to be rated and their level may be established by agreement between the purchaser and producer.
In highly rectangular product, circular conditions may not be compatible with this rating method. In those cases, circular conditions shall be rated as the average of the maximum length and maximum width of the condition and expressed as a percentage of the square root of the transverse area of the specimen.
Other rating methods may be established per agreement between the user and producer. E — 01 Precision and Bias Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every?