AASHTO M299 pdf free download

AASHTO M299 pdf free download.Coatings of Cadmium Mechanically Deposited.
4. Ordering Inforniation
4.1 To make the application of this standard complete, the purchaser should supply the following information to the seller in (he purchase order or other governing document:
4.1.1 (lass, including a maximum thickness, if appropriate, Type, and for Type II, color and need for supplemental lubricant (see 3.1, 3.2, and 6.2.4.2),
4. 1.2 Nature of substrate (for example, high-strength steel. needed for stress relief (6.2.1), and cleaning precautions to be followed 6.2.2 and 6.2.3).
4.1.3 Significant surfaces (6.3),
4.1.4 Requirements for and methods of testing for one or more of the following, if required: need for and type of test specimens (8.1), thickness (6.3 and 8.3), adhesion (6.4 and 8.4). corrosion resistance (6.5 and 8.5), absence of hydrogen embrittlement, and the waiting period before testing and testing loads (6.6 and X.6,
4.1.5 Inspection responsibility (Supplementary Requirement SI) and sampling plan for each inspection criterion (Section 7).
4.1.6 Requirements for certified report of test results (SectiOn 10).
5. WorkmanshIp
5.1 The coating shall be uniform in appearance and free of blisters, pits. nodules, flaking, and other defects that can adversely affect the function of the coating. The coating shall cover all surfaces as stated in 6.3 including roots of threads, thread peaks, corners, recesses. and edges. The coating shall not be stained or discolored throughout to an extent that would adversely affect appearance as a functional requirement. However, superficial staining that results from rinsing or drying and variations in color or luster shall not be cause for rejection.
N(nE I The nature of the mechanical plating process is such that coatings characterishcally will not be as sniooth or as bright as some electroplated coatings.
6. Requirements
6.1 4ppearance—The coating as deposited shall have a uniform silvery appearance, and a matte to medium-bright luster.
6.2 Process:
6.2.1 Stress-Relief Treatment—All steel parts that have ultimate tensile strength of 1000 MPa and above and that contain tensile stresses caused by machining, grinding, straightening, or cold-forming operation shall be given a stress relief heat treatment prior to cleaning and metal deposition. The temperature and time at temperature shall be 190 + 15°C for a minimum of 3 h so that maximum stress relief is obtained without reducing the hardness below the specified minimum.
6.2.2 High-strength steels that have heavy oxide or scale shall be cleaned before application of the coating in accordance with Practice B 242. In general, nonelectrolytic alkaline. anodic-alkaline, and some inhibited acid cleaners are preferred to avoid the risk of producing hydrogen embrittlement from the cleaning procedure.
6.2.3 For low-carbon steels see Practice B 183. Useful guidelines are also given in Practice B 322.
6.2.4 Supplementa,y Treatrnents
6.2.4.1 Colored Chrornate (‘onversion Treatments (Type lI)—Chromate treatment for Type II shall be done in a solution containing hexavalent chromium. This solution shall produce a bright or semi-bright continuous, smooth, protective film with a uniform color that may range from yellow through bronze and olive drab to brown and black including olive drab and that may be dyed to a desired color. Post treatments that do not contain salts that yield films containing hexavalent chromium are not permitted as treatments for producing Type II coatings.
6.2.4.2 Waxes, lacquers, or oilier organic coatings may be used to improve lubricity, and the need fir them shall be supplied in the purchase order or other go’.ienhing document (4.1.1). Supp1emnta1 lubrication treatment shall not be used to ensure conlijmiance to the salt spray conosion resisLince requirements.
6.2.5 Surfiice Defects—Defects and variations in appearance in the coating that arise from surface conditions of the substrate (scratches, pores, roll marks, inclusions, and so forth) and that persist in the finish despite the observance of good metal finishing practices shall not be cause for rejection.
Nort 2-—Applied finishes generally perform better in service when the substratc over which they rc applied is smooth and free of torn metal. indusions. pores. and other defects. 11 is recuniniended that the specilication covering the unfinished product provide limits for these defects. A metal finisher can often remove defects through special treatments, such as grinding, polishing. abrasive blasting. chemical trettJi*eiits, and eketropolishing. However, these are not normal in the treatment steps preceding the application of the finish. When desired they must be specified on the purchase order (4.1.2).AASHTO M299 pdf download.