ASTM D1732-2018 “Traitement de surface des alliages de magnésium pour la peinture”

Abstrait
This specification covers the chemical and anodic treatments used to prepare magnesium alloy surfaces for printing. The procedures for preliminary surface treatment using alkaline and acidic cleaners are described. Class I Type I (chrome pickle) surface treatment procedure is applicable to all forms of magnesium, except for certain special alloys containing silver. I class II (seal cr kimchi) surface treatment procedures are applicable to all types and forms of magnesium alloy, only restricted by the I class I class to handle. Type I and type III processing are applicable to all types and forms of magnesium alloy, but the M1 alloy and some similar to EK30A except for rare earth alloy. Class II Type I (electroplated dichromate treatment) produces a black coating with good protective and analgesic qualities for all alloys and forms of magnesium, including the M1 alloy. Class II, Type II treatment is applicable to all forms and alloys of magnesium. Class II, Type III treatment is applicable to all forms and alloys of magnesium without attachments or inserts of other metals.

ASTM D1732-2018 “Traitement de surface des alliages de magnésium pour la peinture”

The concept
1.1 These practices cover two classes of treatments used to prepare magnesium alloy surfaces for coating, comme suit:

The first categorychemical treatment.

The second categoryanodic treatment.

En général, the latter treatment is more protective in both categories. Mechanical (abrasive) treatment, solvent cleaning, alkaline solution treatment, and acid pickle do not result in protective conversion coatings are preliminary treatments suitable for metals exposed only under mild corrosive (indoor) exposition. When you need a high degree of corrosion protection and paint adhesion, such as in many outdoor environment, surface treatment using conversion coating is one of the categories above. The use of a method based on hexavalent chromium is not recommended because hexavalent chromium is a known carcinogen.

Note 1: Coating testsQuality control tests for coatings are usually desirable. These tests usually include exposure to salt spray, humidity or the natural environment, with or without paint, and have procedures in place to assess the degree of breakdown suffered after fixed time intervals. Coating quality control testing is recommended to use high-purity materials such as AZ31A alloy whenever possible, 2 whose inherent corrosion rate varies from batch to batch, and precautions should be taken to remove surface contaminants prior to coating application. Such contaminants should be removed by pickling to a depth of at least 0.001 pouces (25 micmeters) on each side.

ASTM D1732-2018 “Traitement de surface des alliages de magnésium pour la peinture”

1.2 this standard may involve hazardous materials, opérations, et l'équipement. Cette norme n'est pas destinée à répondre à tous les problèmes de sécurité, si seulement, associé à son utilisation. Il est de la responsabilité de l'utilisateur de cette norme d'établir des mesures de sécurité appropriées., pratiques sanitaires et environnementales et pour déterminer l’applicabilité des restrictions réglementaires avant utilisation. See note 11.

1.3 La présente Norme internationale a été élaborée conformément aux principes de normalisation internationalement reconnus établis dans la Décision sur les principes pour l'élaboration de normes internationales., Lignes directrices et recommandations émises par le Comité des obstacles techniques au commerce de l'Organisation mondiale du commerce.

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