Pitting rating charts

Fig. 7.5 Standard rating charts for pits [5]. Reprinted, with permission, from ASTM G 46-94, Standard Guide for Examination and Evaluation of Pitting Corrosion, copyright ASTM International, West Conshohocken, PA.

ISO 8993—Anodized Aluminum and Aluminum Alloys— Rating System for the Evaluation of Pitting Corrosion— Chart Method... 

ASTM G 46, Practice for Examination and Evaluation of Ktting Corrosion, recommends that pitting corrosion be quantified by destructive methods (metaUographic or by machiiung) or by nondestructive methods (micrometer or microscopical measurements). A standard rating chart for pits is included in ASTM G 46. 

Corrosion of metals and alloys— Removal of corrosion products from corrosion test specimens Metals and alloys— Atmospheric corrosion testing—General requirements for field tests Anodized aluminium and aluminium alloys—Rating system for the evaluation of pitting corrosion—Chart method... 

Pitting corrosion can be assessed by various methods, including simple visual examination of a corroded specimen or monitoring coupon. When the sites of attack are numerous, the tedious job of counting pits can be facilitated by using rating charts, as shown in Fig. 6.18 [7]. 

Rating charts that eliminate tedious counting of pitting sites. 

Fig. 2 Standard rating chart br pits. Source ASTMG 44...

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