Significance and Use

Since the two tendencies are inseparable for a metal to corrode and for water and the materials it contains to promote or inhibit corrosion, the corrosiveness of a material or the corrosivity of water must be determined in relative, rather than absolute, terms. The tendency for a material to corrode is normally determined by measuring its rate of corrosion and comparing it with the corrosion rates of other materials in the same water environment. Conversely, the relative corrosivity of water may be determined by comparing the corrosion rate of a material in the water with the corrosion rates of the same material in other waters. Such tests are useful, for example, for evaluating the effects of corrosion inhibitors on the corrosivity of water. Although this test methods is intended to determine the corrosivity of water, it is equally useful for determining corrosiveness and corrosion rate of materials. Examples of systems in which this method may be used include but are not limited to open recirculating cooling water and closed chilled and hydronic heating systems.

1. Scope

1.1 This test method covers the determination of the corrosivity of water by evaluating pitting and by measuring the weight loss of metal specimens. Pitting is a form of localized corrosion: weight loss is a measure of the average corrosion rate. The rate of corrosion of a metal immersed in water is a function of the tendency for the metal to corrode and is also a function of the tendency for water and the materials it contains to promote (or inhibit) corrosion.

1.2 The test method employs flat, rectangular-shaped metal coupons which are mounted on pipe plugs and exposed to the water flowing in metal piping in municipal, building, and industrial water systems using a side stream corrosion specimen rack.

1.3 The values stated in SI units are to be regarded as standard, other units Values given in parenthesis are for information only.

1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. 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.

2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

ASTM Standards

D1129 Terminology Relating to Water

D2331 Practices for Preparation and Preliminary Testing of Water-Formed Deposits

D2777 Practice for Determination of Precision and Bias of Applicable Test Methods of Committee D19 on Water

G1 Practice for Preparing, Cleaning, and Evaluating Corrosion Test Specimens

G16 Guide for Applying Statistics to Analysis of Corrosion Data

Keywords

bypass corrosion specimen rack; cooling water corrosion test; corrosion test specimen; coupon corrosion test; distribution water corrosion test method; Corrosion--metals/alloys; Corrosivity--water; Coupon corrosion testing; Heat transfer; ISWS machined-nipple test; Machined-nipple tests; Steam; USBM test; Water corrosivity; Weight loss; Wire coil test;

ICS Code

ICS Number Code 13.060.60 (Examination of water for physical properties)

DOI: 10.1520/D2688-11

ASTM International is a member of CrossRef.

ASTM D2688