Embrittlement detector

A boiler s water may have caustic embrittling characteristics. Only a test using a U.S. Bureau of Mines Embrittlement Detector will show whether this is the case. If the water is found to be embrittling, it is advisable to add sodium nitrate inhibitor lest a weak area of the boiler be attacked. 

D 807 1982 Method of assessing the tendency of industrial boiler waters to cause embrittlement (USBM embrittlement detector method)... 

Some boilers are equipped with an embrittlement detector by means of which the chemical treatment of a water can be evaluated continuously in terms of its potential ability to induce stress-corrosion cracking (Fig. 18.3) [13]. A specimen of plastically deformed boiler steel is stressed by setting a screw adjustment of this screw regulates a slight leak of hot boiler water in the region where the specimen is subject to maximum tensile stress and where boiler water evaporates. A boiler water is considered to have no embrittling tendency if specimens do not crack within successive 30-, 60-, and 90-day tests. Observation of the detector is... 

Figure 18.3. Embrittlement detector which, when attached to an operating boiler, detects tendency of a boiler water to induce stress-corrosion cracking.

ASTM D807-05, Standard Practice for Assessing the Tendency of Industrial Boiler Waters to Cause Embrittlement (USBM Embrittlement Detector Method), ASTM International, West Conshohocken, PA. 

Sodium leak wire-detection has shown problems of spurious earthing, and embrittlement of the nickel wire in the long run this has meant several interventions with, notably, a change from nickel to stainless steel. This wire detection system has been further reinforced on secondary piping of over 200 mm diameter by sandwich-type detectors. 

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