damage should be made by both subjective observation and by quantitative 

 measurement of section thickness, depth of pitting, etc. Damage due to 

 causes other than corrosion such as impact, overload, etc., should be 

 identified. 



Samples of the structural components should be taken at this time' 

 for further laboratory analysis to verify the type and extent of damage. 

 Samples should be removed and preserved as indicated in section IV 

 below. This removal and preparation can be done by the inspector in 

 many cases; however, as it may involve the use of power tools or flame 

 cutting equipment, assistance from other personnel is often required. 



Documentation of this stage of the inspection is important but the 

 slower pace makes this duty easier to perform than initial inspection. 

 Visual observations should be recorded in writing or on tape. Careful 

 attention must be given to the location of the areas inspected in order 

 to properly interpret the observations. Photographic documentation 

 should be performed at this stage to record the extent of damage to the 

 structure. Again, indexing of the photographs is important. 



After this stage of the inspection the structure should be retained, 

 if practical, for possible future analysis. 



III. Laboratory Analysis 



The techniques used for the analysis of corrosion product, biological, 

 and material samples will, of course, depend on the material to be 

 analyzed and the desired results. Written or photographic documentation 

 of observations and results of testing performed are an important part 

 of the laboratory analysis. 



A. Corrosion Products. X-ray fluoresecnce spectography , emission 

 spectography, or wet chemical analysis can be used to identify the 

 elemental constituents of the corrosion products. X-ray diffraction can 

 be used to identify crystalline chemical compounds in the corrosion 

 products. Microscopic techniques can be used to determine the morphology 

 of the corrosion products. 



B. Biological Samples. The genus and species of the samples 

 should be identified by a marine biologist. Often, in the deep ocean, 

 new species are discovered or known species are found outside their 

 normally defined habitat. 



C. Metallic Samples. Specimens should be subjected to mechanical 



tests, hardness tests, metallographic examination, and other tests as 

 necessary to evaluate the extent and type of damage to the test samples. 



D. Other Materials. Samples of other materials should be analyzed 

 in the laboratory with guidance or assistance from personnel with expertise 

 in their field. 



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