exposure site (STU II.-l and II~2) in the minimum oxygen zone at a 

 nominal depth of 2,500 feet. This site is also shown in Figure 1. 



A suirimary of the characteristics of the ws.ters approximately 

 10 feet above the bottom at the different exposure sites is given 

 in Table 1. 



The KCEL oceanographic investigations also disclosed that the 

 ocean floor at each of these sites was rather firm and vjas character- 

 ized as sandy, green cohesive mud (partially glauconite) with some 

 rocks. The biological characteristics of this sediment are described 

 in References k through 8 



The details of the construction, emplacement and retrieval of 

 the STU structures are given in References 9 through 12, 



The procedures for the preparation of the specimens for exposure 

 and for evaluating them after exposure are described in Reference 13. 



Previous reports pertaining to the performance of materials in 

 the deep ocean environments are given in References 13 through 17 » 



This report presents and discusses the results obtained from ex- 

 posure of irons, steels, low alloy steels, alloy steels, unalloyed 

 and alloyed cast irons, steel wire ropes, anchor chains and metallic 

 coated products for six periods of time and at two nominal depths 

 shown in Table 1. 



RESULTS AND DISCUSSION 



The chemical con^position of the irons, mild steels, 'nigh-strength 

 low-alloy steels, alloy steels, high strength steels, nickel steels, 

 alloy cast irons, austenitic cast irons, etc., are given in Table 2; 

 their surface conditions and heat treatments, if any, are given in 

 Table 3. 



Included in Table 2 are the chemical compositions of the iron 

 base alloys which were exposed on the STU structures for the inter- 

 national Nickel Company, Inc. Dr , T. P. May, Manager, Harbor Island 

 Corrosion Laboratory of tlie International Nickel Company, Inc. has 

 granted permission to incorporate his corrosion data (Reference 18), 

 obtained from their specimens on the six STU structures, with the 

 NCEL data. 



Some additional data from another participant in the WCSL ex- 

 posures, Aeronautical Materials Laboratory, are also included, (Refer- 

 ence 19), 



Surface data of some alloys of chemical compositions similar to 

 those in Table 2 from the Atlantic Ocean (Reference 20) and similar to 

 those from the Panama Canal Zone, Pacific Ocean (Reference 21) are 



