Reinhart 



The corrosion rate of steel was not affected by nickel 

 additions to 9 percent at either depth. 



Silicon and silicon-molybdenum cast irons were immune to 

 corrosion in deep ocean environments. 



The mechanical properties of the alloys were not impaired. 



The corrosion products of the alloys were composed chiefly 

 of alpha iron oxide, ferric oxide hydrate, ferrous hydroxide and 

 Beta iron (III) oxide-hydroxide. 



Zinc (hot-dipped) (1.7 mils) and titanium-cadmium coatings 

 failed to protect sheet steel for one year of exposure. 



A hot-dipped aluminum coating (4 mils) protected sheet 

 steel for a minimum of one year whereas a sprayed aluminum coating 

 (6 mils, sealed) protected sheet steel for three years. 



The mechanical properties of anchor chains were unimpaired. 

 However, sea water penetrated the forged sockets of one type of 

 chain as evidenced by corrosion at the bottoms of the sockets. 



The mechanical properties of Type 304 stainless steel cables 

 in sizes 0.094, 0.125 and 0.187 inch diameter were decreased by a 

 minimum of 85 percent due to corrosion of the internal wires while 

 those of the larger diameter wires were unaffected. 



The breaking strength of a Type 304 stainless steel cable 

 coated with 90 percent copper-10 percent nickel was not affected. 



The breaking strengths of the aluminum coated steel wire 

 ropes were unaffected. 



The bare steel, zinc and aluminum coated steel and stainless 

 steel wire ropes were not susceptible to stress corrosion cracking 

 when stressed at 20 percent of their respective breaking loads. 

 However, the Type 316 stainless steel wire rope lost 40 percent of 

 its breaking strength due to corrosion of the internal wires. 



The breaking strengths of bare steel, zinc and aluminum 

 coated steel wire ropes, both stressed and unstressed, were unimpaired 

 by exposure to deep ocean environments for periods of time as long 

 as 1,064 days. However, based on visual observations zinc coatings 

 corroded at faster rates than aluminum coatings on the wire ropes. 



ACKNOWLEDGMENTS 



The author wishes to acknowledge the generosity of Dr. T. P. 

 May, Manager, Harbor Island (Kure Beach) Corrosion Laboratory, 

 International Nickel Company, Inc. for granting permission to include 

 his deep ocean corrosion data in this report. 



273 



