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fr) a _ \ ee ae wnat y \ j /T ests Steel Plates of Leviathan Chemical and Physical Investigation of German Made Plates Fails To Show Clearly Why They Have Resisted Corrosion So Well HILE the story of the Levra- THAN is familiar to almost everyone a little of her history may be repeated. She was completed in 1914 at the yards of Blohm & Voss in Hamburg under the name of VATER- LAND. At the beginning of the World war she was at her pier in Hoboken, N. J., and remained until some time after, being taken over by the United States navy in April, 1917. Her first trip as a transport began Dec. 15, 1917, and she was drydocked at Liverpool early in 1918. Her last trip as a_ transport ended Sept. 9, 1919, when she again laid up at Hoboken. After con- siderable delay in regard to policy the contract for her reconditioning was awarded to the Newport News Ship- building & Drydock Co., Feb. 15, 1922. In April, 1922, she arrived at Newport News under her own power and left May 16, 1923, bound for Boston where she was drydocked May 18 in the only dry dock in the United States large enough to accommodate her. On July 4, 1923, she left on her maiden trip under the United States flag as a mer- chant ship. A complete and well il- -lustrated account of the ship and her reconditioning appeared in a special is- sue of Marine REvIEW July, 1923. It will be noticed that over five years elapsed between drydocking at Liver- pool and at South Boston, during which time no attention or care could be given to the hull plates. Nevertheless it was found that the bottom was in remark- ably clean condition, the hull being free from marine growths, pitting and corro- sion. While the ship was at Liver- pool five years before, a skeg of Eng- lish steel plates was rivetted to the stern for carrying a part of the rigging for the paravane or otter gear, a mine Was | BY DR. G. B. WATERHOUSE 4c Why This Resist nce to Corrosio ? HEN the S. S. LeviatHan was drydocked at Boston, it was found that the original Ger- man plates had resisted the corro- sion of sea water much better than a number of plates of English man- ufacture which had been installed at Liverpool in 1918. A. H. Jansson, associate editor of Martne Review, reported the facts to Dr. G. B. Wa- terhouse, professor. of metallurgy, Massachusetts Institute of Technol- ogy, who tested samples of both steels. The results, which are de- scribed by Dr. Waterhouse in the accompanying article, do not clearly indicate why the German steel re- sisted corrosion more successfully during 10 years of service than the other steel in 5 years. Dr. Waterhouse’s conclusions sug- gest tmteresting questions. Is _ the presence of more copper in the orig- inal steel responsible for its greater * resistance; does the banded struc- ture account for it; or does some other factor, not revealed by the tests, hold the key to the problem? sweeping device invented, supplied and installed by the British government. In contradistinction to the plates of the hull this skeg or paravane gear was found to have been badly attacked by the continuous submersion in sea _ water, without attention for over five years. These facts regarding the steel plate were brought to the author’s attention by A. H. Jansson, associate editor of MarINE ReEviEw, and by Prof. James R. Jack, head of the department of naval architecture at the Massachusetts In- stitute of Technology. It was felt that an investigation of the steel plate, par- ticularly of the German steel, would be of interest, and through the cour- tesy of the commandant and officers of the United States navy yard, Boston, samples were secured for examination. Two samples of the German steel were obtained. They were oval in_ shape, about 18 x 20 inches. One was about 1 3/16 inches thick and the other about 1 5/16 inches. They may be called sam- ples A and B. The physical testing was done by men accustomed to making and handling steel plate and thanks are due to A. L. Meyer, ‘metallurgical engineer, Alan Wood Iron & Steel Co., and to William G. Humpton, engineer of tests, Lukens Steel Co. for ‘their co-opera- tion. The chemical analyses were as follows: Sample A Sample B Warboni a cedschieis «sunita a teloroee 0.16 0.15 Man ganesee. cicic occ a viece ew veces -65 EVE PHOSPROrUs pik 5 isis cis psoas vieierees 42 034 Stipes eee se eceleiey a .069 .057 STICOM crea erare ere we Sie scteace at aeenoiaret .006 ‘trace Copper eae abies cs cane e ek .169 -134 NICE eS sarssirietteten ge ree nil nil Gromiinys et eae oes aenetes ee 013 no Mata isin Ysicieia lec eccis eve iece me erste nil nil The samples did not show any alum- inum, titanium, molybdenum or _ zirco- nium. The analyses indicate ordinary steel, rather high in sulphur, except for a high percentage of copper either introduced purposely or present in the steelmaking charge. The results of the physical tests are as follows:: Sample Sample A B Long. Trans. Long. Yield point, pounds per, sdiiare: ane snc ceccn 37,950 37,100 31,300 Ultimate stress, pounds per square~inch..... 63,200 63,300 51,630 Elongation, per cent ; in. 8. inches 4.:.3..%%.. 27 25 28 Transverse FIG, 1—SAMPLE 4 Transverse Longitudinal 319 Longitudinal FIG. 2—SAMPLE B