08 6 71 04 0 44 0 15 0 02 0 251448 8 85 22 02 6 93 03 0 32 0 25 0 01 0 461493 12 16 26 86 4 72 1 88 0 66 0 17 0 06 0 36______________________________________ the mechanical properties of the commercial comparative alloys as furnished by the manufacturers are set forth in table iv table iv______________________________________mechanical properties of comparative alloys tensile yield tensilealloy strength strength elonga designation p s i p s i tion ______________________________________ferralium 255 110 000 80 000 252205 90 000 65 000 25317l 70 000 25 000 40al6x 90 000 40 000 45254smo 95 000 44 000 35vewa963 87 000 43 500 35cor25 100 000 75 000 187 mo plus 90 000 70 000 15______________________________________ in table iv all of the mechanical properties given are for the annealed condition that is prior to any cold working to keep them all on the same comparative basis alloys 317l al6x 254smo and vewa963 are all of the fully austenitic variety while the remaining alloys are duplex stainless steels using the disc samples of example 1 samples of the invention were immersed to a depth of about 13 4 inches in natural seawater taken from the atlantic ocean at myrtle beach south carolina the seawater was held at room temperature in plastic containers with tightly fitting lids for six months with a change of water every two weeks at the end of the six month period none of the samples of the invention showed any pits rust or discoloration when examined under a 10 power magnifying glass further disc samples were similarly placed in plastic containers as in example 2 but employing a salt water.