PENGARUH KONSENTRASI GARAM TERHADAP LAJU KOROSI PADA BAJA ST42, STAINLESS STEEL 304 DAN ALUMINIUM 5083

Abstract

Ship is a floating building which use elementary materials from metal, though there is also which from non metal, which use elementary materials non metal, weared by ordinary mild steel with grade St 42, Stainless Steel 304 and Aluminium 5083. Because of ship reside in ocean representing corrosive area hence making hull of ship react causing the happening of corrosion and lessen the nature of his mechanical, for that require to be conducted by fast solution and research of corrosion from the metal type above. By using heavy degradation method, spesimen which is each amounting to 4 bar and with long dimension 200 mm, width 75 mm, thick 8 mm, put into 4 containing canister of water with various salt content which that is 2,25% at I canister; 2,85% at II canister, 3,50% at III canister and 3,75% at IV canister according to result of laboratory test and each, every 5 day conducted by and perception record keeping of heavy reducing, every specimen up to 4 times perception to be calculated the corrosion rate (Fontana), thats specimen perception before and after examination process ( W ) in gram multiplied by 534 ( Fontana formulation number) divided by multiplication between specimen area ( cm2 ) with specimen density and time proces examination phase ( t ) in (hour). From calculation average corrosion rate mean can know corrosion rate each specimen that is by dividing the amount of average o corrosion rate of each specimen with salt content amount, exist in to 4 canister, for the specimen of Become militant St 42 which everage 0.0214 mpy , with amount of salt content between 2,25%~3,75% , for specimen of stainless steel 304 which everage 0,0159 mp with amount of salt content between 2,25%~3,75%, for specimen of Aluminium 5083 which everage 0,0712 mpy with amount of salt content between 2,25%~3,75%. After 20 days, result of examination every 1% salt content which ingradion on corrosion areas ( sea water), having an effect 0,0017 gram/year, for mild steel St 42 and 0,0012 gram /year for Stainless Steel 304 than 0,0057 gram /year for Aluminium 5083, necessary remembered, salt content on corrosion areas use as electrolyte, to increase corrosion proces. Key words : corrosion rate, mild steel st 42, stainless steel 304 , aluminium 5083 , salt content