S31803 shine tsarin ƙididdigar lamba (mara izini) ƙira don asalin Duplex bakin karfe. Kungiyoyi masu ciniki da yawa sun kirkiro da kungiyoyin kasuwanci da yawa a cikin shekarun 1970 don rage rikicewa yayin da aka kira kowa abubuwa daban-daban, da kuma mataimakinsu. Kowane ƙarfe yana wakilta ta hanyar wasiƙu da lambobi biyar, inda harafin yake wakiltar jerin baƙin ƙarfe, I.e. S for bakin karfe.
Don aikace-aikacen Mill na takarda da ke buƙatar ƙananan ƙwayoyin kuɗi waɗanda ba su da isasshen juriya na lalata. Dangane da abun ciki na 22% na cromium, suna da Austenitic: ferritic microstructure wanda ke samar da babbar ƙarfi da juriya da lalata da tasiri.
Wanda ba a san tantance ba (Ashem F51) da unp2205 (1.4462, Astm F60). Wannan yana nuna sha'awar su kara lalata kayan lalata na kayan ado, godiya ga ci gaban aikin AOD, wanda ke ba da damar sarrafa abun da ke ciki. Bugu da kari, yana ba da damar tasiri matakin nitrogen matakin maimakon kawai kasancewa a matsayin asalin asalin. Sabili da haka, mafi girman maki na Duplex suna neman ƙara yawan abubuwan Chromum (cr), Molybdenum (mo) da nitrogen (n).