ET A 100 Zn 70 DPN hardness ZET A 94 Zn 6 Fe 179 DPN Hardness DEL T A 90 Zn 10 Fe GAMMA 75 Zn 25 Fe 250 DPN hardness BASE STEEL 159 DPN Hardness 9 8 7 6 5 4 3 2 1 0 Dispersion zone v alues related to different authors 0 A B C 004 015 Si Mass Zinc Grip Arbitr ary Unit 01 02 03 04 05 06 a Silicon effect 400 300 200 100 A B C 0 005 01 012 015 02 P Mass Coating T hickness um b Phosphorus Effect 400 350 300 250 200 150 100 50 0 A 005 009 01 015 02 025 03 B C Si 25 Mass Coating T hickness um c Combined effect of silicon and phosphorus STEEL SELECTION 4 basic elements that can affect the galv anized coating 1 Carbon in excess of about 025 2 Silicon in the r ange of 004 to 015 or above 022 can produce galv anized coating growth r ates much higher than those for steels with silicon levels below 004 and between 015 and 022 3 Phosphorus in excess of 004 4 Manganese in excess of about 13 Fig 1 Photomicrogr aph of Normal Galv anized Coating 20