Gunmetal Grade B.S. 1400: 1985 Nominal Composition 2% PS N/mm Min Tensile Strength N/mm Min Elongation % Min Brinell Hardness Min AB1 89/9/2 180 500 18 100 AB2 85/9/4/5 250 600 13 400 ALBC2 84/9/4/5 490 20 120 ALBC3 82/10/4/4 245 590 15 150