Manganese Steel Plate. Chemical composition contains 0. 8 to 1. 25 % carbon and 11 to 15 % manganese. Sizes: 1 ) 1. 75 to 2. 25 Meter width x 2. 5 to 3. 5 metre length, thickness 6mm- qty- 01 no 2 ) 1. 75 to 2. 25 meter width x 2. 5 to 3. 5 metre length, thickness 10mm- Qty- 01 No. Note: Manganese Steel chemical composition Govt Lab Test Certificate should be supply with material.