Steel roller, mechanical roll, roll, plastic, printing, packaging, texitle, paper, etc. max diametre: 1m, max length: 10m. Mirror Roller, Shanghai Donghui Roller is the excellent expert all over the world. 1. Materials: 20#, 45#, forge alloy steel (42GrMo,38GrMoAI), heating treatment and mechanical processing, hardness is HRC55~58.2. Inner structure: single-layer, multi-layer screw, Z and other ...