1.Shell material is alloy steel,strong wear-resisting, ... hoisting, lifting weight usually less than 100t. 2. Shell material is high quality alloy steel, firm, wear-resisting, ... 800 Mpa high strength lifting chain, and the material of the general for 20 M2, intermediate frequency ... wear, anticorrosion of the chain; High strength hook, material is commonly alloy steel, gesture type crane design to ...