Revestimentos de Carcaça para Moinho SAG | ATF

SAG Mill Shell Liners: Engineered for Primary Grinding Duty

Semi-autogenous grinding (SAG) mills process run-of-mine (ROM) ore directly from the mine, creating extreme impact loading conditions that demand the most robust liner designs in comminution equipment. SAG mill shell liners must withstand repeated impacts from large ore chunks up to 300 mm in diameter and heavy grinding media of 100–150 mm forged steel balls, while simultaneously controlling charge trajectory for efficient autogenous and semi-autogenous breakage. Liner profiles in SAG mills feature significantly taller lifter heights (200–350 mm) than ball mills and require thicker shell plate sections to absorb the severe cyclic impact energy without cracking or spalling. ATF manufactures SAG mill shell liners from ASTM A532 Class II and Class III chrome-moly steel at 325–450 BHN, as well as bimetallic composite castings with a 600+ BHN hard face bonded to a tough 300 BHN backing, giving operators flexibility to match material selection to their specific ore abrasiveness and impact severity.

SAG mill liners operate in a fundamentally different and more demanding environment than ball mill liners. The mixed charge of ore and balls produces both high-energy impact at the toe of the charge and severe sliding abrasion along the lifter faces, requiring a carefully balanced combination of hardness and fracture toughness that only chrome-moly steel alloys can consistently deliver. Higher-hardness grades (400–450 BHN) extend wear life in abrasive ores but must be specified cautiously in high-impact zones where toughness is critical to prevent catastrophic liner failure. ATF engineers SAG mill liner systems optimised for each installation, considering mill diameter (6 m to 12 m), rotational speed (typically 68–76% of critical), ball charge percentage (8–15%), total charge volume (25–35%), ore Bond Abrasion Index, and target throughput. Discrete Element Method (DEM) simulation and decades of field performance data from mining operations worldwide inform every profile recommendation, ensuring each liner set delivers maximum grinding efficiency and campaign life.