Gyratory Mantle & Concave Segments | Mn Steel | ATF

Gyratory Mantles and Concaves: Primary Crusher Liners

Gyratory crusher mantles and concaves are the massive manganese steel liners that form the crushing chamber in primary gyratory crushers, representing some of the largest individual cast manganese components produced in the mining industry. Individual segments can weigh from 500 kg for smaller 42-65 units up to 8,000 kg for the largest 60-110 gyratory crushers, and they operate under extreme conditions including continuous heavy loading from run-of-mine feed at rates exceeding 10,000 tonnes per hour, oversized material from blast fragmentation, and occasional tramp metal from mining operations. These liners are manufactured from premium austenitic manganese steel grades (Mn18Cr2, Mn22Cr2, or Mn22Cr3 per ASTM A128) that work-harden from an initial 200-260 HB to surface hardness values exceeding 550 HB under the sustained compressive impact of primary crushing duty.

Unlike cone crushers where liners are typically supplied as one-piece components, gyratory crusher liners are segmented for practical handling, transportation, and installation using the overhead cranes available in most crusher houses. Mantle segments fit around the main shaft head assembly and are secured with a mantle nut or clamping ring and backed with epoxy or zinc compound to fill the void between the segment and the shaft head casting. Concave segments, also called bowl liners, are arranged in multiple rows within the top shell, with each row potentially specified with different profiles and even different manganese grades to optimize wear patterns based on the position-specific balance of impact and abrasion forces. Proper segment profiling and material selection are critical for achieving target throughput, minimizing energy consumption, and maximizing liner life in terms of tonnes processed per set.