Iraeta Powers the World’s Largest-Diameter Shield Machine Main Bearing Offline

On October 12, 2023, China Railway Construction Heavy Industry (CRCHI) unveiled the world’s largest-diameter and heaviest single-unit integral shield machine main bearing in Changsha—an 8.61-meter-diameter, 62-ton colossus standing three stories tall. Capable of driving an 18-meter-diameter shield machine and withstanding 10,000-ton-level loads, this milestone component features critical bearing ring forgings supplied by Iraeta.

Shield machines, dubbed the “crown jewel of global construction machinery,” are pivotal for national infrastructure, enabling tunneling through mountains, rivers, and seas. The main bearing—their “heart”—endures extreme operational conditions: ultra-heavy, eccentric, and frequently changing loads. Its service life and reliability depend on material selection, design precision, manufacturing expertise, and rigorous testing, with development difficulty growing geometrically as size increases.

In the 2023 collaboration for the 8.61-meter main bearing, Iraeta upheld a philosophy of close collaboration and relentless precision, iteratively optimizing design plans and rigorously ensuring the stability and durability of bearing ring forgings. Our efforts culminated in on-time delivery, playing a pivotal role in bringing the world’s largest shield machine main bearing to successful completion.