Corrosion-Resistant Back Head of Atlas Copco RD18U in Malaysia

Malaysia's underground mining and civil tunneling programs—most recently including infrastructure tunneling under Kuala Lumpur's urban core and hard-rock quarrying in Perak's limestone and granite highlands—operate in near-constant high humidity with seasonal flooding events that leave drill equipment sitting in standing water during maintenance shutdowns. The back head of the Atlas Copco RD18U is the rear housing cap that seals the percussion circuit at the high-pressure supply port and houses the rear accumulator interface and hydraulic connections. Corrosion at the external surface is cosmetic; corrosion at the port threads and O-ring groove faces is functional failure.

The back head's port thread and mating face condition determines whether the hydraulic connection maintains torque-loaded sealing or develops a weeping leak that allows sustained low-level oil loss. In Malaysian tropical humidity, exposed steel thread faces that aren't regularly coated with a corrosion inhibitor develop surface oxide in 4–6 weeks. That oxide roughens the thread flank profile, which changes the friction coefficient on tightening and can cause either undertorquing (leak at assembly) or thread stripping (damage that requires replacement of the back head itself).

Back Head Maintenance in Tropical Environments

Malaysian drilling contractors on civil tunnel projects have standardized on fitting blanking plugs to all hydraulic ports during the daily maintenance period rather than leaving them open—a 3-minute procedure that eliminates moisture and dust ingress during the 2–4 hour maintenance window. That single habit extends O-ring service life measurably because it prevents the oxidized grit that forms at open port faces from embedding in the O-ring groove during reassembly. HOVOO supplies RD18U back head O-ring sets alongside port thread repair kits. References at hovooseal.com.