Massive Base Frame for Midstream Gas Compressor
Project Background
An international EPC (Engineering, Procurement, and Construction) firm approached Openex to fabricate a heavy-duty base frame for a massive centrifugal gas compressor package. Intended for a harsh midstream pipeline station, the frame required exceptional structural integrity to absorb severe dynamic operational vibrations without fatigue failure.
The critical challenge of this project lay in its sheer size coupled with ultra-tight tolerance requirements. The mounting pads for the motor and compressor casing had to remain perfectly flat (within a 0.05 mm tolerance across a 12-meter span) after complete structural welding and lifting.
Project Specifications
The Openex Execution Process
Because of the critical flatness tolerance, Openex engineers developed a precise, sequential manufacturing workflow combining advanced thermal management and heavy-duty planar machining.
High-thickness carbon steel beams were CNC profile cut and robotically bevelled to guarantee pristine, uniform root openings for full-penetration joint preparations.
Welders deployed multi-pass FCAW in a tightly choreographed sequence to minimize heat distortion. 100% of major load-bearing weld seams underwent rigorous Ultrasonic Testing (UT) to verify defect-free joints.
*Critical Step:* The entire 35-ton structural frame was transported to our colossal on-site heat treatment furnace. Post-weld heat treatment eliminated locked-in weld stress, stabilizing the frame so it would not warp during final machining or deployment.
Using our heavy CNC gantry mill, all mounting pads for the motor, compressor, and lube-oil console were faced off in a single setup. By utilizing a single CNC envelope, coplanar accuracy between all pads was secured well within the client’s requested ±0.05 mm limit.
The frame was sent to our blasting booth to achieve an SA2.5 finish before being sealed in an offshore-grade, highly durable three-coat epoxy paint system, rendering it completely protected for exterior facility operation.
Conclusion
By consolidating plate cutting, certified heavy welding, oversized heat treatment, and precision milling under one roof, Openex eliminated logistical delays and complex vendor handoffs for our EPC client. The heavy skid was successfully delivered on time and achieved complete vibration harmony at full compressor speeds during the final Field Acceptance Tests (FAT).