HLY-TS-01: Pipe Delamination, Spiral Cracks & Mold Jumping Troubleshooting Guide

Fault 1: Severe Mold Hopping & Impact Noise on Roller Shaft

Root Causes:

1. Non-uniform longitudinal feeding causing dynamic mass imbalance;
2. Runner rings worn out-of-round (>2 mm ovality);
3. Uneven torque on longitudinal flange clamping bolts causing torsional distortion.

Corrective Actions:

1. Adjust feed conveyor scrapers for level distribution;
2. Turn out-of-round runner rings on a vertical lathe or replace with forged steel rings;
3. Enforce star-pattern bolt torque tightening.

Fault 2: Pipe Inner Bore Delamination, Spalling & Spiral Grooving

Root Causes:

1. Excessive water-cement ratio creating thick uncompacted slurry skin;
2. Net rolling stage extended too long, pulverizing setting cement matrix;
3. Sand moisture surge not compensated at batching plant.

Corrective Actions:

1. Target Vebe consistency strictly between 25–35 seconds;
2. Limit net compaction rolling duration to strict engineering limits (max 6 min for DN1200);
3. Calibrate microwave moisture probe for automated water correction.

Fault 3: Joint Honeycombing & Voids at Spigot/Bell Ends

Root Causes: Insufficient end dwell time during feeding; worn end-ring slurry seals.

Corrective Actions: Dwell conveyor at joint ends for 15–20s; replace degraded flange rubber seals.