Investigation of Roll Steel-sticking of Φ460 mm PQF Pipe Mill

Investigated are the causes for and the elements affecting occurrence of roll steel-sticking of the mandrel pipe mill. Accordingly，a solution is proposed，involving such measures as modification of the water nozzle for roll surface cooling and increasing the pressure of the cooling water supply system so as to get consistent pressure and flow rate of the water nozzle；in case of using new rolls，firstly producing limited quantity of pipes as rolled with rather low rolling load；and properly distributing the elongation rate to each individual roll stand，and appropriately reducing the load upon the slot bottom of stand No.3. The testing operation result demonstrates that thanks to the above mentioned measures as taken， the roll steel-sticking severity is remarkably abated， and thus the first pass yield （FPY） goes up to 97.65%，while the downtime of the mill is cut down to 2.5%.