In order to let the rolling mill production being normal, avoiding the impact of downtime, there are several factors that hinder the normal use of the rolling mill.

1. The main reason that affects the productivity of the pusher is the long idle time when the pusher returns. In order to increase productivity, the return speed of the pusher can be made larger than the push speed. Generally, the return speed is 50% to several times larger than the push speed. Some pushers have a slow push motor and a fast return motor to adjust the speed. The hydraulic pusher can adjust the pushing speed easily. The standard pusher stroke is generally 1.5-5.5 m, which is depended on the size of the pushed material and the width of the table. When loading with a crane, the stroke should be greater than the total width of each load and larger than the width of the roller; when feeding with a roller conveyor, in addition to considering the width of the roller conveyor, it should be determined according to the required length of the inspection requirements.

2. During the pressing process, physical and chemical changes such as discoloration, decomposition, melting, and deformation of the billet should be avoided. The inlet temperature of the rolling mill should be kept within the applicable temperature range allowed by the billet, and the optimum temperature is 1,150 degrees. Generally, in the regenerative heating furnace, since the billet is stepped from the low temperature zone to the high temperature zone by the pusher, the temperature of the taphole is the highest, and the billet does not need to be turned, which can make the billet heating evenly, fast and short.

3. When the steel is rolled, corners and surface cracks appear. Since the residence time of the billet in the heating furnace is short, a large driving force is required to increase the heating rate. Generally, the partial pressure of the outlet gas is lower than half of the water vapor pressure on the surface of the outlet material; for the regenerative heating furnace, The partial pressure of water in the outlet gas is generally about 60% of the water vapor pressure on the surface of the billet.