What Should be Paid Attention to When Welding Rolls?

The rolls are the core component of the rolling mill. The use of the roll involves the type selection of the rolling mill, the preparation of the roll, maintenance and periodic repair during the rolling process, all of which affect the productivity, product quality and production economy of the rolling mill. Because the rolling process is a continuous process, the operator needs to constantly check the roll conditions, so that the final products can meet the user’s stricter tolerances and surface quality requirements.

In order to make the product continuously competitive, it is necessary to continuously require the rolling mill operators to reduce production costs, that is, to increase the rolling speed, the production flexibility of the rolling mill and reduce the consumption of rolls. So what should we pay attention to when welding rolls?

(1) Before build-up welding, the fatigue layer or defect on the roll body surface, especially cracks must be completely removed;

(2) During surfacing, in order to prevent the occurrence of cracks, the roll body must be preheated first, and the preheating temperature depends on the roll and the surfacing material;

(3) The key to the success or failure of surfacing during welding is to obtain an ideal surfacing layer. Therefore, certain variable factors must be considered, such as: welding voltage, welding speed, roller speed, roller insulation, welding current, welding material. For some roller cores with high carbon and alloy elements, in order to prevent cracks in the brittle zone, in addition to certain preheating measures, low carbon and low alloy transition layers are mostly used for pre-surfacing transition layers.

(4) Slow cooling and turning after roll surfacing. In order to reduce the cracks caused by the volume stress caused by the different surface and internal cooling rates, the cooling rate must be controlled. Finally, the surfacing rolls are turned to restore the original size and finish.

And the performance of the roll after surfacing:

(1) The service life of rolls after surfacing is generally more than doubled;

(2) Greatly reduced the cost per ton of steel and improved the production effect;

(3) The roll after surfacing has good crack resistance, abrasion resistance, resistance to hot and cold fatigue.