Hitachi crawler crane bottom rollers mainly appear in the preheating section and heating section of the furnace. The main parts of Hitachi crawler crane bottom rollers are shaft head, journal and roller body. The occurrence of roller breakage will affect the production of thick plates and is prone to safety accidents. For the appearance quality and outer diameter size, the processing plant generally performs turning processing at the welding joint. The larger turning thickness will cause chamfering between the edge of the machined surface and the non-machined surface of the journal. The chamfer produces a stress concentration area. When it is too large, roller breakage will occur.
In addition, the fit between the roll body and the roll neck welding part is a clearance fit, and it is easy to accelerate the cracks in the roll body and the roll neck welding part after frequent heating and cooling, and eventually break. Cancel or reduce the turning process at the weld joint, or increase the thickness of the roll body to enhance the overall strength of the joint; improve the matching size of the roll body and the roll neck, so that the roll body and the roll neck are tightly combined. Strictly follow the furnace curve to heat up, and stop the furnace to implement the furnace bottom roll cooling with the furnace to reduce the influence of temperature changes. In addition, defective furnace bottom rollers should be replaced in time.
