Views:0 Author:Site Editor Publish Time: 2021-03-15 Origin:Site
The first is to improve the cleanliness of the molten steel of the straight seam steel pipe and reduce harmful inclusions; increase the proportion of equiaxed crystals in the continuous casting slab to reduce center segregation and center porosity; adopt a reasonable cooling system to avoid internal cracks in the slab; Or the continuous rolling billet adopts a slow cooling process to reduce internal stress, so as to ensure that the structure and mechanical properties of the straight seam steel tube billet and the finished straight seam steel tube meet the technical standard requirements.
Secondly, reasonably control the heating temperature
By measuring the thermoplastic curve, the best heating temperature is selected. When heating the straight seam steel pipe billet, it is also necessary to pay attention to enough heat preservation time to reduce the deformation resistance and improve the plastic toughness of the straight seam steel pipe.
Third, reduce the roll speed
The roll speed is a key parameter of the piercing process. During the change of the roll speed from low to high, there is a critical roll speed at which delamination begins. When the roll speed is low, the tube blank is easy to form a cavity; when the roll speed is high, the straight seam steel tube tube is easy to form layered defects. In order to eliminate the layering defects of the straight seam steel tube billet and the straight seam steel tube, the roll speed should be reduced to below the critical roll speed at which delamination begins.