The current spiral blades generally use continuous cold-rolled spiral blades or winding spiral blades with less than six spiral blades, and more than six commonly used single-piece stamped and formed spiral blades. Today, I will mainly explain the characteristics of continuous cold-rolled spiral blades.

Continuous cold-rolled blades are produced by rolling strip steel to produce plastic deformation. Generally, the formed blades are 1-1.5 mm wider than the strip steel; we generally ignore them in production. The reason is that the spiral blade and the inner pipe wall of the Jiaolong generally have a gap of 10mm. The error of one millimeter can be ignored and there will be no actual production impact. In addition, the blades will be thin inside and outside during production, which is mainly unavoidable due to the production process. However, in the deformation process, due to the extrusion deformation of the rolls on the strip steel, the blades produced have higher hardness and wear resistance, thereby prolonging the service life.

Cold-rolled spiral blades also have their own shortcomings. Generally, the blade pitch is not less than 2/3 of the outer diameter or more than 3/2 of the outer diameter. Once it exceeds this range, the blade is difficult to shape. When using strip steel with a lot of impurities, the pitch of the inner diameter of the blade will change into instability, which will affect the performance of the product. Generally, we will use strip steel produced by Shanghai Baosteel to avoid or reduce the above situation.