Now Jinan galvanized pipe demagnetization generally chooses DC demagnetization coil and magnetic particle flaw detector with demagnetization coil, but demagnetization effect can't satisfy customers. The problem is that the DC magnetic field produces reverse half cycle back, how can only make the internal residual magnetization of large diameter spiral pipe demagnetization partially offset, and the external residual magnetization performance is within the required range, so the effect is not very stable.
It can often reach the standard in the magnetic field. After handling and hammering, the magnetic field exceeds. The reason is that the degaussing internal domain of the large-diameter spiral steel tube has not been "magnetic exercise", and it is in a very stable state. The national demagnetization standard of large diameter spiral steel pipe is below 30gs. The demagnetization system of HT30D steel tube can stabilize the demagnetization of the steel tube at about 10GS, avoiding the demagnetization rebound in the later transportation process. External dimension: 400 * 500 * 600mm working voltage: 220V working current: 5-20A continuously adjustable working frequency: 0-50Hz continuously adjustable demagnetization coil inner diameter: 100-250 (according to customer requirements).
After empty drawing, the surface area of Jinan galvanized steel pipe increases, and the surface area of the inner surface decreases. There will be a neutral layer on the inner and outer surface, and the surface area will increase after surface deformation. After the surface area of each layer between the inner surfaces of the neutral layer decreases after deformation, the inner surface will decrease. The change of surface area of each layer of Jinan galvanized steel pipe affects the inhomogeneity of metal deformation. One of its characteristics is that each layer of natural extension along the wall is inconsistent, the outer surface layer of Jinan natural extension galvanized steel pipe, the inner surface layer of Jinan galvanized steel pipe, and the inner surface layer by layer of the outer surface of the middle layer natural extension gradually increase. The second feature is that due to the overall relationship, the deformation of Jinan galvanized steel pipe layer cannot have different ductility, so the layers must be mutual. The metal (called outer layer) between the outer surface and the neutral layer extending naturally is smaller than that between the neutral layer and the inner layer (called inner layer). The outer layer must be subject to the inner layer deformation period, and its actual extension is larger than that of natural extension, while its thickness decreases due to the increase of extension. On the contrary, the extension of the inner layer is hindered by the outer layer, the extension of the outer layer is actually smaller than the natural extension, and the thickness increases.
The drawing speed of Jinan galvanized steel pipe has a great influence on the productivity of the drawing machine. High speed tube drawing can shorten the period of tube drawing and improve the productivity of tube drawing. At present, the pulling speed of domestic technology has reached 40 m / min (adjustable speed), and that of foreign technology has reached 100 m / min. Generally, the higher the drawing speed of galvanized steel pipe in Jinan area is, the faster the axial movement speed of metal in deformation area is, and the larger the reduction diameter of empty drawing galvanized steel pipe in Jinan area is. However, the experimental study on the 300KN speed adjustable tube drawing machine shows that the effect of the tube drawing speed on the reduction of the empty tube diameter is not significant, which may be due to the slow pulling speed. Therefore, it can be concluded that low speed drawing has little effect on the reduction of Jinan galvanized steel pipe.
The above is the relevant content introduced by Jinan zinc plating control manufacturer. For more information, please visit the website: http://www.jnxxjm.com