Activity :what affect the precision for steel pipe making machine?
Mar 27, 2018
what affect the precision for steel pipe making machine?
ZHONGTUO uses the Electric Resistance Welding (ERW) process in steel pipe making machine. This process depends on a number of important factors to ensure a complete weld. The most important of these factors are:(1)Strip width size
Each size of tube produced has its own unique strip width. The strip width is calculated using various parameters including, finished tube size, tube wall thickness, radius of corners desired (for square and rectangular tubing) and theoretical squeeze out of molten metal at the weld head.You can use metal sheet slitting machine for needed width.
(2)Strip preparation
An integral part of obtaining a sound weld is to ensure the strip edges are prepared properly prior to welding. This is accomplished by passing the strip, which is by this time partially formed into a round section, through a series of rolls called fin passes.The fin passes are designed to burnish the strip edges to clean them for welding and to ensure the edges are beveled to the proper angle to allow the strip edges to come together evenly. The strip edges must meet in such a manner that there is no gap at the top (outside of the tube) or bottom (inside of the tube). This ensures an even amount of extrusion, or squeeze out at the weld head (sometimes referred to as weld pressure rolls) and without mismatch. Mismatch occurs when one strip is higher or lower than the other when the two edges meet.
(3)Welding
Two methods of heating the strip edge are utilized in Electric Resistance Welding. One method is to induce current in to the tube by contact shoes. The contact shoes are copper based contacts that allow the current to flow into the base metal to be welded. The contact shoes are located close to the strip edges prior to the weld pressure rolls. The second method utilizes a high frequency induction coil. (Figure 2.) This is a non-contact method of inducing the current into the strip. This is also located prior to the weld pressure rolls. The current is concentrated onto the strip edges by means of an impeder. This impeder is a cluster of ferrite rods located inside the tube by means of a mandrel. Concentration of the induced current along the strip edges causes the strip edges to heat up. The amount of heat and resultant molten metal is computer controlled and is matched to the speed at which the steel is moving.
