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Large-size seamless pipe forming technology

1. hot spinning method

It is to fix a flat blank or a preformed blank to a rotating mandrel, and apply pressure to the blank with a rotary wheel. The rotary wheel is fed axially at the same time. After one or more processing, various thin-wall hollow rotary systems are obtained. Product process. Its advantages are high product accuracy, good mechanical properties and a wide range of sizes. The tool mold is simple, easy to replace, and the production cost is lower than other methods. The main disadvantages are the long production time and low output. The processed pipe is limited by the length of the equipment and the size is short.


2. hot extrusion method

Machining pretreatment is required before extrusion. When extruding pipes below 100mm in diameter, the equipment investment is small, material waste is small, and the technology is relatively mature. However, once the diameter of the pipe is increased, the method of hot extrusion requires large tonnage and high power equipment, and the corresponding control system must be upgraded.


3. Hot perforation rolling method

Hot piercing rolling is mainly based on longitudinal rolling and diagonal rolling. Longitudinal rolling and extension rolling mainly include limited moving mandrel continuous rolling, small stand limited mandrel continuous rolling, three-roll limited mandrel continuous rolling and floating mandrel continuous rolling. These methods have high production efficiency, low metal consumption, good product quality, advanced control systems, and are increasingly widely used. The diagonal rolling and extension rolling method has also been widely used in the production of seamless pipes with low investment, short processes, suitable for small batches, multiple varieties, multiple specifications, and high precision.


4. Hot push method

Pushing diameter expansion equipment is simple, low cost, convenient maintenance, economical and durable, and flexible product specifications change. If you need to prepare similar products such as large diameter elbow, you only need to add some accessories. It is suitable for the production of medium and thin-walled thick-diameter seamless steel pipes, and it can also produce thick-walled pipes that do not exceed the capacity of the equipment.