The technology enables to make pipes under low tolerances in respect of walls thickness (not more than ±5%) and diameter (±0.5%) of inner and outer surfaces. The process is realized on a pipe rolling mini-mill of innovative design. The production is based on a method of broaching at the screw rolling duo-mill with gards in cone rolls.
The method consists of the following operations:
1) Mechanical cutting of work-pieces into gauges
2) Centering of the work-pieces heads in cold condition.
3) Uniform reheating of the work-piece along its length and diameter
4) Stiff and accurate fixation and maintenance of rolls, guards and mandrels with the bar at the deformation point.
The process to make 30 to 120 mm diameter and 5-36 mm thick wall pipes is realized on a power-saving automated compact equipment . The screw rolling mini-facility is a mobile and efficient unit, designed for the production of high quality pipes of a wide range of sizes from carbonaceous and alloyed grades of steel and various alloys, including those based on titanium and nickel, through a simple and efficient method at a comparatively low capital cost and output of up to 1500 tons per annum. The working stand of the broaching screw rolling mill is made with a weld lighted frame of upgraded stiffness , less then 7 tons in weight. The main equipment is clubbed through transferring facilities into a single production line.
The technology in question and design features of the invention made it possible to realize the concept of a mini-works, featuring the following benefits:
- a possibility to satisfy the need in seamless pipes felt locally, in an industry, company, enterprise.;
- high economic efficiency even in case of small output batches of product
- wide range of sizes and grades