A method of Manufacturing Cast-Iron Pipes and an Installation for effecting same

1,154,264. Making pipes; continuous casting. TSENTRALNOE KONSTRUKTORSKOTEKHNOLOGICHESKOE BYURO. 10 Oct., 1967, No. 46306/67. Headings B3A and B3F. A method of making cast iron pipes includes the steps of continuously casting a strip from molten iron which has been inoculated by the addition of ferrocerium; annealing the strip; cooling the strip and cutting it into narrower strips; bending each strip into a pipe blank and welding the edges together to form a pipe and cutting the welded pipe into separate lengths. As described the molten iron is inoculated before it is fed between a pair of cooled rolls (see below) to form a strip which is then wound into a coil. The coils are then placed in a furnace for annealing at a temperature of 950‹ to 900‹ C. for 6 to 7 hours, followed by rapid cooling to 790‹ to 800‹ C. and slow cooling to 630‹ to 650‹ C. The coil is then cooled in an air current to ambient temperature. The coil is then uncoiled and passed through disc shears to be cut into narrower strips. Each strip is then passed through a multistand mill where it is bent into a cylindrical pipe blank. Alternatively, each strip may be wound into a spiral to form the blank. The edges of the blank are then welded by a high frequency loop inductor, the welding flash is removed, the pipe is passed through two gauging stands and is then cut into shorter lengths. Each pipe length is then tested under pressure, dried, dipped into a waterorganic suspension of polyethylene and finally dried at a temperature of 150‹ to 250‹ C. to fuse the polyethylene to the pipe surface. In the continuous casting step the molten iron is fed from a tundish 8, which is supported by an arm 7 on a rotating column 6, through an electrically heated feeding pipe 11 which is provided with a plurality of holes 12. The molten iron is discharged at a temperature of 1250‹ to 1350‹ C. and falls between rollers or moulds 13 which are urged towards each other by an by - draulic cylinder 14 and cooled inside by running water. The strip 15 thus formed passes over a guide 16 and conveyer 17 and is wound into a coil 19.