GB504889A - Process and apparatus for making tubes from band iron by electric welding - Google Patents

Abstract

504,889. Making welded tubes. NEUNKIRCHER EISEINWERK AKT.-GES. Sept. 13, 1938, No. 26691. Convention date, Nov. 13, 1937. [Classes 83 (ii) and 83 (iv)] Welding; angular heating.- In making longitudinally jointed tubes from band iron by electric welding, the contact surfaces of the band are freed from scale while hot, prior to welding, by a cutting or scraping apparatus. A metal strip 1 is fed by rolls 6, 7, first through sectioning rolls 9-15, then under a gas burner 17, then under a screw-adjusted scraper 24 of alloy steel or metal carbide, which removes scale from the upper surfaces in the vicinity of the joint, then through guide rolls 27 and electric welding rolls 28, 29, 31, and then through finishing tools 34, 34<1>. The burner and scraper may be applied to the strip before conversion into tubular form. The scraper may be in the form of a knife or may be formed with teeth, which may be at different heights. In another form, Fig. 3, the tool 35 may have also a projection 36 for cleaning the abutting edges of the tube. In a further form, Fig. 8, adjustable spring-pressed tools 47 may be arranged to engage opposite edges of die strip, a pair of scrapers being also arranged underneath to clean the surfaces which are to form the upper contact surfaces. The edges and upper surfaces may also be cleaned by two pairs of milling cutters 62, 64, Fig. 9, immediately after the strip has passed the final rolls 51, 52 of a rolling mill so that no supplementary heating is required. Instead of milling cutters a bar 67, Fig. 13, with fixed scrapers 62b may be provided. Spring-pressed milling cutters (66, Fig. 12, arranged on inclined axis or similarly arranged V-shaped stationary cutters may also be used. Emery wheels may be used.