Brief introduction of two steel pipe processes for cold drawing and hot rolling
Drawing (rolled) seamless steel tubes: round tube billet → heating → perforation → head → annealing → pickling → oil (copper plated) → multi-channel cold drawing (cold rolling) → billet Tube → heat treatment → straightening → water pressure test (flaw detection) → mark → warehousing.
Hot-rolled (extruded seamless steel tube): round tube billet → heating → perforation → three-roll skew rolling, continuous rolling or extrusion → off pipe → sizing (or reducing) → cooling → billet Tube → straightening → hydrostatic test (or flaw detection) → marking → warehousing.
Two kinds of pipe flow Cold drawn steel pipe with hot rolling coil as raw material, after pickling and removing the oxidized skin for cold continuous rolling, the finished product is rolled hard roll, because of the cold hardening caused by continuous cold deformation, the strength, hardness and toughness of rolled hard roll are decreased, so the stamping performance will deteriorate and can only be used for the simple deformed parts. Rolled hard roll can be used as the raw material of hot dip galvanizing plant, because the hot Dip galvanizing unit is provided with annealing line.
Rolling hard roll weight generally in 6~13.5 ton, steel coil inside diameter is 610mm.
Generally cold continuous rolling plate, coil should be continuous annealing (CAPL unit) or cover-type furnace annealing eliminates cold hardening and rolling stress, to meet the corresponding standards of mechanical performance indicators. Cold Rolled steel plate surface quality, appearance, size accuracy is better than hot-rolled plate, and its product thickness right rolling thin to about 0.18mm, so well received by the majority of users. The deep processing of the products is made of cold-rolled steel coils as substrates, which becomes high value-added products. such as electroplating zinc, hot dip galvanized, fingerprint-resistant zinc, color coated steel plate and vibration damping composite steel plate, PVC laminating steel plate, so that these products have beautiful, high corrosion resistance and other excellent quality, has been widely used. After annealing the cold-rolled steel coil must be finishing, including cutting head, tail, trimming, leveling, flat, heavy roll, or longitudinal shearing plate. Cold-rolled products are widely used in automobile manufacturing, household electrical appliances, instrument switches, construction, office furniture and other industries. The weight of each package after the steel bundle is 3~5 ton. Flat volume is generally 3~10 ton/volume.
Steel coil inner diameter 610mm. Continuous casting slab or primary rolling slab as raw material for hot-rolled steel pipe, after the step-type reheating furnace heating, high-pressure water descaling into the roughing mill, coarse rolling through the cutting head, tail, and then into the finishing mill, the implementation of computer-controlled rolling, after the end of rolling through laminar cooling and coiling machine coiling, become straight hair volume. The head and tail of straight hair are often tongue-like and fish-like, thickness, width accuracy is poor, the edge often exists wave shape, folding edge, tower shape and other defects. The volume weight is heavier and the diameter of the steel coil is 760mm. (General pipe industry likes to use.) ) will be straight hair through the cutting head, cutting tail, impressing and multi-channel straightening, leveling and other finishing line processing, and then cut plate or heavy volume, that becomes: hot-rolled steel plate, flat hot rolled coil, slitting belt and other products. If the hot rolled finishing coil is removed by pickling and the oxidized skin is oiled, the hot rolled pickling plate rolls. The product has a local alternative to cold-rolled plate trend, affordable, well received by the user favorite.