RU2387495C2 - Fabrication method of tubes of large diametre for transportation of abrasive materials and pulps on installation with pilger mills - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: in fabrication method of tubes of large diametre for transportation of abrasive materials and pulps, which involves drilling of axial hole of workpiece, heating of workpiece, conversion on slant rolling mill and rolling of shell on pilger mill, workpiece is drilled to the depth equal to difference of length of workpiece and drilled diametre, which is filled with briquettes, and plate 2-3 mm thick is welded to the hole; conversion is performed by closing the briquettes by a mandrel on the plate side; at that, briquettes are made from river sand and soluble glass with further drying in the furnace and of the diametre which is less than the drilled diametre by 1-2 mm.

EFFECT: increasing hardness of inner tube surface and reducing production costs when applying various coatings to inner surface, eg corrosion-resistant coatings, when using briquettes of other compositions immediately in process tube fabrication flow.

Description

The invention relates to pipe production, and in particular to a method for the production of large diameter pipes for transporting abrasive materials and slurries, and can be used in the production of them in plants with pilgrim mills.

A known method of coating the inner surface of pipes made of wear-resistant material, including cleaning the inner surface, applying a primer to its surface, then various components: resin; hardener and as a solid fraction - alumina, ceramics, sand, etc. (US Patent M 4515832, publ. 07.05.85, MKI V05IE 7/22, NKI 427/233).

The disadvantage of this method of manufacturing wear-resistant pipes is the complexity of the coating process, special equipment is required, low productivity, because you have to cover a large area, i.e. not in the production process of pipes, but at the final stage of their manufacture.

The closest technical solution is a method for producing large diameter pipes in a plant with pilgrim mills, including drilling a workpiece, heating it, flashing it on a cross-helical rolling mill and rolling the sleeve on a pilgrim mill (TI 158-TrTB 1-39-2006 “Production of seamless hot-wrought pipes for steam boilers and pipelines according to TU 14-3-460-2003 ").

The disadvantage of this method for the production of large-diameter pipes is that for the production of wear-resistant pipes, a special material is required, which, having wear resistance, usually has a reduced ductility and, as a result, an increased expenditure coefficient of the metal in their production and, accordingly, increased cost.

The objective of the proposed method is the development of a new technological process for the production of wear-resistant large diameter pipes for transporting bulk abrasive materials and pulps.

The technical result is achieved by the fact that in the known method of manufacturing large diameter pipes for transporting abrasive materials and pulps on a pilgrim mill, including drilling an axial hole of a workpiece, heating a workpiece, flashing on a cross-helical rolling mill and rolling the sleeve on a pilgrim mill, drilling an axial hole in the workpiece is produced to a depth equal to the difference between the workpiece length and the drilling diameter, before heating the workpiece, briquettes made of river sand and liquid are inserted into its cavity glass with a ratio of 10: 1, respectively, and with a diameter smaller than the drilling diameter by 1-2 mm, followed by drying, after filling the preform cavity with briquettes, the hole is welded with a 2-3 mm thick plate, and the preform is pierced into the sleeve from the side of the welded plate with locking briquettes.

The essence of the method lies in the fact that the axial hole in the workpiece is drilled to a depth equal to the difference between the workpiece length and the drilling diameter, before heating the workpiece, briquettes made of river sand and water glass with a ratio of 10: 1, respectively, and diameter are inserted into its cavity smaller than the drilling diameter by 1-2 mm, followed by drying, after filling the cavity of the preform with briquettes, the hole is welded with a plate with a thickness of 2-3 mm, and the workpiece is pierced into the sleeve from the side of the welded plate with a lock m briquettes. Thus, these differences allow us to conclude that the criterion of "inventive step" is met.

Comparison of the proposed method not only with the prototype, but also with other technical solutions in the art did not allow them to identify signs that distinguish the claimed method from the prototype, which corresponds to the patentability "inventive step".

The proposed method for the production of large-diameter pipes for transporting abrasive materials and pulps was implemented on a TPA 8-16 "ChTPZ" pilgrim installation as follows: After trimming the profitable part, an ingot measuring 600 × 1650 mm of grade 20 steel was drilled with a depth of 1550 mm and a diameter of 100 mm After preliminary mixing the river sand with liquid glass with a ratio of 10: 1 and filling the molds having an inner diameter of 98 mm and a height of 200 mm, the briquettes were dried in the furnace. etami hole plate welding was carried out 2 mm in order to avoid falling out of the cavity drilling briquettes with turnover device during heating and air entrapment during heating.

After heating in a methodical furnace to a temperature of 1290 ° C, the billet was flashed into the sleeve from the side of the welded plate and then rolled on a pilgrim mill in a whip pipe with a size of 426 × 9 × 33000 mm. The inner surface of the pipe with an area of 42 m ² had a glossy appearance. A comparative analysis of the hardness of the outer and inner surfaces showed that the hardness on the inner surface is 2.3 times higher than on the outer surface. With this rolling method, liquid glass acted as a binder when briquetting grease during flashing, and sand rolling into the inner surface of the pipes led to an increase in its hardness.

The proposed method can be used when applying various coatings to the inner surface, for example, anti-corrosion, using briquettes of other compositions directly in the process stream of pipe production.

Claims (1)

A method of manufacturing large diameter pipes for transporting abrasive materials and pulps on a pilgrim mill, including drilling an axial hole in a workpiece, heating the workpiece, flashing on a cross-helical rolling mill and rolling the sleeve on a pilgrim mill, characterized in that the axial hole in the workpiece is drilled on depth equal to the difference between the length of the workpiece and the diameter of drilling, before heating the workpiece, briquettes made of river sand and water glass with a ratio of 10: 1 are inserted into its cavity Actually and with a diameter smaller than the drilling diameter by 1-2 mm, followed by drying, after filling the preform cavity with briquettes, the hole is welded with a 2-3 mm thick plate, and the preform is pierced into the sleeve from the side of the welded plate with the briquettes locking by a mandrel.