CS240182B1 - Process for producing seamless tubes - Google Patents

Abstract

Hollow semi-finished products with a circular cross-section are first mechanically machined on the inner and outer surfaces, e.g. by turning, then heated in a reducing atmosphere to a temperature of 1,180 to 1,220 °C, after which they are hot-rolled by punching, taking into account the distribution of relative compression in the deformation zone with deformation up to 50, while a fluorine-based lubricant is dosed into the cavity of the pre-roll before punching and before further processing of the through-roll on the rolling line.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to a process for the production of seamless tubes of diameters of 60 to 380 mm from non-ferrous metals, in particular nickel.

At present, tube products made of non-ferrous metals, such as nickel and its alloys, are only processed in small diameters up to 60 mm by extrusion technology on special single-purpose equipment at non-ferrous metal producers. Due to the larger pipe sizes, the availability of the required technological units is very limited worldwide. The disadvantages of the prior art methods are that, to date, only single-purpose production facilities have been used for the production of nickel pipes - lines with special equipment for the deformation and in-process processing of non-ferrous metals. Earlier attempts to utilize steel tubes for the processing of a non-ferrous metal batch - nickel and its alloys - had the disadvantages of, inter alia, the difficult conditions of punching a full-size round batch, heating it to a deformation temperature, undefined size parameters and , in the selection of a suitable deformation method for the necessary lengthening of the rolled material, in unfavorable conditions between the rolling tool and the deformed material, etc.

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These disadvantages are avoided by the process for producing seamless pipes of diameter 0 to 380 mm from non-ferrous metals, in particular nickel, according to the invention. The principle of the invention is that hollow blanks of circular cross-section are first mechanically machined on the inner and outer surfaces, for example by turning, then heated in a reducing atmosphere to a temperature of 1 180 to 1 220 ° C, then hot rolled by punching. to distribute the relative compression in the deformation zone with a deformation of up to 30%, wherein a fluorine-based lubricant is metered into the billet cavity prior to punching and before further processing of the strut on the pilgrimage line.

Centrifugally cast billets or billets or forgings with a wall thickness of 3u to 60 mm are used as starting materials. The internal and external surfaces of the batch are mechanically machined, e.g.

240 182 by turning, drilling, so as to remove any defects on both surfaces such as foams, porosity, thinners, bubbles, cracks, inclusions, etc. The treated batch material is processed on pilgrimage lines to produce seamless steel tubes hot. The hollow charge is heated in closed retorts and a reducing atmosphere generator which prevents embrittlement and loss of plasticity of the charge in heating furnaces with a conventional furnace atmosphere.

Advantages of this production process lie mainly in the possibility to manufacture the base of its non-ferrous metal tubes in a dimensional range of pilgrim lines for seamless steel tubes, ie in the diameter range of 60 to 380 mm; In addition, it is also possible to manufacture non-special-purpose devices of non-stainless steel producers, in addition to allowing the production of large pipe diameters.

Example

A batch nickel billet of 210 x 40 mm diameter was machined to a diameter of 200 x 27 mm, the machined billet was then heated in a carousel furnace with carbon monoxide reducing atmosphere developers to a temperature of 1,180 to 1,220 ° C, then punched on a two-cylinder scythe. punching machine with a deformation of up to 30% taking into account the distribution of the relative compression in the deformation zone and the conditions of change of the geometry of the strut. For the actual punching and pilgrimage rolling was used technological lubricant based on fluorine, dosed into the cavity of the casting.

Claims (1)

Process for producing seamless pipes, in particular 60 to 380 mm in diameter, of hollow semi-finished products of non-ferrous metals, in particular nickel, characterized in that the hollow semi-finished products of circular cross-section are first mechanically machined on the inner and outer surfaces, for example by turning; 180 DEG to 1220 DEG C., then hot rolled by punching with a deformation of up to 30%, wherein fluorine-based lubricants are metered into the billet cavity before punching and before further processing of the stock.