RU2545937C2 - Mandrel for production of hot-rolled long-sized hollow parts with periodical taper at rolling mill - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to pipe rolling. Mandrel consists of working, locking and end sections with mandrel ring fitted on end part. Safety margin in increased by making the mandrel working part consisting of three or more n periodical taper sections of decreasing diameter connected by two or more n-1 taper transitions, transition length I_i making 50-100 mm. Larger lengths are located between larger-diameter taper sections. Note here that difference between end diameters of every taper section Δ_d makes 2.0-4.0 mm, larger values of said difference being relates to taper section of larger diameter. Note here that the difference between diameters of tape transition between taper sections Δ_i is specified.

EFFECT: higher safety margin in commercial production.

1 dwg

Description

The invention relates to pipe rolling production, and in particular to the design of a technological tool, in particular mandrels for rolling hot-rolled with periodic taper of long hollow metal products in a rolling mill.

Known mandrel for pilgrim rolling of hot rolled pipes made of heat-resistant wear-resistant steel, consisting of castle, working and guide parts. The locking part of the mandrel is used for mounting in the lock of the feeding device. The working part is selected from the maximum sleeve length and the width of the mandrel ring. The guide part of the mandrel is necessary for seed at the beginning of the rolling process, the size (length) of which depends on the rollback path of the feeding apparatus and the end cone with a length of 30-50 mm (Danilov F.A., Gleiberg A.Z., Balakin V.G. Hot rolling pipes.Metalurgizdat, 1962, pp. 332-333).

The disadvantage of this design of the mandrel is that it is used only for rolling cylindrical pipes in tube-rolling plants with pilgrim mills and cannot be used for the production of long-rolled hollow metal products hot-rolled with periodic taper in tube-rolling plants in three or 3 + n pilgrim stands installed on one axis.

Known for a mandrel with a working part, a mandrel head for fixing the mandrel in the lock of the feeding apparatus, a conical section (shank) between them with a length equal to the length of the pilgrim head, a cylindrical section with a length equal to the width of the mandrel ring, and located between the shank and the head and covering the mandrel dornovy ring (Karpenko NP, Mednikov Yu.A., Safyanov A.V. et al. Improving the quality and efficient use of metal in pipe production. Steel. No. 2, pp. 76-80, 1987).

The disadvantage of this design of the mandrel is that it is aimed only at reducing the mass of the pilgrim heads and reducing metal losses in the cutting edge and does not solve the issues of production of hot-rolled with periodic conical long-length hollow metal products in three or 3 + n pilgrim stands, installed sequentially along one axis .

The closest in technical essence to the described invention is a mandrel pilgrim mill (prototype), containing a mandrel having a working part, a head for fixing the mandrel in the lock of the feeding apparatus, a shank placed between them, consisting of three conical sections with different tapers, placed between the shank and a head section equal to the width of the mandrel ring, and the mandrel ring covering the mandrel (Auth. certificate. USSR No. 1127652, class B21B 21/00, 1983).

Using the known solution provides the maximum possible reduction in the mass of the pilgrim head and the reduction of technological trimmings.

A disadvantage of the known mandrel device is that, like the above analogues, it is aimed only at reducing the weight of the pilgrim heads and does not solve the main issue of the production of hot-rolled with periodic taper long hollow metal products in three or 3 + n pilgrim stands.

The objective of the proposed design of the mandrel is the development of a new technological process for the industrial production of hot-rolled with periodic taper of long hollow metal products in three or 3 + n pilgrim stands, having an aesthetic appearance, safety margin with a significant reduction in their weight, reducing their cost and replacing reinforced concrete products economically and aesthetically competing, durable, lightweight metal products.

, где d_i.min - минимальный наружный диаметр i-го участка конусного длинномерного полого металлического изделия, мм; d_(i+1)max - максимальный наружный диаметр i+1 участка конусного длинномерного полого металлического изделия, мм; D_ki - идеальный диаметр калибра пилигримовых валков в i-той пилигримовой клети, мм; D_k(i+1) - идеальный диаметр калибра пилигримовых валков в i+1 пилигримовой клети, мм.The technical result is achieved by the fact that in the well-known mandrel for the production of hot-rolled long hollow metal products with periodic taper in a rolling mill having three or more pilgrim stands, consisting of a working, locking and end section with a mandrel ring worn on the end section, while the working section the mandrel consists of three or more, the number n of periodic conical sections with decreasing diameters, interconnected by two or n-1 conical transitions with a transition length l _i from 50 to 10 0 mm, large values of which are located between the conical sections of large diameters, while the difference between the end diameters of each conical section Δ _d is from 2.0 to 4.0 mm, the large values of which relate to the conical sections of a larger diameter, and the difference between the diameters of the conical the transition between the conical sections Δ _i is determined from the expression:

where d _i.min is the minimum outer diameter of the i-th section of the conical lengthy hollow metal product, mm; d _{(i + 1) max} - maximum outer diameter i + 1 of the section of the conical lengthy hollow metal product, mm; D _ki is the ideal diameter of the caliber of the pilgrim rolls in the i-pilgrim stand, mm; D _{k (i + 1)} is the ideal diameter of the caliber of the pilgrim rolls in i + 1 of the pilgrim stand, mm.

, где d_i.min - минимальный наружный диаметр i-го участка конусного длинномерного полого металлического изделия, мм; d_(i+1)max - максимальный наружный диаметр i+1 участка конусного длинномерного полого металлического изделия, мм; D_ki - идеальный диаметр калибра пилигримовых валков в i-той пилигримовой клети, мм; D_k(i+1) - идеальный диаметр калибра пилигримовых валков в i+1 пилигримовой клети, мм. Таким образом, заявляемый дорн соответствует критерию "изобретательский уровень".Comparative analysis with the prototype shows that the inventive mandrel for the production of hot-rolled long hollow metal products with periodic taper in a rolling mill differs from the known one in that the working section of the mandrel consists of three or more, the number n of periodic conical sections with decreasing diameters, interconnected by two or n-1 transitions from the conical transition length l _i of 50 to 100 mm, larger values of which are disposed between the tapered portions of large diameters, wherein the difference between end diameters of each of the tapered portion Δ _d is from 2.0 to 4.0 mm, larger values which relate to tapered portions of larger diameter, and the difference between the diameters of the conical transition between the tapered portions Δ _i is determined from the expression:

where d _i.min is the minimum outer diameter of the i-th section of the conical lengthy hollow metal product, mm; d _{(i + 1) max} - maximum outer diameter i + 1 of the section of the conical lengthy hollow metal product, mm; D _ki is the ideal diameter of the caliber of the pilgrim rolls in the i-pilgrim stand, mm; D _{k (i + 1)} is the ideal diameter of the caliber of the pilgrim rolls in i + 1 of the pilgrim stand, mm. Thus, the inventive mandrel meets the criterion of "inventive step".

A comparison of the inventive mandrel for the production of hot-rolled long hollow metal products with periodic taper in a rolling mill, not only with the prototype, but also with other technical solutions in this technical field did not reveal the signs that distinguish the claimed solution from the prototype, which allows us to conclude that patentability condition "inventive step".

Since there is no similar equipment for the production of hot-rolled long hollow metal products with periodic taper in a rolling mill in world practice, it is not possible to give an example of a specific use of the design of the proposed mandrel for a given period of time.

Instead of a specific use example, the calculated data on the geometrical dimensions of mandrels for rolling hot-rolled long hollow metal products with periodic taper in a rolling mill measuring 426 × 70 × 3500 + 325 × 25 × 3500 + 273 × 10 × 8000 mm in three stands of the pilgrim mill. The geometric dimensions of the conical transitions between the conical sections, the lengths and diameters of the conical sections are calculated according to the formula given in the claims. The calculated geometrical dimensions of the mandrels for rolling hot-rolled with periodic tapering of hollow metal products measuring 426 × 70 × 3500 + 325 × 25 × 3500 + 273 × 10 × 8000 mm in three pilgrim stands are shown in Table 1, and the general view of the mandrel in FIG. 1: 1 - the castle part of the mandrel; 2 - conical section of the mandrel for forming a base with periodic taper of a long hollow metal product; 3 - conical transition from the first conical section to the second; 4 - middle conical section for forming the middle part of a long hollow metal product; 5 - conical transition from the middle conical section to the upper; 6 - conical section of the mandrel for forming a peak with periodic taper of a long hollow metal product.

The use of this tool (mandrels) together with the proposed production method for the first time in world practice will allow for the production line production of hot-rolled with periodic taper of long hollow metal products of various lengths and shapes instead of reinforced concrete at fundamentally new plants in three or 3 + n pilgrim stands, to ensure the need for the people economy of the country and produce competitive products. Compared to existing hot-rolled, periodically tapering, long-length hollow metal products will have an aesthetic shape, an increased margin of safety with a significant reduction in their mass, and, consequently, increased durability.

The calculated data on the geometrical dimensions of the mandrel for rolling hot-rolled with periodic tapering of long hollow metal products measuring 426 × 70-273 × 10 × 15000 mm (426 × 70 × 3500 + 325 × 25 × 3500 + 273 × 10 × 8000) mm in three pilgrim stands camp The geometric dimensions of long hollow bimetallic products (mm) Workpiece Size (mm) Sleeve Size (mm) Geometrical sizes of a mandrel Total product length Product Base Size The size of the middle part of the product Product Top Size Total mandrel length (mm) The first conical section is the base (mm) The second conical section is the middle (mm) The third conical section is the top (mm) The length of the mandrels. heads (mm) Diameter Length Length transition. Diameter Length Length transition. Diameter Length max min max min max min 15,000 426 × 70 × 3500 325 × 25 × 3500 273 × 10 × 8000 600 × 18
25 ± 25 600 hvn.
310 × 2500 9100 290 288 1600 one hundred 282 279 1300 fifty 256 254 5600 600

Claims (1)

Dorn for the production of hot-rolled long hollow metal products with periodic taper in a rolling mill having three or more pilgrim stands, consisting of a working, locking and end section with a mandrel ring worn on the end section, while the working section of the mandrel consists of three or more, number n periodic conical sections with decreasing diameters, interconnected by two or nl conical transitions with a transition length l _i from 50 to 100 mm, large values of which are located between the conical and sections of large diameters, the difference between the end diameters of each conical section Δ _d is from 2.0 to 4.0 mm, the larger values of which relate to the conical sections of a larger diameter, and the difference between the diameters of the conical transition between the conical sections Δ _i is determined from expressions:

where d _i.min is the minimum outer diameter of the i-th section of the conical lengthy hollow metal product, mm;
d _{(i + 1) max} - maximum outer diameter i + 1 of the section of the conical lengthy hollow metal product, mm;
D _ki is the ideal diameter of the caliber of the pilgrim rolls in the i-pilgrim stand, mm;
D _{k (i + 1)} is the ideal diameter of the caliber of the pilgrim rolls in i + 1 of the pilgrim stand, mm.