CN112588828A

CN112588828A - Non-standard hole type system

Info

Publication number: CN112588828A
Application number: CN202011499433.8A
Authority: CN
Inventors: 戴诗浩; 周玉涛; 张小峰; 汤智涛; 董家祥
Original assignee: Heilongjiang Jianlong Iron and Steel Co Ltd
Current assignee: Heilongjiang Jianlong Iron and Steel Co Ltd
Priority date: 2020-12-18
Filing date: 2020-12-18
Publication date: 2021-04-02
Anticipated expiration: 2040-12-18
Also published as: CN112588828B

Abstract

The invention belongs to the technical field of steel production, and particularly relates to a non-standard hole type system, wherein a non-standard hole type consists of three arc sections which are respectively a segmented arc R1, a segmented arc R2 and a transition arc between a segmented arc R1 and a segmented arc R2; the segmented circular arc R1 adopts a circular hole type, and the segmented circular arc R2 adopts an oval hole type. By combining the advantages of the appearance quality of the oval hole type, namely the outer surface quality without the blue line and the nail print, and the advantages of the inner surface quality of the round hole type, namely the inner surface quality without the inner hexagon, the hole type system is redesigned, so that the diversified demands of the market are met, and meanwhile, the production cost of enterprises is greatly reduced.

Description

Non-standard hole type system

The technical field is as follows:

the invention belongs to the technical field of steel production, and particularly relates to a non-standard hole type system.

Background art:

a tension reducing mill (hereinafter called as a stretch reducing mill) is an important process in the steel pipe production industry, and is a production process formed by reducing the hollow steel pipe without a core rod and continuously rolling a reducing wall. Generally, the stretch-reducing mill requires a large reduction in diameter and wall thickness to achieve the purpose of producing various specifications and varieties from large-sized pierced billets, so the number of working frames is large, and the rolling mill can be called the most important rolling mill. However, on the premise of the current economic market, the seamless steel tube in China only stays in the production and design of standard specifications, and for the difference of different users on the variety and specification requirements of the steel tube, the prior art cannot meet the requirement of frequent specification replacement in the market, so that a new model for the stretch reducer is urgently needed to be produced, and the market requirements of multiple specifications and multiple varieties are met.

At present, the pass system of the stretch reducing mill in the domestic seamless steel pipe industry only has two pass systems: one is an oval hole type system, and the other is a round hole type system. When the thin-walled pipe is produced, considering the defect of avoiding the quality of the outer surface of the thin-walled pipe, such as 'blue lines' and 'nail print', an elliptical hole type system is adopted, but the specification of the thick-walled pipe cannot be produced, when the thick-walled pipe is produced, the defect of 'inner hexagon' appears on the inner surface of the steel pipe, and the rolling load of a motor is high; when thick-wall pipes are produced, the defect of internal hexagonal shape of the inner surface quality of the steel pipe is avoided, and a circular hole type system is adopted, but when thin-wall pipes are produced, the defects of 'blue lines' and 'nail marks' are easy to appear on the outer surface of the steel pipe, so that the two hole type systems cannot be used universally, the current product varieties and specifications cannot be met, and the production cost of an enterprise is high.

According to the diversity of products used by users, the standard specification of the steel pipe can not meet the use requirements of the steel pipe, and in order to meet the requirements of customers, the market is developed, and related nonstandard specification pass is developed.

The invention content is as follows:

in order to solve the technical problems, the invention provides a non-standard hole type system, which combines the advantages of the quality of an oval hole type appearance without a blue line and the quality of a nail print with the advantages of the quality of a round hole type inner surface without an inner hexagon, redesigns the hole type system, meets the diversified demands of the market, and greatly reduces the production cost of enterprises.

The technical scheme adopted by the invention is as follows: a non-standard hole type system is provided, wherein the non-standard hole type system consists of three arc sections which are respectively a segmented arc R1, a segmented arc R2 and a transition arc between the segmented arc R1 and the segmented arc R2; the segmented circular arc R1 adopts a circular hole type, and the segmented circular arc R2 adopts an oval hole type.

The invention has the beneficial effects that: at present, the pass system of the stretch reducing mill in the domestic seamless steel pipe industry only has two pass systems: one is an oval hole type system, and the other is a round hole type system. In consideration of the surface quality problem of steel pipes, the oval hole type system can only produce thin-wall pipes, while the round hole type system can only produce thick-wall pipes. In order to solve the technical problems, a nonstandard hole type system is provided, the hole type system is redesigned by combining the advantages of the appearance quality of an oval hole type, namely the outer surface quality has no ' blue line ' and the nail print ' and the advantages of the inner surface quality of a round hole type, namely the inner surface quality has no ' inner hexagon ', so that the diversified demands of the market are met, and meanwhile, the production cost of an enterprise is greatly reduced.

Description of the drawings:

FIG. 1 is a schematic model of a non-standard bore type system;

fig. 2 is an assembly schematic of a non-standard bore type system.

The specific implementation mode is as follows:

example one

Referring to fig. 1 and 2, a non-standard hole pattern system, the non-standard hole pattern is composed of three arc segments, namely a segmented arc R1, a segmented arc R2 and a transition arc between the segmented arc R1 and the segmented arc R2; the segmented circular arc R1 adopts a circular hole type, and the segmented circular arc R2 adopts an oval hole type.

Segmented arc R1: when the thick-wall pipe is rolled, the expansion amount is small, and in consideration of the appearance of the defect of inner hexagon of the quality of the inner surface of the steel pipe, the R1 adopts a round hole type. Segmented arc R2: when the thin-walled tube is rolled, the spreading amount is large, and in order to avoid the defects of ' blue lines ', nail marks ' and the like on the outer surface of the steel tube, the R2 circular arc adopts an oval hole; and the circular arcs R1 and R2 are in smooth transition.

In order to solve the defects of 'blue lines', 'fingernails' and 'inner hexagons' in the surface quality of the existing steel pipe, when a novel non-standard hole type system is designed, the existing design concept must be overturned, the concept of 'existing expansion and contraction in a set of hole type system' is adopted for design, when in design and calculation, the original design concept of a section of circular arc is overturned, and the concept of 'three sections of circular arcs' is adopted for design.

Combining the steel rolling concept, and due to factors such as the pipe wall and deformation pressure, when the thin-walled pipe is rolled, metal in the hole pattern easily flows out of the roll gap; when the thick-wall pipe is rolled, metal in the hole pattern is mainly concentrated at the bottom of the roller; by combining the concept, the design is calculated and designed by adopting the concept that the roller bottom is a round hole type and the side wall is a wide-spread hole type.

Example two

A method of designing a non-standard hole type system, the method comprising the steps of:

firstly, according to the principle of steel rolling temperature, when the reduction ratio is distributed, the rolling load is designed by adopting the forward moving concept;

secondly, calculating deformation resistance according to the wall thickness of the steel pipe and the corresponding steel grade, and distributing arc lengths of the segmented arcs R1 and R2;

and thirdly, when the side wall arc is calculated, considering the metal with poor outer surface quality and plasticity, the broadening coefficient takes the value as follows: 0.988-0.991.

Example two

A production process design method of a non-standard hole type system comprises the following steps:

step one, a hole pattern design basic formula:

hole diameter: d = a + b

Ovality: ρ = a/b

Reducing the diameter ratio: rho_i=((d_i-1-d_i)/d_i)×100%

Spreading amount: c_i= a_i-b_i-1；

Step two, determining the distribution relation of the R1 arc length and the R2 arc length according to the wall thickness of the steel pipe and the calculated deformation resistance of the steel grade; as shown in the following table:

frame position	R1 arc length (mm)	R2 arc length (mm)	R1/R2 Angle (°)
				No. 1 shelf	79.52	11.57	26
No. 2 shelf	74.41	14.44	29
				No. 3 shelf	70.56	15.52	29
No. 4 shelf	68.24	14.98	29
				The 5 th shelf	64.58	15.85	29
6 th shelf	62.46	15.27	29
				7 th shelf	60.41	14.73	29
No. 8 shelf	58.42	14.19	29
				9 th shelf	56.50	13.68	28
The 10 th frame	54.65	13.18	28
				The 11 th shelf	52.85	12.69	28
The 12 th shelf	51.12	12.23	28
				13 th shelf	50.52	10.70	28
The 14 th shelf	48.86	10.30	28
				The 15 th shelf	47.25	9.91	28
The 16 th shelf	45.70	9.53	28
				17 th shelf	44.20	9.17	28
18 th shelf	42.75	8.82	28
				The 19 th frame	41.35	8.49	28
No. 20 shelf	39.99	8.16	28
				The 21 st shelf	38.67	7.84	28

The frame of the roughing mill in front of the frame shares the frame, when producing products with various specifications and varieties, only three finishing mill frames in the back need to be replaced, only the external diameter specification needs to be considered, the wall thickness does not need to be considered, the production efficiency is greatly improved, and the production cost is reduced.

After the design of the technical scheme, the front rough rolling frame can be repeatedly used, the production cost is greatly reduced, compared with the prior traditional pass series, the roller does not need to be replaced for many times when the rough rolling frame is used for dealing with products with various specifications and varieties, and one set of roller can be used for producing the products with the same outer diameter and different wall thicknesses.

After the test of the project is successful, 48 specifications such as phi 73.02 multiplied by 5.51 and phi 99.00 multiplied by 8.50 are produced

And specifications such as 160.05X 17.80, and the outer diameter precision of the rolled 160.05X 17.80 steel tube is as follows: 0.45mm, wall thickness precision: 0.85mm, and the quality of the inner surface and the outer surface of the steel pipe is good, and surface quality defects do not occur; when the steel pipe is rolled to phi 73.02 multiplied by 5.51, the precision of the outer diameter of the steel pipe is 0.10mm, the precision of the wall thickness is 0.40mm, and no surface quality defect occurs.

When the gas cylinder pipe is produced, for example, the specifications of phi 140 multiplied by 4.50, phi 159 multiplied by 4.50, phi 108 multiplied by 4.50 and the like, the outer surface quality of the steel pipe has no defects of 'blue lines' and the like, and the quality is stable.

Claims

1. A non-standard hole type system is characterized in that: the non-standard hole type consists of three arc sections which are respectively a segmented arc R1, a segmented arc R2 and a transition arc between the segmented arc R1 and the segmented arc R2; the segmented circular arc R1 adopts a circular hole type, and the segmented circular arc R2 adopts an oval hole type.