RU2371264C2 - Method for production of cold-rolled strip from carbon tape - Google Patents

Abstract

FIELD: technological processes.

SUBSTANCE: method is intended for improvement of consumer properties of strip from carbon steel. Method includes cold rolling of strip from steel with content of carbon, wt %: 0.05-0.14% till final thickness 0.1-1.7 mm in single-stand reversing mill, annealing and longitudinal cutting of strip with cutting facilities. Improved punching of strip is provided by the fact that cold rolling of strip till thickness of 1.7 mm is carried out with pressing of up to 35-40% and intermediate annealing, rolling of strip with thickness of up to 0.45 mm is carried out with pressing of 61-75% and intermediate annealing, rolling of strip with thickness of up to 0.22 mm - with pressing of 41-65% and intermediate annealing and rolling of strip with thickness of 0.1 mm - with pressing of 50% and intermediate annealing, and final annealing of strip of any size is carried out after rolling with 6-52% of pressing after the last annealing, at the same time cutting facilities use are disk knives, which are installed with gap between side surfaces of knives of not more than 0.02 mm and radial partition δ=(0.2-0.51)×S, where: S is thickness of tape, mm.

EFFECT: improved punching of strip.

2 cl, 3 ex, 2 tbl

Description

The invention relates to rolling production and can be used in the production of cold rolled strips of carbon steel grades on single-strand reversible rolling mills.

A known method of manufacturing a cold-rolled carbon steel strip with a compression of 30-60%, additional cold rolling with a compression of 5-20% and annealing in two steps with holdings at temperatures of 350-400 ° C and 600-700 ° C [RF Patent No. 2155645, IPC (7) B21B 3/00, publ. 10/09/2000].

The disadvantage of this method is its low versatility and the inability to use on a single-strand reversing mill when executing orders for tape with a thickness of 0.1-1.7 mm

The closest in technical essence and the achieved results to the proposed invention is a method for the production of cold-rolled strips of 0.2-2.5 × 500-1050 mm ^{2 in} size from carbon steel on a single-strand reversing mill with a total deformation of more than 75-80% [Konovalov Yu. AT. and others. Directory distributor. // M .: "Metallurgy", 1977, p.112-113].

The disadvantage of the prototype method is that its use will not provide a full range of mechanical properties necessary for stamping in the strip that has passed only the final annealing after these deformations.

The technical problem solved by the invention is to improve the consumer properties of the strip (stampability) of carbon steel during reversible cold rolling on a single-strand mill.

The solution to the technical problem is achieved by the fact that in the method for producing a cold-rolled strip with a thickness of 0.1-1.7 mm from carbon steel with a content of, carbon, wt.%, 0.05-0.14%, including rolling in a single-strand reversing mill, annealing and longitudinal cutting of the strip by cutting means, while cold rolling of a strip up to 1.7 mm thick is performed with compression of up to 35-40% and intermediate annealing, subsequent rolling of a strip up to 0.45 mm thick with compression of 61-75% and intermediate annealing, subsequent rolling of a strip up to 0.22 mm thick - with compression of 41-65% and between precise annealing, subsequent rolling of a strip with a thickness of 0.1 mm - with a compression of 50% and intermediate annealing, after rolling a strip of final thickness, the final annealing is carried out, while the compression between the last intermediate and final annealing is 6-52%, and use as cutting means disc scissors, which are installed with a gap between the side surfaces of the knives not more than 0.02 mm and a radial overlap δ = (0.2-0.51) × S, where S is the thickness of the tape.

The essence of the proposed technical solution is to optimize the total compression and heat treatment during cold reverse rolling of a strip of carbon steel with a carbon content of 0.05-0.14% (steel type 08kp, 08ps, 08, 08yu, 10kp, 10ps, 10) on a single-strand mill, depending on its thickness. As a result of this, the microstructure of the resulting tape provides an improvement in its consumer properties, the main of which is stampability, i.e. the ability to local exhaust and bending without the appearance of fatal defects.

The proposed method is carried out as follows on one of the following two-, four- or six-roll single-roll reversible cold rolling mills, the characteristics of which are given in table 1.

Table 1 Indicators Mills 180/380 × 425 130/335 × 330 160/400 × 350 400 × 450 100/250 × 300 Diameter of rolls, mm:
workers
supporting 130
335 400 180
380 160
400 one hundred
250 Roll barrel length, mm 425 330 350 450 300 Number of rolls:
workers
supporting 2 2
four 2
6 2
6 2
6 Total drive power, kW 218.0 104.5 204.5 140.0 57.0 Rolling Speed, m / min:
working
gas station 80
thirty 60
thirty 60
thirty fifty
thirty fifty
thirty Thickness of rolled strip, mm 0.5-5.0 0.13-2.0 0.3-2.5 0.1-2.0 0.1-2.0 Rolled dimensions, mm ² 2.5 × 110-250

Rolls of tackle are installed in the unwinder, refueled in the mill, secured with their front end to a coiler located on the output side of the mill, the rolls are accelerated to operating speed and the rolling process with a predetermined compression is started.

At the end of rolling in the first pass, the mill slows down to the filling speed, and when the length of the rear end of the strip that does not enter the rolls roll is 300-500 mm, the mill stops, the rolls are reversed, a new solution is established between them, the rear end of the strip is refueled into the coiler located in front of the mill and the mill accelerates to operating speed. The rolling process is carried out in 5-16 passes with a total compression of 32-96%.

Due to the large total reductions, especially when rolling strips of a final thickness of 0.1-0.45 mm, a number of intermediate recrystallization anneals are necessary. Intermediate and final recrystallization annealings are carried out in a bell furnace in a shielding gas medium (4-6% H ₂ , the rest N ₂ ) at a temperature of 640-690 ° C using a bench thermocouple.

The alternation of rolling with recrystallization annealing makes it possible to ensure the optimal microstructure of the strip metal and the plastic properties necessary for rolling.

To achieve minimal anisotropy of the mechanical properties of the strip metal after the final recrystallization annealing, the reductions between the intermediate and final annealing are set within 6-52%, and with decreasing the magnitude of the reductions, the time required for annealing increases.

Rolling of a strip of final thickness 0.1-1.7 mm begins along the route 2.5 → 2.2 → 2.0 → 1.8 with recrystallization annealing at a size of 1.8 mm and then according to the established pattern of rolling and annealing alternating with exit to final thickness.

After annealing, the coils are cooled in a warehouse to a temperature below 40 ° C. Then the metal is trained with a compression of 0.5-2% (as agreed with the customer), the side edges are trimmed and dissolve on disk scissors onto a tape with a width of at least 20 mm. The quality of the edges of the tape, the absence of waviness, burrs, undercuts and other defects on them depends on the setting of the disk knives, which are installed with a gap between the side surfaces of the knives not more than 0.02 mm and a radial overlap δ = (0.2-0.51) × S, where δ is the radial overlap of circular knives, mm; S - tape thickness, mm.

The manufacture of a carbon tape in accordance with the claimed method makes it possible to obtain on the tape the required GOST 503-81 complex of mechanical properties for the state tape M (soft) and OM (extra soft). This results in a tape of the required dimensional accuracy, including the width, with the size of the ferrite grain of 8-7 numbers according to GOST 5639-82, suitable for processing by cold stamping.

The analysis of the prior art by the applicant, including a search by patent and scientific and technical sources of information, and the identification of sources containing information about analogues of the claimed invention, allowed to establish that the applicant did not find a source characterized by features identical to all the essential features of the claimed invention. The definition from the list of identified analogues of the prototype as the closest in the totality of the features of the analogue allowed us to establish a set of essential distinguishing features in relation to the technical result perceived by the applicant in the claimed method set forth in the claims.

Therefore, the claimed invention meets the condition of "novelty."

In the study of other well-known technical solutions in this technical field, signs that distinguish the claimed solution from the prototype were not identified. Therefore, the claimed invention meets the condition of "inventive step".

Industrial tests were carried out on a method for producing cold rolled carbon steel strip.

Example 1. Rolled strip 1.0 × 120 mm ² from steel 08kp and 08ps (M - soft) along the route 2.5 → 2.2 → 2.0 → 1.8 → 1.3 → 1.1 → 1, 0 with a total compression of 60% and compression between intermediate and final annealing of 44%, annealing at a size of 1.8 mm (intermediate) at a temperature of not more than 650 ° C for 9.5 hours and at a size of 1.0 mm (final) at temperature no more than 680 ° C for 9.5 hours and training. The grain size of ferrite is 8-7 numbers according to GOST 5639-82. Edge scissors were cut at 5 mm on each side and longitudinally cut to a width of 55 mm (2 tapes). The tape was intended for the manufacture of locks for connecting steel straps for strapping pipe bundles.

Example 2. Rolled strip 1.5 × 205 mm ² of steel 08kp (OM - especially soft) along the route 2.5 → 2.2 → 2.0 → 1.8 → 1.6 → 1.5 with a total compression of 40% and compression between the intermediate and final annealings of 17%, annealing at a size of 1.8 mm (intermediate) at a temperature of not more than 650 ° C for 9.5 hours and at a size of 1.5 mm (final) at a temperature of not more than 650 ° C within 12 hours without training. The grain size of ferrite is 8-7 numbers according to GOST 5639-82. Edge scissors were trimmed with 10.5 mm edges on each side and lengthwise cut to a width of 92 mm (2 tapes). The tape was intended for the manufacture of metal housings for combined parts for oil pipes, in particular for rings for NKV pipes with a diameter of 73 mm.

Example 3. Rolled tape 0.45 × 100 mm ² of steel 10 (OM - especially soft) along the route 2.5 → 2.2 → 2.0 → 1.8 → 1.3 → 1.05 → 0.9 → 0.6 → 0.5 → 0.45 with a total compression of 82% and compression between additional intermediate and final annealing of 50%, annealing at a size of 1.8 mm (intermediate) at a temperature of not more than 650 ° C for 9.5 hours and at a size of 0.9 mm (optional intermediate) at a temperature of not more than 650 ° C for 8 hours and at a size of 0.45 mm (final) at a temperature of not more than 650 ° C for 11 hours with training. The grain size of ferrite is 8-7 numbers according to GOST 5639-82. Edge scissors were cut at 4 mm on each side and longitudinally cut at a width of 46 mm (2 tapes).

The mechanical properties and geometric dimensions of the tape are shown in table 2.

table 2 №№ steel grade Width mm Thickness mm Mechanical properties According to GOST 503-81 Fact. According to GOST 503-81 Fact. Tensile strength according to GOST 503-81, kgf / mm ² Fact. Relates. elongation according to GOST 503-82,% Fact. one 08kp 55 ^-0.4 54.70 1 ^-0.09 0,996 32-45 34 No less 36 0,995 17 one 08ps 55 ^-0.4 54.70 1 ^-0.09 0,991 32-45 40 No less 26 0.987 17 2 08kp 92 ^-0.5 91.06 1.5 ^-0.05 1,494 28-42 36 No less 44 1,493 35 3 10 46 ^-0.5 45.60 ^0.45-0.05 0.444 28-42 32 No less 40 0.442 35

The yield according to the achieved mechanical characteristics and geometrical dimensions is 98-100% and allows using the tape in the following limits related to bending, upsetting, stamping (bending and molding of locks for connecting steel straps when tying pipe bundles, bending metal rings to combined safety parts for oil assortment pipes, etc.) without ruptures, cracks and other fatal defects.

Claims (2)

1. Method for the production of cold rolled strips with a thickness of 0.1-1.7 mm from carbon steel with a carbon content, wt.%: 0.05-0.14%, including cold rolling in a single-strand reversing mill, annealing and longitudinal cutting of the strip by cutting means while rolling strip with a thickness of up to 1.7 mm is produced with compression up to 35-40% and intermediate annealing, subsequent rolling of strip with thickness up to 0.45 mm - with compression 61-75% and intermediate annealing, subsequent rolling of strip with thickness up to 0, 22 mm - with compression 41-65% and intermediate annealing, subsequent rolling of a strip of thickness hydrochloric 0,1 mm - with a reduction of 50%, and intermediate annealing, after the final thickness of the rolled strip is carried out final annealing, wherein the compression between the last intermediate and final annealing is 6-52%. 2. The method according to claim 1, characterized in that the cutting means use disc shears, which are set with a gap between the side surfaces of the knives not more than 0.02 mm and a radial overlap δ = (0.2-0.51) × S where S is the thickness of the tape, mm