SU1729639A2 - Rolling roll - Google Patents

Abstract

Use: in rolling production can be used on the rolls of hot or cold rolling mills. The essence of the invention: a rolling roll consists of materials with different elastic moduli, moreover, the thickness of the layer with a lower elastic modulus is defined by the formula 3i C (1 + K), and the thickness of the layer with a large modulus of elasticity b2 And (1-K) where C- metal removal rate for one regrind, mm; And - the allowable amount of wear for one campaign, mm; K - coefficient equal to 0.15-0.25. 3 tab., 1 Il.

Description

The invention relates to rolling production, can be used on the rolls of hot or cold rolling mills and is complementary to the basic by the authors. St. No. 1154015.

The durability (service life) of the mill roll is determined by the allowable wear of the layer consumed during the rolling process and during regrinding (regrinding). In the known device, the roll has a multi-layer barrel made of at least two materials with different elastic moduli alternating in height of said layer within ratios of 1: 1.1: 1 to 1.5: 1. The working layer of such a roll has high crack resistance, however, its durability is insufficient, since the alternation of layers with higher and lower modulus of elasticity does not take into account the allowable wear values for one campaign, as well as the metal removal rate for regrinding (repolishing).

The aim of the invention is to increase the service life of the mill roll and reduce the labor intensity of machining the rolls after each rolling campaign.

. The goal is achieved by the fact that the working layer of the roll barrel, consisting of materials with different elastic moduli, varying within 1: 1.1: 1-1: 1.5: 1, is such that the thickness of the layer with a smaller the modulus of elasticity is determined according to the expression

di C (1 + K),

and the thickness of the layer with a large modulus of elasticity is equal to

(52 I (1-K),

X |

Yu

about s

Yu

where C is the metal removal rate for one regrind, mm;

And - the amount of wear per one campaign (between regrinding or regrinding) in the place of the greatest loading, mm;

K - coefficient taking into account the need to reduce the thickness of the more solid layer and increase the thickness of the softer layer.

It is empirically found that the coefficient K varies in the range of 0.15-0.25.

The maximum amount of the word with thicknesses 5i and dg is determined by the outcome of the minimum and maximum diameters of the roll barrel in accordance with the expression

DMHH

 Omax

Pmax 5 (

 wed

where dsr is the average layer thickness

A OSP2

l chuck is rounded to the nearest whole, with the number of more ductile layers

W P2 + 1,

where niz is the number of more wear-resistant layers.

The choice of these dependencies is due to the following.

During the campaign, as a result of wear of the working layer of the roll, a more wear-resistant layer located on the surface (before the filling, the top layer di is removed to eliminate unevenness of the weld surface, to obtain the desired profile and diameter) wears out and outwards the underlying more plastic layer 5i. This layer is characterized by lower machining resistance, which is carried out in order to remove the high net, eliminate uneven wear, and obtain the necessary barrel profile.

When regrinding (repolishing), the soft layer is removed and gives way to a durable layer. Moreover, as a result of machining, the upper part of the wear-resistant layer is additionally strengthened as a result of work hardening, which increases the service life of the layer.

With the ratio (5i C (1 + K) remaining after treatment, a significant part of the softer layer wears out intensely during the rolling process, reducing the diameter and rolling productivity. The ratio fa I (1-K) leads to the same result.

In this case, the thickness of the more wear-resistant layer is insufficient for the operation of the roll during the campaign. If

5i C (1 + K), a fa And (1-K), during machining a significant part of the wear-resistant layer will be removed.

Thus, the proposed scheme

Layer layouts is a SENDWICH type structure, made for example by welding, in which the dimensions of the layers and their alternation are chosen based on the conditions of operation of the roll and

inter-transshipment period (see drawing).

In order to evaluate the effectiveness of the invention, for rolling rolls of a hot rolling mill 2000, multilayered surfacing on a steel roll was carried out.

9ХФ materials with different modulus of elasticity. According to the known roll construction, the individual layers were deposited in the appropriate order (see Table 1).

The ratio of elastic moduli E1: E2: Ez 1: 1.5: 1; 1: 1.23: 1: 1: 1.1: 1. The thickness of each layer was determined in connection with the indicated dependencies: 5i - C (1 + K);

c52 I (1-K)

with K values of 0.15; 0.20; 0.25.

Samples for abrasive wear testing with a thickness of 50 mm and a working area of 60x80 were cut from the weld rolls. mm The tests were carried out on a Haworth-Brinel installation, using dry ground granite as an abrasive material.

Wear was determined by the weight loss of the sample compared to a standard sample of similar dimensions made of steel 45. The crack resistance of the compared variants was evaluated by tests for dehardness (loading mode: Tmax 500 ° C; Tmir. 20 ° C; Gnagr 8.5 s; g0hl 3.0 s).

The test results are shown in table 1.

From table 1 it is seen that the wear resistance

the proposed design of the roll above K 0.25. The output of the value of the coefficient K beyond 0.15-0.25 does not allow to realize the capabilities of the laminated material.

A series of deposited working rolls of the proposed design was tested in a series of deposited 18HGSA and 25H5FMS layers.

The surfacing of the rolls was carried out on the AD-231 surfacing unit, the total number of the deposited layers was 15, of which 25ХФМС-7; 18HGSA-8.

Hot rolled strips 40x1 mm in size and flux AN-60 were used as electrodes. As a result of the analysis

of the rolls built-up using the basic technology, it was found that the roll diameter per campaign was reduced by 10 mm on average, including wear and tear of 6.5 mm, and removal of 3.5 mm during machining. The calculation of the proposed thickness of the wear-resistant layer, taking into account the increase in durability of the rolls, showed that the amount of wear And 4.5 mm. The thickness of the layer on the regrind remains the same

The proposed formulas were used to calculate the thickness of the deposited layers. The value of the coefficient K was taken 0.2; d 3,5 (1 + 0,2) 4,2 mm; (52 4.5 (1-0.2) 3.6 mm. Total thickness (5 $ di + & 4.2 + 3.6 7.8 mm. Obtaining the required thickness of the layers was carried out by selecting the appropriate modes of surfacing ( Table 2).

Table 3 presents the results of the operation of the rolls of the proposed design in comparison with the base case.

Thus, at the same duration of the rolling campaign, the service life for

The fused rolls are increased 1.4 times.

Invention Formula

Rolling roll aut. St. No. 1154015. characterized in that, in order to increase the service life of the roll and reduce the labor intensiveness of machining the rolls after each rolling campaign, the thickness of the layer with a lower modulus of elasticity is determined from

5i C (1 + K), mm,

and the thickness of the layer with a large modulus of elasticity - from the expression 52 And (1-K), mm,

where C is the metal removal rate for one groove, mm;

And - the permissible amount of wear per one campaign (between regrints) in the place of the greatest loading, mm;

K - coefficient taking into account the need to reduce the thickness of a more solid layer and increase the thickness of a softer layer, K 0.15-0.25.

Table 1

table 2

Table 3

/

Claims (1)

Claim Rolling roll by ed. St. No. 1154015, 5 characterized in that, in order to increase the life of the roll and reduce the complexity of machining the rolls after each rolling campaign, the thickness of the layer with a lower modulus of elasticity 10 is determined from the expression di = C (1 + K), mm, and the layer thickness with a large modulus of elasticity - from the expression 02 = I (1-K), mm, 15 where C is the amount of metal removal in one groove, mm; And - the allowable amount of wear for one campaign (between regrindings) at the place of greatest loading, mm; K - coefficient taking into account the need to reduce the thickness of the harder layer and increase the thickness of the softer layer, K = 0.15-0.25. Table 1 Surfacing option and types of alloy layers The values of the coefficient K Wear coefficient Heat resistance, the number of cycles of heat exchange According to the known design of the roll: 1) 10X11N20TZR 0.15 1.30 2030 2) 10X7MVFVR 0.20 1.45 1980 3) 10X11N20TZR 0.25 1.55 1950 1) 18HGSA 0.15 1.25 1926 2) 25X5FMS 0.20 1.35 1900 3) 18HGSA 0.25 1.45 1870 1) 19N9MVBT 0.15 1.32 1855 2) 15X11 MF 0.20 1.43 1938 3) 19N9MVBT 0.25 1,54 1805 1) 31X19H9MVBT 0.15 2,35 1888 2) 15X11MF 0.20 2,55 1855 3) 31X19N9MVBT 0.25 2.60 1823 table 2 Layer material Welding current I, A Arc voltage U, V Surfacing speed S, m / h Layer thickness <5 mm 18HGSA 750-900 28-32 14-18 3.5-4.5 25X5FMS 800-900 28-32 16-22 2.5-4.0 Table 3 Parameters Proposed option Basic version Diameter reduction per campaign (average), mm Number of roll fillings 7.7 10.0 (average) 9.0 6.4 δρΓ (ί'Κ) b _g --and (1-k) 5, b ₂ b1