JPH02101135A - High hardness conductive roll for electroplating - Google Patents

Abstract

PURPOSE:To obtain the title roll having excellent wear resistance and corrosion resistance and having specific hardness by specifying the compsn. constituted of C, Si, Mn, Fe, Cr, Mo, Nb, Cu, N and Ni. CONSTITUTION:The high hardness conductive roll for electroplating contains, by weight, <=0.10% C, <=1.0% Si, <=1.0% Mn, >=5.0% Fe, 35.0 to 60.0% Cr, <=10.0% Mo, <=3.0% Nb, <=10.0% Cu and <=0.15% N, furthermore contains, at need, one or more kinds among <=2.0% Zr, <=3.0% Ta, <=1.5% Ti, <=1.0% Al, <=6.0% W, <=1.0% V and <=1.0% rare earth elements and the balance substantial Ni. The roll has excellent wear resistance and corrosion resistance and has >=40 Hs hardness; it has no faults of local wear.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high-hardness current-carrying roll for electroplating that has excellent wear resistance and corrosion resistance.

In recent years, as a current-carrying roll for electroplating, Japanese Patent Laid-Open No. 57-19350 filed by the present applicant and Japanese Patent Laid-Open No. 5
Starting with the current-carrying roll J for electroplating disclosed in Japanese Patent No. 7-60044, various corrosion-resistant alloys based on the old Mo-Cr system have been proposed to be used as the base material of this roll.

These corrosion-resistant alloys are used as current-carrying rolls for electroplating.
Although truly effective, the main reason for the resharpening required to correct various surface defects resulting from the long use of these rolls in actual plating operations. This includes surface abrasion, particularly local abrasion at the ends of the roll corresponding to the edges of the metal strip to be plated.

Therefore, the present invention aims at solving the above-mentioned Ni-N which is currently used.
The objective is to obtain a high-hardness current-carrying roll for electroplating that has high wear resistance and high corrosion resistance, which can eliminate the common drawback of local wear in o-Cr corrosion-resistant alloys. It is something.

As a result of various experiments to solve this problem, the inventor of the present invention solved the common drawback of localized wear of the above-mentioned NNo-Cr corrosion-resistant alloys currently in use. It has been found that this can be achieved not only by increasing the strength but also by increasing the hardness.

That is, the present invention, based on the knowledge obtained from this experimental result, consists of a matrix made of Ni and Cr,
By creating a two-phase structure of a (Cr-rich) and 7 (Ni-rich), and adding No, Cu, Nb, etc. to this.

An extremely stable structure and corrosion resistance can be obtained, and by precipitation hardening of this α phase, a hardness of IIs 40 or higher can be obtained, resulting in a high hardness electrically conductive material for electroplating that has both high wear resistance and high corrosion resistance. I was able to get a roll.

Specifically, the present invention provides 1) CO, 10 or less Si, 1.0 or less Mn 1.0 or less Fe 5 , O or less Cr 35.0 to 60.0 Mo 10.0 or less Nb 3 .0 or less Cu 10.0 or less N 2 ) in weight% CO, 10 or less Si 1.0 or less Mn 1.0 or less Fe 5. '0 or less Cr 35.0-60. O No 10.0 or less Nb 3.0 or less Cu 10.0 or less NO Contains O, 15 or less, and further Zr 2.0 or less Ta 3.0 or less Ti 1.5 or less^1 1,0 or less -6,0 Hereinafter v i, o rare earth element One of the following 1.0 or less contains two or more types, and the remainder is substantially composed of old Hs with excellent wear resistance and corrosion resistance Electrical with hardness of 40 or more It is characterized by a high hardness energized roll for plating.

DEN-1 Hereinafter, the present invention will be described in detail with respect to its embodiments.

The chemical components and respective ranges of the current-carrying roll for electroplating according to the present invention are defined as described above. First, in the present invention, such chemical components are selected and each The reason why the range of scientific components was determined as above will be explained.

In the as-cast state, the #1'I weave of the roll according to the present invention is composed of a γ phase that is a solid solution of N1-rich and an α phase that is a solid solution of Cr-rich that does not precipitate therein. . When this is subjected to aging treatment at a temperature of 650 to 850°C, an α phase is further precipitated in the γ phase, and a remarkable increase in hardness is observed.

In particular, the alloy of the present invention is characterized in that it improves the corrosion resistance of the above-mentioned 7 trix and contains Mo in order to maintain this property.

For this reason, precipitation of α phase increases, resulting in deterioration of ductility due to precipitation hardening. However, by adding Cu and Nb in combination, this deterioration in ductility can not only be prevented but also improved. Further, the combined addition of Cu and Nb has a remarkable effect on improving corrosion resistance.

Furthermore, by adding zr in addition to the combined addition of Cu and Nb, the ductility can be further improved and the alloy can be stabilized.

Next, the reason why the above chemical components were selected and the range of each chemical component was determined to be a specific range in the present invention will be explained.

Ni: This element is present in the alloy of the present invention together with Cr.
It is a basic element that constitutes the matrix of the chγ phase and the Cr-rid+α phase, and stabilizes this matrix.

Originally, Ni itself is a liability due to the potential series of metals, so the corrosion dissolution rate is small, and the corrosion formed film is
Because it is dense, it has a large protective effect and has passivating ability. Note that the amount of Co contained as an impurity in Ni is allowed to be 2.5 weight 2 or less.

Cr: Similar to Ni, this element is
It is a basic element constituting the matrix of the ichγ phase and the Cr-ricl+α phase, and plays the role of hardening these 7 trixes.

In the alloy of the present invention, age hardening is controlled by the amount of Cr, and when CrJl is less than 355 weight 2, the age hardening ability is low, and when it is 60 weight 2 or more, it becomes brittle (becomes brittle). Therefore, select 35 to 60 weight 2.

Mo: This element increases the amount of α phase and increases the age hardenability. As the content increases, the corrosion dissolution rate decreases, the passivation ability increases, and the corrosion resistance is significantly improved. Weight 2 is the upper limit.

C1 This element does not need to be added. Moreover, this addition causes a decrease in the corrosion resistance of the alloy and also causes embrittlement. However, less than 1% by weight is acceptable.

Si This element is necessary from the viewpoints of deoxidation and swirl flow in the production of the roll according to the present invention, but as the amount is increased, the ductility after age hardening decreases, so the upper limit is set at 1 weight 2.

Mn: This element is effective in deoxidizing and fixing S, but its limit is defined as 1 weight 2.

Nb, this element helps to prevent embrittlement due to fixation of nitrogen in the α phase by changing the nitrogen in the α phase to NbN, and also improves the ductility of the alloy by granulating the layered α layer of the grain boundary reaction type. Increase. Furthermore, it contributes to strengthening the passivation film and increases corrosion resistance, but this ability is saturated at 3% by weight.

Ta: This element exhibits the same effect as Nb, and by converting nitrogen in the α layer to TaN, it helps prevent embrittlement due to the fixation of nitrogen in the α phase, and also helps prevent embrittlement due to the fixation of nitrogen in the α phase.
Grainize the phase to increase the ductility of the alloy.

However, the effect saturates at 3wt2.

Cu: When this element coexists with -Nb, the effect of Nb further refines the grain-boundary-reactive layered α layer in the α phase, thereby significantly increasing ductility. It also contributes to strengthening the passive film and significantly improves corrosion resistance. However, its content is 7 weight 2
If it exceeds 10 weight 2, it will gradually become brittle, so the upper limit is set at 10 weight 2.

Zr・This element helps prevent embrittlement due to fixation of nitrogen in the α phase by replacing nitrogen in the α phase with ZrN, and also forms a metal layer at the boundary between the γ phase and the α phase due to eutectic formation with Ni. The ductility of the boundary is significantly improved by forming intermediate compounds (Ni, Zr). It is particularly effective against weld cracks. However, when the weight exceeds 2, the α phase becomes coarse and
On the contrary, it deteriorates. Therefore, the upper limit is 2 weight 2.

Note that by adding Nb and Cu in combination, their effects are significantly increased, and by adding Zr together with the weight increase of Cr, the combined addition of Nb, Cu, and Zr becomes effective.

N: Since this element causes embrittlement due to fixation of nitrogen in the α phase of Cr-rich, it is better to keep the amount as small as possible, but up to 0.15 fold iEz is acceptable.

H = This element improves corrosion resistance similar to No, and also
Although the matrix is strengthened by solid solution treatment, 6.0
If the weight exceeds 2, it will instead become brittle.

Therefore, its content is limited to 6.0 weight 2 or less.

V: This element contributes to the refinement of the structure, and for this purpose it is necessary to add 1.0% by weight or less.

Ti, this element is a deoxidizing element and has a remarkable effect on drastically reducing the amount of oxygen in the alloy. Furthermore, the formation of TiN helps prevent embrittlement due to fixation of nitrogen in the α phase, contributing to improvement in ductility. However, this element is 1.
If 5 weight 2 or more remains, conversely, embrittlement will occur due to precipitation of intermetallic compounds (such as NisTi) after age hardening.

^1: Like Ti, this element is a deoxidizing element, and has a remarkable effect on drastically reducing the amount of oxygen in the alloy. Also, by producing ^IN, it reduces the brittleness caused by the fixation of nitrogen in the α phase. This helps prevent corrosion and contributes to improving ductility. However, if 1.0 weight 2 or more of this element remains, conversely, embrittlement occurs due to precipitation of intermetallic compounds (Ni, ^1, etc.) after the aging effect.

Rare earth elements, metals, Cc, Ln, and other rare earth elements can have a significant deoxidizing effect by adding them after deoxidizing with Si, L, Ti, etc., and may cause defects in this alloy. significantly improves vulnerabilities.

The roll according to the present invention is characterized by having the above-mentioned chemical components and component ranges, but in manufacturing it, in order to avoid as much as possible the contamination of N and 0 in the air. Therefore, it is preferable to devise a melting/casting method. For this, e.g. vIN lysis, VAR
By selecting melting, ESR melting, etc., the purpose can be achieved. The rolls obtained by these methods can be hardened by precipitation hardening for 700'CX4 to 100 hours, but this time is selected depending on the desired hardness. shall be taken as a thing.

Next, the results of an experiment conducted to compare an example of the current-carrying roll for electroplating according to the present invention with a conventional roll material will be described.

First, the outline of the test apparatus adopted for this experiment is shown in FIG. 1 of the attached drawings. That is, as shown in the figure, this test device has a container 1 containing:
A solution F of pH 4,0 and 30$ZnSO4+31H2SO- is contained, and the test roll 2 is immersed in this solution so as to be rotatable horizontally.A brake roll 3 and a drive roll 4 are placed outside the container 1. Further, inside the container 1, an anode 5 is arranged at the bottom of a test roll 2. In the test, each of these rolls is exposed to a mild steel strip 6 in the order of 3 → 2 → 4. is passed through as shown by arrow X, applying constant tension to the strip 6, and test roll 2
Negative and positive voltages are applied to the anode 5, respectively, and the anode 5
In addition to measuring the corrosion resistance and abrasion resistance of the test roll 2, a current was passed through the solution F to the test roll 2 at a current density of 40^/dm2. The weight loss, hardness, and cracking susceptibility were also measured. In addition, the corrosion resistance and wear resistance test is
The amount of corrosion wear of the test roll 2 after being energized for 10 days was determined by the amount of wear on the radius of the roll, the maximum wear depth, the minimum wear depth, and the average wear depth. That is, the maximum ear loss depth was measured at the passing portion of the mild steel strip edge on the surface of the roll, and the minimum wear depth was measured at the passing portion at the center of the mild steel strip in the width direction. The average wear depth was determined by measuring the wear depth over the entire length of the roll and taking the average value. Furthermore, this measured value is expressed as a percentage of the maximum wear depth of the conventional product as 1.0,
Further, as a life ratio, the maximum wear amount of the conventional product was set as 1.00, and each life ratio was determined from the ratio of the maximum wear amount of each test acid roll.

Regarding cracking susceptibility, each sample was melted and cast into the shape of an ingot I, and then heated at 700°C.
72b was subjected to age hardening treatment. Thereafter, it was cut to a diameter of 30 mm x length of 200 mm, and a U notch was added in the center to prepare a test piece (see Figure 2).

After holding this test piece at 700°C for 111 hours, it was vertically
It was immersed in water at 0°C and cooled in water. Thereafter, the test piece was examined for cracks at the U notch by color check.

Incidentally, five specimens were prepared for each type, and the occurrence and incidence of cracks in these specimens were investigated. Regardless of the degree of crack occurrence or the size of the crack, if a crack was found, it was considered that a crack had occurred, and the incidence rate was calculated from the number of cracks that did not occur among the five test pieces. With this method,
Naturally, the crack incidence rate is 0.20.40.60.80.
However, in this test, those with a crack incidence of 40π or less, that is, although they are susceptible to cracking, based on experience, the manufacturing method should be placed under appropriate control. Therefore, it was determined that the rolls could be manufactured.

The test results are shown in Tables 1 and 2. Table 1 shows the chemical composition (weight 2) of the sample melt, and the examples in the type column are No. 1 to 2. As shown in No. 24, as the amount of Cr was increased from 39 weight 2 to 57 weight π, No. was changed from 8 weight 2 to 0.5 weight 2. Furthermore, Zr is added to these compositions.
alone, or those with combined addition of Zr, Ti, 81, and RE (rare earth elements) are shown, but No. 7 to No. 12
indicates a material containing 47% by weight of Cr and 2 levels by weight of No. 4.5, to which Ta, I'l, and V are added singly or in combination.

Table 1 also shows the chemical components of I to Vl as comparative alloys.

Next, Table 2 shows the electrical corrosion resistance and wear resistance of the conventional alloy, the present invention alloy, and the comparative alloy, 50 $ Hz SO + boiling bladder reduction,
Hardness, cracking susceptibility, etc. are shown.

-t°- As is clear from this Table 2, regarding the life ratio,
1.100 to 1.2 compared to 1.000 for conventional rolls
00, indicating an increase of 10 to 2 oz. In particular, No. 11 and No. 12 show the best values. However, the crack occurrence rate was 40% in all cases, indicating that a certain control in manufacturing is required.

From the viewpoint of ease of manufacture, No. 4.5.6.8.
9.10.15 and 18 can be said to be excellent components.

From the maximum weight loss, it decreases from No. 1 to No. 12 and No.

Since the numbers increase from No. 12 to No. 24, it can be seen that corrosion resistance and hardness are the dominant factors for maximum weight loss, and there is a correlation between them.

In addition, from the minimum weight loss, it is almost proportional to the corrosion resistance, and N
Since it increases from o, 1 to no, 24, it is inferred that corrosion resistance is the dominant factor.

The fact that cracks occur at the same level of C'' when Zr is added to Cr46 weight 2 or more, or that the occurrence rate is high, indicates that Zr is effective in preventing cracks. -It indicates something.

Even when the weight of Cr2O is 2 or less, those to which Zr is added are considered to be potentially more stable.

Furthermore, those to which Ti, ^l, and RE were added showed a remarkable effect in preventing the occurrence of cracks.

Regarding -, the life can be extended by increasing the hardness, but this increases the sensitivity to cracking, so manufacturing control is required.

For ■ and Ta, No. 10 and No. 12 are
Since the life ratio is excellent, the addition of these elements is considered to be effective.

Next, for comparison alloys, those with Cr weight 2 of 40.47 and 55 weight 2 were selected so that they could be compared with the present invention alloy, and in both cases Ti, ^l, N
Although they were manufactured by adding effective elements such as b, they were inferior in corrosion resistance and wear resistance, 50ff2SO4 boiling loss, and were also inferior in cracking sensitivity, and their properties as a roll were inferior. It is clear that there are difficulties in manufacturing.

Taken together, it can be seen that the combined addition of Nb and Cu and the addition of Zr in the present invention are effective.

As explained above, the current-carrying roll for electroplating according to the present invention has a matrix composed of Ni and Cr, and two of a (Cr-rich) and γ (Ni-rich).
By adding No, Cu, Nb, etc. to this phase structure, an extremely stable structure and corrosion resistance can be obtained. Due to the precipitation hardening of this α phase, a roll with high hardness and particularly excellent wear resistance can be obtained. It provides:

Further, according to the present invention, the wear resistance of the current-carrying roll at the threading portion corresponding to the ear portion of the steel strip to be plated is excellent, and therefore, PlI O, 6 to 1,8, current density 3
The present invention provides an energized roll suitable for being incorporated into an electroplating line that passes the steel strip at high speed under a large reduction blade between the roll and the steel strip under conditions of 0^/dm2 or more.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a roll testing apparatus according to the invention;
FIG. 2 is a front view showing a test piece for cracking susceptibility test. DESCRIPTION OF SYMBOLS 1... Container, 2... Test roll, 3... Brake roll, 4... Drive roll, 5... Anode, 6... Mild steel strip.

Claims (1)

[Claims] 1. In weight %: C0.10 or less Si1.0 or less Mn1.0 or less Fe5.0 or less Cr35.0-60.0 Mo10.0 or less Nb3.0 or less Cu10.0 or less N0.15 or less 1. A high-hardness current-carrying roll for electroplating, characterized in that the remainder is substantially Ni, and has a hardness of Hs40 or higher and excellent wear resistance and corrosion resistance. 2. C0.10 or less Si 1.0 or less Mn 1.0 or less Fe 5.0 or less Cr 35.0 to 60.0 Mo 10.0 or less Nb 3.0 or less Cu 10.0 or less N0.15 or less in weight%, and further contains Zr2. 0 or less Ta 3.0 or less Ti 1.5 or less Al 1.0 or less W 6.0 or less V 1.0 or less Contains one or more of rare earth elements 1.0 or less, and the remainder is substantially Ni. A high-hardness current-carrying roll for electroplating, characterized by having a hardness of Hs40 or higher with excellent wear resistance and corrosion resistance.