JPS6119696B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a current-carrying roll material for electroplating. Conventionally, JIS
- Corrosion-resistant steels such as SCS14 and JIS-SUS316 have been used, but these corrosion-resistant steels have poor corrosion resistance such as electrical corrosion and acid solution corrosion, as well as wear resistance, and can cause significant roughness on the roll surface. As a result, polishing was required for reuse within a short period of time (for example, one week). The present applicant has already solved the above-mentioned drawbacks of the conventionally used corrosion-resistant steel, and has made it possible to use it as a current-carrying roll for electroplating without impairing its conductivity, and to use it for particularly harsh hard-wearing processes such as electrolytic galvanizing and electrolytic tin plating. Patent Application No. 55-134399 (Showa
The purpose of the present invention is to improve this current-carrying roll for electroplating so as to further improve its corrosion resistance. In order to achieve the purpose, the roll according to the present invention has, in weight percent, C0.10% or less, Si1.5% or less,
Contains Mn 1.5% or less, Cr 14% or more and 21% or less, Mo 13% or more and 20% or less, Cu 1% or more and 5% or less, Fe 6% or less, Al 0.5% or less, Ti 1.0% or less, Nb 1.5
% or less, V 0.5% or less, W 3.0% or less, Co 5.0% or less, and the remainder is substantially composed of Ni. The chemical composition differs from that of the previous patent application in that Cu is added in a range of 1% to 5%. Hereinafter, the present invention will be explained in detail based on examples thereof. As mentioned above, the roll according to the invention is made of Ni
It is characterized by containing Cr, Mo, and Cu as main components, but as will be explained in detail later, it is solution-treated to provide both corrosion resistance and wear resistance. The austenite base material is made uniform and made into a roll. First, the reason why each chemical component is limited to the above specific range in the roll of the present invention will be explained. As a basic component, Ni stabilizes the matrix as an austenitic structure, and since Ni itself is noble due to the ionic tendency of metals, the corrosion dissolution rate is low, and the corrosion film formed is dense, so it has a protective effect. It is large and has excellent passivation ability. When Mo is added to this Ni, as the content increases, the corrosion dissolution rate decreases, the passivation ability increases, and the corrosion resistance is significantly improved. This corrosion resistance is
The effect appears from a content of 13 wt%, and if it exceeds 20 wt%, it becomes saturated and intermetallic compounds easily precipitate, which actually deteriorates the corrosion resistance. Cr forms a matrix with Ni and Mo, which have a low corrosion dissolution rate and also have passivating ability, forming a stronger protective film and providing passivating ability. In this alloy, the effect of Cr content is remarkable at 14wt%,
If it exceeds 21 wt%, it becomes saturated, causes embrittlement due to the formation of intermetallic compounds, and further deteriorates corrosion resistance. Cu is added for the first time in the present invention, but Cu forms a matrix due to the coexistence of Ni and Mo, forming a strong protective film on the surface layer.
It provides passivation ability. The content of Cu is
In this alloy, the effect appears at 1wt%, and 5wt%
If the temperature exceeds the
It causes embrittlement and further deteriorates corrosion resistance. Although the inclusion of C, Si, and Fe is unavoidable in manufacturing, it is preferable that the content be as small as possible. However, C content precipitates carbides and deteriorates corrosion resistance, so it is preferably 0.06 wt% or less; can be done. However, to stabilize this excess carbon,
Addition of elements such as Ti and Nb is effective. To achieve this effect, Ti≧5×Cwt%, Nb≧10×Cwt
% is required. Therefore, Ti is 1.0wt% or less, Nb
is limited to 1.5wt% or less. Although Si precipitates intermetallic compounds due to its inclusion, deterioration of corrosion resistance can be prevented by completely performing solution treatment. The content of Si varies depending on the manufacturing method, but it is necessary to contain 1.5 wt% or less from the viewpoint of deoxidation, melt flow, etc. In order to prevent the precipitation of this intermetallic compound, it is necessary to effectively use a deoxidizing element such as Al in place of Si as much as possible in production. The effective content of this Al is 0.5 wt% or less. As for Fe, if it is 6 wt% or less, although there is some deterioration in corrosion resistance, the effect is not significant. Although the effect of Mn is not so remarkable, it seems that γ
It widens the phase region, stabilizes it, and improves hot workability. Its amount is 1.5wt% or less. Regarding V, when the content is 0.5 wt% or less, crystal grains are made finer, some hardening is observed, and wear resistance is improved, but when the content is 0.5 wt% or more, corrosion resistance is deteriorated. As for W, like Mo, it improves corrosion resistance,
An improvement in strength can be seen, but if it exceeds 3%, intermetallic compounds tend to precipitate, and solution treatment at 1220°C is required to obtain a uniform structure. Therefore, it is limited to 3% or less. The effect of Co is to strengthen the austenitic base containing Ni, Cr, and Mo, form a dense passive film on the surface, strengthen passivation ability, and improve corrosion resistance. However, if it exceeds 5.0%, the toughness decreases and the price increases economically, so it is limited to 5.0% or less. Al improves oxidation resistance, but if it exceeds 0.5%, it produces intermetallic compounds and reduces corrosion resistance, so it is limited to 0.5% or less. Next, an example of the current-carrying roll for electroplating of the present invention will be described based on the results of experiments conducted in comparison with conventional roll materials. Table 1 shows the chemical components (wt%) of the sample materials,
Table 2 shows the electrical corrosion resistance and the mechanical properties. In addition, as shown in the attached drawing, this electrical corrosion resistance and wear resistance is 30% ZnSO ₄ +3
The test roll 2 is immersed in the solution 1 under the conditions of %H ₂ SO ₄ , PH 1.2, and current density 40A/dm ² , a brake roll 3 and a drive roll 4 are arranged before and after this, and a mild steel strip 5 is passed through the test roll 2 . Tests were conducted with constant tension applied. In addition, this corrosion and abrasion resistance test evaluates the roll life ratio (see Note 2 in Table 2) and the incidence of flaws such as scratches and punch marks that occur on the roll surface due to mechanical factors after one week of energized use. (Note 3 of Table 2
(Reference). Note that Table 2 also shows the results of tests on the amount of corrosion conducted on some of the rolls of the present invention in the as-cast state. As shown in Table 1, the sample materials include JIS SCS14 and SCS316 as conventional alloys, and those of Japanese Patent Application No. 55-134399 "Electrifying Roll for Electroplating" related to the applicant's earlier patent application. No. 1, 2, 3, which are described as examples of the invention alloy in the specification.
As examples of the alloys of the present invention, Nos. 6, 7, and 14 are adopted, in which the basic components are changed within the limited range of each component of the present alloy.
The basic components of No. 7 (center values for both Cr and Mo),
Nos. 10, 11, 12 and 13 were added with CO, Al and Ti, Al and Nb, V, and W, respectively.
In addition, the basic component of No. 14 (center value of Cr,
upper limit of Mo), Co, Al and Ti, Al and Nb, V,
Added W, respectively.
They are numbered 15, 16, 17, 18 and 19. In addition, regarding the amount of corrosion in Table 2, the test piece was 50%
It was immersed in a boiling sulfuric acid solution with a concentration of 20% and a boiling hydrochloric acid solution with a concentration of 20% to determine the degree of erosion in g/cm ² /day. As can be seen from Table 2, the alloy of the present invention (solution treatment temperature 1150°C) is compatible with JIS SCS14, SCS316 and
Compared to alloys No. 1, 2, 3, 4, and 5, this shows relatively excellent corrosion resistance. Furthermore, from this table, it can be seen that the alloys of the present invention exhibit extremely excellent corrosion resistance even in the as-cast state. Furthermore, as is clear from Table 2, the corrosion and wear resistance of the roll according to the present invention is 15 to 20% higher than that of the conventional roll using JIS SUS316.
It has doubled. Furthermore, the flaw occurrence rate is between 25 and 40%, which is thought to be because the roll surface has excellent mechanical properties and no scratches or indentation flaws occur on the roll surface. Furthermore, the electrical conductivity is inferior to the JIS-SUS316 electrical resistance of 74 μΩcm, at 125 μΩcm, but it is said that up to 170 μΩcm is acceptable in practice, so this point does not pose a problem. Next, considering Table 2 for each composition, among No. 6, 7, and No. 14, which have different basic components, No. 14, which has a Cr center value and an upper limit of Mo, is superior, and JIS-SUS311 The lifespan ratio is 22 times that of the previous model, and the flaw occurrence rate is approximately 1/3 that of the previous model. In addition, the amount of Si was reduced and Al was added, and furthermore, C
No.10 and 16 with Ti added to stabilize
and No. 11 and 17 with Nb added, in terms of life ratio,
They are 18 times and 20 to 23 times that of JIS-SUS316, respectively. In this way, in terms of life ratio,
No. 10, 16, 11, 17 are the basic components No. 6, 7,
No.8 and No.14 life ratios, Al, Ti and Nb
The effect of the addition of is not apparent. In addition, for No. 12 and 18 with V added, the lifespan is JIS -
The values are 21 times and 17 times higher than SUS316, respectively, and the flaw occurrence rate is also about 1/3 to 1/4. No.20 contains No.7 Si, which is the basic component.
This alloy has a low Si content of 0.1%, and exhibits good corrosion resistance among these alloys of the present invention, and the effect of having a low Si content is recognized. However, in terms of mechanical properties, no significant difference was observed between this composition and other compositions. As described above, the basic components of the roll according to the present invention are Ni-MoCr and Cu-based, but the roll according to the present invention has sufficient corrosion resistance even under particularly severe corrosion conditions during galvanic corrosion. It has corrosion resistance,
This corrosion resistance is even better than that of the previous patent application. Therefore, the current-carrying roll according to the present invention conforms to JIS-SCS14
It can be used even under current corrosion resistance conditions of PH0.6 to 1.6, which cannot be obtained with JIS-SOS316, and even under particularly severe conditions of PH0.6 to 1.8.
In addition, it not only has sufficient wear resistance due to its excellent mechanical properties, but also has no hindrance in terms of electrical conductivity. It can be fully put to practical use. Therefore, the present invention provides a current-carrying roll for electroplating that has these properties indispensably, and is more suitable than that of the previous patent application.

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【table】 [Brief explanation of the drawing]

The figure is an explanatory diagram showing a test method for energizing electrical corrosion resistance and wear resistance.

Claims (1)

[Scope of Claims] 1% by weight: C: 0.10% or less Si: 1.5% or less Mn: 1.5% or less Cr: 14% or more, 21% or less Mo: 13% or more, 20% or less Cu: 1% or more, 5% or less Fe: 6% or less; This includes Al 0.5% or less, Ti 1.0% or less,
Nb1.5% or less, V0.5% or less, W3.0% or less, Co5.0
A current-carrying roll for electroplating, characterized in that the current-carrying roll contains one or more of the following components: