JPS63103097A - Conductor roll for electroplating - Google Patents

Abstract

PURPOSE:To prolong the service life of the title roll under the conditions where the current to be applied and sheet passing velocity are high by coating the surface of the roll barrel with a composite layer consisting of the dispersed phase of an Ni-based corrosion-resistant alloy matrix and a specified amt. of chromium carbide particles. CONSTITUTION:The barrel 10 of the conductor roll has a laminated structure wherein a sleeve base material 11 and the composite layer 12 are joined and integrated at the interface. The composite layer 12 consists of an Ni-based corrosion-resistant alloy and 10-70wt% chromium carbide particles mixed in the matrix as a dispersed phase. The hardness of the composite layer 12 increases almost in proportion to the mixing ratio (wt%) of the chromium carbide particles, and the surface hardness of the composite layer 12 must be controlled to a value equal to or higher than that of the passing sheet to secure the wear resistance to the high-velocity passing sheet. For the purpose, the mixing ratio of chromium carbide particles is controlled to >=10%, however the toughness of the composite layer is deteriorate at >=about 70%.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a conductor roll for electroplating that has excellent resistance to corrosion and wear.

[Conventional technology]

Conductor roll (used for continuous electrogalvanizing, etc.)
As shown in FIG. 6, the current-carrying roll (current-carrying roll) basically consists of a sleeve (10) forming the roll body and roll ends (20, 20) fitted at both ends of the sleeve (20) as power supply members.

The surface of the body of the above-mentioned conduct roll has corrosion resistance against the plating solution, which is a strongly acidic corrosive liquid, and wear resistance that can withstand friction with the plated steel plate (threading material) that comes into contact with the surface and runs through the plating solution. is required. Note that the corrosion caused by the plating solution is galvanic corrosion that has a strong correlation with the amount of current applied, and becomes more prominent as the amount of current applied increases.

Conventionally, the conductor roll has been made of austenitic stainless steel such as 5US316 or Hastelloy C.
'' and ``Hastelloy C-276J, etc., whose sleeve (body) material is made of a Ni-based alloy have been used.

[Problem that the invention seeks to solve]

Recently, □Electroplating conditions are such that the amount of current applied is 10 to 15
The current flow rate has been increased from KA to 40-50KA, the pH of the plating solution has been lowered to 1-2, and the plate passing speed has been reduced to 10 KA compared to the conventional one.
The speed is increasing from about 0 m/min to 150-200 m/min.

As electroplating conditions become more severe, 5LI
Conductor rolls whose sleeve material is made of austenitic stainless steel such as S316 lack corrosion resistance to plating solutions and have a low surface hardness of about Hv160, so surface deterioration due to corrosion and wear progresses rapidly. On the other hand, "Hastelloy C" and "Hastelloy C-27"
Conductor rolls whose sleeve material is made of Ni-based alloys such as 6" have excellent galvanic corrosion resistance against plating solutions, and their surface hardness is relatively high at Hv190-210. It cannot adequately cope with the threading conditions, and especially when it comes into contact with a hard threading material such as a high-tensile steel plate, the contact portion with the edge of the threading material is likely to be damaged.

For this reason, conventional conduct rolls have a short service life, and the surface of the roll body must be re-polished at very short intervals (approximately 10 to 30 days). The reality is that it costs a lot of effort and money.

The present invention provides an improved conductor to solve the above problems.

[Means and effects for solving the problems] The electroplating conduct roll of the present invention has a roll body surface comprising a Ni-based corrosion-resistant alloy matrix and 10 to 70% by weight of a Ni-based corrosion-resistant alloy matrix mixed in the matrix as a dispersed phase. It is characterized by being coated with a composite material layer consisting of chromium carbide particles.

FIG. 1 shows the conductor roll of the present invention.

The roll body (10) has a laminated structure in which a sleeve base material (1) and a composite layer (12) covering the surface of the sleeve base material (1) are bonded and integrated at the interface between the two.

The Ni-based corrosion-resistant alloy constituting the matrix of the composite layer covering the surface of the roll body is an alloy with a composition equivalent to "Hastelloy C" (Cr: 15-18 %, Mo: 16-18%,
W: 3.5-5.5%, Fe: 4, 5-7%, Co
: 2.5% or less, 5il1% or less, Mn: 1% or less, C
: 0.15% or less, balance Ni) or Hastelloy C
-276J equivalent alloy (Cr: 14-17%,
Mo: 15-17%, W: 3-4.5%, Fe:
4 to 7%, Co: 2.5% or less, Si: 0.05% or less, Mn: 1% or less, C: 0.02% or less, balance Ni), etc. are suitable. In addition, "Inconel 625"
Ni-based alloy with equivalent composition (Cr: 20-23%, Fe,:
5.0% or less, Mo: 8-10%, Nb: 3.15-4
．． 15%, Ni: 5B% or more, C: 0.1% or less, Mn
: 0.5% or less, Si: 0.5% or less 1,6 [: 0.4
% or less, Tt: 0.4% or less).

The particle size of the chromium carbide particles (for example, Cr, C2) mixed as a dispersed phase in the Ni-based corrosion-resistant alloy matrix is not particularly limited, but from the viewpoint of dispersion strengthening effect, etc.
A range of μm is appropriate.

The proportion of chromium carbide particles in the composite layer (mixing ratio) greatly affects the hardness and wear resistance of the composite layer. Figure 2 shows
The mixing ratio of chromium carbide (weight%) and the hardness of the composite layer (Hv
, 10 kg). The composite layer under test was
A powder mixture of "Hastelloy C" alloy powder as a Ni5 alloy and chromium carbide (Cr, C, particle size: 50 to 200 μm) powder was used as an overlay welding material, and was processed by plasma transfer arc welding (PTA welding). , a weld overlay layer formed on the circumferential surface of the roll body (carbon steel sleeve).

As shown in the figure, the hardness of the composite layer increases approximately in proportion to the mixing ratio (wt%) of chromium carbide particles. In order to ensure abrasion resistance for highway temporary use when the plate to be plated is a high-tensile steel plate (HV: about 200 to 250), etc., the surface hardness of the composite layer should be equal to or higher than that of the plate material. It is necessary. For this purpose, the mixing ratio of chromium carbide particles is set to 10% by weight or more. This ensures a high surface hardness of Hv: about 300 or more as the surface hardness of the composite layer. From the point of view of wear resistance, it is advantageous to increase the amount of chromium carbide particles, but if it exceeds about 70% by weight, the toughness of the composite layer decreases and cracks are likely to occur during the process of forming the composite layer. The upper limit is 70% by weight.

FIG. 3 shows the hardness distribution in the thickness direction of the same test composite layer as above. However, the mixing ratio of chromium carbide particles is 30
% by weight, and was welded overlay with a target overlay thickness of ~10. It can be seen that the area having a depth of about 12 mm from the outer surface always has an approximately average hardness of HV: 400 or more.

Table 1 shows the electrical conductivity and electrical resistance of the composite layer formed by the welding overlay method using a powder mixture of "Hastelloy C" alloy powder and chromium carbide particles (particle size: 50 to 200 μm) in the same manner as above. Corrosion and corrosion wear resistance is achieved by using conventional roll body materials, “Hastelloy C” alloy and 5U.
This is shown in comparison with S316 stainless steel. The method for measuring each characteristic value is as follows.

(i) To simulate the actual usage conditions of electrical corrosion resistant conductor, it was placed in a heated strongly acidic corrosive solution (<23 g/l H2SO4 solution, liquid temperature 55°C) as shown in Figure 4 (1). Test piece (T
+) (test area: 1 col) and test piece (T1
) as a cathode and an anode (P[) as shown in the figure (II).
As shown in , the pulse current of IA (0.2 seconds of current -
, energization is repeated for 2 seconds) and the corrosion weight loss (g/m h ) of the test piece is measured after 24 hours have elapsed.

(1)) Corrosion and wear resistance As shown in Figure 5, the rotating wheel (al (S G P
1008 carbon steel, rotation speed 40 rpm) as the mating material,
Test piece (Tz) ctsxtsxto, m
] with a pressing force of 2 kg, and applied plating solution (bl (150 g/IZnSO4・
7 Hz, 100g/ (IN azs O4,
23 g/I Hz S 04 ) is supplied to create a corrosive humid environment, and the abrasion loss (■) of the test piece is measured after 7 days (168 hours) have elapsed.

(iii) Measurement is performed at room temperature using a test piece with an electrical specific resistance of 5φ×1501 <m weight).

Table 1 As shown in Table 1, the composite layer coating the body surface of the roll of the present invention has a corrosion abrasion loss of approximately 1/10 of that of 5US316 stainless steel, approximately 1/10 of that of ``R Hastelloy C'' alloy, and The loss due to galvanic corrosion is approximately 1 of that of 5US316 stainless steel.
The amount is as small as /100, which is on the same level as "Hastelloy C" alloy, and it has excellent galvanic corrosion resistance and corrosion abrasion resistance.

Further, although the electrical resistivity value is slightly higher than that of 5US316 stainless steel, it is lower than that of the "Hastelloy C" alloy, indicating that there is no problem in terms of electrical conductivity.

To explain an example of the manufacturing process of the conductor roll of the present invention, first, a hollow cylindrical body made of an appropriate material such as carbon steel or stainless steel is centrifugally cast, and the hollow cylindrical body is subjected to primary rough machining to form a sleeve base. Material (1)) is coated with a predetermined layer thickness by overlay welding using PTA welding or the like while supplying a mixed powder of Ni-based eclipsing alloy powder and chromium carbide powder to the outer peripheral surface of the material (1)). A composite layer (12) is formed. The thickness of the composite layer may be about 3 to 51 m, but it is also possible to form a layer as thick as about 10 mm if desired. After forming the composite layer (12), separately prepared roll ends (
20, 20) are baked and joined by welding (W) at appropriate places, the outer surface is polished, and further finishing is performed to produce a conductor roll as shown in FIG.

In addition to the welding method described above, the composite layer (12) can be formed by, for example, a thermal spraying method, or a sintering method can be used to form the composite layer (12) around the sleeve base material (1). A cylindrical canning material is fitted onto the sleeve base material (1).
) and the canning material is filled with a mixed powder of Ni-based alloy powder and chromium carbide powder, and then subjected to sintering treatment such as hot pressing and hot isostatic pressure sintering to form a composite layer. You can also do that.

〔Effect of the invention〕

In the conduct roll of the present invention, the roll body surface is coated with a composite layer that has excellent current corrosion resistance and corrosion wear resistance against plating solutions, so it can be used under plating operating conditions of high current flow and high speed sheet passing, compared to conventional conduct rolls. stainless steel,
It also guarantees an excellent service life that surpasses that of Hastelloy alloy rolls, and maintains a smooth and beautiful surface for a long time. Therefore, the frequency of replacing the rolls is reduced, the cost of repolishing the rolls is reduced, stable continuous electroplating operations can be maintained, and the quality of plated products can also be improved.

[Brief explanation of the drawing]

Figure 1 is a partially cutaway front view of the conductor roll of the present invention, Figure 2 is a graph showing the relationship between the chromium carbide particle mixing ratio and surface hardness in the composite layer, and Figure 3 is the hardness distribution in the thickness direction of the composite layer. Figure 4 is an explanatory diagram of galvanic corrosion test procedures, Figure 5 is a graph showing
The figure is an explanatory diagram of corrosion abrasion test procedures, and FIG. 6 is a partially cutaway front view of a conventional conductor roll. 10: roll body (sleeve), 1) sleeve base material,
12: Composite layer.

Claims (1)

[Claims] (1) The surface of the roll body is composed of a Ni-based corrosion-resistant alloy matrix and a 10-70
A contact roll for electroplating with excellent corrosion resistance and abrasion resistance, characterized by being coated with a composite layer consisting of chromium carbide particles in the weight percent.