JPH01178385A - Manufacture of lead clad steel sheet - Google Patents

Abstract

PURPOSE:To obtain the lead clad steel sheet having the adhesion more than requested for its use by executing nickel plating or copper plating on a plain steel sheet or stainless steel sheet and after executing lead plating in succession laminating the lead by cold rolling. CONSTITUTION:Electrolytic nickel plating or copper plating is executed on a degreased and pickled steel sheet 1 after sufficiently washing it so that no residue of an acid cleaning liquid remains. At this time a nickel or copper plating layer 2 may be small at its plating amt. provided the small exposed part of the base does not remain. This nickel or copper plated steel sheet is subjected to lead cladding by cold rolling after subjecting to electrolytic lead plating in succession. This time, it is necessary that no stain nor the stable oxide film of a lead remains on the lead plated steel sheet 1 and the lead sheet surface to be cladded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for producing a lead-clad steel sheet that has excellent corrosion resistance, sound insulation, etc., and can be used for roofs, walls, and various types of equipment.

[Conventional technology]

As roofing and wall materials used outdoors without painting,
Lead plates have a long history of use.

However, the weight per unit area is large (the specific gravity of lead is 11
．． ．． 34) or have low rigidity, so they have disadvantages such as not being able to guarantee the strength as a structural member, being easily deformed during use even if processed into a certain shape, and being difficult to construct.

For this reason, hot-dip lead-tin alloy plated steel sheets are sometimes used, but under normal usage environments, the lead-tin alloy plating layer has a negative potential against the steel sheet, so it may occur during construction or during actual use. A thick plating layer of about 1 oy must be applied to prevent possible scratches from reaching the surface of the steel plate. Furthermore, extreme care must be taken to avoid damaging the plating layer during processing. If the base steel sheet is exposed at the scratched portion, the lead-tin alloy plating layer will not originally serve as a sacrificial anode for the steel sheet, and pitting corrosion will occur in the steel sheet. In other words, in cases where there is a risk of such corrosion occurring, even hot-dip lead-tin alloy plated steel sheets are insufficient;
A lead clad steel plate having a lead layer of approximately 0μ or more as a surface layer is used.

Conventionally, methods for manufacturing lead-clad steel sheets are described, for example, in the literature Bowers, J.E. and Goodwin.
+C, J, “The Pre-paration a
nd Testing of Lead-and Le
ad.

' A11oy C1ad 5teel 5heet
Produced by Roll Bonding,
” Journal of the In5titud
te of Metals, 1970. 98. 8
16, a method of using a molten lead-tin alloy plated steel plate as a base material and cladding it with lead by cold rolling has been put into practical use. Alternatively, as a completely different method, there are practical examples of products in which lead plates are bonded to ordinary steel plates or stainless steel plates with adhesive.

The conventional method for manufacturing lead-clad steel sheets described above has the following drawbacks because it uses a hot-dip lead-tin alloy plated steel sheet as a base material.

■Large-scale hot-dip plating equipment is required to manufacture hot-dip lead-tin alloy plated steel sheets.

■The plating layer of the base material turn sheet plays the role of surface treatment to strengthen the bond between the lead cladding and the steel plate, but since it is hot-dip plating, it is difficult to control the amount of plating to the minimum necessary. This is difficult and results in an excessive amount of plating for the purpose. For this reason, although the tin content in the plating layer of a typical hot-dip lead-tin alloy plated steel sheet is 10 to 15%, an excessive amount of expensive tin is used. One method is to reduce the tin content, but this reduces the adhesion of the plating layer.

■Due to the characteristics of use, it is often desirable to leave the surface opposite to the lead-clad surface as a plain steel plate or stainless steel plate.
Manufacturing tin alloy plated steel sheets is not easy.

■When hot-dip-plating is carried out on the hot-lead-tin alloy plated steel sheet production line, the steel sheet is subjected to heat treatment, which makes it difficult to provide the clad steel sheet with the optimal mechanical properties required for its use. In some cases, it may be impossible.

On the other hand, in the case of a product in which a lead plate is bonded to a board with adhesive,
The adhesive strength itself is inferior to the above-mentioned cladding material. Therefore, during actual use, peeling problems tend to occur during bending or cutting. Alternatively, secondary adhesion failure is likely to occur due to water penetration from the cut surface.

Furthermore, when these laminated materials are joined together, the organic resin with a low melting point easily burns, melts, and flows out, making it difficult to solder or braze.

[Problem that the invention seeks to solve]

The present invention is directed to the above-mentioned method of manufacturing a lead-clad steel sheet using a conventional molten lead-tin alloy coated steel sheet as a base sheet.
～■ Problems or disadvantages of laminating agents using adhesives,
This was done to solve the problem in an advantageous manner.

That is, according to the present invention, it is possible to manufacture lead-clad steel sheets with strong adhesion and mechanical property values optimal for the purpose of use, including those with one side left as the surface of the base material, using simple equipment and at a lower cost. becomes possible.

[Means for solving problems]

Instead of a thick molten lead-tin alloy plating layer, a thin pure lead layer with the same composition as the cladding lead is used as an intermediate layer, and in order to ensure the adhesion between the pure lead layer and the steel plate, A feature of the present invention is that an electrolytic nickel plating or copper plating layer is provided.

That is, the present invention is as shown in FIG. This is a method for manufacturing a lead clad steel sheet, which is characterized by lamination.

A steel plate that has been degreased and pickled using a known method is first plated with nickel or copper. Not only stainless steel plates but also ordinary steel plates must have sufficient wettability with the plating solution on the surface of the steel plate after pickling.

Although it is not necessary to limit to a specific degreasing/pickling method, for example, C=0.05%, Mn=0.2%+'5i=0
．． 02%.

In the case of an ordinary steel sheet with P = 0.01% and S = 0.01%, it is electrolytically degreased in sodium orthosilicate and then pickled in 5% dilute sulfuric acid. In the case of stainless steel sheets, ferritic or austenitic types are used, especially Or, N
i, The pickling resistance varies depending on the Si content, but for example, 5U
S430 (ferrite type, Cr=18%, N1=O%
), a surface with good water wettability was obtained by pickling in a 15-1% hydrochloric acid solution (room temperature) using a stainless steel plate as a cathode at 3 A/dm'' for 5 minutes.

The pickled steel sheet is thoroughly washed with water so that no pickling solution residue remains, and then electroplated with nickel or copper. The role of these plating layers is to ensure adhesion between the subsequently plated lead plating layer and the base material, which is an ordinary hollow plate or a stainless steel plate.

Therefore, it is necessary to uniformly cover the entire surface of the steel plate with the nickel or copper plating layer so that no minute exposed parts of the base material remain, but as long as this point is ensured, the amount of plating may be small. There is no need to limit the plating conditions such as plating bath composition, temperature, and current density (even when SUS 430 was used as the base material, a sufficient effect was achieved with a plating amount of about 1.0 g/rrf.

SOS 4 directly without nickel or copper plating
When lead plating is applied on 30, if the surface of the plating layer is strongly rubbed after the lead plating, the lead plating layer will peel off.

Even in this case, if the steel plate after lead plating is heat-treated at 100"C for several minutes, the residual stress in the plating layer will probably be relaxed, but the plating layer will not peel off. However, when a lead-clad steel plate based on this steel plate is subjected to an OT bending test or a 3% salt water immersion test (30°C for 17 days) after the bending test,
Peeling of the lead cladding layer was observed, making it unsuitable for practical use.

As described above, the nickel or copper plating layer exhibits a remarkable effect in securing secondary adhesion.

Nickel or copper plated steel sheets are subsequently electroplated with lead. Nickel or copper plating and lead plating do not necessarily need to be performed continuously, and discontinuous processing is also acceptable as long as the passage of time after nickel or copper plating does not adversely affect the adhesion of the lead plating layer to the base. Even if there is an adverse effect, it is sufficient if lead plating with good adhesion can be achieved by, for example, mild pickling with hydrochloric acid or surface brushing immediately before lead plating. The role of the electrolytic lead plating layer is to ensure the adhesion of the lead clad layer to the nickel- or copper-plated base steel sheet. It is important that the surface of the underlying nickel or copper plating layer is uniformly coated with lead, and if this point is guaranteed, an excessively thick plating layer is not necessary in terms of manufacturing technology or quality.

Since the uniformity of lead deposition varies depending on the lead plating solution or plating conditions, it is generally not possible to determine the lower limit of the amount of lead plating deposited.
1.0g on rf nickel or copper plated steel plate
/rd lead plating, the primary adhesion and secondary adhesion of the lead plating layer were at a sufficiently satisfactory level.

Steel sheets with nickel or copper plating and lead plating on top are lead-clad in a cold rolling mill. It is important that there is no dirt or stable oxide film of lead remaining on the surface of the pre-lead plated steel plate that serves as the base material and the lead plate that will be clad.

For example, if cladding rolling is performed within several days after lead plating, the surface of the lead-plated steel sheet may be lightly brushed with nylon or Scotchbrite. On the other hand, the oxidation state of the surface of lead plates differs depending on whether the lead plate is manufactured using an electrolytic method or a casting method. It is necessary to polish strongly with a wire brush, sandpaper, etc.

The thickness of the lead plate used and the rolling rate during cold rolling are determined as follows.

First, the predetermined thickness of the lead plate at the entrance side of the rolling mill is determined based on the thickness of the lead clad layer necessary for the final lead-clad steel plate product and the rolling rate of the base material. The adhesion of a clad rolled steel plate is thought to be controlled by the van der Waals force between the clad material and the clad material that is generated at the adhesive interface during rolling. Since lead is a soft metal, it is thought that a new pure lead surface will appear at the interface even at a relatively low rolling rate, and in fact, sufficient adhesion was obtained at the apparent rolling rate of about 30%.

The apparent rolling ratio R at this time was calculated as follows.

When R = 30% for SO3430 base material, the thickness reduction rate of the base material is at most 1%, and the thickness reduction rate of the lead plate is 35.8
%Met. Therefore, almost no change in mechanical property values was observed before and after rolling.

For convenience, Fig. 1 shows a steel plate that is clad on only one side, and the other side is not plated with both the nickel or copper plating layer and the lead plating layer, but if necessary, the first layer Of course, the second plating layer may also be applied to the other surface. Further, according to the present invention, it is also possible to easily manufacture a double-sided clad steel plate.

〔Example〕

Next, the present invention will be specifically explained based on examples.

(Example 1) 0.611IIn aluminum killed cold rolled steel plate (temporary width 160
M, length 220mm+) in 5% sodium orthosilicate at 40°C, with the steel plate as a minus, 10 A/dm2.2
After electrolytic degreasing for seconds, it was thoroughly washed with water, pickled by immersion in 5% sulfuric acid at 60°C for 5 seconds, thoroughly washed with water, electrolytically nickel plated under the following conditions, and then electrolytically lead plated.

■Nickel plated nickel chloride 240 g/12. Hydrochloric acid 100g//! In the plating bath, the current density was fixed at 10 A/dm'' at room temperature, and the amount of adhesion was varied by changing the plating time. After thorough water washing, lead plating was performed under the following conditions.

■Lead-plated lead borofluoride Pb (BF2)z 280 g / E
, fluoroboric acid HBFa 50 g/l = boric acid 25 g/It.

In a plating bath consisting of 3 g/f resorcinol, the liquid temperature was fixed at 50°C, the current density was fixed at 20 A/dm'', and the amount of adhesion was varied by changing the plating time. After thorough water washing, the steel plate for lead cladding was did.

■Lead Clad 2 Using a cold rolling mill (roll diameter 300 amφ), a cast lead plate having a thickness of 2.0IIII was cold clad on a nickel and lead plated aluminum killed cold rolled steel plate.

The rolling load was 9.0 TON/10 cylinders.

(Example 2) Only the nickel plating step in Example 1 was changed to copper plating as described below. Other conditions are the same as in Example 1.

■Copper plating Copper birophosphate 90g/f, metal copper 30g/j! .

Potassium birophosphate 320g/C ammonia water (specific gravity 0.8
8) In a plating bath consisting of 4 cc/12 and potassium nitrate 20 g/g, the liquid temperature was set at 50° C., the current density was 4 A/dl.
The amount of adhesion was adjusted by fixing II2 and changing the plating time.

(Example 3) SO3430 steel plate of 0,611111 (plate width 160mm
, length 220 mm) in 5% sodium orthosilicate at 40°C, electrolytically degreased for 2 seconds at IOA/dm, rinsed thoroughly with water, and soaked in 20 wt% hydrochloric acid, with the steel plate made negative for 3 A. /dn+z, After electrolytic pickling for 1 minute, washing thoroughly with water and electrolytic nickel plating under the same conditions as in Example 1 except for the electrolysis time, electrolytic lead plating was further applied.

■Nickel plating electrolytic conditions 10 A/dn+”X 1 minute Nickel deposition amount is 10
．． It was 2g/r+f.

■Lead plating electrolytic conditions 5 A/dm” x 1 minute Nickel deposition amount is 12.5
It was g/po.

■Lead Clad Using the same cold rolling mill (roll diameter 300-φ) as in Example 1, cold clad a cast lead plate with a thickness of 2.0 mm on an SO5 steel plate plated with nickel and lead. did. The effect of rolling reduction on quality was investigated by changing the rolling load.

(Comparative Example 1) In Example 3, nickel plating and lead plating were omitted, that is, only pickling was performed, and lead cladding was attempted. The rolling load was 9.0 TON/10 ff1ffl.

(Comparative Example 2) In Example 3, only nickel plating was omitted, that is, lead plating was performed after pickling, and lead cladding was attempted. The rolling load was 9.0 TON/10 mm.

(Comparative Example 3) In Example 3, only lead plating was omitted, that is, after pickling,
I tried nickel plating and lead cladding. The rolling load was 9.0 TON/10 am.

(Comparative Example 4) In Example 2, only lead plating was omitted, that is, after pickling,
I made 9 rows of copper plating and tried lead cladding.

The rolling load was 9.0 TON 710 mm.

Regarding the above samples, a test for evaluating adhesion of the cladding layer was conducted in the following manner.

1) 180 degree beer test Cut out a 25+n+a width clad steel plate sample,
The adhesion of the cladding layer to the substrate was evaluated using an 80 degree beer test.

2) OT bending back test OT close bending was carried out for each case where the cladding layer was on the inner surface side and when it was on the outer surface side, and the degree of adhesion of the cladding layer to the base material was visually observed from the cross-sectional direction.

3) Salt water immersion test The unbending test piece of 2) was immersed in 3% salt water (room temperature).
The specimens were immersed in water for two weeks to evaluate their resistance to saline penetration from the end faces.

4) The test piece that had been bent back from the cold/heat cycle test 2) was immersed in warm water at 80°C.
Fifteen cycles of the test were conducted in which one cycle was 16 hours of storage in a freezer at −10° C., and changes in the state of adhesion of the cladding layer to the base material were mainly observed at the unbending portion.

The evaluation results for each sample are summarized in Table 1.

In the table, Example 2 and Comparative Example 4 are data obtained when copper plating was performed instead of nickel plating.

In addition, ◎ in the 180@T beer test indicates that the adhesion strength is sufficient and leads to breakage of the lead white body. In other 07 unbending tests, salt water immersion tests, and thermal cycle tests, ◎ means that no abnormality is observed compared to before the test, Δ means that some peeling of the lead cladding layer is observed at the bending part, ×
means that peeling of the cladding layer is clearly observed.

〔Effect of the invention〕

As explained in detail above, after performing nickel or copper plating in an amount that sufficiently uniformly covers the base steel sheet, lead plating is applied as a second plating layer that sufficiently uniformly covers the first layer plating. A lead-clad steel sheet manufacturing method in which cladding is performed by cold rolling has produced a lead-clad steel sheet that exhibits primary and secondary adhesion that exceeds the quality required for its usage characteristics.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a cross section of a lead-clad steel sheet obtained by the present invention. 1... Steel plate (ordinary steel plate or stainless steel plate). 2... Nickel or copper plating layer, 3... Lead plating layer. 4...Lead cladding layer. 3. Pufferfish. There is a lot of cladding waste and lead in six places.

Claims (1)

[Claims] After applying nickel plating or copper plating on a normal steel plate or stainless steel plate, and then sequentially applying lead plating,
A method for producing a lead clad steel sheet, characterized by laminating lead by cold rolling.