JPS60114596A - Manufacture of surface treated steel sheet for electric resistance welding - Google Patents

Abstract

PURPOSE:To manufacture the titled steel sheet having superior weldability and superior durability after coating by successively forming a specified Fe-Ni layer, a specified amount of a tin layer by tinning and a layer consisting of metallic Cr and Cr oxide hydrate on a steel sheet and by specifying the amount of the metallic Cr and the amount of Cr in the Cr oxide hydrate. CONSTITUTION:The 1st layer of an Fe-Ni alloy having a composition satisfying 0.02-0.50wt. ratio of Ni/(Fe+Ni) is formed on a steel sheet. The thickness of the 1st layer is 10-5,000Angstrom . The 1st layer is tinned by 0.1-1g/m<2>, and the resulting tin layer is optionally melted to form the 2nd layer. The 2nd layer is electrolytically chromated to form the 3rd layer consisting of metallic Cr and Cr oxide hydrate. Thus, the titled steel sheet is manufactured. In the 3rd layer, the amount (x) (mg/m<2>) of the metallic Cr and the amount (y) (mg/m<2>) of the Cr oxide hydrate (expressed in terms of Cr) are regulated to x>=2 and 5<=x+y<=20.

Description

[Detailed description of the invention] 木-Ii'; Ming & J. Tunshi (Regarding a method for manufacturing a surface-treated steel plate for resistance 78 contact, weldability particularly suitable for the method of fully joining the can body of a good can by electric resistance welding) and a method for producing a surface-treated steel sheet with excellent corrosion resistance after painting.

As a material for food cans, tin-plated steel sheets, commonly referred to as yellowtail, have been widely used1. In the past, solder was used to join these can bodies, but due to problems with the 1U nature of lead contained in solder, pure tin solder has come to be used in recent years. [7]However, there are technical problems with solder joints because pure tin solder has inferior properties when joining, and there is also the problem of increased manufacturing costs due to the use of expensive pure tin solder. Ta.

In recent years, food containers have been faced with the entry of low-priced competing materials such as polyethylene, aluminum, glass, and paper, and the amount of tin deposited on them is 2.8 to 11.2 f.
/i thickly coated cans are expensive to manufacture, so even though they have all the JFC characteristics, they are very easy to eat on one side. It's here.

Solving the above disadvantages of tin cans [4 points, i + Q near'
Instead of ltIEI bonding, a method of bonding can bodies by electric resistance welding has been developed and has become popular.

Therefore, it is suitable for electric resistance welding (and a material for cans is required).

There is a conventionally used can material (7) and a chromium type Teinfriesdale, which is similar to the above-mentioned material. [Also, the thick chromium water 1J oxide film existing on the surface has high resistance, resulting in poor weldability and insufficient strength in the welded part. -C is excellent, but it is not suitable as a material for welded cans.

Since all of the conventional can materials other than U are unsuitable as materials for welded cans, various attempts have been proposed.
1 For example, ``American National Nutail?'' Published by 1-g tl, typified by "Nickelite" 1
．． There is a nickel-plated steel sheet that is coated with nickel plated with a weight of approximately 1.5r/nl'.
The upper surface is treated with conventional chromate treatment, but it has not been widely used due to poor paint adhesion.

Yet another example is ``Tin Alloy,'' released by Jones, Rollin, and Nuteil in the United States. This is about (), 6? /d light weight tinmetsu@ is treated in a melting pot, and then subjected to conventional chromate treatment [7
However, both rust resistance and paint adhesion are insufficient.

When it comes to the need to have a material for cans suitable for electric resistance welding, it is important to have excellent weldability and corrosion resistance after painting. To explain this requirement specifically,
It has sufficient welding strength during welding, and has an appropriate welding current range that does not cause welding defects such as so-called "splatters" at the bath welding part [2. When used by coating the contents of the can. , the crossroads of the coating film that can take full advantage of the corrosion resistance of the coating film)
[-1] In the coating film defects that inevitably occur in history, corrosion must be prevented by the excellent corrosion resistance of the material itself.

The purpose of the present invention is to eliminate the above-mentioned conventional drawbacks of materials for welded cans, and to provide the "λ5" properties that the materials for welded cans should have.
(Providing materials for food cans.

The 92 advantages of the present invention are as follows.

In other words, Ni/(Fe+Ni
) = (+, + 10 to 5 raw wool having a composition in the range of 12 to 050 (+ (+ (l) forming a first layer consisting of an iron-nickel alloy of A;
Tin plating in the range of O, 1 to 1 f/d 1. After that, process the molten pot if necessary.・1. forming a second layer on the second layer, and forming a third layer of metallic chromium and chromium oxide (C) on the second layer. In the method for manufacturing a surface-treated steel sheet for electrical resistance Ilf drawing, the chromium conversion capital of metal chromium t (n?) is limited to the above range 'f: Characteristic electrical resistance bath contact surface treatment 6V4
& manufacturing method.

22≦;x5;X-+-Y≦20 It is.

The inventors have conducted various studies on the weldability and paint corrosion resistance of the above-mentioned materials for welded cans, especially those with thin coatings, and have found that weldability is good unless the amount of chromium water-retaining oxide film exceeds a certain value. It has been found that corrosion resistance is poor in this region, and although corrosion resistance improves when the total amount of chromium water-retaining oxide film is increased, weldability deteriorates, making it impossible to obtain an appropriate welding range. That is, from the point of view of economy, there is a limit such as 12/d or less. Within the range of tin adhesion, weldability and coating
The material that satisfies the eating quality is produced using the ordinary tinplate manufacturing method.-C
It was found that this could not be achieved by limiting the amount of chromium water-retaining oxide film.

The present inventors previously proposed a method for producing a thin coating that satisfies weldability and paint corrosion resistance at the same time.
No. 1,242,351 (hereinafter referred to as the prior art) was disclosed. The gist is as follows:C1<.

1-Nawachi, j'Ji / (F” in weight ratio on steel plate
forming a first layer consisting of an iron-nickel alloy of 10 to 50 (l O^) having a composition in the range of 01 to 1f on the first layer;
After complete tin plating in the range of /m', iron is treated with hot tin.
forming a second layer consisting of a tin-nickel alloy; and electrolytic chromate treatment on the second layer to convert it into ROM equivalent.
(a method for manufacturing a surface-treated αθ plate for electric resistance welding, comprising the step of forming a third layer consisting of metallic chromium and chromium water-conserving oxide in the range of 5 to 20 strokes/d) ,.Certainly, with this method, 1. The thin tint had both weldability and corrosion resistance of -rg1+, and it was possible to make C with some success, but as a result of subsequent investigation, the C contained in the can content was found to have sufficient corrosion resistance. It turns out that there are some things that aren't. Therefore, as a result of detailed investigation and re-examination ΔJ, the present inventors found that molten pot treatment is not necessarily necessary for forming the second layer in the prior art.
They also discovered that the structure of the chromate film makes a difference in its corrosion resistance, and completed the present invention by improving the technology of the prior application. In other words, the prior art uses chromium metal and chromium water-containing oxide to control the amount of water used, but although it is similar, it does not have sufficient corrosion resistance.
It was found that the amount of metallic chromium in the chromate film was small l/+. The metal layer in the chromate film D A
And the scattering of chromium hydroxide has changed dramatically! :? '
); investigated the relationship between cracking corrosion resistance and weldability, and found that the appropriate range and 14 paint corrosion resistance and bath weldability were both within the immediate range in Figure @1, and the metal chromium [11x was 2~/♂ on the embankment] In some cases, corrosion resistance is extremely low, but 2 W
/rr1, some had poor corrosion resistance. This is thought to be due to the increase in metallic chromium and the increased adhesion with the VC paint [7, especially at 2 mf/m or more, the effect of λ)1 is significant. From Figure 1, metallic chromium and chromium If the total amount of hydrated oxides (fx+y) is less than 5/d, the corrosion resistance will be poor; if it exceeds 2 (1"/11'), the weldability will be poor; if 5≦x+y≦20, the corrosion resistance will be poor; It can be seen that both the weldability is within the appropriate range of tl.From these results, in the present invention, the chromium equivalent of 1 of the metal chromium The range of ^y(η/rr?) is 2≦x,
It was limited to 5≦x −t−y≦2().

However, in the prior art, the formation of the second Fc-Ni-8n alloy layer depended on the molten pot treatment (However, if the 1111 erodibility after painting is a problem, it is necessary to form it before the paint bakes.) Subsequent training revealed that a sufficient effect can be recognized with an alloy layer as thick as the alloy layer. Therefore, in the present application, at the stage of forming the second layer, M+H- may be used with or without melting pot treatment.

The present invention is directed to the first t1 made of iron-nickel alloy as shown in t1: above.
The second layer consists of a tin-plated alloy on top of the first layer.
The metal chromium and oxide formed in the second layer of paralysis limit the hydrated oxide N1 (and the chromate film
, 3 layers νrE゛C5 The surface treatment 6t4 plate of the present invention is welded 4'l, 1', -, i thickness + 'E property 1cm4-g]1
．． Is it possible to provide a large amount of injection can material? r tl, 2 wm cold rolled with 5 rolls (7 tons 1'1'/after cleaning (7 tons,
Test materials 1 to 5 are made of wood r; For welding by the method θ The conditions for comparison are as follows.

(First layer formation step consisting of Al-nickel alloy.

Either one of the following methods or a combination of 2 fj or more was used. (a) Method of annealing after nickel plating.

1) Method of annealing after iron-nickel alloy plating.

(c) Method of iron-nickel alloy plating.

For example, 0.2 m original size cold rolled steel plate kRr
After 17 electrolytic cleaning in a sodium chloride solution, nickel plating was carried out.
A steel plate annealed in a so-called IINX gas atmosphere of 0 cm I-1, +90 cm N is electrolytically cleaned in a caustic soda bath, pickled in a sulfuric acid solution, and then subjected to iron-nickel alloy plating. processed. An example of the composition of the plating bath is as follows.

What) Nickel plating bath Nickel sulfate 250 f/Nickel chloride 459/l IR30f/l 1 mouth) Iron-nickel alloy plating bath Iron chloride 20~230 f/Nickel chloride 30~3(109/l Boric acid 25 Ill) As shown in Table 1, the first layer made of iron-nickel alloy was formed on the surface, but in the present invention examples of test materials A1 to A5, vf, as shown in Table 1, <Ni/(I・
``e l Ni ) = 0.fl With a composition in the range of 2 to 05 (], the layer jII sum + +1 to 5 (l o
The limiting requirements of the present invention for OA are:
J: Ni/(Fe-1-Nj)-(101, Al l
0゜ya 12 is (1,85 and neither C satisfies the limitation requirements, and the thickness of ('I"n')i is also the same as sample material A.
13 is 6oooi and 11. ”, a friend of mine who was not satisfied with the results of this investigation.

(Ill　2A　2-layer formation process.

After carrying out tin plating on the first layer, the second layer 2e was formed by tin plating as required. The reason why molten pot treatment is not necessarily safe is that an alloy layer is formed during paint baking.
In order to improve corrosion resistance after painting, it is better to consider the corrosion resistance after painting 1q, that is, after baking, and therefore, it is better to consider the corrosion resistance after painting 1q, that is, after baking. It is not necessarily necessary to carry out molten tin treatment (7L). Even if an alloy layer is formed during painting (2), the effect of improving the corrosion resistance of the alloy layer is sufficiently recognized. A halogen bath with the following composition was used (7).

Stannous chloride 60? / to y sex → t 'I +'y ], 2 0 f
/ is fluorinated, 50 li/ is sodium chloride, 6 (l k'/l).
5 shi 1 - J', ++ also tin 11 ma 01 ~ 1 y7M
, i.e. 1()0~I O+1 +1 ”?/n?
All the limiting requirements of the present invention are satisfied 1, but the sample j3'A]4 of the comparative example is 50 m? /rr? and 4'i: familiar
[Is 11- too small and Sho 11 is 2800m? /d is too large and meets the requirements of the present invention (111 to 12). Sample material A ] 1 is the thinnest #25 furiki currently in general use. Consisting of chromium and chromium hydrate t' + yi compound@
3 layer formation process.

1! , ', J+9', 'iij 'Il'l' The chromate treatment bath used in the following 4(1) Cros
20? /l +Na 2 Cr 2075'/l-
10E-L S 040.2'/l (■1Cry, 15
f//=+NaF 1.59/1(III) CrO
s 60 t /lff%Q Na2Cr20□55
r/l +Cr2O35? /l The amount of metallic chromium in the third layer formed by these electrolytic chromate treatments
As shown in Table 1, the test materials of the present invention were 71. Also metal chromium MX≧2 (Tng/rl), chorus chromium t,
Although the limiting requirements of the present invention of x y = 5 to 20 ("lf/n?) are satisfied, among the comparative materials, sample material 6
7.11 has a metallic chromium content of 0.1. Oη/rrl, which is too low, and the total amount of chromium in sample material A8.9, which was -1, was 25.
30η/m2, which was excessive, and neither of them satisfied the requirements of the present invention.

All test pieces were cut out from all the test materials obtained in this way and the following characteristics were investigated. In addition, iron in Table 1-
The composition of the first layer of nickel alloy and the raw stone were measured by IMMA, and the corrosion resistance after weldability and O coating ξ was evaluated according to the following ant standard.

(a) Weldability Mf welding 7; using copper wire with a diameter of about 15 mm as the pole [
The specimens were stacked together under a constant pressure while moving ~, this, and electrical resistance welding was performed at a welding speed of 40 m/min to ensure that the welded part had sufficient strength [7 and the so-called l'
ji! Created based on the condition that "/su" does not occur.
Tang'+'j4. Evaluate the frequency of irrigation using a thick awn with an appropriate range of flow and pressure.12.

In addition, the strength of the m-joint part! is V from the cylindrical end sandwiching the bath contact part.
Make a letter-shaped cut and hold the 2.3 corners with pliers.
(All the so-called beer tests that pull towards the IIJ end (
However, it is necessary to make sure that the bath contact part does not break in the middle (7).

([1) After painting the surface, apply Goboyan phenolic paint to a thickness of 50"J/dn., then seal the edges and back surface.

Immerse the lower half of all the corrosion resistance test pieces in various test solutions, wet the upper half with the same test solution, and then let the test pieces rise above the surface of the solution at 55°C. Retained for 18 days.1
After 8 days had passed, the test pieces were taken out and the corrosion resistance after painting was evaluated based on the situational pressure of corrosion under the paint film in the area above the liquid level.

As a test liquid, use the commercially available Grapeful 7.)
x-su, tomato jeune, and milk were all used.

The evaluation results of the weldability test pieces and corrosion resistance test pieces cut out from the above sample materials A1 to A14 are shown in Table 1. The symbols for evaluating bath contact properties and post-painting corrosion resistance in Table 1 are as shown in Tables 2 and 3, respectively.

Regarding the comparative materials &6 to 14 shown in Table 1, the numerical values that do not satisfy the limiting requirements according to the present invention are all marked with f underline [7], but as shown in Table 1, /? The weldability and corrosion resistance after painting of the finished steel sheet specimens of the present invention, which satisfy all the limiting requirements of the present invention, are
Nos. 1 to 5, for example, compared to the comparative example of sample &11 made of #25 tin, even though the tin weight was 173 or less, the iron-
The surface structure has a multi-layer structure consisting of a first layer made of a nickel alloy, a uniform, non-pole-free second layer made of an iron-tin-nickel alloy, and a third layer treated with a controlled amount of chromate, making it easy to weld and paint. This shows that both the corrosion resistance and the subsequent corrosion resistance are excellent.

In contrast, the comparative examples that do not satisfy at least one of the limiting requirements of the present invention are inferior to the examples of the present invention in either weldability or corrosion resistance.

j", 'j41: So, (as is clear from the examples, electricity according to the present invention) 1 (surface treatment for anti-bath agitation i! 1! Steel plate is
A first layer consisting of iron and gold is formed on the steel plate, and tin plating is applied on top of it.Group 1. A second layer is formed by molten tin treatment using Bisha, and a third layer of chromate film is formed on the second layer by electrolytic chromate treatment (a multilayer surface structure is formed in step 7 [7, and the third layer is formed by electrolytic chromate treatment). Because we have strictly controlled the composition of the first layer and the adhesion of the second and third layers, its weldability and corrosion resistance after painting are extremely excellent, and the adhesion of the paint film is also excellent, making it a genuine product. The inventors were able to provide a surface-treated steel sheet for bath cans that satisfies all of the above-mentioned requirements for materials for welded cans.

[Brief explanation of the drawing]

FIG. 1 is a region diagram showing the influence of the amount of chromium in the gold part in the chromate film and the amount of chromium equivalent of chromium water-retaining oxide on weldability and paint corrosion resistance. Agent Patent Attorney Takeo Nakamichi

Claims (1)

[Claims] (i) Ni/(Fe+Ni
)=thickness 11 with a composition ranging from 0.02 to 0.50
forming a first layer consisting of an iron-nickel alloy with a hardness of 0 to 5,000; after applying tin plating in a range of 01 to 12/r11' on the first layer, a hot tin treatment is carried out; a step of forming a second layer on the second layer by electrolytic chromate treatment, and a step of forming a third layer consisting of metal chloride and chromium water-containing oxide on the second layer? In the method for producing a surface-treated steel sheet for welding resistance, the amount of metal chromium x (q/m') in the third layer and the amount of chromium hydroxide t11 Y <"f/rr?)'lf: Manufacturing method for electrical resistance bath surface treatment 6i111, which is limited to the following range.