WO1989008730A1

WO1989008730A1 - PROCESS FOR PRODUCING Zn-Ni ALLOY-PLATED STEEL SHEET HAVING EXCELLENT PRESS MOLDABILITY

Info

Publication number: WO1989008730A1
Application number: PCT/JP1989/000276
Authority: WO
Inventors: Ryoichi; Muko; Kazuo; Mochizuki; Hajime; Kimura; Toshio; Ichida
Original assignee: Kawasaki Steel Corporation
Priority date: 1988-03-16
Filing date: 1989-03-15
Publication date: 1989-09-21
Also published as: EP0364596B1; EP0364596A1; CA1338621C; JPH0535234B2; DE68925858T2; EP0364596A4; JPH01234592A; DE68925858D1

Abstract

A Zn-Ni alloy-plated steel sheet having stable moldability is produced by subjecting the plated surface of a Zn-Ni alloy (Ni content: 10 to 17 wt.%)-plated steel sheet to dipping, spraying or anodizing using a solution containing one or both of H2?PO4??- and HPO4??2-.

Description

Description Name of Invention

Method of manufacturing Zn-Ni alloy-coated steel sheet with excellent breathability

More particularly, the present invention relates to a method for producing a Zn—Ni alloy with excellent breathability. Background art

Zn-Ni alloy-plated steel sheets have a corrosion resistance of 5 to 10 times that of Zn-plated steel sheets with the same amount of adhesion. Prevention of premature corrosion of automobile body by the use of steel sheets The usage of steel sheets has increased, and the parts to be used have been changed from front-end to front-end bridges and bridges. It has spread to a wide variety of people. The steel plate used is a single-sided steel plate with the aim of providing a protective effect (a perforation-preventing effect) in areas where the paint is not sufficiently distributed, such as the inner surface of an automobile body in the early days. As a result, the steel sheet has been shifting to double-sided steel sheets with the aim of improving the corrosion resistance (prevention of the outer surface) after peeling off the paint film after splashing pebbles etc. on the outer surface of the car body. is there.

In making this Zn-Ni alloy-plated steel plate double-sided,-the double-sided plate requires different properties from the single-sided plate. 'One of them is breathability.

Considering the above-mentioned purpose of use of single-sided steel sheet, the plating surface often becomes the inside of the bonnet during breath processing, in other words, the extended surface becomes the overhang surface during blessing. The effect on the brace formability of the plating surface was small.

However, in the case of double-sided steel plates, the plating surface became the overhanging surface during breathing, and the friction of the plating surface itself became a problem. Of course, the use of high-viscosity breathing oil during press processing makes brazing work difficult, but in reality it is degreasing by the user. To make painting easier, apply low-viscosity oil-proof oil to the steel sheet. -Each user performs breath processing with this oil. The metal plate needs to have good workability with this oil.

As a method for improving the breathability of a Zn-Ni alloy, there is known a method of improving the formability of a Zn-Ni alloy as disclosed in Japanese Patent Application Laid-Open No. Sho 60-141894. There is a method to increase the Ni content in the upper layer by turning the layer into two layers.

This method makes use of the bounding of the upper Z η — Ni layer. In the case where a large number of samples are improperly formed, the separated powder adheres to the mold of the breath, so that it is difficult to form a large number of samples. It is not practical because it causes Disclosure of the invention

The invention of wood is intended to solve the problem of press formability reduction based on the frictional resistance of the plated surface of a Zn-Ni alloy-plated steel sheet. The purpose of the present invention is to improve the press formability without accompanying the coating layer.

That is, according to the first aspect of the present invention, Z n surface N i content of 1 0 ~ 1 7 wt% of the steel sheet - N i alloys dark-out alms, after mow and H ₂ P0 ₄ - , Z n excellent breath formability characterized that you immersing the dark-out surface with a solution containing both one or the the HP 0 ₄ ² _ i O emissions - one Me n i alloy A method for manufacturing a steel sheet is provided.

According to a second aspect of the present invention, Z n of N i content on the surface of the steel sheet 1 0 ~ 1 7 wt% - N i alloys dark-out alms, H ₂ P0 ₄ and thereafter -, HP0 ₄ Breath formability characterized by spraying the surface with a solution containing one or both of ² -ions .

According to a third aspect of the present invention, there is provided a steel sheet having a Ni—Ni alloy having a Ni content of 10 to 17 wt%. Z n - applying-out n i alloy _{_{dark, H 2 P 0 HP 0 4}} 2 thereafter - Breath characterized that you anodizing the dark-out surfaces and have甩a solution containing one or both of the ions A method for producing a ηη-Ni alloy-plated steel sheet having excellent formability is provided. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a graph of LDR showing the effect of the present invention after immersion treatment.

FIG. 2 is a graph showing the change in LDR after the immersion treatment. Fig. 3 is a graph showing a comparison of LDR between the Zn-Ni alloy-plated sheet and the cold-rolled sheet.

Fig. 4 is a schematic diagram of a cylindrical deep drawing tester.

Fig. 5 is a schematic diagram of a sliding resistance tester.

FIG. 6 is a diagram showing a difference in sliding resistance between a Zn-Ni alloy-plated plate and a cold-rolled plate. BEST MODE FOR CARRYING OUT THE INVENTION

First, the process leading to the present invention will be described.

Figure 3 shows the difficulty of breathability of cold-rolled sheet, single-sided Zn-Ni alloy-plated steel sheet, and double-sided Zn-Ni alloy-plated steel sheet. ). The critical drawing ratio is determined by changing the blank diameter between 60 and 80 mmø using a cylindrical deep drawing tester as shown in Fig. 4 and using a punch to break the plate. It was measured by taking the ratio of diameter to blank diameter. In this test, the steel sheet with a single-sided Zn-Ni alloy was tested so that the cold-rolled surface was on the overhanging side. The oil used was Duff 21 Oil Coat Z5 (trade name), a fire protection oil manufactured by Idemitsu Kosan Co., Ltd. The steel sheet grade was used to observe only the effect of the plating layer. Is constant (equivalent to SPCC). The basis weight per one side of the plating layer was 30 g Zm ² , and the Ni content was 12.5%.

As is apparent from this figure, the LDR of the double-sided plate is smaller than that of the cold-rolled plate, and the formability is several steps worse. Since the plated steel sheet is an alternative to cold-rolled sheet, it is pressed with a press type designed for cold-rolled sheet, but it is designed especially on the assumption that ultra-deep drawn steel sheet is used. In the breath type, the plate was broken and broken.

Next, the LDR with the lower plating is affected by the friction of the plating surface. Therefore, the abrasion resistance of the surface of the plating-plate was determined from a dynamic resistance test. Figure 5 shows the shape of the test machine used. This tester pulls the sample at a constant speed across the sample, and evaluates the magnitude of the frictional force on the surface based on the magnitude of the load required at that time. The test was performed without oil coating. Figure 6 shows the test results.

? As is clear from this figure, the difference in surface friction between the rolled sheet and the plated sheet seems to have affected the formability.

Next, as a result of intensive studies to elucidate the factors that control the friction coefficient of the plated surface of the Zn-Ni alloy-plated steel sheet, the following was found.

① Press formability changes when the outermost surface of the plating layer is changed.

② There is no noticeable deterioration in the quality of the cold rolled sheet due to plating.

A result of extensive studies to focus suggested et al Of this Chi ①, Z n - N i dark-out surface of the _{_{H 2 P 0 4 -, HP}} 0 4 2 - immersion treatment using a solution containing one or both of Ion It was found that the breathability was significantly improved. Figure 1 shows the change in LDR when the Zn-Ni alloy-plated plate was immersed in the following solution for 4 seconds. The basis weight per side of the plate used was 30 gm Ni, the content was 12.5%, and the type used was SPCC.

Processing liquid

Liquid temperature 60 t:

P H 5.8

It can be seen that the treatment with this solution increases the LDR.Glow discharge analysis (GDS) shows that there is a P beak on the surface of the plate after immersion. It is known that the lubricating property is improved by the P on the surface to be welded, and that the breathability is improved.

Although the present invention has been constructed based on the above findings, a more specific structure will be described below.

Solution used for the immersion process H ₂ P0 ₄ - I on-, HP0 ₄ ² - may be either including hand or both I on-.

Also, the concentration and temperature of this solution are not limited, but some effects take time because of the immersion treatment.In order to obtain a quick effect, it is preferable to increase the temperature 'concentration for industrial production. Suitable Was 1 0: soaking temperature ho in a short time processing of the sub-second is 4 0- ^e C or more, the concentration of Hitasai liquid H ₂ P0 ₄ - and HP0 ₄ ² _ a total of 1 O 0 g Roh or preferred - 0

Also, the metal plate used should have a Ni content of 10 to 17 wt%, preferably 11 to 15%. At less than 10%, this treatment method has no effect, and at more than 17%, the Zn—N i plating layer is apt to cause powdering, and is therefore an object of the present invention. The Ni content of the Zn-Ni alloy-coated steel sheet is limited to 10 to 17 wt%. In order to further improve the corrosion resistance, Co, Fe, Cr, Cu, Mn, AJ £, and the like are added to the plating alloy layer of the present invention in order to further improve the corrosion resistance. Does not detract from the spirit of the present invention.

The pH of the solution is preferably from 4 to about I0. If the value is less than 4, the dissolution of Zn particularly in the plating layer becomes severe, and the amount of adhesion of the plating decreases greatly, which is not practical.If the value exceeds 10, the effect of improving the breathability is lost. The pH of the solution was limited to 4-10.

The positive ion contained in the liquid used is more electric than K +, Na ⁺ , Mg ^{2 +} , Ca ² \ NH ₄ ⁺ , and AJ £ ^{3 +} Zn and Ni. It should be chemically low. The reason is that when the plating plate is immersed in a liquid containing metal ions, it is electrochemically more active than Zn and Ni. This is because the noble metal may cause a substitution reaction with Z η and Ν i and precipitate on the plating surface, resulting in deterioration of the appearance.

The amount of P adhered to the plating surface is preferably 0.1 to 5 mg / m ^{2 in} terms of P. 0. 1 mg Roh m ho effect in less than ² rather than name, 5 mg / m ² had more than in rather than to preferred because you deterioration chemical conversion treatability

HP0 ₄ ² - and or H ₂ P0 ₄ - process that by the solution containing may be a spray process by addition to the solution of the above immersion treatment. The conditions at this time should be almost the same as those obtained by immersion treatment.

In addition, in order to improve the breathability of the Zn-Ni alloy-plated steel sheet, anodic treatment may be performed in the above solution in addition to dipping and spraying. Is an anodized conditions, it is l OO c / dm ² or less. in l OO c Z when dm ² a exceeds the Ki one because layers Ku is because dissolution of Z n is Naru rather large.

Example

Table 1 also shows the test steel sheets, their mounting conditions, immersion conditions, and breath formability expressed by LDR. The lubricating oil used in all cases was Daphne Oil Coat Z5 (trade name) manufactured by Idemitsu Kosan Co., Ltd., which is used as a protective oil. FIG. 2 shows the LDR values of Example 1 and Comparative Examples 1 and 2 to further clarify the effects of the present invention.

Table 2 shows examples of spraying and anodizing. It can be seen that, similarly to the above-mentioned immersion treatment, a Zn-Ni-alloy-plated steel sheet having stable breathability can be obtained by these treatments.

1 (Part 1)

FF, test plate immersion liquid

± \ ± Steel grade Ni content Coating amount Liquid type / concentration PH Liquid temperature Immersion LDR

Rate (%) (g / m ² ) Time Example 1 SPCC 11.5 30 NaH ₂ P0 ₄ 350 / j2 4,3 60 4s 2.2 Comparative example 1 SPCC 11.5 30 1 _ 1.75 Comparative example ϊ SPCC ― ― 1 1 1 ― 2.2 Example 2 SPCC 11.5 30 NaH ₂ --aP0 ₄ 100 g / jZ 4,8 35 10s 1.9 Example 3 SPCC 11.5 30 NaH ₂ P0 ₄ 100 g / j2 4.8 3δ 60s 2.1 Example 4 SPCC 12.5 30 NaH ₂ P0 ₄ 150 g / j2 4,6 35 10s 2.0 'cpr r ^

Example 5 A A

Or Z 3 ΰU Ι αΠ2 U4 0 UU 5 / .DU 2.2 Example 6 SPCC 13.4 30 NaH ₂ P0 ₄ 250 § / J2 5.8 60 4s 2.2 Example 7 SPCC 10.5 30 NaH ₂ P0 ₄ 250 g / j2 5.8 60 4s 2.2 Example δ SPCC 14.8 30 NaH ₂ P0 ₄ 100 § / J2 6.6 60 4s 2.2

SPCC 16.5 30 K2HPO4 350 g / j £ 9.1 60 4s η?

L. L Comparative Example 3 SPCC 9.5 30 6.6 60 4s 1.75 Comparative Example 4 SPCC 9.5 30 1.75 Comparative Example 5 SPCC 12.5 30 1.75 Comparative Example 6 SPCC 13.4 30 1.81

5 o

PCT / JP89 / 6

12

1 (Part2) 0 5

0

Two

Industrial applicability

Ri by the present invention, HP0 ₄ 2 - and Noma other solution thus Z n comprising _ H ₂ PG ₄ - dipping a plating-out surface of the N i alloy dark-out steel sheet subtilis - Les first processing or anodization By doing,

(1) The breathability of a steel sheet with a Zn-Ni alloy is improved to the same level as that of a cold-rolled sheet, and breakage during breathing is eliminated.

(2) Since the same breath formability is exhibited at any Ni content in the Ni content range of 10 to 17%, it may be caused by fluctuations in the plating bath composition or line speed. There is no variation in brass workability due to variations in the layer composition.

For example, it is possible to manufacture Zn-Ni alloy steel sheets with stable formability, which has great industrial value.

Claims

The scope of the claims

(1) N i content on the surface of the steel sheet Z n of 1 0 ~ 1 7 wt% - applying-out N i alloy dark, H ₂ P0 ₄ and thereafter -, HP 0 ₄ ² - Lee on-one A method for producing a Zn—Ni alloy-plated steel sheet having excellent breathability, characterized by immersing the plated surface using a solution containing one or both of them.

(2) N i content on the surface of the steel sheet 1 0 ~ 1 7 wt% of Z n - applying-out N i alloy dark, H ₂ P0 ₄ _ Thereafter, HP0 ₄ ² - hand Lee on- A method for producing a Zn—Ni alloy-plated steel sheet excellent in breathability, characterized by spraying the plated surface with a solution containing both.

(3) N i content on the surface of the steel sheet of 1 0 ~ 1 7 wt% Z n - N i alloys dark-out alms, H ₂ P0 ₄ and thereafter -, HP0 ₄ ² - hand Lee on- A method for producing a Zn—Ni alloy-plated steel sheet having excellent breathability, characterized by anodizing the surface with a solution containing both.