JPS5952645A - Welding painted steel plate having excellent powdering-resisting property - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The invention relates to a thick-rich weldable coated steel sheet that causes less powdering during processing such as press working.

In recent years, in the case of automobile bodies, areas that require corrosion protection, such as the undercarriage and doors, are coated with a chromate-based coating on cold-rolled steel sheets.
A coated steel plate with zinc-rich paint that is weldable is used.
Film A only contains zinc powder, and its corrosion resistance is superior to that of 114 galvanized steel sheet and electrogalvanized steel sheet. However, the zinc clench film has the disadvantage that it contains a large amount (usually 80 ifS, i% or more) of zinc powder Y, which causes powdering during press processing.

The object of the present invention is to provide a zinc clinch weldable coated steel sheet that has improved the powdering problem of the zinc clinch coating.

The invention is to improve the powdering resistance of a zinc clinch coating film containing a high content of zinc powder. Corrosion resistance has also been improved.Based on the knowledge of T-roto, the gist is that zinc powder and zinc-magnesium base metal powder are coated with a chromate-based coating on a uniquely roughened steel plate. A zinc clinch film containing 1% or more of 4601 ml is formed at this point.

Detailed description of the present invention 'T'b below.

Schematically, the coated steel sheet of the present invention has a chromate-based film 2 formed on the surface of the steel sheet 1, as shown in the attached drawing.
, and further thereon, a zinc clinch coating film 5 containing zinc powder 3 and zinc-magnesium base metal powder 4 is formed in the shape 11i′i.
, 3 is T-komono.

As the steel plate 1, a cold-rolled steel plate is usually used, but a steel plate with the first side roughened is used. This increases the amount of chromate film 2 deposited and improves corrosion resistance. Furthermore, it is intended to impart effects and stiffness to the zinc-rich coating film 5.For this different surface roughening, an average surface texture Rz of 4 to 20μ is appropriate.4μ.
7. If it is unfinished, as mentioned above. C effect cannot be obtained, 20μ
If it exceeds the surface roughness, the coating film surface becomes rough and the corrosion resistance becomes low IS1.
Let's get up.

Chromate-based film 2-striped reaction type [+mate treatment (for example, chromic acid alone; entinction to 5rL).

agent ytβ≦addition 1. There are two types of chromate treatment: No-rinse coating type chromate treatment, and other well-known chromate treatments such as No-Rinse Chromate Treatment.

However, after various inspections and examinations, we found that QI cloth-type creamate treatment with the composition shown above provides corrosion protection, nl l! I like it a lot better.

Treatment liquid 1 (ah 40-50% or irritable in trivalent state (・
10 parts by weight (b) Phosphoric acid (100% H3P04) 3-4 ht
Part (C) Polyacrylic acid 4 to 5 layers (dl 7
Krill construction/base solid content 17-20%, 200-4,000% water soluble
m1t amount part treatment liquid 2 Depending on the composition of the treatment liquid 1, the chromium trifluoride in (a) is reduced to a trivalent state of 61 chromium or 61 chromium, and hexavalent chromium 1 Law/3 The ratio of both chromium amounts is O ~ 2,
The processing liquid has become 3.

Uninvented place soup with a mate film 2? The total chromium content in the film is controlled by the total amount of chromium contained in the film.

Is this l U mf/n? If it is less than this, the corrosion resistance will be poor and the adhesion of the coating film will not be stable, making it impossible to always obtain good adhesion. On the other hand, 5 (l
Nf/n? ``*: Exceeding Φ improves corrosion resistance, but decreases coating film density and causes peeling and tearing during dance processing.

Zinc clinch coating film 5 is produced by adding zinc-magnesium alloy powder to a conventional zinc clinch coating film containing only zinc powder, thereby reducing the roughness during processing.

Improved corrosion resistance and anti-corrosion properties! :1 powder, the mixing ratio of meat powder is Zn powder/Zr1- Mg base metal powder-5
o15U~98/2. Addition amount of zinc-magnesium alloy powder to zinc powder, upper limit χ50%
This is because even if the content exceeds 50%, the effects of improving laddering properties and anticorrosion properties cannot be expected any further.

On the other hand, the lower limit was set at 2% because if it is less than 2%, there is no effect of adding it. .

If the content of zinc powder and zinc-magnesium@gold powder in zinc-rich coating film 5 is less than 60%, the conductivity will decrease and the electric weldability will be poor, so the content should be 60% or more. ^. [2 Resilience exceeds 91% and processing resistance I・11^
1 to 91% or less because the sex is lowered.
Wow.

The resin for the coating film containing the meat powder has a molecular weight of 1-1.
00,000 linear epoxy system (e1 fat is similar to IJ7J, and is easy to work with).

If the coating film (dry coating) thickness is less than 5μ, the anticorrosion property will be poor, so if it is more than 5μ, it should not be used. If the resistance exceeds +-50μ, the conductivity will not be improved even if the surface assembly degree is increased, so make sure that it is less than 50μ. Corrosion resistance is insufficient, and even higher corrosion resistance is required
In the case of gold, it is also possible to add anti-rust pigments. Suitable rust-preventing pigments include Stro7'chiumuku'1 mate, di/Kukurome-1, f[佼calcium/sudo];
．． Also U) y, <o2~5 and b addition 1 tbsp. More than 5% ke 16j addition-f z,,) and from the Sai Rei translation song (i Ii
...The accumulation of chlorine, etc. becomes significant, and the anticorrosion effect becomes saturated, and the effect of increasing the amount of addition is small.

As mentioned above on the platform of ``Main Production'', the Zinguri tuna film contains zinc powder and zinc-magnesium base metal powder.
! The powder link resistance and anti-corrosion properties during machining are improved.''
．． 10I0 IEzuii1] ↑Bowtery/G1t1 Three prongs...
This is thought to be due to the fact that the hardness of the zinc-magnesium base metal powder is significantly higher than that of zinc. 1. In general, if the hardness of the powder during press processing is 1 ton, it is difficult to form the powder into the desired shape. Since the layer is a little gold, it is harder than zinc powder (in the case of zinc-magnesium base metal powder, there is less adhesion to the mold, and as a result, the powder link resistance improves 4). It will be done.

It is thought that the corrosion resistance is due to the anti-galvanic effect of zinc and gold on zinc-magnesium.

Magnesium is electrochemically more base than zinc, but when exposed to a dietary environment, stable I-island phagocytic products are produced and a galvanic effect is exerted on zinc. Therefore, the details are unclear), but it is presumed that the zinc-magnesium base metal also exhibits the same effects as magnesilano. This 1-piece zinc-magnesium base metal is included; It is considered a mental thing.

In the case of the invention, when the zinc-magnesium base powder is contained together with the zinc powder in the zinc-rich coating film 5, the powder link resistance and corrosion resistance are improved compared to the case where only the support powder is used. When anti-corrosion properties are determined, apply anti-rust pigments as described above.

The processing action of this rust-preventing pigment is similar to that of zinc-1-gnesium base metal powder, and in addition to the corrosion-preventing action of the rust-preventing pigment itself, it also has the action of suppressing the appearance of excessive zinc.

In the case of non-invention, the magnesium content of the zinc-magnesium base metal is not limited to 7%, but it is preferable to manufacture it on an industrial scale at 1 to 5% from the viewpoint of workability and quality. This is because when magnesium is added, the hardness increases rapidly as shown in FIG. 2, and an arbitrary amount of base metal can be used in relation to corrosion resistance.

Next, the effects of the present invention will be explained with reference to Examples.

Table 1 shows the dull skin pass with more unusual roughening (Rz=1
2μ) cold-rolled steel plate (thickness 0.8 rrrm) %-
Degrease and coat the surface with a film fit' 30 m? /rr?
(total amount of chromium), and then a film with a thickness of 15μ
Forming a zinc-rich coating film 1. This summarizes the coating film composition and performance of 7. The formation of the S chromate-based film and the zinc-rich coating film was carried out under the following conditions.

(1) Chromate film formation conditions: Chromium trioxide 1ON, 3M parts of acid, 5 parts by weight of polyacrylic acid, 18 parts by weight of acrylic emulsion N combined solids, 2000 parts of water, Cr+6/Cr
+3-L4 to 100ml chromate treatment liquid applied using roll coating method.

(2) Zinc clinch coating film formation After coating by Toji roll coating method, 60°C at 250'C (rice temperature)
Burns in seconds.

/ / 7/ / / / / / 7・′ The performance of the Mayu coating film was investigated in the following manner.

(tl) A bending test was carried out in accordance with the test method for colored galvanized iron plates in JIS-G 3312.The bending test was carried out with the number of sheets at an interval of 0 (0 turtle) on the inside of the bend, One sheet (It) and two sheets (2T) were bent and bent 180 degrees with a trowel.Cellotape was attached to the membrane (9), and then it was rapidly peeled off and peeled off according to the following standards ( (1 more rated) 1 71-99 1(2) mi
After cutting the J powdering test specimen into a blank diameter of 360+11111, apply rust-preventing lubricant (Oil Coat Z2, Yamamoto Kosan A)? Apply '71
-3001・/Hydraulic press machine with punch diameter of 200,
Punch Ri3wn, die R4m+n, aperture height -265
tm, a cylindrical deep drawing test was conducted with the painted surface facing outward under the conditions of a 22-ton wrinkle presser, and after the test, the die mold was filled with bamboo chips and 7C/< Udaan abrasive paper was used to remove the paper. It was evaluated visually and based on the following criteria.

(3) Cross-cant the anti-corrosion test piece with a knife in advance, and
180 degree close bending, 7 rows of 1 piece, and deep drawing test for powdering resistance, and 1 piece of paper was JIS@Z
Tested for 50.0 hours and 240 hours at -2371, respectively, and evaluated according to the following criteria. 4) Weldability After performing spot welding under the above welding conditions, a tensile test was conducted (・To investigate the incidence of tensile/shear strength JX less than 350Ayf. Direct bullet Pi less than 350Qf outbreak military part 1
As is clear from the table (even if the powder content is the same, those with zinc-magnesium powder have better electric weldability and corrosion resistance. Improve by adding.

As described above, according to the present invention, the powdering resistance of the zinc clinch type cavity steel sheet is improved, and the corrosion resistance is also improved accordingly.

[Brief explanation of drawings]

Fig. 1 is a schematic cross-sectional view of the uninvented mountain fold steel plate, Fig. 2 is a schematic cross-sectional view of Zn
- A graph showing the relationship between Mg absorption of Mg base metal and hard IY.
・)/). 1... Steel plate, 2... Chromate-based film, 3... Zinc powder, 4... 4-magnesilano base metal powder on Il[-S', 5... Zinc rich (rIl!, l!, patent Applicant date [Mitsui Steel Co., Ltd. Mitsui Kinzoku Kokuri Co., Ltd. Mitsuru Shindo Fig. 1 et al. Fig. 2 M9°10 Continued from page 1 0 Inventor Mr. Sanefuji - Funabashi type Kaishin 2-12-17 0 shots Author Yuki Kuyama 628-19 Hagidai-cho, Chiba City 0 Author 1556-4 Masuo, Hakuso-shi, Narabe 0 Author Juntabe Kobayashi 1-1-2 Sekino-cho, Koganei City 0 Applicant Mitsui Kinzoku Mining Co., Ltd. 2-1-1 Nihonbashi Muromachi, Chuo-ku, Tokyo

Claims (3)

[Claims] (1) Zinc powder and zinc-magnesium base metal powder Y, 6 are coated on a surface-roughened steel plate via a chromate-based film.
The zinc clinch coating film containing 0 MM% or more is type 5X,
A weldable painted steel sheet with excellent powdering resistance. (2) Zinc powder/zinc-magnesium base metal powder ratio is 5
0/50 to 98/2, and the total content of both in the coating film is 60 to 91% by weight. Weldable painted steel plate. (3) The refurbished weldable steel sheet with excellent powdering resistance as set forth in claim 1, characterized in that a rust preventive pigment is added to the sink lint coating film.