JP3204156B2 - High lubrication rust-proof steel plate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pickled steel sheet among hot-rolled steel sheets, and has a high lubricating property, is excellent in press working, and has a good rust prevention property. About.

[0002]

2. Description of the Related Art A normal pickled steel sheet is a hot-rolled steel sheet which is pickled (generally treated with hydrochloric acid) to remove the scale. Rolled or stacked in a stack and shipped to users such as car manufacturers.

[0003] The rust preventive oil applied by a steel maker generally has not only a sufficient rust preventive property even during long-term storage, but also a good handleability of other steel sheets and a good degreasing property. Performance such as not hindering processability and weldability is required. In order to satisfy these required performances, a low-viscosity rust-preventive oil having a kinematic viscosity at 40 ° C. of 25 cSt or less is usually used.

[0004] A steel sheet is processed by a user by combining various press moldings such as punching, bending, overhanging, and drawing. At the time of this press working, the kinematic viscosity at 40 ° C. is 50 to 10
The press working is performed by applying a medium / high viscosity press working oil of about 0 cSt. Further, in order to avoid the trouble of applying press working oil during press working, a solid lubricant (for example, mill bond) is applied to a steel sheet using a roll coater or the like.
After coating, the surface is coated with rust-preventive oil and shipped, and the user presses without applying or with a very small amount of press working oil.

[0005] In the case of pickled steel sheets having a thickness greater than that of cold-rolled steel sheets, the surface pressure during press forming is increased, and as a result, there is a problem that galling easily occurs. Application of the agent was necessary. In the case of a high-strength steel sheet, in particular, galling tends to be a problem.

[0006]

In recent years, rust-preventive oils applied to users in the automobile industry and the like are provided with a lubricating property of a press working oil so that a solid lubricant can be omitted. Development of lubricating rust preventive oil is an important issue.

However, if the viscosity of the rust-preventive oil is made as high as that of press working oil, the degreasing property and the handling property of the steel sheet are deteriorated, which is not suitable. In addition, sufficient lubricity cannot be obtained only by increasing the viscosity. Furthermore, in order to enhance lubricity, it is conceivable to add a general extreme pressure additive to the rust preventive oil. However, extreme pressure additives of this type are very reactive and thus significantly reduce rust resistance. For example, the moisture in the air reacts with the extreme pressure additive to generate an acidic substance, resulting in rust, oil stain, and discoloration of the plate surface.

On the other hand, if the viscosity of the press working oil is as low as that of the rust preventive oil, the oil film is broken during the press working, and the working surface is frequently broken due to cracks, galling and other damages.
In the case of a thick pickled steel sheet having a thickness of about 1 to 8 mm, the surface pressure during press forming is increased, and as a result, there is a problem that galling is particularly likely to occur. Prone to problems.

As described above, it is not possible to satisfy both the rust prevention property and the press workability with either the conventional rust preventive oil or press working oil. In particular, in the case of pickled steel sheet which has a high surface pressure at the time of working and is liable to generate galling, it was practically impossible.

For example, JP-A-51-87461 discloses that a pickled steel sheet is coated with a specific component of a lubricating rust-preventive oil and dried to obtain rust-preventive properties, press workability (evaluated by Er value), and detergency. A good anti-rust lubricated surface-treated steel sheet is disclosed in Japanese Patent Application Laid-Open No. 58-136.
Japanese Patent Publication No. 98 discloses a lubricated steel sheet which is coated with a specific amount of a lubricating rust-preventive oil of a specific component and has excellent intermediate rust prevention properties.
However, even with these techniques, high lubricating performance that does not allow the elimination of a solid lubricant cannot be achieved, and there has been a problem that galling failure often occurs at the time of press working of a pickled steel sheet.

Therefore, the present invention has high lubricity, is excellent in press workability, and has excellent rust prevention by coating by the same working method as before, without impairing the efficiency and workability of pickling. An object of the present invention is to provide a good lubricating and rust-prevention treated steel sheet.

[0012]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, the base oil of the lubricating rust-preventive oil for pickled steel sheets has been improved with a rust-preventive additive. That high lubricity can be imparted without impairing rust prevention by combining and compounding an agent and an extreme pressure improver,
Furthermore, it has been found that an extremely high lubricating performance can be imparted by optimizing the surface roughness of the pickled steel sheet, and the present invention has been completed.

That is, the present invention relates to a base oil comprising (a) 1 to 20% by weight of a rust preventive additive, and (b) overbased calcium sulfonate having a calcium content of 0.5% by weight or more,
(C) The sulfur content of sulfurized fats and oils or sulfurized esters is 0.1%.
25% by weight or more and (d) 0.15% by weight or more of potassium borate as a boron content, and a highly lubricating rust-preventive oil having a viscosity of 30 mm ² / s or less at 40 ° C. An object of the present invention is to provide a highly lubricated rust-proof steel sheet coated on the surface of a pickled steel sheet having an Ra of 0.5 to 2.5 μm.

[0014]

Embodiments of the present invention will be described below in detail.

In the present invention, the pickled steel sheet is 0.5 to
It has a surface roughness Ra of 2.5 μm. If the surface roughness is extremely small, there is a problem that galling occurs during press forming. Therefore, Ra is 0.
It is necessary that the thickness be 5 μm or more. However, if the surface roughness becomes too rough, the coefficient of friction (evaluated by a plane sliding test)
Increases, causing cracks due to insufficient lubrication and deteriorating press formability. Therefore, the upper limit of Ra is 2.5 μm
The upper limit of Ra is preferably 1.5 μm.

In the present invention, the highly lubricating rust-preventive oil applied to the pickled steel sheet comprises (a) a rust-preventive additive, (b) an overbased calcium sulfonate, (c) a sulfurized oil or a sulfurized ester. , (D) potassium borate is added at a specific ratio, and the viscosity at 40 ° C. is 30 mm ² / s
Adjusted below.

The base oil of this highly lubricated rust-preventive oil is 40 ° C.
Mineral oil or fats and oils in viscosity is 1 to 100 mm ² / s, synthetic oil, it is preferable to use one or more of the mixture of ester oil.

As the rust preventive additive (a) to be added to the base oil, known rust preventive additives such as metal soaps, esters and metal sulfonates can be used. Of these, oxidized wax derivatives and metal sulfonates are preferred.

The rust-preventive additive (a) is selected from the group consisting of
-20% by weight, preferably 2-10% by weight.

Overbased calcium sulfonate (b)
It is preferable to use an overbased calcium sulfonate having a base number of 300 or more. Examples of such calcium sulfonates include Ca salts of various sulfonic acids such as aromatic petroleum sulfonic acids, alkyl sulfonic acids, and aryl sulfonic acids.

Overbased calcium sulfonate (b)
Is 0.5% by weight of calcium in highly lubricated rust-preventive oil
At the above ratio, preferably 0.5 to 4.0% by weight, more preferably 0.6 to 2.2% by weight.

The sulfurized fat or oil or the sulfurized ester (c) is obtained by adding sulfur to the fat or oil or the ester, and desirably has a sulfur content of 8 to 15% by weight.
Sulfur may be active or inactive. Examples of sulfurized oils and fats include sulfurized whale oil, sulfurized lard, sulfurized rapeseed oil, sulfurized castor oil, sulfurized soybean oil, sulfurized rice bran oil, and the like, and sulfurized esters such as methyl oleate.

The sulfurized fat or oil or the sulfurized ester (c) is blended in a high lubricating rust preventive oil at a sulfur content of 0.25% by weight or more, preferably 2.4% by weight or less.

The potassium borate (d) can be added to the base oil in the form of a dispersion. Such a potassium borate dispersion is obtained by treating potassium borate with an amine soap or the like so that it can be dispersed in oil. For example, OLOA97
50 (manufactured by Chevron Chemical Co.) can be used.

Potassium borate (d) is used in an amount of 0.15% by weight or more as a boron content, preferably 0.15% by weight.
1.0% by weight, more preferably 0.2 to 0.7% by weight
In the proportion of

The viscosity of the final products of high lubricity rust-preventive oil in the present invention is 30mm ² / s (40 ℃) or less, preferably in the range of ^{10~25mm 2 / s (40 ℃)} . If the kinematic viscosity at 40 ° C. is lower than 10 cSt, the oil film breaks during press working, and cracks and galling due to insufficient lubrication occur.
If the kinematic viscosity is higher than 25 cSt, the handleability of the steel sheet becomes poor, and the degreasing property also decreases, which is not preferable.

[0027]

EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to these examples.

An oil composition having the composition shown in Table 1 below was prepared.
Each of the lubricity evaluations and the evaluation of solubility, rust prevention and degreasing were performed. The results are shown in Table 1. For comparison, results for an acrylic resin coat (solid lubricant) and a chlorine-based press oil are also shown.

(1) Specimen A low-carbon Al-killed steel sheet having a thickness of 2.6 mm was subjected to hydrochloric acid pickling treatment (SPHC, 70 × 100 mm, surface roughness Ra =
1.0-1.5 μm).

(2) Lubricity test (i) Plane sliding test Plane-plane pressing and pulling sliding test. The test piece was sandwiched between a flat die and a flat die, a pressing load was applied, and the test piece was pulled out at a constant speed for evaluation.

Conditions Die: flat, SKD-11 Pressing surface: 12 × 25 mm Pressing force: 240, 480, 720 kgf Pulling speed: 200 mm / min Sliding distance: 140 mm Evaluation item: 70 to 140 mm Average friction coefficient when sliding (Ii) Bead pull-out test Press-pull pull-out sliding test of plane-3R bead. The test piece was sandwiched between a flat die and a bead at the tip 3R, a pressing load was applied, and the test piece was pulled out at a constant speed and evaluated.

Conditions Die: flat, SKD-11 Bead: tip 3R, SKD-11 Pressing force: 250, 500, 750, 1000 kgf Pulling speed: 200 mm / min Sliding distance: 140 mm Evaluation item: 70-140 mm sliding Average friction coefficient of

(3) Solubility test The lubricating oil composition was heated and melted at 50 ° C., and left standing at room temperature for 24 hours to evaluate.

：: No fogging or precipitation Δ: Slight fogging or precipitation occurs.

(4) Rust Prevention Test A salt water spray test was performed for 24 hours in accordance with JIS K-2246.

(5) Degreasing test After applying the lubricating composition to a cold-rolled steel sheet, the oil was drained at room temperature for 24 hours, and the degreasing liquid (Surf Cleaner SD) was heated to 40 ° C.
The test piece was immersed in 400% (2% by weight aqueous solution of Nippon Paint Co., Ltd.) for 2 minutes, washed with water, and after 10 seconds, evaluated by the water wet area (%) of the test piece surface.

[0037]

[Table 1]

In Table 1: 1) Base oil: each having a viscosity at 40 ° C. of 4 mm ² / s
And a mixture of paraffinic mineral oil of 32 mm ² / s 2) Rust preventive additive A: oxidized wax metal soap type 3) Rust preventive additive B: barium sulfonate 4) Additive C: calcium sulfonate (base number: 50)
5) Additive D: sulfurized fat (sulfur content: 10% by weight) 6) Additive E: potassium borate dispersion OLOA 9750
(Manufactured by Chevron Chemical Co.).

Table 2 below shows the results of evaluating the correlation between the surface roughness of the pickled steel sheet and the following flat sliding test and galling test using the highly lubricating rust-preventive oil of Example 1.

(1) Flat sliding test A steel plate (SPHC, 30 × 200 mm, surface roughness Ra = 0.4 to 2.2 mm) obtained by subjecting a low-carbon Al-killed steel having a thickness of 1.2 to 3.2 mm to a hydrochloric acid pickling treatment. 6 μm), and the test was performed under the following conditions, and the friction coefficient was evaluated at the following level.

(Test conditions) Tool conditions (width 10 mm x length 3 mm); pressing force: 2
00kgf; Sliding speed: 1m / min; Sliding distance: 150m
m; oiling amount: 1.5 g / m2.

(Evaluation Criteria) Rating Friction coefficient μA: 0.130 or less B: 0.130 or less, 0.140 or less C: 0.140 or less, 0.150 or less D: 0.150 or less

(2) Galling test A steel plate (SPHC, 30 × 250 mm, surface roughness Ra = 0.4 to 2.6 μm) obtained by subjecting a low-carbon Al-killed steel having a thickness of 1.2 to 3.2 mm to a hydrochloric acid pickling treatment. The test was carried out under the following conditions, and evaluation was performed at the following level by the limit pressing load at which galling occurred.

(Test conditions) Tool: flat tool (width 50 mm × length 30 mm); pressing bead: triangular bead (tip R = 0.5 mm); pressing load: 0.5 to 1.5 tons; sliding speed: 200mm /
Min; sliding distance 150 mm; oiling amount: 1.5 g / m ² .

(Evaluation Criteria) Rating Critical pressing load for torsion (ton) A: 1.0 ton or more B: 0.8 ton or more, less than 1.0 ton C: 0.6 ton or more, less than 0.8 ton D: Less than 0.6 tons.

[0046]

[Table 2]

[0047]

As is clear from the results of the above examples, the highly lubricated rust-prevented steel sheet of the present invention has high lubricity, excellent press workability, and good rust prevention. . For this reason, it is possible to omit the solid lubricant conventionally used in the pickled steel sheet, and it is very useful in industry.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification code FI C10M 135: 06 139: 00) C10N 30:12 (72) Inventor Yuji Yamazaki 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nippon Kokan (56) References JP-A-5-339589 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C23F 11/00 C10M 163/00

Claims (1)

(57) [Claims] 1. A base oil comprising (a) 1 to 20% by weight of a rust preventive additive, (b) 0.5% by weight or more of calcium based on overbased calcium sulfonate, and (c) sulfurized fat or oil. 0.25% by weight or more of ester as sulfur,
(D) 0.15% by weight of potassium borate as boron content
30 mm ^{2 at} 40 ° C.
A highly lubricated rust-resistant steel sheet obtained by applying a highly lubricated rust-preventive oil having a viscosity of not more than / s to the surface of a pickled steel sheet having a surface roughness Ra of 0.5 to 2.5 μm.