JPH0627358B2 - Coated steel and its manufacturing method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a cold-worked coated steel material and a method for producing the same.

[Background of the Invention]

Vehicles, home appliances and many other parts of machinery are produced by cold working. Since cold-worked parts form an active new surface by working, rusting during storage after working causes some problems. In order to prevent this, some kind of rustproofing treatment is applied. Generally, in order to prevent seizure during processing, a lubricating treatment film applied before processing remains on the surface after processing to obtain a rust preventive effect. Conventionally,
For this purpose, a phosphate coating treatment is used as a treatment method (see Japanese Patent Publication No. 57-19159). According to this method, since a thick phosphate film remains on the surface, rust resistance after processing is good. However, probably because the coating is too thick, when plating is performed, a step of completely removing the coating by pickling or the like is required, which complicates the subsequent steps.

On the other hand, steel materials such as steel materials, steel rods, and steel sheets are produced by hot rolling, but are usually shipped with a stable oxide film (scale) formed on the surface. However, these steel materials become useful parts by further performing plastic working such as press working, cold forging, and wire drawing. However, with conventional materials, first, the scale on the surface is removed by pickling, etc., and then pretreatment for lubrication and seizure prevention during processing is performed, and after that it is necessary to send it to the processing step. Become. Such pretreatment is complicated and requires dedicated equipment.

On the other hand, in recent years, there has been a tendency to ship with a rust-preventive and lubricious coating formed on the surface of the steel material in advance.
For example, JP-B-57-19159 mentioned above, by a treatment liquid prepared by mixing an aqueous solution or a water-dispersible resin in a phosphoric acid aqueous solution,
By immediately processing the steel material after hot rolling,
It is described that instead of an oxide film, a film having a high lubricity is formed and shipped in that state. However, this treatment is complicated because the temperature of the steel material becomes high during cold working, the resin used is charred, the appearance is extremely deteriorated, and a film removing step is finally required.

[Object of the Invention]

An object of the present invention is to provide a coated steel material which does not require a pretreatment such as coating removal prior to working and plating, and a method for producing the same.

[Outline of Invention]

The gist of the present invention for achieving the above object is to provide the following formulas (I) to (II
I) (RO) _m -P (OH) _3-m (I) (Wherein R is selected from a saturated or unsaturated hydrocarbon group having 1 to 8 carbon atoms, a phenyl group and an alkylphenyl group, and m is 1 or 2), and one or more acidic phosphoric acid ester, and A coated steel material is characterized in that it is coated with a reaction product of cold working of condensed phosphoric acid and a steel material component.

Furthermore, a base medium containing one or more of the acidic phosphoric acid esters represented by the above formulas (I), (II) and (III) and condensed phosphoric acid is applied to the surface of the steel material and cold worked. It is in the method of manufacturing steel.

As the condensed phosphoric acid, the following formula (IV) or (V) H _{n + 2} P _n O _{3n + 1} (IV) (where n is an integer of 1 to 6) H ₁ P ₁ O _3l (( V) (provided that 1 represents an integer of 1 to 8).

One aspect of the present invention is achieved as follows. That is, a liquid lubricant containing one or more of the phosphorus compounds represented by the above general formula as a component is applied to the surface of the steel material before being worked and deformed. It is easily conceivable that the coating film containing phosphorus has the rust preventive ability from the examples of the phosphate coating treatment, but it is generally said that plating inhibition is caused.

There are various possible causes for the inhibition of the plating, but the electrical properties on the surface of the coated product often obstruct the plating process. It is thought that such obstacles can be eliminated if the coating is sufficiently thin, and it has been found that the object of the present invention can be better achieved by leaving the coating having a high rust preventive property to the minimum necessary amount. Unlike the conventional method, a film is formed on the surface of a processed product in the process of processing, without adopting a method of previously forming a film and processing. The object of the present invention can be sufficiently achieved if the acidic phosphoric acid ester and condensed phosphoric acid are contained in an amount of 1 part or more per 100 parts by weight of the base medium. Therefore, the compounding amount has no particular upper limit, but the upper limit concentration is determined depending on each compound in consideration of processing performance, rust preventive property and plating property. Even if the material to be processed is preheated before processing and then the above-mentioned liquid lubricant is applied and processed, it is possible to obtain the cold-worked product which is the object of the present invention. Also, in special cases, the mold may be preheated.

As the medium for holding the above-mentioned phosphorus-based compound, it is desirable to use a product having a high lubricity in order to keep the load during processing as low as possible. For example, in addition to mineral oil, polyhydric alcohol ester, dibasic acid ester, polyolefin Synthetic oils such as polyalkylene glycol and alkylbenzene are suitable.

Examples of the acidic phosphoric acid ester include monomethyl phosphate, dimethyl phosphate, monoethyl phosphate, diethyl phosphate, monobutyl phosphate, dibutyl phosphate, monooctyl phosphate, dioctyl phosphate, monolauryl phosphate, dilauryl phosphate, Diphenyl phosphate, monophenyl phosphate, monostearyl phosphate, dioleyl phosphate, phenyl octyl phosphate, methyl butyl phosphate, monomethyl phosphite, diethyl phosphite, monobutyl phosphite, monophenyl phosphite, Diisodecyl phosphite, dioleyl phosphite, dilauryl phosphite, diphenyl phosphite, monodecyl phosphite, dibutyl phosphite, diii Decyl hydroperoxide diene phosphite, dioleyl hydro diene phosphite, dilauryl hydro diene phosphite, di-butyl hydroperoxide diene phosphite, methyl A Sid phosphine benzoate, butyl A Sid phosphine oleate, and octadecyl A Sid phosphine benzoate is.

The coating can be formed by treating the coated steel material of the present invention with a treatment liquid or a treatment bath containing the acidic phosphoric acid ester and condensed phosphoric acid and cold working.

Among the components contained in the treatment liquid or the treatment bath, the general formula (I), (II), (III) or the following formula (VI) The phosphoric acid ester represented by (n is 1 or 2, R is the same as above) is formed on the steel surface by cold working a compound of phosphorus and iron, and at the same time formed by cleavage of the ester bond. It is particularly effective because it forms an organic polymer-based lubricating film. In particular, acidic phosphoric acid esters are preferable in that the above reaction proceeds at a relatively low temperature.

Condensed phosphoric acid, which is another main component of the treatment liquid or treatment bath in the embodiment of the present invention, includes pyrophosphoric acid, metaphosphoric acid, polyphosphoric acid, polymetaphosphoric acid, and the like, of the general formula H _{n + 2} P _n O _{3n + 1} ( n: 1 to 6) or _{H n P n O 3n (n} : 1~8) means a group of compounds represented by.

These ingredients can be used directly, but in general,
It is cheaper and more versatile to use it after diluting it with a medium such as oil. As the diluting medium, various synthetic oils such as polyhydric alcohol esters, dibasic acid esters, polyolefins, polyalkylene glycols, alkylbenzenes, etc., as well as mineral oil, and water are used. According to the experience of the present inventors, a suspension in which the above-mentioned components are emulsified and dispersed in a medium exhibits a remarkable treatment effect. In that case, a dispersion stabilizer, an emulsion stabilizer, etc. are used in combination in order to improve the dispersion stability.

The treatment temperature is in the range of 100 to 450 ° C., and the higher the temperature, the shorter the film formation is completed.

Only with the above-mentioned phosphoric acid type additive, seizure during cold working can be prevented and not only a high lubrication effect can be obtained, but also an excellent anticorrosion effect can be obtained, but a solid lubricant or another kind of anticorrosion additive etc. There is no problem in adding.

FIG. 1 is a schematic diagram showing a cross section of a coated steel material as an example of the present invention. In the figure, 1 is a steel material, and the coating 2 is a phosphorus-containing coating layer that covers the surface of the steel material 1.

This steel material may be further subjected to plastic working. An example of the processing method is shown in FIG. Regardless of whether or not the coating 2 is applied, the pre-worked steel material 3 is processed by the punch 4 by the forward extrusion method to become the post-worked steel material 5. The die 6 has an extrusion angle of 120 degrees and a drawing diameter of 6 mm.

Example (Note that Sample No. 23 is a comparative example) 100 parts of mineral oil (viscosity grade ISOVG32) containing phosphoric acid ester, phosphonic acid ester and condensed phosphoric acid shown in Table 1 on the material surface of a cylinder (S10C) having a diameter of 10 mm and a flow of 30 mm. After coating 3 parts of the lubricating oil, the coated steel material was processed by the forward extrusion method in the apparatus shown in FIG.

The rust prevention ability of the processed product was evaluated and scored by the following method.

That is, the processed product was allowed to stand in the gas phase of a desiccator with water at the bottom. The stationary temperature is 40 ° C. The rust preventive ability is represented by the number of days until rust occurs, and the longer the number of days, the better the rust preventive property.

Regarding the plating property, the processed product was degreased with trichlorethylene, and then rusted, nickel and zinc plated.

Table 2 shows the composition and working conditions of each plating bath.

According to this example, a treated steel material having excellent rust prevention and workability can be obtained by a simple method, and almost no special pretreatment is required at the time of working, and the press working process can be greatly simplified. Becomes

〔The invention's effect〕

The coated steel material of the present invention has excellent rust prevention properties and does not require pretreatment such as film removal prior to plating or the like.

[Brief description of drawings]

FIG. 1 is a sectional view of a coated steel material according to an example of the present invention, and FIG. 2 is a sectional view of a processing apparatus showing a steel material processing example of the present invention. 1 ... Steel material, 2 ... Coating, 3 ... Steel material before processing, 4 ... Punch, 5 ... Steel material after processing, 6 ... Mold.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Fumio Nakano 4026 Kuji Town, Hitachi City, Hitachi, Ibaraki Prefecture Hitachi Research Institute, Ltd. (72) Inventor Toshikazu Narahara 4026, Kuji Town, Hitachi City, Ibaraki Prefecture Nitate Works Co., Ltd. Within Hitachi Research Laboratory (56) Reference JP-A-55-113832 (JP, A) JP-A-55-21529 (JP, A)

Claims (4)

[Claims] 1. The following formulas (I) to (III) (RO) _m -P (OH) _3-m (I) (Wherein R is selected from a saturated or unsaturated hydrocarbon group having 1 to 8 carbon atoms, a phenyl group and an alkylphenyl group, and m is 1 or 2), and one or more acidic phosphoric acid ester, and A coated steel material, which is coated with a reaction product obtained by cold working of condensed phosphoric acid and a steel material component. 2. The condensed phosphoric acid according to the following formula (IV) or (V) H _{n + 2} P _n O _{3n + 1} (IV) (wherein n is an integer of 1 to 6) H ₁ P ₁ O The coated steel material according to claim 1, which is selected from compounds represented by _3l ... (V) (wherein l represents an integer of 1 to 8). 3. The following formulas (I) to (III) (RO) _m -P (OH) _3-m (I) (Wherein R is selected from a saturated or unsaturated hydrocarbon group having 1 to 8 carbon atoms, a phenyl group and an alkylphenyl group, and m is 1 or 2), and one or more acidic phosphoric acid ester, and A method for producing a coated steel material, which comprises applying a base medium containing condensed phosphoric acid to the surface of a steel material and performing cold working. 4. The condensed phosphoric acid has the following formula (IV) or (V) H _{n + 2} P _n O _{3n + 1} (IV) (wherein n is an integer of 1 to 6) H ₁ P ₁ O _3l ... (V) (however, 1 shows the integer of 1-8) The manufacturing method of the coating steel material of Claim 3 represented by these.