JPH09248619A - Method for lubricating alloy steel pipe and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an alloy steel pipe with smooth metallic gloss, which is free from the problem of permeation by phosphor even if degreasing is not performed before a heat treatment after drawing. SOLUTION: Before performing the cold drawing of the alloy steel pipe containing 0. 5% Cr or over, after immersing the alloy steel pipe in compound liquid with pH 8 to 11, consisting of compound containing titanium and phosphate so that the deposit of phosphor is 100mg/m<2> or below, the alloy steel pipe is dried. Then, lubricating oil consisting of the compound of fats and oils with 21% S or over, by weight, and olefin, is applied to the alloy steel pipe.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a Cr content of 0.50.
The present invention relates to a lubrication treatment method for cold drawing of an alloy steel tube containing at least 1% and a manufacturing method for obtaining an alloy steel tube without phosphorus after heat treatment.

[0002]

2. Description of the Related Art As a pretreatment for cold drawing of a steel pipe, descaling and lubrication are performed. Descaling is a very important work for dies during drawing, preventing seizure of plugs, preventing surface defects on steel pipes, and activating surfaces for lubrication. There are salt treatment method and mechanical descaling method. In addition, the lubrication treatment reduces friction between the steel pipe and the die or between the steel pipe and the plug during cold drawing, and prevents seizure due to local concentration of friction heat.
There are a resin coating method and an oil lubrication method.

As shown in Table 1, the chemical conversion treatment method is as follows: in the case of oxalate coating, pickling → neutralization → oxalate coating → stearate coating → drying → drawing → heat treatment, in the case of phosphate coating, The process is complicated because it undergoes the steps of pickling → neutralization → phosphate coating → stearate coating → drying → drawing → degreasing → heat treatment. Similar to the chemical conversion treatment method, the resin coating method has complicated steps. The oil lubrication method, as shown in Table 1, is pickling →
The process can be extremely simplified by neutralization → drying → oil lubrication drawing → heat treatment, and cost reduction can be achieved, but it has not been implemented due to the problem of seizure.

[0004]

[Table 1]

The target steel grades for the oxalate coating of the chemical conversion treatment method are high alloy steels such as low alloy steel and stainless steel, and the target steel grades for the phosphate coating are carbon steel and low alloy steel. Further, in the method of performing the phosphate coating treatment, since phosphorus is contained, there is a problem of phosphorus immersion due to heat treatment after cold drawing, and it was necessary to perform degreasing treatment before heat treatment. For this reason, in the cold drawing of an alloy steel pipe containing 0.50% or more of Cr, which has the problem of phosphorus infiltration, the method in which the oxalate coating is applied after the pickling is the mainstream.

Conventionally, as a lubrication method for steel pipes, colloidal titanium formed from a reaction product of a titanium-containing compound and an alkaline phosphate is used as titanium in an amount of 0.001 to 0.001.
It is brought into contact with a liquid containing 0.5 g / l of colloidal titanium having a pH of 8 to 11 and then dried.
40 to 95% by weight of a mixture of 3 to 30% by weight of a compound of fats and oils and an olefin and a compound of a higher ester compound having a sulfur content of 23 to 30% by weight and a compound of an olefin, 40 to 95% by weight, and oil solubility 5 to 50% by weight of one or more selected from polymer compounds, fats and oils, synthetic oils, mineral oils, higher fatty acids and amines of higher fatty acids,
There has been proposed a method of applying a lubricating oil containing a phosphorus-based extreme pressure additive if necessary and adjusting the viscosity at 20 ° C. within the range of 100 to 3000 centipoise (JP-A-4-33998).

[0007]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
The method disclosed in Japanese Unexamined Patent Publication No. 98 has a problem that the target steel type is a carbon steel pipe and that there is a problem of phosphorus immersion in the heat treatment after the cold drawing process, and it is necessary to perform degreasing treatment before the heat treatment. .

An object of the present invention is to solve the above-mentioned drawbacks of the prior art, and in cold drawing of an alloy steel pipe containing Cr by 0.5% or more, without degreasing treatment before heat treatment after drawing. It is an object of the present invention to provide a method for lubricating an alloy steel pipe and a method for manufacturing an alloy steel pipe, which does not have the problem of phosphorus immersion and which can omit the manufacturing process.

[0009]

The lubrication method for alloy steel pipes according to the present invention has a pH of 8 including a titanium-containing compound and a phosphate.
It is soaked in a compound solution of ~ 11 so that the amount of adhered phosphorus is 100 mg / m ² or less, and then dried.
A lubricating oil composed of a compound of 1% by weight or more of oil and olefin is applied. Thus, by immersing in a compound liquid of pH 8 to 11 consisting of a titanium-containing compound and a phosphate so that the amount of adhered phosphorus is 100 mg / m ² or less and then drying, it is possible to perform degreasing treatment before heat treatment. Phosphorus can be prevented. Also, a titanium-containing compound and a phosphate coating are applied and dried to obtain a sulfur content of 21
By applying a lubricating oil consisting of a compound of fat and oil and an olefin in an amount of at least wt%, it is possible to dramatically prevent seizure as compared with conventional oil lubrication, and to perform processing in the same process as conventional oil lubrication process, Compared with the chemical conversion treatment method, the manufacturing process can be largely omitted.

The alloy steel pipe manufacturing method according to the present invention has a pH of 8 to 11 comprising a titanium-containing compound and a phosphate.
It is soaked in the compound liquid of (1) so that the amount of adhered phosphorus is 100 mg / m ² or less, then dried, and then cold drawn while applying a lubricating oil consisting of a compound of an oil and fat and an olefin having a sulfur content of 21% by weight or more. After processing, 200 ℃ or more 10
Heat treatment at 50 ° C. or lower is applied. Thus, by immersing in a compound liquid of pH 8 to 11 consisting of a titanium-containing compound and a phosphate so that the amount of adhered phosphorus is 100 mg / m ² or less and then drying, it is possible to perform degreasing treatment before heat treatment. It is possible to manufacture alloy steel pipes without phosphorus immersion. Further, after applying a titanium-containing compound and a phosphate coating and drying, and applying a lubricating oil composed of a compound of an oil and fat and an olefin having a sulfur content of 21 wt% or more, after cold drawing, 200 ° C. or more and 1050 By performing the heat treatment at a temperature of ℃ or less, seizure during cold drawing can be prevented, and the same process as the conventional oil lubrication process can be performed, and the manufacturing process can be largely omitted as compared with the chemical conversion treatment method.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION According to the present invention, a compound liquid consisting of a titanium-containing compound and a phosphate is adjusted to pH 8 to 11 before cold drawing of an alloy steel tube containing 0.50% or more of Cr, It is dipped so that the amount of phosphorus adhered is 100 mg / m ² or less, and then dried. On the inner and outer surfaces of the alloy steel pipe subjected to this treatment, Fe on the surface of the steel pipe reacts with phosphate to produce iron phosphate, and phosphate and titanium oxide are attached. After the coating is formed, the alloy steel tube is coated with a lubricating oil composed of a compound of an oil and fat and an olefin having a sulfur content of 21% by weight or more on the inner and outer surfaces of the steel tube.

The titanium-containing compound used in the present invention is a titanium oxyacid salt such as titanyl sulfate (TiS).
O ₄ ), titanyl nitrate and the like can be mentioned, but titanyl sulfate is particularly preferable. Further, as the phosphate, a dibasic alkali metal salt such as sodium diphosphate is preferable, and a condensed phosphate such as sodium pyrophosphate can also be used. The pH of the compound solution containing the titanium-containing compound and the phosphate can be adjusted to pH 8 to 11 by adding an alkali metal carbonate, an alkali metal hydroxide or an alkali metal phosphate. Specific examples thereof include sodium carbonate, sodium hydroxide, dibasic sodium phosphate, and tribasic sodium phosphate.

In the present invention, the pH of the compound solution comprising the titanium-containing compound and the phosphate is set to 8 to 11 because the pH, solution concentration and seizure of the compound solution comprising the titanium-containing compound and the phosphate by the Bowden test. The results shown in FIG. 1 were obtained, and when the pH was less than 8, the dispersibility of phosphate and titanium oxide decreased, so iron phosphate and phosphoric acid on the inner and outer surfaces of the alloy steel pipe The amount of salt and titanium oxide attached decreases, and seizure resistance decreases. Also, the pH is 1
Even if it exceeds 1, dispersibility of phosphate and titanium oxide is lowered and seizure resistance is lowered.

The reason why the phosphorus deposition amount on the inner and outer surfaces of the alloy steel pipe is 100 mg / m ² or less in the present invention is as follows. Phosphorus in heat treatment is a phenomenon in which the surface of the steel pipe melts and phosphorus invades. At 900 ° C or lower, phosphorus does not enter regardless of the phosphorus content, but above 900 ° C, the melting temperature decreases in proportion to the phosphorus content. Then, it becomes easier to soak. For this reason, in the alloy steel pipe containing Cr by 0.50% or more, phosphorus infiltration occurs when the phosphorus deposition amount exceeds 100 mg / m ² in the heat treatment temperature range of 200 to 1050 ° C.

The sulfur content used as the lubricating oil in the present invention is 2
The compound of 1% by weight or more of oil and olefin is, for example, unsaturated animal and vegetable oil and fat, mercaptan compound of olefin and sulfur in the presence of a basic catalyst at 150 to 160 ° C.
After reacting for a period of time, the unreacted fraction is removed by distillation under reduced pressure, and then hydrogen sulfide is removed by aeration at about 80 ° C. The higher the sulfur content, the higher the extreme pressure property of the lubricating oil, but the oiliness tends to decrease. Therefore, the sulfur content should be determined in consideration of both the extreme pressure property and the oiliness to be provided. In the present invention, the sulfur content in the lubricating oil is set to 21% by weight or more. When the sulfur content is less than 21% by weight, the extreme pressure property is lowered and seizure is likely to occur during cold drawing of the alloy steel pipe. In addition, since a compound having too much sulfur content is unstable and sulfur is deposited, the upper limit of the sulfur content in the lubricating oil should be determined in consideration of these, but preferably 30% by weight.
That is all. The oil and fat used in this invention includes rapeseed oil,
Examples include lard oil, coconut oil, castor oil, and beef tallow.

[0016]

【Example】

Example 1 Outer diameter 48.6 mm of steel types A to D having chemical components shown in Table 2,
A 5.0 mm thick seamless steel pipe was pickled, neutralized with sodium hydroxide, washed with water and dried, and 5 l of a lubricating oil containing 21% by weight of sulfur consisting of fats and oils (rapeseed oil) and olefins. / Min, while using taper type die and semi-floating plug, cross-section reduction rate is 32%,
Cold drawing at a drawing speed of 40 m / min, outer diameter 3
A drawn seamless steel tube having a conventional process of 8.1 mm and a wall thickness of 4.4 mm was obtained. In addition, after the seamless steel pipes of the steel types A to D were pickled, the compound liquid having a pH of 8 to 11 containing a titanium-containing compound and a phosphate had a phosphorus adhesion amount of 100 mg.
/ M ² or less, and then dries, and 5 l / l of lubricating oil composed of fat and olefin and having a sulfur content of 21% by weight
While coating with min, cold drawing is performed at a cross-section reduction rate of 32% and a drawing speed of 40 m / min using a taper type die and a semi-floating plug, and an outer diameter of 38.1 m.
A drawn seamless steel pipe having a thickness of m and a thickness of 4.4 mm was obtained by the process of the present invention. The seizure rate after cold drawing of the drawn seamless steel pipe obtained by the conventional process and the drawn seamless steel pipe obtained by the process of the present invention was investigated. The result is shown in FIG.

[0017]

[Table 2]

As shown in FIG. 2, the drawn seamless steel pipes of the steel types A to C according to the process of the present invention are steel types A according to the conventional process.
The seizure resistance is significantly improved compared to the drawn seamless steel pipes of ~ C. Regarding the drawn seamless steel pipe of the steel type D according to the process of the present invention, the seizure rate is higher than that of the drawn seamless steel pipes of the steel types A to C, but it is still 1/2 of that of the conventional process. It is reduced below.

Example 2 Steel types A to D having the chemical composition shown in Table 2 used in Example 1
After pickling a seamless steel pipe of an alloy steel having an outer diameter of 48.6 mm and a wall thickness of 5.0 mm, it is immersed in a compound solution having a pH of 8 to 11 composed of a titanium-containing compound and a phosphate having different concentrations, and then dried. A seamless steel pipe having a phosphorus deposition amount of about 100, 200, 300 and 400 mg / m ² was coated with a lubricating oil having a sulfur content of 21% by weight consisting of oil and fat (rapeseed oil) and an olefin at 5 l / min and a taper die. And a semi-floating plug are used for cold drawing at a cross-section reduction rate of 32% and a drawing speed of 40 m / min.
A drawn seamless steel pipe having a thickness of 8.1 mm and a thickness of 4.4 mm was obtained. Each drawn seamless steel tube was heat-treated at 900 ° C., 975 ° C., 1050 ° C. and 1 in an oxygen-free atmosphere.
Each was heat-treated at 100 ° C. The relationship between the phosphorus deposition amount and the phosphorus immersion depth of each of the obtained heat-treated seamless steel pipes was determined. The results are shown in FIGS. 3 (a) and 3 (b).

As shown in FIG. 3A, at the heat treatment temperature of 900 ° C., the steel pipe of steel type A is not soaked with phosphorus regardless of the phosphorus adhesion amount, but at the heat treatment temperature of 1050 ° C., the phosphorus adhesion amount is 100 mg / m ² or more. At the heat treatment temperature of 1100 ° C., phosphorus was observed even at a phosphorus adhesion amount of 100 mg / m ² . Further, as shown in FIG. 3B, the steel pipes of the steel types B to D are not soaked with phosphorus at the heat treatment temperatures of 900 ° C. to 1050 ° C. regardless of the phosphorus deposition amount. Phosphorus was observed at a density of / m ² or more.

[0021]

Industrial Applicability According to the present invention, before a cold drawing process of a steel pipe of an alloy steel containing 0.50% or more of Cr, a compound liquid having a pH of 8 to 11 composed of a titanium-containing compound and a phosphate is added with a phosphorus deposition amount. To 100 mg / m ² or less, then dried, and then applied with a lubricating oil composed of a compound of an oil and fat and an olefin having a sulfur content of 21% by weight or more to obtain a smooth and metallic luster, and a heat treatment. An alloy steel tube free from the problem of phosphorus immersion can be obtained without degreasing treatment, and the manufacturing process can be simplified.

[Brief description of drawings]

FIG. 1 is a graph showing the relationship between the concentration of a compound solution containing a titanium-containing compound and a phosphate in a Bowden test, pH, and the number of times before baking.

FIG. 2 is a graph showing a relationship between seizure rates of steel types in the conventional process and the process of the present invention in Example 1.

FIG. 3 is a graph showing the relationship between the heat treatment temperature for each steel type, the phosphorus deposition amount, and the phosphorus immersion depth in Example 2, where (a) is the case for steel type A and (b) is the case for steel types B to D. Is.

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Claims (2)

[Claims] 1. Prior to cold drawing of a steel pipe of an alloy steel containing 0.50% or more of Cr, a compound liquid having a pH of 8 to 11 containing a titanium-containing compound and a phosphate has a phosphorus deposition amount of 1%.
Immerse it to less than 00 mg / m ² and dry it,
Next, a method for lubricating an alloy steel pipe is characterized in that a lubricating oil consisting of a compound of an oil and fat having a sulfur content of 21% by weight or more and an olefin is applied. 2. Prior to cold drawing of a steel pipe of alloy steel containing 0.50% or more of Cr, a compound liquid having a pH of 8 to 11 containing a titanium-containing compound and a phosphate has a phosphorus deposition amount of 1%.
Immerse it to less than 00 mg / m ² and dry it,
Next, a cold-drawing process is performed while applying a lubricating oil composed of a compound of an oil and fat with an olefin having a sulfur content of 21% by weight or more, and then a heat treatment of 200 ° C. or more and 1050 ° C. or less is performed to produce a steel alloy steel pipe. Method.