JP2002146378A - Cutting oil composition for gear cutting - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cutting oil composition for gear cutting that has excellent cutting performance, is freed from chlorine-containing extreme pressure additive and particularly suitable in the case where the gear-cutting step is followed by the carburizing step. SOLUTION: The objective cutting oil composition for gear cutting is freed from chlorine-containing extreme pressure additive as well as zinc and calcium elements and comprises the base oil (for example, mineral oil, synthetic oil) with a kinematic viscosity of 8-50 mm2/s at 40 deg.C, a sulfur-containing extreme pressure additive (for example, sulfurized mineral oil or sulfurized fat oil and the like) in an amount of 0.15-0.7 wt.% of the sulfur content on the basis of the total of the cutting oil composition, ester (for example, butyl stearate and the like) in an amount of 2-50 wt.% and alcohol (for example, oleyl alcohol) in an amount of 0.5-8 wt.%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cutting fluid composition for gear cutting, and more particularly, to a cutting fluid composition for gear cutting which has excellent cutting performance and does not contain a chlorine-based extreme pressure additive. . The cutting fluid composition for gear cutting of the present invention is preferably used as a cutting fluid for gear cutting involving a carburizing and quenching step, since the carburizing property is not adversely affected when the carburizing and quenching step is performed in the subsequent step. Can be

[0002]

2. Description of the Related Art In recent years, there has been a demand for a cutting oil which does not use a chlorine-based extreme pressure additive, that is, a so-called chlorine-free oil, from the viewpoint of environmental protection. The same applies to gear cutting oils represented by hobbing and shaving, and various gear cutting oils not containing a chlorine-based extreme pressure additive have been used so far. Many of them include (1) organic molybdenum compounds such as molybdenum dithiophosphate and molybdenum dithiocarbamate, organic zinc compounds such as zinc dithiophosphate and zinc dithiocarbamate, and metal components such as calcium salts such as calcium sulfonate and calcium carboxylate. ,
Or (2) containing a relatively large amount of sulfur-based extreme pressure additive to form a reactive coating on the surface of the workpiece, and both show good cutting performance.

[0003] On the other hand, gears are often accompanied by a carburizing and quenching step (hereinafter also referred to as a carburizing step) after a gear cutting process and a heating and degreasing step. However, in such a carburizing process, when carburizing a gear that has been subjected to gear cutting using a conventional chlorine-free oil agent, poor carburization often occurs. On the other hand, those containing no metal component or extreme pressure additive as described above hardly cause poor carburization, but the cutting performance is greatly reduced and is not practical. It is considered that one of the causes is that the metal component or the reactive coating remaining on the surface of the workpiece has an influence.

Since gears are processed using expensive tools and are one of the most important parts among machine parts and automobile parts, occurrence of poor carburization is not preferable in terms of productivity and quality. Therefore, there has been a demand for an oil agent for gear cutting that does not cause poor carburization in the carburizing step, has excellent cutting performance, and does not contain chlorine.

[0005]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above circumstances, and has an excellent cutting performance and does not contain a chlorine-based extreme pressure additive. It is an object of the present invention to provide a cutting oil composition for gear cutting that is suitable when a carburizing and quenching step is involved in a post-cutting process.

[0006]

Means for Solving the Problems The present inventors have reduced the amount of substances remaining on the surface of a workpiece in a heating degreasing step, which is a step prior to a carburizing and quenching step, so that poor carburization hardly occurs. We paid attention to. As a result of intensive studies on various lubricating additives, a gear cutting process using a cutting oil composition having a specific composition to reduce the amount of substances remaining on the surface of the workpiece has been performed, thereby carburizing in the carburizing process. They have found that defects can be reduced, and have completed the present invention. The cutting oil composition for gear cutting according to claim 1 contains a base oil, a sulfur-based extreme pressure additive, an ester compound and an alcohol compound, and does not contain a chlorine-based extreme pressure additive.
A cutting oil composition for gear cutting which does not contain zinc element and calcium element, wherein the kinematic viscosity of the base oil is 40 ° C.
In 8~50mm ² / s, the content of the sulfur-based extreme pressure agent, a sulfur content, 0.15 to 0.7 wt% based on the total present cutting oil composition, the content of the ester compound 2 to 50% by weight, the content of the alcohol compound is 0.5
-8% by weight.

The type of the "base oil" is not particularly limited as long as it has an kinematic viscosity at 40 ° C. of 8 to 50 mm ² / s, and any type of mineral oil or synthetic oil is used. be able to. Examples of the mineral oil include spindle oil, machine oil, and neutral oil. Examples of the synthetic oil include polybutene and α-olefin oligomer.

The kinematic viscosity at 40 ° C. of this base oil is 8 to 5
It is a 0mm ² / s, preferably 10~45mm ² / s. When the kinematic viscosity at 40 ° C. is less than 8 mm ² / s, the amount of mist generated is not preferable. On the other hand, if it exceeds 50 mm ² / s, the amount of oil adhering to the work is undesirably increased.

The above "sulfur-based extreme pressure additives" include, for example, sulfurized mineral oils, sulfurized fatty oils and polysulfides. Examples of the sulfide mineral oil include those obtained by dissolving elemental sulfur in mineral oil. The sulfurized mineral oil has a sulfur content of 0.1 to 0.6% by weight (more preferably 0.3 to 0.6% by weight).
0.4% by weight) is preferred in terms of solubility, stability and economy. As the sulfurized fatty oil, for example,
Examples include sulfides of animal and vegetable oils such as sulfurized lard, sulfurized rapeseed oil, sulfurized castor oil and sulfurized soybean oil, and also include sulfurized esters such as sulfurized methyl oleate. These sulfurized fatty oils containing 5 to 30% by weight (more preferably 10 to 20% by weight) as a sulfur content are preferable in terms of solubility, stability and economy.

[0010] Examples of the above polysulfide include olefin polysulfide and dialkyl polysulfide. These polysulfides containing 5 to 50% by weight (more preferably 10 to 40% by weight) of sulfur are preferable in view of solubility, stability and economy. These sulfur-based extreme pressure additives may be used alone or as a mixture of two or more. Also, JI
Copper plate corrosion test of SK 2513 (100 ° C, 1 hour)
Can be used irrespective of activity or inactivity.

The amount of the sulfur-based extreme-pressure additive is 0.15 to 0.1% in terms of sulfur content based on the entire cutting fluid composition.
0.7% by weight, preferably 0.2 to 0.5% by weight
It is. If the compounding amount is less than 0.15% by weight, the extreme pressure property is insufficient, and the processing accuracy may be lowered and abnormal wear of a tool or the like may occur, which is not preferable. On the other hand, this is 0.
If the content exceeds 7% by weight, carburization failure occurs in the subsequent carburizing and quenching step, which may undesirably affect the quality and productivity of the gear.

The "ester compound" includes a straight-chain or branched-chain fatty acid (whether saturated or unsaturated) having 12 to 20 (preferably 14 to 18) carbon atoms and 1 to carbon atoms.
Ester with a straight-chain or branched-chain alcohol (regardless of saturated or unsaturated) of 8 is preferably used.
Butyl stearate, methyl oleate and the like. These may be used alone or as a mixture of two or more. The amount of this ester compound is
It is 2 to 50% by weight, preferably 5 to 40% by weight, based on the entire cutting fluid composition. 2% by weight
If it is less than this, the lubricity becomes insufficient, which is not preferable. on the other hand,
If it exceeds 50% by weight, the improvement in lubricity will level off, which is not preferable in terms of economy.

As the above-mentioned "alcohol compound", a linear or branched alcohol (whether saturated or unsaturated) having 12 to 20 (preferably 14 to 18) carbon atoms is preferably used. Oleyl alcohol and the like can be mentioned. These may be used alone or as a mixture of two or more. The amount of the alcohol compound is 0.5 to 8% by weight, preferably 1 to 5% by weight, based on the whole cutting fluid composition.
It is. If the amount is less than 0.5% by weight, the evaporating property of the oil agent is not improved, so that residues are likely to be generated in the subsequent heat degreasing step, which is not preferable. On the other hand, when it exceeds 8% by weight, the improvement of the evaporating property reaches a peak and is not preferable from the viewpoint of economic efficiency.

The cutting oil composition for gear cutting according to the first aspect does not contain a chlorine-based extreme pressure additive. It is not preferable to contain a chlorinated extreme pressure additive such as chlorinated paraffin or chlorinated diphenyl from the viewpoint of environmental protection. Further, it is preferable that the composition does not substantially contain a chlorine component.

Further, the cutting fluid composition for gear cutting according to the first aspect does not contain elemental zinc and elemental calcium. The reason for this is that when cutting is performed using a cutting fluid composition containing at least one of a zinc element and a calcium element, dirt adheres to the surface of the object to be cut or a film is formed, and surface treatment or the like in a later step is performed. Is not preferable because it causes trouble. Further, the cutting fluid composition for gear cutting of the present invention preferably does not contain a metal element such as a molybdenum element in addition to a zinc element and a calcium element.

According to the first aspect of the present invention, the cutting oil composition for gear cutting has a kinematic viscosity at 40 ° C. of 8 to 40 mm ² / s, preferably 10 to 40 mm ² / s.
３０30 mm ² / s. When the kinematic viscosity at 40 ° C. is less than 8 mm ² / s, it is not preferable because mist is easily generated. On the other hand, this is 40 mm ² / s
When the value exceeds, it is not preferable in that the amount of oil adhering to the work increases.

The cutting fluid composition for gear cutting of the present invention has an effective carburized layer depth of at least 0.30 mm (more preferably at least 0.38 mm, under the conditions shown in the following examples).
More preferably, it is 0.40 mm or more). At the same time, the tool wear amount is preferably 0.16 mm or less (more preferably 0.15 mm or less).

The cutting oil composition for gear cutting of the present invention contains a known lubricating additive, metal deactivator, which does not contain zinc element and calcium element (preferably, other metal elements). Rust prevention additives, antioxidants, defoamers and the like may be added. The production of the cutting oil composition for gear cutting of the present invention can be carried out by mixing the respective components by a conventional method.

The cutting oil composition for gear cutting according to the present invention comprises:
As shown in claim 3, it can be used in the gear cutting step which involves a heating degreasing step and a carburizing and quenching step in the next step.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to examples and comparative examples. (1) Preparation of Cutting Fluid Composition for Gear Cutting The compositions of Examples 1 to 6 and Comparative Examples 1 to 7 were prepared from the components shown in Table 1 at the ratios shown in the table. The details of the composition components in the table are shown below. “*” In Table 1 indicates a component not included in the scope of the present invention.

[0021]

[Table 1]

(A) Spindle oil; manufactured by Nisseki Mitsubishi, kinematic viscosity: 10 mm ² / s, 40 ° C. (b) Machine oil: manufactured by Nisseki Mitsubishi, kinematic viscosity: 45 mm ² /
s, 40 ° C. (c) Sulfurized spindle oil: A spindle oil in which a predetermined amount of powdered sulfur is added to the spindle oil, heated to 130 to 150 ° C. and dissolved to adjust the sulfur content to 0.4% by weight. (D) Sulfurized machine oil: A machine oil obtained by adding a predetermined amount of powdered sulfur to the above machine oil, heating to 130 to 150 ° C. and dissolving to adjust the sulfur content to 0.4% by weight. (E) Sulfurized fatty oil; manufactured by Dainippon Ink and Chemicals, trade name "DAILUBE GS-230", sulfur content: 10.1
(F) Ester compound; butyl stearate, manufactured by Wako Pure Chemical Industries, Ltd. (g) Alcohol compound: oleyl alcohol, manufactured by Wako Pure Chemical Industries, Ltd. (h) Calcium sulfonate; manufactured by Nippon Lubrizol Industries, Ltd., trade name “LZ5283” ( i) Zinc dithiophosphate; trade name "Aditin RC3048" manufactured by Rhein Chemie Co., Ltd. (j) Chlorinated paraffin; trade name "Empara K50" manufactured by Ajinomoto Co. (k) Antioxidant; 2,6-di-t-butyl -P-cresol, manufactured by Wako Pure Chemical Industries, Ltd. (l) Metal deactivator; benzotriazole, manufactured by Wako Pure Chemical Industries, Ltd.

(2) Performance Evaluation Using each composition (Examples 1 to 6 and Comparative Examples 1 to 7),
Under the following conditions, gear cutting, degreasing of cutting oil, and carburizing and quenching of gears were performed. Further, the following performance tests were performed to evaluate the carburizing property, the cutting property, and the dirt adhesion property. Table 2 shows the results. In Table 2, "*" indicates
Indicates that the following evaluation criteria are not met.

[0024]

[Table 2]

Gear cutting conditions (hobbing) Test material: Alloy steel for machine structure (SCr420H, SC
M420H) Gear specifications: module 2.5 Processing conditions: rotation speed 200-250 rpm, feed speed 2.0-2.4 mm / rev

Degreasing conditions for cutting oil Degreasing temperature: 450 to 500 ° C Degreasing time: 17 to 25 minutes Atmosphere: air Heating method: gas combustion

Gear carburizing and quenching conditions Carburizing temperature: 880 to 940 ° C. Quenching temperature: 100 to 150 ° C. Atmospheric gas: CO (vol%) = 18 to 24 Facility machine: Continuous gas carburizing furnace

(Performance Test and Evaluation Method) (a) Carburizing property: Evaluation was made by measuring the effective carburized layer depth after carburizing and quenching. This effective carburized layer depth is the standard value [H
v Depth from the surface when indicating 513 (standard: 0.3 to
0.5 mm)], it was determined that the carburization was poor. (B) Machinability: The tool abrasion amount [abrasion amount (mm) of tool rake face (mm)] after 500 tooth cutting operations was measured and evaluated. If the tool wear exceeds 0.16 mm, it was determined that the cutting was defective. (C) Stain adhesion: Stain of the workpiece after heating and degreasing was visually observed, and the degree of the stain was evaluated according to the following criteria. ◎: No dirt, ○: Small amount of dirt, ×: Many dirt

According to Table 2, Comparative Example 1 in which the sulfur content was as small as 0.1% by weight with respect to the entire cutting fluid was sufficiently evaluated with respect to the effective carburized layer depth and the stain after heat degreasing. However, in terms of the amount of tool wear, the wear was severe at 0.17 mm, and the cutting performance was poor. Conversely, in Comparative Example 2 in which the sulfur content was as high as 0.8% by weight, sufficient evaluation was obtained for the tool wear amount and the stain after heat degreasing, but the effective carburized layer depth was 0.28 mm, It did not reach the standard value and was poor in carburization. In Comparative Example 3 containing no alcohol compound, sufficient evaluation was obtained in the effective carburized layer depth and the tool abrasion amount, but a small amount of dirt was found after heat degreasing.
In Comparative Example 4, which did not contain an ester compound, sufficient evaluation was obtained for the effective carburized layer depth and the stain after heat degreasing, but the tool wear amount was 0.18 mm.
Cutting performance was not enough. Further, Comparative Examples 5 and 6, which contain calcium or zinc, etc., were both sufficiently evaluated in terms of cutting performance, but the stains after heat degreasing were severe, and the effective carburized layer depth did not reach the standard value. Carburization was poor. In contrast, Example 1 containing no chlorine
Nos. To 6 are 0.41 mm in effective carburized layer depth and 0.
14-0.15mm, and no dirt after heat degreasing,
It exhibited excellent performance in all of carburizing property, machinability and dirt adhesion, and exhibited performance equivalent to that of the chlorine-containing cutting fluid of Comparative Example 7 having excellent conventional cutting performance and the like.

As described above, the cutting oil compositions of Examples 1 to 6 do not contain chlorine such as chlorine extreme pressure additives, are excellent in cutting performance, do not stain the surface of the work, and are a post-process. In the carburizing and quenching process, it does not adversely affect carburization
It can be seen that the cutting oil composition for gear cutting is excellent in performance balance.

It should be noted that the present invention is not limited to the above specific embodiments, but may be variously modified within the scope of the present invention according to the purpose and application.

[0032]

The cutting oil composition for gear cutting according to the present invention is excellent in cutting performance and does not adversely affect the carburizing property in the subsequent carburizing and quenching step. Further, since the present cutting fluid composition does not contain a chlorine-based extreme pressure agent,
It corresponds to environmental protection.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C10M 135/22 C10M 135/22 // C10N 20:02 C10N 20:02 40:22 40:22 (72) Inventor Masao Ohara 1580 Tabata, Samukawa-cho, Koza-gun, Kanagawa Prefecture Inside of Yushiro Chemical Industry Co., Ltd. BB03C BB32C BG02C BG04C BG12C DA02A EA02A EA02Z EB02 PA22

Claims (3)

[Claims] 1. A cutting fluid for gear cutting which contains a base oil, a sulfur-based extreme pressure additive, an ester compound and an alcohol compound, does not contain a chlorine-based extreme pressure additive, and does not contain zinc and calcium elements. A kinematic viscosity of the base oil at 40 ° C. of 8 to 50 mm ² / s,
The content of the sulfur-based extreme pressure additive is 0.15 to 0.7% by weight, based on the entire cutting fluid composition, as sulfur content, the content of the ester compound is 2 to 50% by weight, A cutting oil composition for gear cutting, wherein the content of the compound is 0.5 to 8% by weight. 2. The cutting oil composition for gear cutting according to claim 1, wherein the kinematic viscosity of the cutting oil composition for gear cutting is 8 to 40 mm ² / s at 40 ° C. 3. The method according to claim 1, wherein the next step is used in a gear cutting step accompanied by a heating degreasing step and a carburizing and quenching step.
Or the cutting oil composition for gear cutting according to 2.