JPH0931485A - Cold rolling oil - Google Patents

Abstract

(57) [Summary] [Structure] [I] A dithiophosphoric acid compound represented by the following general formula, wherein the content of at least one of polyhydric alcohols having 6 or less carbon atoms is 5% by weight or more, and [II] At least one of
[I] and [II] are dissolved in water so that the content of the seeds is 1% by weight or more and water is included, and the sum of the contents of [I] and [II] is 60% by weight or less. Cold rolling oil. Embedded image However, R is an alkyl group having 4 to 18 carbon atoms, an alkenyl group,
An aryl group or an alkylaryl group, n is an integer of 1 to 10, and M is a metal element. [Effect] Even if high speed rolling is performed, seizure does not occur, there is no risk of fire when the plate breaks, and it is possible to manufacture a steel plate having a good surface gloss.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to cold rolling of cold rolling oil, especially stainless steel, in which the surface of the material to be rolled maintains high gloss even at high speed rolling, and is excellent in lubricity and roll cooling. Cold rolling oil.

[0002]

2. Description of the Related Art The most important performance required for cold rolling oils of metals is lubricity, but when used in an actual machine, various performances are also required from the viewpoint of product quality and maintenance. It For example, in cold rolling of stainless steel sheets, the luster of the product surface is most important. This is because stainless steel is excellent in corrosion resistance and is used in a portion that is directly visible such as for decoration without surface treatment.

The luster is greatly affected by the lubrication state during rolling. Between the roll and the steel plate during rolling (generally,
The oil pressure of the oil film generated "in the roll bite" causes depressions called oil pits on the surface of the steel sheet after rolling, but when the oil film is thick or the viscosity of the rolling oil under high pressure, that is, When high-pressure viscosity is high,
The amount of oil pits generated is large, and the gloss of the steel sheet surface decreases.

Explaining this situation in detail, first, during rolling, the metal undergoes plastic deformation, so at the interface between the roll and the steel plate, the pressure is higher than the deformation resistance of the material to be rolled, and It is considered that the existing rolling oil is also in a high pressure state. Now, when using a rolling oil with a high high-pressure viscosity, this rolling oil has low fluidity in the high-pressure state, so it is easily confined in the space created by the roughness of the roll and the steel plate in the roll bite, and the oil Pits are formed, but in the case of rolling oil with low high-pressure viscosity, it has high fluidity even under high pressure, so it flows out from the gap of the roughness of the roll and the steel plate to the lower pressure side before being contained, and the oil pit Are hard to form. However, when the high-pressure viscosity is too low, the rolling oil has too high fluidity and flows out of the roll bite through the gap between the roughness of the roll and the steel plate, and an oil film is not formed in the roll bite. There will be insufficient lubrication.

Therefore, in the cold rolling of a stainless steel plate,
Rolling oil that has a low high-pressure viscosity and a small amount drawn into the roll bite is used as a lubricating oil.

As a material satisfying this condition, there is a low-viscosity mineral oil, which has a low high-pressure viscosity. However, since low-viscosity mineral oil has poor lubricity, a synthetic ester or an aliphatic alcohol added as an oiliness agent is used to improve seizure resistance. However, since oil has a low specific heat and the cooling performance of the roll and the steel sheet is poor, the temperature of the roll and the surface of the steel sheet rises during high speed rolling. When the temperature of the surface of the roll or the steel plate rises, the oiliness agent is thermally decomposed or detached from the surface of the roll or the steel plate, the lubricity decreases and seizure occurs. Cooling performance can be improved by further reducing the viscosity of cold rolling oil to increase fluidity, but mineral oil has a lower flash point as the viscosity decreases, so if plate breakage occurs during rolling. There is a risk that a fire will occur due to the sparks of and the viscosity cannot be extremely lowered.

On the other hand, as a cold rolling oil which is flame-retardant and excellent in cooling property, there is an oil-in-water dispersion (O / W) type cold rolling oil which has been conventionally used for rolling ordinary steel. . However, the O / W emulsion cold rolling oil has excellent cooling properties because most of the components are water, but on the other hand, the amount of oil adhering to the surface of the roll and the steel sheet is difficult to be uniform, and uneven glossiness is likely to occur. . In addition, Japanese Patent Publication No. 3-80199
Japanese Patent Laid-Open Publication No. 2003-242242 discloses a cold rolling oil of water-in-oil dispersion (W / O) type emulsion in which 1 to 50% by weight of water is dispersed in a base oil containing one or more of fatty acid, petroleum sulfonic acid and naphthenic acid. Proposed. Since this rolling oil is mainly composed of oil, the cooling property does not extremely improve like the O / W emulsion cold rolling oil, and a large amount of an emulsifier is required to keep the W / O emulsion stable. Since a surfactant is required, there is a problem in wastewater treatment.

[0008]

DISCLOSURE OF THE INVENTION The present invention does not cause seizure even when high speed rolling is performed, there is no risk of fire, and
An object of the present invention is to provide a cold rolling oil capable of producing a steel sheet having high surface gloss.

[0009]

DISCLOSURE OF THE INVENTION As a result of repeated studies to achieve the above object, the present inventor has found that both a water-specific water-soluble thickener and a water-soluble lubricity improver. It was found that the cold rolling oil to which a specific amount of is added has a high cooling performance equivalent to that of water and also has a good lubricity, and has completed the present invention.

The gist of the present invention resides in the following cold rolling oil.

[I] The content of at least one kind in the polyhydric alcohol having 6 or less carbon atoms is 5% by weight or more, and [II] At least one kind in the dithiophosphoric acid compound represented by the following general formula. Content of 1% by weight or more and water, and [I] and [II] are dissolved in water so that the sum of the contents of [I] and [II] is 60% by weight or less. Cold rolling oil made by.

[0012]

Embedded image

However, R is an alkyl group having 4 to 18 carbon atoms, an alkenyl group, an aryl group, or an alkylaryl group,
n is an integer of 1 to 10 and M is a metal element.

The term "cold rolling oil dissolved in water" as used herein means a cold rolling oil which is completely dissolved in water to form a single phase, and a surfactant or the like is used. It is different from the cold rolling oil in the emulsion state in which it is dispersed in water and the cold rolling oil in the suspension state in which fine particles are suspended in water.

How the cold rolling oil of the present invention solves the above problems will be described below.

The cold rolling oil of the present invention comprises water, a thickener (component [I] above) and a lubricity improver (component [II] above). The cold rolling oil of the present invention is flame-retardant because it is based on water, and has a specific heat as high as that of water, and the cooling performance is considerably better than that of the conventional cold rolling oil based on oil. Yes, it has a cooling performance equal to or higher than that of an emulsion type cold rolling oil. this is,
In the emulsion type cold rolling oil, the roll, the oil film attached to the steel sheet becomes heat transfer resistance and reduces the cooling performance, but in the cold rolling oil of the present invention, only a completely water-soluble substance is converted into water. This is because, since the components are melted, there is no problem that part of the components adheres to the roll or the steel plate and becomes heat transfer resistance. Further, the cold rolling oil of the present invention is a uniform one-phase fluid, and there is no problem that the oil film thickness becomes nonuniform, and therefore uneven glossiness does not occur.

The cold rolling oil of the present invention is characterized by using both the lubricity improver and the thickener in combination.

In the case of the cold rolling oil in which only the lubricity improver contained in the cold rolling oil component of the present invention is dissolved in water, most of the components are water, and the high pressure viscosity of the entire cold rolling oil is Since it is extremely low, cold rolling oil flows out from the gap between the roll and steel plate roughness in the roll bite where the pressure becomes extremely high during rolling, and the lubricity improver cannot be sufficiently retained in the roll bite. . However, the cold rolling oil of the present invention contains not only the lubricity improver but also the thickener in an amount of 5 to 60% by weight (since the lubricity improver is contained at least 1% by weight, the upper limit is exactly 59% by weight. ), The overall high-pressure viscosity is similar to that of low-viscosity mineral oil, and cold rolling oil does not flow out from the gap between the roll and steel plate roughness even in the roll bite during rolling. Retained within. Therefore, the lubricity improver in the cold rolling oil, which is retained even on the new surface generated by rolling, is adsorbed to prevent seizure. Further, since the upper limit of the content of the thickening agent in the cold rolling oil of the present invention is about 60% by weight, the problem that oil pits are excessively generated and the gloss of the steel sheet is lowered does not occur.

On the other hand, in the case of a cold rolling oil in which only the thickening agent contained in the cold rolling oil component of the present invention is dissolved in water, the high-pressure viscosity is similar to that of mineral oil, but the lubricity improver adsorbed on the new surface Since it does not contain, it is likely to cause seizure.

As described above, it is necessary to use both the lubricity improver and the thickener in combination.

The thickener used in the present invention is a polyhydric alcohol having 6 or less carbon atoms. Polyhydric alcohols having 7 or more carbon atoms cannot be used because of their low solubility in water. Examples of such thickeners include ethylene glycol, propylene glycol, butanediol, hexanediol, diethylene glycol, neopentyl glycol, glycerin, trimethylolpropane, pentaerythritol and the like. Among them, ethylene glycol and glycerin are more preferable. These substances have the function of increasing the viscosity by hydrogen bonding of alcoholic hydroxyl groups in the molecule in water. Further, when the phosphoric acid generated by the hydrolysis of the phosphoric acid compound added as the lubricity improver increases,
Although it corrodes rolling mills and steel sheets, these polyhydric alcohols have the effect of esterifying and neutralizing this phosphoric acid.
It is also useful for eliminating the adverse effects of the addition of the phosphate compound and maintaining the lubricating action.

The content of the thickener according to the present invention is 5% by weight.
That is all. If it is less than 5% by weight, the high-pressure viscosity is too low, and the cold rolling oil is not sufficiently retained in the roll bite.

The lubricity improver used in the present invention is a dithiophosphoric acid compound represented by the above general formula. here,
The number of carbon atoms R of the dithiophosphoric acid compound is set to 4 to 18,
If it is less than 4, the thickness of the adsorbed molecular film is small and the seizure resistance is not sufficient, and if it is 19 or more, it becomes difficult to dissolve in water even if the number n of added moles of ethylene oxide is increased. The range of n that can be uniformly dissolved in water in the range of 4 to 18 carbon atoms is 1 to 10. When 0, that is, when ethylene oxide is not added, this phosphoric acid compound does not dissolve in water, and when it is 11 or more, the dithiophosphoric acid compound forms micelles, and the adsorptivity to the metal surface is extremely lowered. Furthermore, problems such as easy foaming occur.

As the metal in the dithiophosphate compound, a divalent metal is used, and zinc (Zn), lead (P
b) and molybdenum (Mo) are preferable.

The following compounds are suitable as the dithiophosphoric acid compound used in the present invention. That is, zinc dipolyoxyethylene oleyl dithiophosphate (mol number of ethylene oxide: 1 to 10), lead dipolyoxyethylene oleyl dithiophosphate (mol number of ethylene oxide: 1 to 10)
10), molybdenum dipolyoxyethylene oleyl dithiophosphate (mol number of ethylene oxide: 1 to 10), zinc dipolyoxyethylene lauryl dithiophosphate (mol number of ethylene oxide: 1 to 10), dipolyoxyethylene lauryl Lead dithiophosphate (moles of ethylene oxide: 1 to 10), dipolyoxyethylene lauryl molybdenum dithiophosphate (moles of ethylene oxide: 1 to 1)
0), zinc dipolyoxyethylene stearyl dithiophosphate (moles of ethylene oxide: 1-10), lead dipolyoxyethylene stearyl dithiophosphate (moles of ethylene oxide: 1-10), dipolyoxyethylene stearyl Molybdenum dithiophosphate (moles of ethylene oxide: 1-10), zinc dipolyoxyethylenephenyldithiophosphate (moles of ethylene oxide: 1-1)
0), lead dipolyoxyethylene phenyldithiophosphate (the number of moles of ethylene oxide: 1-10), molybdenum dipolyoxyethylenephenyldithiophosphate (the number of moles of ethylene oxide: 1-10), dipolyoxyethylenebenzyl. Zinc dithiophosphate (moles of ethylene oxide: 1-10), lead dipolyoxyethylenebenzyldithiophosphate (moles of ethylene oxide: 1-10), molybdenum dipolyoxyethylenebenzyldithiophosphate (of ethylene oxide) Number of moles: 1 to 10), zinc dipolyoxyethylenenonylphenyldithiophosphate (number of moles of ethylene oxide: 1 to 10), lead dipolyoxyethylenenonylphenyldithiophosphate (number of moles of ethylene oxide: 1 to 10) ), Molybdenum dipolyoxyethylene nonylphenyl dithiophosphate (Ethylene The number of moles of oxide:
1 to 10) etc.

These lubricity improvers act by a mechanism similar to that of the organometallic extreme pressure agents described in, for example, "Physical Chemistry of Lubrication" (Sakurai, Koshobo), and P and S reacts with the surface of the steel sheet to improve lubricity.

The content of the lubricity improver according to the present invention is 1
% By weight or more. If it is less than 1% by weight, even if a cold rolling oil containing a thickening agent is held in the roll bite, it cannot be adsorbed and covered on all new surfaces generated by rolling, and seizure easily occurs.

The total amount of the thickener and the lubricity improver according to the present invention is 60% by weight or less.

The total amount of the thickener and the lubricity improver is 60% by weight.
If it exceeds, the water content will be too small, and the cooling performance will drop sharply.

[0030]

The present invention will be specifically described below with reference to examples.

First, Examples 1 to 33 of the present invention shown in Tables 1 to 3
And 44 types of cold rolling oils of Comparative Examples 1 to 11 shown in Tables 4 and 5 were prepared. Here, Comparative Example 10 was an O / W emulsion type cold rolling oil, and the average particle size of the oil droplets was adjusted to about 4 μm with a homomixer.

Using these cold rolling oils, coil rolling was performed under the conditions shown in Table 7 by a four-stage rolling mill shown in Table 6 to evaluate lubricity (seizure resistance) and gloss. As a rolling roll, SKD11, semi-high speed steel (0.4% C, 5% C
r, 1% Mo, 0.3% V, 1% W) and SKD11 with Cr plated rolls all have a surface roughness (Ra) of 0.01 μm.
SUS430, SUS304 and carbon steel (SPCC-SB) were used as the material to be rolled. In addition, each cold rolling oil is directly applied to the roll and the steel plate at the inlet side of the rolling mill at a pressure of 5 kgf / c.
It was supplied at m ² and a flow rate of 6 l / min.

The seizure resistance was evaluated by observing the presence or absence of seizure flaws with the naked eye, and was evaluated as good only when one coil (800 m) was rolled and seizure did not occur at all.
The glossiness is evaluated by measuring the surface glossiness (Gs45 °). For SUS430 and carbon steel, the glossiness is 7
Only when the value exceeded 00, was good, and for SUS304, when the glossiness exceeded 600, it was considered good.

Table 8 shows the results when SUS430 was rolled, Table 9 shows the results when SUS304 was rolled, and Table 10 shows the results when carbon steel was rolled. The glossiness of SUS430 was evaluated by measuring the surface glossiness when the rolling reduction was 30%. Regarding seizure resistance, SUS43
For each of 0, SUS304 and carbon steel, one coil was rolled and evaluated as good only when seizure did not occur at all, and marked with x when seizure occurred. Table 8 shows the coil surface temperature immediately after rolling when SUS430 was rolled with the SKD11 roll.

From these results, by using the cold rolling oil of the present invention, it is possible to suppress the temperature rise of the roll and the steel sheet and to prevent seizure even when any of SUS430, SUS304 and carbon steel is rolled. It became clear that it could be completely prevented. In addition, it was confirmed that the cold rolling oil of the present invention produced a small amount of oil pits and had good gloss. Furthermore, the cold rolling oil of the present invention did not cause uneven gloss as seen in the emulsion type cold rolling oil. In Comparative Example 8, the component II was not dissolved in water and did not become homogeneous, so that the test could not be performed.

Further, the same effect was obtained when any of the rolling rolls of SKD11, semi-high speed steel and Cr plating roll was used.

[0037]

[Table 1]

[0038]

[Table 2]

[0039]

[Table 3]

[0040]

[Table 4]

[0041]

[Table 5]

[0042]

[Table 6]

[0043]

[Table 7]

[0044]

[Table 8]

[0045]

[Table 9]

[0046]

[Table 10]

[0047]

EFFECTS OF THE INVENTION By using the cold rolling oil of the present invention, it is possible to produce a steel sheet which does not cause seizure even at high speed rolling, has no risk of fire when the sheet breaks, and has good surface gloss. You can

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Claims (1)

[Claims] 1. [I] The content of at least one of polyhydric alcohols having 6 or less carbon atoms is 5% by weight or more, and [II] at least one of dithiophosphoric acid compounds represented by the following general formula. [I] and [II] are contained in water such that the content of one kind is 1% by weight or more and water, and the sum of the contents of [I] and [II] is 60% by weight or less. Cold rolling oil formed by melting. Embedded image However, R is an alkyl group having 4 to 18 carbon atoms, an alkenyl group,
An aryl group or an alkylaryl group, n is an integer of 1 to 10, and M is a metal element.