JP2009144100A - Hot-rolling oil for stainless steel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hot-rolling oil for stainless steel reducing a using amount of a sulfur compound and having excellent seizure resistance. <P>SOLUTION: This hot-rolling oil for stainless steel contains one kind, two kinds or more selected from the group of synthetic esters and/or fats and oils as a base oil, and contains 10 wt.% or more to less than 40 wt.% of sulfur compound, and an iodine value of the base oil mixed with the one kind, the two kinds or more selected from the group of the synthetic esters and/or the fats and oils is 40 or less. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a rolling oil used during hot rolling of stainless steel.

In the field of hot rolling, rolling lubricants are used for the purpose of preventing seizure resistance and reducing roll wear. In particular, stainless steel has a feature that the surface is difficult to be oxidized even at a high temperature, and therefore, the rolled material is very easy to seize on the roll surface as compared with general carbon steel in which a scale having an anti-seizure effect is easily formed at a high temperature. Due to this seizure, the surface quality of the rolled material is greatly deteriorated, so that the rolling oil is required to have high seizure resistance.
In hot rolling, unlike cold rolling performed at a rolled plate temperature of about 60 ° C. to 150 ° C., the rolling is performed in a hot region where the rolled plate temperature is about 800 ° C. to about 1000 ° C. The following lubrication performance is required. Therefore, the required performance, the design concept of the rolling oil, and the like are different in the hot rolling oil from the normal cold rolling oil.

  In conventional hot rolling oils, synthetic esters, fats and oils are used as base oils, and anti-seize additives such as sulfur compounds and solid lubricants are dissolved or dispersed in these to improve seizure resistance. I came.

In the use example of the sulfur compound, there is an example using 40 to 90% by weight of a sulfurized ester or polysulfide. In order to improve the seizure resistance, a very large amount of use is required for this sulfur compound. On the other hand, due to the heat applied during rolling, the influence of microorganisms in the subsequent drainage process, etc., this sulfur compound is required. The compound decomposes and a new decomposition product is generated. This includes mercaptans, which are considered to be offensive odor, and have a great adverse effect on the working environment and the surrounding environment. (Patent Document 1)
Therefore, there is a demand for a hot rolled oil for stainless steel having excellent seizure resistance even if the amount of sulfur-based compound used is small.

  On the other hand, in the usage example of the solid lubricant, there is an example in which the calcium compound particles are dispersed in the lubricating oil. Since a solid lubricant cannot be dissolved in oil, it is required to disperse effectively, but a problem remains in maintaining the dispersed state. When the dispersion state changes over time, sedimentation due to aggregation occurs, resulting in a non-uniform system, resulting in a lack of the required amount of solid lubricant and insufficient amount of introduction into the roll bite. Not only does the seizure resistance be insufficient and the expected effect is not achieved, but also clogging occurs in the strainer and nozzle portion, resulting in a decrease in operability. (Patent Document 2)

  In addition, studies have been made on the base oil used as the base, and there are examples where palm olein is used as the base oil to improve lubricity and reduce the friction coefficient, but there is seizure resistance in hot rolling of stainless steel. The heat resistance is not considered, and cannot be used as a hot rolling oil having seizure resistance. (Patent Document 3)

  Regarding the base oil, there is an example in which a modified oil and fat having an iodine value of 50 to 90 is used not in the field of hot rolled oil but in, for example, cold rolled oil for steel sheet. This is a requirement to achieve both the stain resistance around the rolling mill and the alkali cleaning removal property of the steel sheet, and does not take into account the seizure resistance in the hot region, as a hot rolling oil having seizure resistance. Cannot be used. (Patent Document 4)

In lubricating welding wires, there is an example in which a feed lubricating oil having an iodine value of 40 or less is used. This takes into account the oxidation stability of the feed lubricating oil, and prevents an increase in pour point due to oxidative polymerization / polymerization. Also in this regard, the seizure resistance in the hot region is not taken into consideration and cannot be used as a hot rolling oil having seizure resistance. (Patent Document 5)
In addition, in order to temporarily protect the metal surface and make it lubricous, there is an example of using an oil having an iodine value of less than 100. This is in consideration of oxidation of fatty acid and room temperature fluidity. However, the seizure resistance in the hot region is not taken into consideration and cannot be used as a hot rolling oil having seizure resistance. (Patent Document 6)

JP2000-230187A JP 2000-160181 A Japanese Patent Laid-Open No. 11-80764 JP-A-8-337791 JP 2000-117486 A Special table 2004-515564

  An object of this invention is to provide the hot rolling oil for stainless steel which reduces the usage-amount of a sulfur type compound, and has the outstanding seizure resistance.

As a result of earnestly examining the seizure resistance improvement in hot rolling of stainless steel, the present inventors obtained knowledge that the above problem can be solved by using a specific base oil as the base oil in the rolling oil, This completed the present invention.
That is, the present invention includes hot rolling for stainless steel containing one or more selected from synthetic esters and / or fats and oils as a base oil and containing 10% by weight or more and less than 40% by weight of a sulfur compound. Provided is a hot rolled oil for stainless steel, characterized in that the iodine value of the base oil obtained by mixing one or more selected from the synthetic esters and / or fats and oils is 40 or less.

  When the hot rolling oil for stainless steel of the present invention is used, the seizure resistance of the rolling oil is greatly improved, and the surface quality of the rolled material can be improved. Furthermore, the usage-amount of the sulfur type compound to be used can be reduced significantly, and the influence on a working environment and surrounding environment can also be reduced significantly.

  The base oil used in the hot rolled oil for stainless steel of the present invention is a low iodine number synthetic ester and / or fat and oil, and is a group obtained by mixing one or more selected from the synthetic ester and / or fat and oil. The iodine value of the oil is 40 or less. Preferably, the iodine value is 32 or less, and all of the base oil is a synthetic ester or a mixture of a synthetic ester and fats and oils. The iodine value can be easily measured, for example, by a method such as the Japan Oil Chemists' Society established standard oil analysis method (Wiis-cyclohexane method).

  In the present invention, mineral oil can be further used as the base oil. In this case, the mineral oil is preferably 50% by weight or less, particularly 40% by weight in the hot rolled oil for stainless steel of the present invention. % Or less is preferable.

  In the synthetic ester and oil and fat used in the present invention, the properties vary greatly depending on the constituent fatty acid species, and a base oil having the required iodine value can be obtained by selecting the fatty acid species.

  Synthetic esters include mono- and / or polyhydric alcohols such as 2-ethylhexanol, neopentyl glycol, trimethylolpropane, pentaerythritol, dipentaerythritol, glycerin, polyglycerin, capric acid, lauric acid, myristic acid, palmitic acid. Any one or more selected from the group consisting of C10-C36 linear, branched, saturated, unsaturated fatty acids and polybasic acids such as stearic acid, isostearic acid, oleic acid, and dimer acid It is preferable to use the esterified product.

  As fats and oils, it is preferable to use refined and hydrogenated soybean oil, rapeseed oil, palm oil, beef tallow, lard, etc., and glycerin and C10-C36 linear, branched, and saturated types It is preferable to use an esterified product of any one or more selected from the group consisting of unsaturated fatty acids and polybasic acids.

  The iodine value of the synthetic ester and / or fat used in the base oil has a great influence on the seizure resistance, and contains one or more selected from synthetic esters and / or fats and oils. When the iodine value of the base oil obtained by mixing one or more selected from fats and oils is 40 or less, a rolling oil having excellent seizure resistance can be obtained.

  The iodine value of the synthetic ester and / or fats and oils constituting the base oil is preferably 40 or less.

  The iodine value of the base oil is determined by the degree of unsaturation of the constituent fatty acids. It is known that a fatty acid having a high degree of unsaturation, for example, a fatty acid having a double bond, deteriorates rapidly as the number of double bonds in the fatty acid increases.

  By suppressing the iodine value of the synthetic ester and / or fats and oils constituting the base oil, effective lubrication can be provided during rolling at a high temperature.

The hot rolling oil for stainless steel of the present invention contains 10% by weight or more and less than 40% by weight of a sulfur compound. The amount of the sulfur compound is preferably 35% by weight to 10% by weight, and more preferably 30% by weight to 10% by weight.
In the present invention, known sulfur-based extreme pressure additives can be used as the sulfur-based compound.

  Known sulfur extreme pressure agents include sulfurized fats and oils, sulfurized esters, sulfurized olefins, and polysulfides. Of these, it is preferable to use sulfurized olefin or polysulfide.

  The rolling oil according to the present invention can be used by dissolving or dispersing a known extreme pressure additive or solid lubricant in the base oil for the purpose of further improving seizure resistance. Such extreme pressure additives and solid lubricants include phosphate esters, phosphites, thiophosphites, dialkyldithiophosphates (eg ZnDTP), carbon compounds such as graphite, layered compounds such as mica, Molybdenum fluoride, metal particles, and metal oxide particles can be mentioned, and these are preferably contained in the hot rolling oil for stainless steel of the present invention in an amount of 0.001 to 30% by weight.

  The rolling oil according to the present invention can be used by adding other known antioxidants, surfactants, thickeners, viscosity index improvers, pour point depressants and the like to the base oil.

  The rolling oil according to the present invention can be used as neat oil or diluted with water as an emulsion or dispersion. At this time, the concentration of the hot rolling oil for stainless steel of the present invention in the emulsion or dispersion is preferably 1 to 10% by weight.

  The rolling oil according to the present invention can be used when rolling not only stainless steel but also metal steel plates including ordinary steel and silicon steel.

  The rolling oil according to the present invention can be applied to a roll or a rolled plate by spray, roller, brush or the like.

  The rolling oil according to the present invention can be used not only for rolling but also as a lubricating oil for plastic working such as cutting, grinding, pressing, bending, drawing, drawing, and ironing.

  Examples and comparative examples are shown below.

  A predetermined amount of the components shown in Table 1 was blended to produce the rolling oil of the present invention.

  A predetermined amount of the components shown in Table 2 was blended to produce a rolling oil for a comparative example.

About the Example and comparative example which are shown in Table 1 and Table 2, the rolling test was done, the surface roughness of the board after rolling was investigated, and the seizure resistance was evaluated.
In addition, the iodine value of the base oil in a table | surface was measured by the method shown below.
Iodine value measuring method Dissolve the sample in 10 mL of cyclohexane, add 25 mL of the Wies solution, and leave it at room temperature with occasional shaking.
Add 10 g / 100 mL potassium iodide 20 mL and water 100 mL and shake well.
Titrate with 0.1 mol / L sodium thiosulfate standard solution. When the solution turns slightly yellow, add a few drops of starch solution and continue titration. The end point is when the blue color of the solution disappears.
Iodine value = (A−B) × F × 1.269 / C
here,
A: Amount of 0.1 mol / L sodium thiosulfate standard solution used for blank test (mL)
B: Amount of 0.1 mol / L sodium thiosulfate standard solution used in this test (mL)
F: Factor of 0.1 mol / L sodium thiosulfate standard solution C: Sample collection amount (g)

Table 1

Table 1 (continued)

表中、^*1の付いた値は、鉱油を含まない基油のヨウ素価である。 Table 1 (continued)

In the table, the value with ^{* 1} is the iodine value of the base oil not containing mineral oil.

Table 2

Table 2 (continued)

The substances shown in Tables 1 and 2 were as follows.
Synthetic ester 1: Trimethylolpropane complex ester Iodine number 23
Synthetic ester 2: Trimethylolpropane palm oil fatty acid ester Iodine value 6
Synthetic ester 3: 2 ethyl hexanol stearate Iodine value 0.3
Synthetic ester 4: 2 ethylhexanol oleate Iodine value 62
Synthetic ester 5: Trimethylolpropane oleate Iodine value 88
Fat and oil 1: Palm oil refined product Iodine value 40
Fat and oil 2: Palm oil refined product Iodine value 46
Fat 3: Oil refined palm oil (modified oil) Iodine value 69
Fats and oils 4: Palm oil refined product (palm olein) Iodine value 70
Sulfur compounds: Sulfurized olefins, 8 carbon atoms, sulfur content 39% by weight

<Rolling test>
Test piece: SUS430 30 mm (width) x 100 mm (length) x 2 mm (thickness)
Test piece heating temperature: 900 ° C
Rolling speed: 10 mpm
Roll diameter: 100mm
Roll roughness: Ra 0.16 μm
Reduction ratio: 50%
Rolling oil application: 0.03 g of neat oil was dropped and then spread evenly on the roll surface.

<Test method>
A test piece is rolled by heating a test piece in a 900 degreeC thermostat for 1 hour or more, and introduce | transducing into the roll currently rotated with a predetermined | prescribed speed | rate. The roll was # 240 sandpaper and polished each time the test piece was rolled.

<Surface roughness evaluation>
Test equipment: Surface roughness profile measuring machine Surfcom 570A (Tokyo Seimitsu Co., Ltd.)
Roughness measurement direction: Roughness measurement length perpendicular to the rolling direction: 3 mm
Evaluation item: Ra
Ra of 0.50 or less was evaluated as having excellent seizure resistance (○ evaluation)
Furthermore, 0.45 or less was evaluated as being particularly excellent (特 に evaluation). Moreover, the thing exceeding 0.50 was evaluated as a bad thing (x evaluation).

<Test method>
The test piece after rolling was set in a testing machine, the surface roughness at the center in the width direction and the length direction was measured, and the average value was calculated.

From Tables 1 and 2 and FIG.
(1) From Examples 1-4 and Comparative Examples 1-5, the seizure resistance which was excellent as rolling oil by using as a base oil what the iodine value of a synthetic ester and / or fats and oils is 40 or less respectively. Show.

(2) From Examples 5 to 10 and Comparative Example 6, even in the rolling oil containing two or more kinds of synthetic esters and / or fats and oils, if the iodine value obtained by mixing them is 40 or less, excellent seizure resistance is achieved. Show. However, it is more excellent in seizure resistance that the iodine value of the synthetic ester and / or fat and oil constituting the base oil is 40 or less.

(3) From Examples 11-14, the synthetic ester and / or fats and oils constituting the base oil each had an iodine number of 40 or less, two or more synthetic esters and / or fats and oils, and these were mixed. Even if mineral oil is mixed with an iodine value of 40 or less, it shows excellent seizure resistance as a rolling oil.

(4) From Examples 1 and 15 and Comparative Example 7, if the amount of sulfur compound used is 10 to 30% by weight, sufficient seizure resistance is exhibited.

(5) From Comparative Example 5, even when palm olein is used, excellent seizure resistance is not exhibited.

(6) From Comparative Examples 4 and 8, even in the case of cold rolling oil that uses a modified oil and fat and requires both the stain resistance and the alkaline cleaning removal property of the steel sheet, excellent seizure resistance is not exhibited.

(7) From Comparative Example 9, in consideration of oxidation resistance stability, even in the case of a feed lubricating oil having an iodine value of 40 or less that prevents an increase in pour point due to oxidative polymerization / polymerization, excellent seizure resistance is exhibited. Not shown.

  From the examples and comparative examples, it can be determined that the rolling oil according to the present invention can be used as the hot rolling oil for stainless steel sheets.

FIG. 1 summarizes the iodine value and surface roughness of synthetic esters or fats from Examples 1-4 and Comparative Examples 1-5.

Claims (8)

  A hot rolling oil for stainless steel containing one or more selected from synthetic esters and / or fats and oils as a base oil, and containing 10% by weight or more and less than 40% by weight of a sulfur compound, A hot rolled oil for stainless steel, wherein the iodine value of a base oil obtained by mixing one or more selected from synthetic esters and / or fats and oils is 40 or less.   The hot rolled oil for stainless steel according to claim 1, wherein the iodine value of each of the synthetic ester and the fat and oil constituting the base oil is 40 or less.   The hot rolling oil for stainless steel according to claim 1 or 2, wherein the base oil further contains a mineral oil.   Any one or more selected from the group consisting of monovalent and / or polyhydric alcohols, straight-chain, branched, saturated, and unsaturated fatty acids and polybasic acids having 10 to 36 carbon atoms, The hot-rolled oil for stainless steel according to any one of claims 1 to 3, wherein   The oil or fat is an esterified product of glycerin and any one or more selected from the group consisting of linear, branched, saturated, unsaturated fatty acids and polybasic acids having 10 to 36 carbon atoms. The hot rolling oil for stainless steel according to any one of 3.   The iodine value of the synthetic ester is 40 or less, the synthetic ester is a monovalent and / or polyhydric alcohol, a linear, branched, saturated or unsaturated fatty acid and polybasic acid having 10 to 36 carbon atoms. The hot rolled oil for stainless steel according to any one of claims 1 to 3, which is an esterified product of any one or more selected from the group consisting of:   The iodine value of fats and oils is 40 or less, and the fats and oils are any one selected from the group consisting of glycerin and linear, branched, saturated, unsaturated fatty acids and polybasic acids having 10 to 36 carbon atoms The hot-rolled oil for stainless steel according to any one of claims 1 to 3, which is an esterified product as described above.   A hot rolling method comprising using the hot rolled oil for stainless steel according to any one of claims 1 to 7 as neat oil, an emulsion obtained by diluting with water, or a dispersion.

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