JPH01121389A - Production of stainless steel abraded specification material having excellent corrosion resistance - Google Patents

Abstract

PURPOSE:To efficiently obtain a stainless steel abraded specification material having excellent corrosion resistance, by using a cutting oil agent having a low S content, comprising a chlorine-containing compound and a P-containing compound. CONSTITUTION:A cutting oil agent having <0.35wt.% (preferably <0.10wt.%) S content, comprising preferably 0.1-5wt.% chlorine-containing compound such as chlorinated paraffin and/or P-containing compound such as tricresyl phosphate, is used to give the aimed specification material. The oil agent is applicable not only for production of HL specification material and BG specification material by cutting belt but also for production of abraded specification material such as HL specification material by rotary brush and scaly pattern specification material by rotary whetstone.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for efficiently manufacturing a polished stainless steel material having excellent rust resistance.

<Prior art and its problems> In recent years, the uses of stainless steel materials have become extremely diverse.
In response to this trend, products with various surface specifications have been manufactured. Among these, BA specification materials and 2B specification materials, which take advantage of the surface gloss unique to stainless steel, are in the widest demand, but depending on the application, materials with less surface gloss are often preferred, and recently they have been used as interior construction materials. , Stainless steel materials with scratches on the entire surface (polished materials) used for home appliances or kitchen products, etc.
” demand is rapidly increasing.

Conventionally, in order to manufacture the above-mentioned stainless steel polished materials on an industrial scale, a method was generally adopted in which a rotating grinding belt was brought into contact with the stainless steel material to be processed, such as a continuously running belt. Among these methods, the following two methods have been predominant, which are broadly classified depending on the contact mode between the stainless steel material to be treated and the grinding belt and the surface pattern of the resulting product. That is, i) As shown in FIG. 1, by a method in which the stainless steel material 2 to be treated is run at a speed faster than the rotational movement speed of the grinding belt 1, scratch patterns parallel to each other are generated on the entire surface of the resulting product. This method is called HL (Hair Line) specification.

ii) As shown in Fig. 2, this is a method in which the rotation speed of the grinding belt 1 is made faster than the running speed of the stainless steel material 2 to be processed, and relatively short scratches are intermittent in the longitudinal direction of the stainless steel material to be processed. A pattern is created,
This method is called BG (Belt Grinded) specification.

Depending on the size of the abrasive grains in the belt used, a variety of abrasive materials can be obtained with surface roughness ranging from coarse to fine. In order to prevent oxidation and coloring of the surface of stainless steel materials and to increase grinding efficiency, it is essential to sprinkle grinding oil (cutting oil) on the grinding belt and the stainless steel materials before grinding.

However, it has been reported that the polished stainless steel material manufactured in the manner described above, which has a unique appearance, ``occasionally rusts when used outdoors near the coast.'' B was used under similar conditions.
Since A specification materials and 2B specification materials do not rust, polished specification materials were generally considered to have inferior corrosion resistance to BA specification materials and 2B specification materials.

Therefore, in order to eliminate such problems, the present inventors first proposed that ``When manufacturing stainless steel polishing materials, the S content in the cutting fluid used at least in the final polishing process should be reduced to less than 0.35% by weight. He proposed a method for polishing with limited polishing (Japanese Patent Application No. 178956/1983).

In addition, the above-mentioned method proposed earlier is: (a) Cooling tools and workpieces that tend to rise in temperature due to processing heat during cutting or grinding of metal materials, and lubrication between the cutting edge of the tool and the finished surface of the workpiece. It is essential to use a "cutting fluid (grinding fluid)" consisting of an alkaline aqueous solution, emulsified oil, mineral oil, animal or vegetable oil, etc., in order to maintain the ease of work by washing away the shavings. ,
Moreover, up to 3% by weight of S (sulfur) is usually added to this cutting fluid in order to improve the anti-friction effect, suppress tool wear, and obtain a good machined surface. However, S in this S-containing cutting fluid (sulfurized oil) reacts with the surface of stainless steel during the polishing (grinding) process, and as a result, the corrosion resistance of stainless steel polishing specification materials is lower than that of BA specification materials and 2B specification materials. In other words, although HL polishing and BG polishing are performed while cooling with a large amount of grinding fluid, the stainless steel surface being polished locally has a temperature of several hundred degrees (probably 600 to 800 degrees). It is estimated that the temperature rises to about 30°F (℃), but due to this heat, the Cr component on the surface of the stainless steel preferentially reacts with the S in the cutting fluid to form chromium sulfide. In addition to causing a decrease in concentration, the formation of sulfides on the surface prevents the formation of a passive film (a dense and highly protective film mainly composed of Cr oxides), and as a result, stainless steel (b) One way to prevent this phenomenon is to slowly polish the surface and suppress the temperature rise of the workpiece as much as possible; If the polishing speed is reduced to the point where the temperature of the workpiece reached is below the temperature that causes the above-mentioned disadvantages, this will lead to a significant decrease in productivity and increase the cost of the product, so this method is adopted industrially. (C) However, if the surface of stainless steel is polished using a cutting fluid with a suppressed S content of less than 0.35% by weight, stainless steel polishing specifications can be achieved. A polished surface with good corrosion resistance can be obtained without significantly reducing the current grinding speed in material manufacturing, and there are no problems such as "defects in the finished surface" caused by insufficient lubrication of the cutting fluid. This was done based on the knowledge of the present inventors.

However, the inventors of the present invention, through subsequent studies through actual work, found that ``the previously proposed method using a cutting fluid with a low S content certainly improves stainless steel polishing specifications with good rust resistance. Although the material can be obtained, it is difficult to do anything about the fact that the machinability deteriorates to a certain extent, and the economic disadvantages due to deterioration of polishing efficiency and wear and tear of the polishing belt cannot be ignored. I ended up having one.

Measures to Solve the Problems From the above-mentioned viewpoint, the present inventors have developed a stainless steel polishing specification that not only has sufficient rust resistance but is also more advantageous in terms of work efficiency and manufacturing cost. As a result of further research to provide a method for manufacturing the material, it was found that [in order to ensure the desired excellent rust resistance for stainless steel polished materials, the S content in the cutting fluid used must be reduced to 0.35% by weight. It is essential to limit the S content to less than %, but if a cutting fluid containing one or two of a Cl (chlorine)-containing compound or a P (phosphorus)-containing compound is used at the same time, the S content can be suppressed to prevent induction. "This method ensures good machinability without sacrificing the effect of improving polishing properties, and makes it possible to manufacture stainless steel abrasive materials with sufficiently excellent rust resistance at high efficiency with less wear and tear on the abrasive belt." The facts have become clear.

This invention has been made based on the above-mentioned findings, and includes the following: ``When manufacturing stainless steel polishing materials, the cutting fluid used at least in the final polishing process has an S content of less than 0.35% by weight, and By containing one or more of a chlorine-containing compound and a P-containing compound, stainless steel polishing specification material with excellent rust resistance can be manufactured at low cost and with high efficiency.''

In addition, S which is carried out in the method of this invention
Polishing using a cutting fluid containing one or more of a chlorine-containing compound and a P-containing compound with a content of less than 0.35% by weight is sufficient only in the final polishing step in the manufacturing process of stainless steel polishing specification materials, and is only an intermediate polishing step. This kind of consideration is not necessarily necessary in the polishing process; for example, in the manufacturing process of stainless steel polished specification plates, similar considerations are taken for the purpose of removing surface flaws on the stainless steel hot coil even before the final polishing process that imparts the polishing pattern. However, even if a normal cutting fluid containing a large amount of S is used at this time, the corrosion resistance will deteriorate because annealing and pickling are performed afterwards to remove the surface layer with a low Cr concentration. This is because there is no risk of it leading to

If the S content of the cutting fluid used in the final polishing step is 0.35% by weight or more, it will not be possible to obtain a stainless steel abrasive specification material that will not rust even when used outdoors near the coast. A product exhibiting good corrosion resistance even under the above environment can only be realized by limiting the S content to less than 0.35% by weight, but preferably the S content is 0.1% by weight.
It is recommended that the content be less than 0% by weight.

This is because if a cutting fluid with an S content of 0.10-0.35% by weight is used in the final polishing process of stainless steel polishing specification materials, it is true that rusting will not occur even when used outdoors near the coast. However, with a cutting fluid with such a degree of S content reduction, when heated to about 100 to 300°C (for example, by baking the paint,
This is because there are slight signs of deterioration in corrosion resistance when used in an environment where water vapor is sprayed.

This is because even if a relatively low S cutting fluid is used, some chromium sulfide is generated on the surface of the polished stainless steel material during the final polishing process, creating a condition where oxidation is likely to occur. It is thought that this is because when this occurs, the Cr concentration in the surface layer portion decreases due to preferential oxidation of Cr, resulting in deterioration of corrosion resistance.

Furthermore, when using stainless steel polishing specification materials coated with organic paints outdoors, if the final polishing is done with a cutting oil containing 0.10% or more of S, "flawed areas of the paint film" may occur.
Corrosion may occur in areas where the stainless steel surface is exposed, such as the edges of the plate, and the coating may gradually peel off, so from this point of view, the cutting fluid used in the final polishing process should be It is desirable that the content be less than 0.610% by weight.

Note that cutting fluids generally contain “free S” and “combined S.”
``The former has stronger reactivity, but when mechanical grinding is applied, local overheating occurs, so the latter also fully participates in the reaction, so it is necessary to control the content based on the total amount of both. There is.

In addition, various types of chlorine-containing compounds and P-containing compounds can be used in the cutting agent used in the method of the present invention, and are not particularly limited. Among P-containing compounds such as paraffin, those that can be dissolved in base oils such as tricresyl phosphate are desirable. From this point of view, it is preferable to adjust the amount of each of these additives to 0.1 to 5% by weight.

Incidentally, attempts have already been made to use not only sulfurized mineral oil, dibenzyl disulfide, sulfurized spam, oleic alcohol, or oleic acid, but also chlorine-containing compounds, P-containing compounds, etc. as additives for cutting oil. 3
In cutting fluids in which a small amount of S (less than 5% by weight) is present (complete removal of S would result in a major economic disadvantage in industry), it is possible to reduce S without aggravating the negative effect of S on rust resistance. A chlorine-containing compound or a P-containing compound is an irreplaceable additive in that it exerts an effect of improving machinability while suppressing the above-mentioned adverse effects of .

In other words, chlorine-containing compounds and P-containing compounds not only do not react with the surface of stainless steel even if the temperature rises due to local heating during polishing, and do not cause any adverse effects on corrosion resistance. When a chlorine-containing compound or a P-containing compound is added to a cutting fluid with a reduced S content, "good machinability during polishing" and "excellent rust resistance of stainless steel materials after polishing" are achieved by adding S in the cutting fluid. Content 0.35% by weight
This effectively appears as a synergistic effect with the fact that it is less than 20%.

The type of stainless steel that can be applied to the method of the present invention is not particularly limited, but if a highly corrosion-resistant stainless steel with a high content of Cr, Ni, or Mo is used, a product with better rust resistance can be obtained. Needless to say, you can obtain

Furthermore, the finer the abrasive grains of the abrasive material (such as an endless belt) used, the more advantageous it is to obtaining a product with excellent rust resistance. From the perspective of improving the resistance of the product, it is preferable that the relative speed between the abrasive material and the stainless steel material during polishing is lower, and that the pressure and time for pressing the abrasive material are smaller. Roughening of the abrasive material, increase in polishing speed,
This is because increasing the pressure and time of pressing the abrasive material locally increases the temperature of the stainless steel material, thereby promoting rusting.

Note that the method of the present invention is not limited to the production of HL specification materials and BG specification materials using a grinding belt, but can also be applied to HL specification materials using a rotating brush and polished specification materials such as scale pattern finished materials using a rotating grindstone. Of course it can be applied.

Next, the present invention will be specifically explained using examples and comparing with comparative examples.

<Example> SU343 G stainless steel i and 5O3304 stainless steel plates, both of which have a thickness of 1.0 fi, were polished using an I240 or Yu40 belt grinder wetted with four types of cutting fluid shown in Table 1 while changing the belt speed. Then, the amount of grinding and rust resistance were investigated.

Among the cutting fluids, Daphne Polishing Oil #43 (trade name: Idemitsu Kosan Co., Ltd.) is a base oil and does not substantially contain S. A cutting fluid that meets the conditions of the present invention is prepared by adding and dissolving one or both of chlorinated paraffin (70% chlorinated) and tricresyl phosphate into the base oil.

Moreover, the rust resistance was investigated by repeating the salt water spray test specified in JIS Z2371 [16 hours of spraying - 8 hours of stopping the spraying] three times.

These results are also shown in Table 1.

As is clear from the results shown in Table 1, 2% by weight
When using a cutting fluid containing chlorinated paraffin,
Even though the amount of grinding is the highest, there is very little rust (
(same level as base oil only).

Also, when using a cutting fluid containing 2% by weight of tricresyl phosphate, or a cutting fluid containing a combination of 12% by weight of chlorinated paraffin and 1% by weight of tricresyl phosphate,
It can be seen that rust formation is small even though the amount of grinding increases.

On the other hand, a cutting fluid containing an S-containing compound (1,
When using 5% by weight benzyl disulfide addition) or sulfurized mineral oil (Daphney Polishing Oil F-1 [trade name: Idemitsu Kosan Co., Ltd.] contains Yu-1i11S),
Although the amount of grinding is greater than when using only base oil, it is clear that at the same time the product rusts significantly.

Summary of Effects> As explained above, according to the present invention, it is possible to produce a polished stainless steel material with excellent corrosion resistance, which hardly causes rust even in a relatively severe corrosive environment, with sufficiently high production efficiency. It brings about extremely useful effects industrially, such as being able to manufacture at low operating costs.

[Brief explanation of the drawing]

FIG. 1 is a conceptual diagram illustrating the polishing situation of HL specification material. FIG. 2 is a conceptual diagram illustrating the polishing situation of BG specification material. In the drawings: 1...Grinding belt, 2...Stainless steel material to be processed.

Claims (1)

[Claims] When manufacturing stainless steel polishing specification materials, the cutting fluid used at least in the final polishing step has an S content of less than 0.35% by weight and contains one or more of a chlorine-containing compound and a P-containing compound. and
A method for producing polished stainless steel material with excellent rust resistance.