JPS6233005A - Cold rolling method for titanium plate - Google Patents

Abstract

PURPOSE:To prevent titanium from building up on a rolling roll and to obtain titanium plates having excellent surface quality by forming a titanium fluoride film on the surface of a titanium plate and rolling the plate with a rolling oil or a water soluble rolling liquid. CONSTITUTION:A treating liquid forming a titanium fluoride film on a titanium plate is an aqueous solution containing fluorine compounds and heavy metal ions and inorganic acid ions as additives. The titanium fluoride film of about 0.1-10g/m<2> as a unit of square meter is formed on a titanium plate surface by dipping or spraying the titanium plate in or with the treating liquid. Rolling is performed with a rolling oil such as a mineral oil, natural oil, synthetic esther, or mixture of those oils or a water soluble lubricant. By that method, a coefficient of friction is reduced and titanium is prevented from building up on a rolling roll.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention is applicable to cold rolling of titanium plates.
It has excellent properties such as titanium build-up in the rolling process.
This relates to a cold rolling method that does not cause any transfer.

[Prior art] Cold rolling of titanium plates is usually carried out in stainless steel plate rolling equipment, that is, small-diameter multi-roll mills, and the rolling lubricant is mineral oil, natural oil, synthetic ester, or a mixture of these oils. Neat products are used in which oiliness improvers, extreme pressure additives, etc. are added.

Stainless steel sheet rolling equipment is used because the processing characteristics of titanium sheet, especially the rolling load, are relatively similar to those of stainless steel. Both speeds are lower than stainless steel plates.

Therefore, even if the various rolling lubricating oils mentioned above were used, rolling was extremely difficult, and it was not possible to manufacture a 6-inch roll with a standard gauge. Even for thick gauge products, the reduction ratio and rolling speed had to be kept low, resulting in very low productivity and the surface quality of the finished product was never good.

In recent years, the excellent properties of titanium, such as excellent chlorine resistance and the highest specific strength (tensile strength/specific gravity), have been reconsidered, and along with its high added value, productivity has rapidly increased. It shows an increasing trend. In the past, only thick gauges could be produced, but since titanium is very expensive, there is a trend toward thinner rolls, and the need for thinner gauge rolling has arisen.

In order to efficiently roll to a thin gauge, it is necessary to increase the rolling reduction ratio of each bath, but when the rolling reduction ratio is increased, there is a tendency for the coefficient of friction to increase rapidly. The friction coefficient increases because titanium builds up from the titanium plate onto the rolling roll, and this build-up could not be prevented using any conventional rolling lubricating oil.

In the case of titanium plates, build-up begins to occur when the I9 friction coefficient reaches 0.05 or more, and it rapidly develops thereafter, but this phenomenon is not observed when the friction coefficient is at the same level as that of ordinary steel plates or stainless steel plates. be.

Generally, in the case of cold rolling, a mixture of fluid lubrication and boundary lubrication is used, but in the case of ordinary steel sheets and stainless steel sheets, oiliness improvers and extreme pressure additives are effective in the boundary lubrication region. On the other hand, in the case of a titanium plate, it is thought to have little effect and build up. When it builds up on the rolling rolls, its high coefficient of friction makes further rolling impossible, and at the same time it significantly impairs the surface quality of the rolled plate. Therefore, a high-quality product with the desired thickness cannot be obtained. As a response to these problems, saponification value 17
A method of cold rolling titanium with rolling oil of 0 or more (Unexamined Japanese Patent Publication No. 5
3-154349) and 200 on the titanium surface before rolling.
A method (Japanese Patent Application Laid-open No. 88858/1983) of cold rolling with rolling oil after forming an oxide film of about 00000000000000000000000000000000000000000 type type type type type type type type type type type form type form type type has been developed. Since this has become possible, attempts have been made to increase the reduction ratio during cold rolling, but in both of the inventions mentioned above, seizure is completely prevented in thin gauge cold rolling and high speed cold rolling of titanium plates. Therefore, it is not possible to obtain a titanium plate with high quality surface texture.

[Objective of the Invention] The object of the present invention is to lower the *m coefficient in cold rolling of titanium sheets to enable high reduction rolling, and to improve surface quality by preventing build-up of titanium on the rolling rolls. The purpose of this invention is to provide a method for cold rolling titanium plates that yields products with excellent thin gauge.

[Structure of the Invention] The present invention, which has been made to achieve the above object, involves forming a titanium fluoride film on the surface of a titanium plate in advance, and then rolling it in the presence of rolling oil or water-soluble rolling fluid. The present invention provides a method for cold rolling a titanium plate characterized by the following.

First, fluorine compounds are used as agents for adjusting the treatment solution. Examples include potash. One or a combination of two or more of these may be used.

Next, as additives, heavy metal ions such as Zn, Ni, Go, and Mn, and inorganic acid ions such as nitrate ions, sulfate ions, and phosphoric acid are arbitrarily selected from their respective ranges, and the area weight of the film is determined. 0.1-10 g/-rti is preferred. More preferably, it is 1 to 8 g/TIt.

Next, the process of forming a film will be explained.

After hot-rolled steel sheets are descaled by pickling, shot blasting, or liquid honing, they are immediately subjected to chemical conversion treatment. In the case of liquid honing, descaling and chemical conversion treatment can be performed at the same time by blending the above-mentioned composition into the bath solution. For the chemical conversion treatment, a method normally used for steel sheet products, ie, an immersion method, a spray method, or a combination of these methods, is used.

The rolling oil used is mineral oil, natural oil, synthetic ester, or a mixture of these oils, and oiliness improvers, extreme pressure additives, antioxidants, oil stain inhibitors, etc. are blended as necessary. Rolling oil is generally used in knee i~, but it may also be used in emulsion to increase the cooling effect. A direct method or a recirculation method is applied to supply rolling oil. It is also possible to roll with a water-soluble rolling fluid using a water-soluble lubricant without using oils and fats.

[Function] The rolling method of the present invention is based on forming a film on the surface of the titanium plate, and the main component of the film is titanium fluoride, which is formed by reacting with a fluorine compound in the processing solution. . When rolling with rolling oil or water-soluble rolling fluid with this film applied, the film prevents the gold R from coming into contact with each other between the titanium plate and the rolling roll, and prevents build-up of titanium on the rolling roll surface. The rolling oil or water-soluble rolling fluid plays the role of lubrication.

The titanium fluoride film is relatively soft and firmly adheres to the surface of the titanium plate, so even when the titanium plate is rolled and the surface area increases, it fully follows the increase in the surface area of the titanium plate, resulting in an isolation effect between the rolling roll and the titanium plate. You can maintain it. Also, due to its softness, the shear surface resistance at the interface between the rolling roll and the titanium plate is reduced.
Lower the coefficient of friction. Since titanium fluoride coating is relatively porous, it has excellent retention of rolling oil and water-soluble rolling fluid used as 'IB lubricating oil.

The basis weight of the titanium fluoride film should be at least 0.1 in order to follow the increase in surface area of the titanium plate that occurs during thin gauge rolling.
However, if it becomes 10 g/m or more, it is economically disadvantageous, and at the same time, as a pre-process of cold rolling, the chemical conversion treatment takes too much time and tends to cause unreasonable processes. . Also, some of it may build up on the rolling rolls. Therefore, it was found that 0.1 to 10 g/rrI is preferable, and more preferably 1 to 8 g/rrI.

After rolling, the titanium fluoride film can be easily removed by a conventional electrolytic cleaning process. For example, a titanium original plate (thickness 3
．． 2 m) is formed with a titanium fluoride film of 5 g/TIL, and then rolled to a thickness of 0.4 mrn by 10 bus rolling. /m of titanium fluoride film remained, but when this titanium plate was passed through an alkaline electrolytic cleaning line, most of the titanium fluoride film was removed from the surface of the plate.

Examples of the present invention are shown below along with comparative examples.

[Example] Rolling tests were conducted on sheets with and without titanium fluoride film formed, and the friction coefficient during rolling, the amount of titanium build-up on the rolling rolls, and the surface roughness of the sheets after rolling were evaluated. The degree was measured.

(1) Treatment bath Acidic sodium fluoride 2.1 g/fJ Manganese sulfate 3 g/ρ Sodium nitrate 1 g/ρ Temperature 70 to 75°C Immersion treatment The treatment time was as shown in the table below in order to adjust the basis weight 4.

(2) Coating weight distance (3) Rolling oil (4) Rolling conditions/Material to be rolled: Pure titanium (JiS class 2) Hot rolled plate 3.0mm tX30mm ωX200M ・Work roll diameter: 708φ ・Work roll surface Nibrite ( Rmax O, 8μm
)・Rolling speed: 2Gm/1n・Number of passes and rolling reduction rate: 7 baths, each bath 25%° Lubrication method: 2 Spray oil on the upper and lower rolls, flow flk 1.5J!
/ n+1n (5) Evaluation method ■ rIl friction coefficient Find the advanced rate for each bus Bland & Ford
h2: Thickness of the plate after rolling) R': Radius of flat roll (rolling) r: Reduction ratio φ: Advance ratio ■ Amount of build-up of titanium on the rolling rolls Before rolling and after 7-bus rolling The difference in lff1 of the plates is g/TIt(
(converted to the original plate surface M) and is defined as the build-up period. However, both the bacterial film and the plate molding were measured without any film or oil on them.

(2) Surface roughness of rolled plate The surface of the plate after 7-bath rolling was measured in the cC direction with a stylus roughness meter, and expressed in 1lax (μm).

The test results are shown in the table below.

In Examples 1 to 3, the coefficient of friction is lower than that of the comparative example, the upper limit for each pass is very small, and the amount of build-up is also very small at about 1710. Therefore, it can be seen that the surface roughness after rolling is maintained approximately equal to the roughness of the rolling roll, and the surface quality is significantly improved.

[Effects of the Invention] As explained above, the titanium plate cold rolling method of the present invention has the following effects:
By contacting the titanium plate in advance with a treatment solution containing fluorine compounds, heavy metal ions, and inorganic acid ions to form a titanium fluoride film on the surface, and then rolling in the presence of rolling oil or water-soluble rolling fluid. , *Reduces the coefficient of friction, prevents titanium from building up on the rolling rolls, and has the excellent effect of producing titanium plate products with excellent surface quality. This has made it possible to roll thin gauge titanium plates that were previously impossible to roll.

Claims (5)

[Claims] (1) A method for cold rolling a titanium plate, which comprises forming a titanium fluoride film on the surface of the titanium plate in advance, and then rolling it in the presence of rolling oil or water-soluble rolling fluid. (2) The treatment liquid used to form the titanium fluoride film is an aqueous solution containing a fluorine compound with heavy metal ions and inorganic acid ions added as additives, and the titanium plate is added to this treatment liquid. 2. The method for cold rolling a titanium plate according to item 1 above, which comprises contacting to form a titanium fluoride film. (3) The basis weight of the titanium fluoride film is 0.1 to 10 g/m^
2. The cold rolling method according to Items 1 and 2 above. (4) The cold rolling method according to item 1 above, wherein the method of bringing the titanium plate into contact with the treatment liquid in forming the titanium fluoride film is immersion. (5) The cold rolling method according to item 1 above, wherein the method of contacting the titanium plate treatment liquid in forming the titanium fluoride film is spraying.