JPH0442081B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a method for manufacturing a titanium thin plate or a titanium clad plate, and more specifically, in hot rolling of a titanium thin plate or a titanium clad plate.
Laminated rolling is performed for the purpose of thinning or to compensate for the asymmetry of deformability and deformation resistance in the thickness direction, and the sheet is peeled off after rolling to form a thin plate. The present invention provides a method for laminated rolling of titanium in which peeling does not occur during rolling and peeling after rolling is easy. (Prior Art) Titanium sheets are usually produced by hot rolling and cold rolling. Although it depends on the performance of the rolling mill, the maximum thickness of hot rolling is about 2 mm at most, and cold rolling is used to roll to a thickness less than that. Cold rolling produces a fine surface finish, but requires large mill power and is expensive to manufacture. On the other hand, hot rolling requires heating costs and the rolling surface has a rougher finish than cold rolling, but it is advantageous in terms of cost, especially when rolling in large quantities, as a relatively small mill power is sufficient. . A hot-rolled surface may be sufficient for the surface finish, but stack rolling has traditionally been used when thinning is required. (Problems to be Solved by the Invention) Although stack rolling is excellent in terms of making it thin, it has a major drawback in that the interfaces are bonded and it is difficult to separate them after rolling. Particularly in the case of titanium and titanium alloys, this bond is particularly strong, making peeling extremely difficult. On the other hand, stack rolling is sometimes performed with the titanium surfaces butted against each other in order to avoid stress generation due to warping due to asymmetric rolling in single-sided titanium clad steel sheets and the like. (“Titanium/Zirconium” Vol.35No.
1 23 pages, published in 1987). In this case as well, the titanium surface was firmly bonded and peeling was extremely difficult. Conventionally, in order to prevent adhesive bonding at such interfaces,
Ceramic powder was applied to the interface and the interface was oxidized. For example, fluxes and antioxidants containing Al ₂ O ₃ and CaO have been used as ceramic powders. Preventing adhesion by these ceramic powders is certainly effective as long as they remain at the interface, but of course the risk of peeling during rolling increases significantly. Therefore, in these methods,
Since contradictory properties are required in that it is necessary to aim at adhesion prevention while bonding, both properties are inevitably insufficient as a result. Because of the lack of a suitable release agent, laminated rolling, which is advantageous for producing ultra-thin materials, has not been widely used. The present invention solves the above-mentioned problems and provides a laminated rolling method that satisfies industrially the requirements of bonding without peeling and facilitating peeling. (Means for Solving the Problems) The present invention provides a method for manufacturing plate materials in which titanium or titanium alloy slabs are laminated, hot-rolled, and then peeled off. This is a method for laminated rolling of titanium and titanium alloys, which is characterized in that organic compound films consisting of C, H, O, and N are sandwiched and hot rolled. The present inventors have focused on the fact that the contradictory required properties of facilitating bonding and facilitating peeling are required at different times. That is, the time when bonding is required is during hot rolling, and the time when peeling is required to be easy is after hot rolling and cooling. If they are not bonded during hot rolling, they will separate into two pieces, making it impossible to perform laminated rolling and not be able to take advantage of this advantage. The laminated rolled material is peeled off after hot rolling, but in this case the temperature is lower than that during rolling. Of course, it is possible to peel off the film by heating it to a high temperature, but considering the cost of heating, it is much more advantageous to peel it off at a low temperature, even at room temperature. Based on the above idea, we searched for materials that have excellent bonding properties at high temperatures and excellent peeling properties at low temperatures, and as a result, we found that carbide nitrides and oxides meet these requirements. In other words, titanium carbides, nitrides, and oxides maintain a relatively good bond at high temperatures because they partially form a solid solution, but at room temperatures they precipitate in large amounts and behave similarly to inclusions, causing their surfaces to become brittle. I will do it. Therefore, although there is no fatal peeling factor at the interface between titanium, titanium alloys, or iron at high temperatures, at low temperatures cluster-like carbide nitride oxides precipitate at the interface and peel off under light pressure. It turns out. By sandwiching titanium carbide nitride oxide at the interface in this way, it becomes possible to simultaneously satisfy the contradictory required characteristics of bonding and facilitating peeling. Next, the limiting conditions of the present invention will be explained. There is no problem with the carbon, nitrogen, and oxygen sources sandwiched between the laminated interfaces of titanium or titanium alloys as long as they are film-like materials that do not contain particularly harmful elements other than C, N, and O. It is limited to organic compound films consisting of O and N. Since hydrogen is dissolved as a solid solution in titanium, it is desirable to have a small amount of hydrogen, but in reality it is oxidized by the oxygen contained at the same time, so there is no particular limitation. There is no lower limit to the thickness of the paper or organic compound film made of C, H, O, N, which is sandwiched between the laminated interfaces of titanium or titanium alloys, since it is desirable that it be as thin as possible. However, if the thickness exceeds 0.2 mm, the amount of carbide nitrides and oxides generated increases, which not only reduces the bondability during rolling, but also reduces the amount of solid solution in the rolled titanium or titanium alloy. The upper limit was set because the amount increases and hardens. (Function) As shown above, in stack rolling of titanium, hot rolling can be achieved by sandwiching paper or an organic compound film made of C, H, O, and N with a thickness of 0.2 mm or less at the stack interface. During rolling, stacking rolling is less harmful, and at room temperature after rolling, carbide nitride oxides, which function as release agents that promote peeling, are generated on the stacked surfaces, so there is no concern about peeling during rolling, and peeling is easy. It becomes possible. Although carbide nitride oxide remains at the interface after peeling, this can be removed by a conventional method such as pickling or polishing after peeling. As an application example of the present invention, the laminated material 2 shown in Fig. 1 is made of titanium or a titanium alloy, and the present invention is also applied to the production of clad steel plates in which the surfaces of the laminated materials are butted together, laminated, hot rolled, and then peeled off. is possible. In the figure, reference numeral 1 indicates a release agent for the base material 3, and reference numeral 4 indicates an interpolation material for reinforcement. (Example) Two JIS Class 1 pure titanium forged slabs having a thickness of 30 mm were stacked and heated to 850°C, and hot rolled to 2.5 mm in the stacked state. Then, it was peeled off under a light pressure of about 5% at room temperature. At this time, various release agents were applied or sandwiched to the stacked surfaces of the forged slabs. The rolling and peeling results are shown in Table 1. As is clear from Table 1, in the method of the present invention, there was no peeling during rolling, and peeling by light reduction after hot rolling could be easily carried out. In the case of the aluminum plate used for comparison,
It melted and peeled off during rolling, and in the case of a ceramic release agent, it could not be peeled off when applied thinly, but it peeled off during rolling when applied thickly. In addition, in the case of paper with a thickness of 0.3 mm, rolling and peeling were possible, but the solid solution of C and O in titanium increased, and the surface hardened severely and the quality deteriorated. In the case of paper with a thickness of 0.7 mm, it peeled off during rolling. Next, in the assembled slab of pre-rolled clad steel shown in Fig. 1, a 3.0 mm thick JIS Class 1 pure titanium plate was used as the laminate material 2, 19.2% Cr, 0.4% Cu as the base material 1,
A 30 mm thick stainless steel slab containing 0.6% Nb and 0.008% C was layered symmetrically with a titanium clad steel slab with the titanium surfaces aligned, heated to 880℃, and hot rolled to 4 mm in the stacked state. I did this. Then, it was peeled off under a light pressure of about 5% at room temperature.
At this time, various release agents were applied or sandwiched between the overlapping surfaces of titanium and titanium. The rolling and peeling results are shown in Table 2. As is clear from Table 2,
In the method of the present invention, there was no peeling during rolling, and peeling by light rolling after hot rolling could be easily carried out. In the case of the aluminum plate used for comparison, it melted and peeled off during rolling, and in the case of the ceramic release agent, it could not be peeled off when applied thinly, but when it was applied thickly, it peeled off during rolling. In addition, in the case of paper with a thickness of 0.3 mm, rolling and peeling were possible, but when a large amount of carbide oxide was removed, the titanium layer of the laminated sheet disappeared locally. In the case of paper with a thickness of 0.7 mm, it peeled off during rolling.

【table】

[Table] (Effects of the invention) According to the present invention, paper or C, H, O,
By simply sandwiching an organic compound film made of N, stack rolling of titanium and stack rolling of titanium clad steel, which are free from peeling during rolling and are easy to peel, are possible. As a result, not only the rolling process is simplified, but also the production of thin hot-rolled materials that can be substituted for cold-rolled materials and the rolling of single-sided titanium clad materials asymmetrical in the thickness direction are facilitated.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an assembled slab of clad steel before rolling, showing an application example of the present invention. 1... Base material, 2... Laminating material, 3... Release agent, 4... Interpolation material.

Claims (1)

[Claims] 1. In the manufacture of plate materials in which titanium or titanium alloy slabs are laminated, hot rolled, and then peeled off, paper or C with a thickness of 0.2 mm or less is added to the laminated interface.
1. A method for laminated rolling of titanium and titanium alloys, characterized in that hot rolling is carried out by sandwiching an organic compound film consisting of H, O, and N.