JP2005298942A - Roll for rolling plate material mainly containing silicon and producing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a roll for rolling, used for formation of a high melting point plate material mainly containing silicon, especially containing lead with which even in the case of using for long term under severe using condition, the bending to the whole body of the roll is not only developed, and the fine crack on the roll surface is not developed, and therefore, this roll can be used for long term. <P>SOLUTION: This roll is produced, by which a Co-base material composed by wt% of 0.03-0.60% C, ≤1.0% Si, ≤3.0% Mn, 2-40% Ni, 15-25% Cr, ≤15% Fe, 5-20% W and(or) Mo and the balance substantially Co, is formed into a roll-shape with hot-rolling to obtain a roll blank. and after applying a solid-solution treatment to this roll blank at 1,000-1,160°C, an annealing treatment is performed at 880-980°C, and lastly, a specular-finishing is performed to this surface. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to a roll for rolling a plate material mainly composed of silicon, and a method for producing the roll. The present invention provides a roll capable of providing a high-quality product plate material over a long period of time even when used under severe conditions.

Various methods are possible for manufacturing a plate material mainly composed of silicon. Among them, there is a method in which a molten plate material is rolled with two forming rolls and molded to obtain a product. The rolling roll used at this time, particularly when producing a plate material containing lead or the like, has a high melting temperature due to its material characteristics, so the heat load applied to the roll is very high and the roll life is not long. When the roll is curved, the product plate thickness becomes non-uniform, and when a fine crack enters the roll surface, it is transferred to the surface of the product plate material and the product quality is lowered. This is a problem to be solved in manufacturing this kind of roll for rolling sheet materials.

As a material for a rolling roll used for a plate material mainly composed of silicon, a Co-based alloy is considered suitable, and most of them are actually manufactured from a Co-based alloy. The applicant also made efforts to develop it, and found a Co-based alloy having an appropriate alloy composition, which has already been disclosed (Patent Document 1). The alloy is, by weight, C: 0.03 to 0.60%, Si: 1.0% or less, Mn: 3.0% or less, Ni: 2 to 40%, Cr: 15 to 25%, Fe : 15% or less, W and / or Mo: 5 to 20%, with the balance being substantially composed of Co, and in order to increase the heat damage resistance of the roll surface, Is a fine grain having a JIS grain size number of 8 or more, and the area ratio (%) of the precipitated carbide has a homogeneity that the difference between the maximum value and the minimum value when measured at 20 locations is 5% or less. It is required to have.

The applicant has also developed a method for producing a rolling roll of a sheet material mainly composed of silicon using a Co-based alloy having the above alloy composition as a material, and has disclosed it together with the above alloy (Patent Document 2). The method starts with an ingot of a Co-based alloy having the above alloy composition. First, the ingot is subjected to soaking at a temperature of 1160 to 1220 ° C., and then hot working at a temperature of 1160 to 1220 ° C. with a forging ratio of 2 or more. Followed by soaking at a temperature of 1160-1220 ° C. and then finishing at a temperature of 1050-1160 ° C. with a forging ratio of 2 or more. The soaking process in the finishing process is performed to dissolve the precipitated carbide.
JP-A-4-202732 JP-A-4-202733

Despite these technical improvements, the above-mentioned problems have not been completely solved in terms of the life of the rolling roll. One of the problems is macro bending of the roll for rolling, and the other is unevenness on the surface of the product plate caused by fine cracks generated on the roll surface. The restrictions on the unevenness are extremely severe, and the cracked rolling roll can no longer withstand use.

The object of the present invention is that, even if it is used for a long time under harsh usage conditions, the entire roll does not bend, and fine cracks do not enter the roll surface, so it can be used for a longer period of time. An object of the present invention is to provide a roll for rolling a plate material mainly composed of silicon and a method for producing the roll.

The method for producing a roll for rolling a sheet material mainly composed of silicon according to the present invention that achieves the above object is as follows: C: 0.03 to 0.60%, Si: 1.0% or less, Mn: 3 Alloy composition containing 0.0% or less, Ni: 2 to 40%, Cr: 15 to 25%, Fe: 15% or less, W and / or Mo: 5 to 20%, and the balance being substantially Co A Co-base alloy is used as a material, and is formed into a roll shape by hot forging to obtain a roll material. The roll material is subjected to a solution treatment at a temperature of 1000 to 1160 ° C, and then annealed at a temperature of 830 to 1000 ° C. And finishing the mirror surface.

The roll for rolling produced according to the method of the present invention does not cause the entire roll to bend even if it is used under severe conditions as compared with the roll produced by the conventional production method. The service life is significantly improved until the quality of the product plate is deteriorated due to the crack. This has an advantageous effect on the production of a plate mainly composed of silicon containing lead or the like, which is particularly demanding for product quality, and contributes to a reduction in production cost.

Best Mode for Carrying Out the Invention

The annealing treatment needs to be performed at a temperature of 830 to 1000 ° C. as described above, but is preferably performed at 880 to 980 ° C.

In the production method of the present invention, it is preferable that the roll material is formed by hot forging of a Co-based alloy according to the method of the invention disclosed above. That is, a soaking process is performed in which a Co-based alloy ingot is heated to a temperature of 1160 to 1220 ° C., and rough forging with a forging ratio of 1.8 or more is performed at a temperature of 1160 to 1220 ° C., followed by heating to a temperature of 1160 to 1220 ° C. This is a step of performing finish forging with a forging ratio of 1.8 or more at a temperature of 1050 to 1160 ° C. after performing soaking.

The rolling roll of the present invention produced in this way is a fine grain having a surface having a JIS crystal grain size number of 8 or more in accordance with the findings of the invention described above. It is desirable that the area ratio (%) be uniform so that the difference between the maximum value and the minimum value when measured at 20 locations is 5% or less.

The alloy composition of the Co-based alloy is the same as that of the invention previously disclosed by the applicant (Patent Document 1), and the reasons for limiting the alloy composition are as described above. The surface grain size number limitation and the homogeneity that the precipitated carbide area ratio should have are also the same as those required for the previously disclosed invention. A preferable process for producing a forming roll from the ingot of this alloy is not different from the process of the invention disclosed above (Patent Document 2).

In the present invention, the difference from the above-described known technique regarding the roll for rolling is that after the solution treatment, an annealing treatment at a temperature of 830 to 1000 ° C., preferably at a temperature of 880 to 980 ° C., is performed prior to finishing the surface into a mirror surface. There is to do. The heating time for annealing is appropriate for several hours after soaking. The range of the annealing temperature described above is determined by comprehensively judging the results of annealing at various temperatures from various viewpoints as seen in the examples described later.

The significance of the annealing treatment is to improve the ductility by appropriately agglomerating carbides precipitated in the matrix of the Co-based alloy. Precipitated carbide is considered to be the starting point of fracture when tensile stress is applied, and when agglomeration does not occur, that is, when a large number of fine carbides are dispersed, the matrix metal is in the form of a fine mesh. When the agglomeration progresses extremely and a small number of enlarged carbides exist, the mesh formed by the matrix becomes rough. In both extreme cases, the ductility is low, and high ductility can be obtained in an intermediate state where the agglomeration of carbides has progressed moderately. This mechanism is supported by the ductility values in the implementation data described below and micrographs of the fracture surface. If the annealing temperature is too low, the above-described agglomeration of carbides does not proceed, and if it is too high, the roll surface is roughened by coarsened carbides, and the quality of the product plate is lowered.

For this reason, considering the ductility at high temperature, roll life and product quality comprehensively, the appropriate annealing temperature is selected within the range of 830 to 1000 ° C., preferably 880 to 980 ° C. Table 1 below shows the factors considered.

表１において、「高温延性」は、ロールから採取した試験片を７５０℃における引張り試験にかけたときの、絞りの値である。

In Table 1, “hot ductility” is the value of drawing when a test piece taken from a roll is subjected to a tensile test at 750 ° C.

A Co-based alloy having the following composition (mass%) was produced by a vacuum induction furnace melting-remelting method and cast into a 2t ingot.
0.10% C-0.1% Si-1.5% Mn-11% Ni-20% Cr-15% W-2% Fe-balance Co

After forging and finishing forging, after solid solution treatment, annealing (830 ° C. or 930 ° C.) was performed, and the shape of the forming roll was formed by machining. When the crystal grain size of the surface was investigated, both were fine grains having a JIS grain size number of 8 or more, and the area ratio (%) of the precipitated carbide was the maximum value and the minimum value when measured at 20 locations. A preferable rolling roll condition of 5% or less was satisfied.

Test pieces were collected from the heat-treated products having the annealing temperatures of 830 ° C. and 930 ° C., and subjected to a tensile test at normal temperature and high temperature (750 ° C.). The results are compared as shown in Table 2 below.

Comparing the results of the tensile test shown in Table 2, there is almost no difference in the normal temperature tension, but in the high temperature tension, with the improvement of the drawing value, the ratio between the elongation and the drawing value is particularly 1 when the annealing at 930 ° C. It is noted that it exceeds .0. That is, even when annealing according to the present invention is performed, those annealed at 930 ° C., which is a preferable range of temperature, are well stretched and fractured after being highly squeezed, and the improvement in ductility is remarkable. When the fracture surface is observed with a microscope, it is as shown in FIG. 1 (annealed at 930 ° C.) and FIG. 2 (830 ° C.), and the former shows that the matrix network is appropriately large. It can be seen that the degree of agglomeration of the carbide that is the starting point of the process proceeds moderately.

This rolling roll has a longer life than the one subjected to annealing at 750 ° C., which is outside the scope of the invention, and as shown in Table 1, the one that has been annealed at a particularly preferable temperature reaches a maximum of five times the life. Can be enjoyed. Compared to the conventional solution-treated one, the life is even longer. What affects the life of the roll for rolling is a deterioration in which the quality of the product plate material is deteriorated due to microcracking on the roll surface when the entire roll is not curved. Improvements delay the generation of microcracks caused by use under harsh conditions.

The microscope picture (annealing temperature 930 degreeC) which image | photographed the fracture surface of the high temperature tensile test piece extract | collected from the roll for rolling of this invention. Micrograph similar to FIG. 1 (annealing temperature 830 ° C.).

Claims (4)

By weight, C: 0.03 to 0.60%, Si: 1.0% or less, Mn: 3.0% or less, Ni: 2 to 40%, Cr: 15 to 25%, Fe: 15% or less W and / or Mo: 5 to 20% containing a Co-based alloy having an alloy composition substantially consisting of Co as a material, first formed into a roll shape by hot forging to obtain a roll material, A method for producing a roll for rolling a sheet material mainly composed of silicon, which comprises subjecting this roll material to a solid solution treatment at a temperature of 1000 to 1160 ° C, followed by an annealing treatment at a temperature of 830 to 1000 ° C, and finally finishing the surface into a mirror surface. The manufacturing method of Claim 1 which implements an annealing process at the temperature of 880-980 degreeC. Forming of a roll material by hot forging of a Co-based alloy, soaking treatment in which a Co-based alloy ingot is heated to a temperature of 1160 to 1220 ° C., rough forging with a forging ratio of 1.8 or more at a temperature of 1160 to 1220 ° C., a temperature of 1160 The manufacturing method of Claim 1 performed by the process consisting of soaking | uniform-heating which heats to 1220 degreeC, and the finishing forging of the forging ratio 1.8 or more in temperature 1050-1160 degreeC. It is manufactured by the method according to claim 1 or 2, and the surface is a fine grain having a JIS grain size number of 8 or more, and the area ratio (%) of the precipitated carbide is a maximum value and a minimum value when measured at 20 locations. Roll for rolling plate material mainly composed of silicon having a difference of 5% or less.

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