JPS59225801A - Rolling method of round ingot by reversible two-high mill - Google Patents

Abstract

PURPOSE:To manufacture efficiently in high yield a slab excellent in dimensions and shape by rolling the long side part of a slab by turning and holding it by a manipulator after rolling the short side part of a round ingot and rolling its short side part in the succeeding stage. CONSTITUTION:In manufacturing a slabs from a round ingot R by a reversible rolling mill; a part corresponding to the short side (b) of slab S is first rolled to form a side having a prescribed length, and then the cast structure of the surface of short side (b) is sufficiently forged to form the surface to be held by a manipulator M. Next the ingot R having the formed surface is held and turned by 90 deg. by the manipulator M to roll the surface corresponding to the long side (a) of slab S in a stable state. Thereafter the long side (a) of slab S is formed at the 2nd rolling stage and the short side (b) is rolled by a caliber rolling by turning it 90 deg. at the 3rd rolling stage, to obtain a slab S having the desired long side (a) and short side (b).

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of rolling a round ingot using a reversible double rolling mill. More specifically, it relates to a method of rolling a titanium round ingot into a system slab using a reversible rolling mill. Conventional methods for producing a slab from a round ingot include casting or press blooming, a thick plate rolling mill, and a universal method. There are rolling methods such as a blooming mill.

The forging or press blooming method has many problems such as low yield and poor manufacturing efficiency due to poor slab dimensions, shape, and surface quality. On the other hand, as shown in Figure 1, the rolling method using a plate rolling mill is significantly improved in terms of manufacturing efficiency, slab dimensional accuracy, yield, etc. compared to the former method, but it requires rolling of the short sides of the slab. Since the surface quality of the short side surface is poor, it is necessary to correct it by cutting or manual work in the slab finishing process, resulting in a problem of lower yield.

The present invention uses a conventional reversible double rolling mill, but by changing the rolling process and performing groove rolling in the latter stage, it improves the slab size, shape, and yield, which are problems in the conventional methods. This solves problems such as poor manufacturing efficiency.

In other words, the present invention, when manufacturing a round slab from a round ingot using a reversible double rolling mill, first rolls a portion corresponding to the short side of the slab, forms a side of a predetermined length, and then rotates and holds it with a manizolator. The gist of the present invention is a method for rolling a round casting mill, which is characterized by rolling a portion corresponding to the long side of the slab, and then rolling the short side of the slab in the middle and final stages of rolling.

In addition, in rolling the portion corresponding to the short side of the slab, it is preferable that the length of the side formed thereby is within the length of the long side when the slab is formed.

Normally, when rolling a slab from a round casting slab, it is better to roll the slab successively in one direction to form the long sides and then form the short sides with a rear hole die, which results in more stable rolling and prevents collapse. However, if a round ingot is rolled in only one direction, the casting structure will be the same! ! As rolling progresses, wrinkle-like defects occur on the free surface (corresponding to the short side surface) of the wheel, and the shape becomes irregular.

The reason for rolling the part corresponding to the short side of the slab first according to the present invention is to sufficiently train the casting structure before rolling of the long side and to roll the long side in a stable state without collapsing. The purpose is to form a pressing surface by the manipulator for starting. In addition, the reason for groove rolling the short sides of the slab in the middle and final stages is to prevent the irregularities in the shape of the short sides caused by long side rolling and the growth of wrinkle-like defects, and to improve the accuracy of dimensions and shapes. This is what I am trying to do.

By rolling round cast canisters in such a process, it is possible to roll in a stable state from the beginning, and the quality of the slab after rolling is further improved. Most of the corrections by Therefore, the yield is improved by 2 to 3% compared to the method of unidirectional continuous rolling of the portion corresponding to the long side surface using a thick plate rolling mill.

90% in a soaking furnace using a conventional reversible double blooming pressure of 1 hPb.
A method of rolling a titanium round ingot R heated to 0°C in one direction through an initial rolling process 11, a middle rolling process 11, and a final rolling process (2) on a portion corresponding to the long side a of the slab S as shown in FIG. As shown in FIG. 2, rolling was carried out by the method of rolling the portion corresponding to the short side face of the slab S in the intermediate rolling step (2) and the final rolling step 8n1, and by the method according to the present invention as shown in FIG.

As a result, although the rolling stability and rolling efficiency were good with the method shown in Figure 1, the shape of the short side of the obtained slab was poor and there were many wrinkles, and the short side of the slab was cut as shown at point S. It was necessary to make corrections. In the method shown in Fig. 2, when the part corresponding to the short side face of the slab is rolled in the middle rolling process (■), the irregular shape and wrinkles have already progressed, and as a result of rolling the part corresponding to the short side face, Although the surface became smooth, irregularities in the shape and wrinkles were folded in, and fold-in defects C occurred on the short sides of the final slab. In the method according to the present invention shown in FIG. 3, the slab obtained had good dimensions and shape, and had no surface defects. Table 1 shows the rolling conditions and yield.

[Brief explanation of the drawing]

FIG. 1, FIG. 2, and FIG. 3 are diagrams showing the rolling method. Explanation of symbols a...Slab long side surface, b...Slab short side surface, R...
・Round ingot, S...rolled slab, D...wrinkle-like defect, C...folding flaw, Pn...multiple rolling rho thread name,
■...90° rotation, M...mani break. Patent applicant Nippon Steel Corporation (7) Procedural amendment (spontaneous) June 14, 1980 Director General of the Patent Office Kazuo Wakasugi Patent application filed on June 4, 1982 (3) 2. Name of the invention Method for rolling round ingots using a reversible rolling mill 3 and its relationship to the case of the person making the amendment Patent applicant Takeshi Takeshi, representative of Nippon Steel Corporation, 2-6-3 Otemachi, Chiyoda-ku, Tokyo (665) 1) 6. Column for the title of the invention in the specification to be amended, column 7 for the scope of claims and detailed explanation of the invention, Contents of the amendment (1) Name of the invention on page 1, line 3 of the description “Reversible type” "Method for rolling a round ingot using a double rolling mill" is revised to "Method for rolling a round ingot using a reversible rolling mill." (2. The claims are amended as per the attached sheet. (3) "Reversible double rolling mill" is amended to "reversible rolling mill" on page 1, line 13 of the specification. (4) Page 2, line 10 of the same specification and line 16, “reversible double rolling mill” is amended to “reversible rolling mill.” (5) On page 4, line 9, “reversible double rolling mill” is amended to “reversible rolling mill.” Claims: In manufacturing a slab from a round ingot using a reversible rolling mill, first roll a portion corresponding to the short side of the slab to form a side of a predetermined length, then rotate and hold it with a manipulator,
A method for rolling a round ingot using a reversible rolling mill, which comprises rolling a portion corresponding to the long side of the slab, and then rolling the short side of the slab in the middle and final stages of rolling.

Claims (1)

[Claims] When manufacturing a slab from a round ingot using a reversible double rolling mill, first roll the part corresponding to the short side of the slab to form a side of a predetermined length. 1. A method for rolling a round ingot using a reversible double rolling mill, which comprises rolling a portion corresponding to , and then rolling the short side of the slab in the middle and final stages of rolling.