JPH0332405A - Constant-temperature rolling method - Google Patents

Abstract

PURPOSE:To attain a constant-temp. rolling and to suppress the generation of crack by restraining both transverse sides of the part of a material to be rolled where the material is to be rolled down by means of rolls to the section corresponding to the part to be rolled down of the material to be rolled and part near the same by means of a pair of side guides internally provided with heat generating means to roll the material. CONSTITUTION:The material 5 to be rolled is deprived of its heat in the upper and lower rolls, 3 by contact with the upper and lower rolls 1, 2 by which the temp. thereof is forced to be lowered. Whereas, the heat corresponding to the heat deprived of in the upper and lower rolls 1, 2 is replenished from the heaters 4 sealed in a pair of the side guides 3, 3' restraining the width expansion by coming into contact with the inner side thereof and, therefore, the material 5 to be rolled is rolled without allowing the temp. from falling down to the temp. within the prescribed range or below. The material to be rolled is efficiently rolled at a constant temp. and low strain speed in this way. The mass production of hardly workable materials is thus possible.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a constant temperature rolling method for rolling materials that require hot plastic working at low strain rates within a predetermined temperature range.

[Conventional technology]

Materials such as intermetallic compounds, which have high heat-resistant strength and are difficult to hot plastically process due to their appearance, and materials that conventionally needed to be encapsulated and processed in a semi-molten state, cannot be deformed. Due to its morphology, a hydrostatic pressure component is required, and hot working at a constant temperature and low strain rate is essential. On the other hand, when hot working these difficult-to-process materials at a constant temperature and low strain rate, the contact time between the tool and the workpiece increases, and the temperature of the workpiece increases. A decrease is inevitable, making it difficult to achieve the desired hot working.

Therefore, as is well known, the mold used is heated and maintained at a high temperature to prevent the temperature of the workpiece from decreasing, and these difficult-to-work materials are produced in the high temperature and low strain rate range where they exhibit superplastic behavior and low deformation resistance. Hot die forging methods, isothermal forging methods, and superplastic region forging methods have been successively developed and put into practical use.

[Problem to be solved by the invention]

However, the above-mentioned forging method essentially processes a single item into a fixed shape, and when trying to continuously hot-work a difficult-to-work material like the one mentioned above into a long shape, , which is difficult to apply in practice.

On the other hand, there is a hot rolling method that allows continuous and efficient hot working of elongated materials.

However, in the hot rolling method, the rolls that press the material to be rolled are transferred at the same time, making it extremely difficult in terms of equipment to heat and maintain these rolls at high temperatures like the molds in the forging method described above. Therefore, it is difficult to avoid the temperature of the rolled material due to contact with the rolls. Therefore, when rolling difficult-to-work materials such as those mentioned above, the strain rate during rolling is determined by the amount of reduction and Although it can be controlled and adjusted by lowering the rolling speed, on the other hand, the contact time with the cold rolls becomes longer, making it difficult to maintain the rolled material within a predetermined temperature range.
It was not possible to achieve rolling at the desired constant temperature and low strain rate.

The present invention can solve the above-mentioned conventional problems, and can process difficult-to-work materials that require hot plastic working at a low strain rate within a predetermined temperature range at a constant temperature and a low strain rate. The object of the present invention is to provide a constant temperature rolling method that enables efficient rolling.

[Means to solve the problem]

In order to achieve the above object, the constant temperature rolling method of the present invention provides heat generation means on both widthwise sides of the lower part of the rolled material to be rolled by the rolls, at a portion corresponding to the lower part of the rolled material and its vicinity. Rolling is performed while restrained by a pair of internally installed side guides.

[Effect]

In the constant temperature rolling method of the present invention, both sides in the width direction of the lower part of the material to be rolled to be rolled by the rolls are connected to a pair of side guides each having a heating means internally installed at a portion corresponding to the lower part of the material to be rolled and its vicinity. Since the rolled material is restrained and rolled, the heat from the lower part of the material to be rolled, which is taken away by contact with the rolls during rolling, is replenished by heat from the heating means of the pair of side guides on both sides in the width direction. The lower part of the material to be rolled can be maintained at a temperature within a predetermined range, and the desired constant temperature rolling can be achieved. Moreover, the heat generating means need only be installed inside a pair of fixedly arranged side guides. becomes much easier.

In addition, since both sides in the width direction of the lower part of the material to be rolled are constrained by a pair of side guides, the lower part of the material to be rolled is subjected to isostatic pressure without forming a free surface. It is possible to apply a large amount of pressure and suppress the occurrence of cracks in the rolled material.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

1 and 2 are conceptual explanatory diagrams of the rolling equipment used in this example. be.

In Figure 1 and 2v4, (1) is the upper roll, (
2) is the lower roll, and these upper and lower rolls (1) (
This) is provided with a pair of pressurizing convex portions (la) (2a) each having a rectangular cross section on its outer periphery. In this example, the upper roll (1) is used as the rolling means, and the lower roll (2) is used as the rolling means.
) is connected to the co-rotating drive means, and the upper roll (
The pressurizing convex portion <la) of 1) is provided around the periphery and protrudes more than the pressurizing convex portion (2a) of the lower roll (2).

(3) (3°>) are a pair of side guides, and these pair of side guides (3) (3') are square bar-shaped with a rectangular cross section, and are used for the upper and lower rolls (1) and (2). The inlet side communicates with the outlet, and the upper and lower rolls (1) and (2) are paired on both sides of the pressurizing convex portions (la) and (2a), and are fixed with their longitudinal sides facing each other in parallel. It is arranged as follows.

In addition, as shown in FIG. 3, which is a front cross-sectional view, these pair of side guides (3) and (3') are provided with an insertion hole (3a) in the longitudinal direction. A rod-shaped enclosed heater (4) is fitted into this insertion hole (3a). In addition, on the outer surfaces of these pairs of side guides (3) (3') other than the opposing inner surfaces, heat insulating plates (3b
> is pasted. In this example, the pair of side guides (3) and (3') are restricted from moving in the vertical direction and the longitudinal direction (rolling direction), but the distance between them is adjustable.

(5) is a material to be rolled, which is rolled by being rolled by upper and lower rolls (1) and (2) while being restrained on both sides by a pair of side guides (3) and (3'). Shows the state where it has been applied.

The following constant temperature rolling was performed using a rolling apparatus having the above configuration.

First, as the material to be rolled (5), a Ti, Al intermetallic compound whose optimum plastic working temperature range is 1000°C to 1100°C was rolled into a material having a size of 30 mm square, a wall thickness of 2 mm, and a length of 100 mm.
Prepare a formed rod enclosed in a square pipe-shaped mild steel sheath, and after heating this rolled material (5) to 1100°C, feed it between the upper and lower rolls (+1 (2)). , the reduction rate is 3
0%, rolling speed of 1m/H1, thickness 14III
+, rolled to a width of 31 mm.

Here, the pressure projections (la) (2a) provided around the outer peripheries of the upper and lower rolls (1) and (2) are made of ceramics from the viewpoint of heat resistance strength and heat conduction. The outer diameters of the two were set to be the same (300 mm) in order to equalize the reduction in the vertical direction.

In addition, the enclosed heater (4) fitted into the pair of side guides (3) (3°) has a length of the soaking part of about 600 mm and an output of 2.5 KN. The total output was 5 poems.

During rolling, the position of the lower roll (2) is kept constant, and the rolling amount of the upper roll (1) is adjusted to
), and the rolling speed was controlled by adjusting the rotation speed of the lower roll (2).

During this rolling, the material to be rolled (5) also tries to deform in the width direction, but both sides of the material (5) are
As a result, a free surface is prevented from being formed in the lower part of the rolled material (5) under pressure, and the rolled material (5) is subjected to isostatic rolling. It is rolled with reduced area without being subjected to heavy pressure.

In addition, the material to be rolled (5) is a low-temperature upper and lower roll (1) (
2), especially the longer contact due to Is/sin and low rolling speed, the heat is transferred to the upper and lower rolls (1).
(2) tries to lower the temperature, but
A pair of side guides (3) (3°) that contact both sides of the side guides (3°) restrain the width expansion, which corresponds to the heat taken from the enclosing container (4) to the upper and lower rolls (1) and (2). Since heat is replenished, the material to be rolled (5) is rolled without the temperature falling below a predetermined range.

The rolled material (5) rolled as described above maintained a temperature of 1000"C immediately after rolling, indicating that the rolling was performed within the expected temperature range. When the surface mild steel sheath was removed and several detailed plans were made for the resulting rolled material, it was confirmed that the material was sound and free of cracks.

On the other hand, for comparison, the same rolled material (5) as above was used.
When heated in the same manner as above and rolled without applying electricity or input to the enclosed heater (4), the entry side of the material to be rolled (5) passed between the upper and lower rolls (1) and (2). 300 at the time
As the temperature decreased to .degree. C., cracks were generated inside, and the temperature of the main body of the material to be rolled (5) continued to decrease rapidly, so that the rolling had to be interrupted.

In this example, a rolled material in which Ti and AI intermetallic compounds were encapsulated in a mild steel sheath was explained.
The present invention is not limited thereto, but is effective when applied to isothermal rolling of other difficult-to-work materials that require hot plastic working at a low strain rate within a predetermined temperature range.

In addition, during implementation, a lubricant such as Ho5t is applied to the inner surfaces of the pair of side guides that come into contact with the rolled material in order to reduce sliding and frictional resistance with the rolled material. It is desirable that the spacing between the opposing sides of the pair of side guides be fixed to a desired constraint width, but as in this embodiment, the spacing between these may be adjustable. This makes it possible to easily handle multi-pass rolling.

〔Effect of the invention〕

As described above, according to the constant temperature rolling method of the present invention,
Difficult-to-work materials that require hot plastic working at a low strain rate within a predetermined temperature range can be rolled efficiently at a constant temperature and at a low strain rate, making it possible to mass-produce these difficult-to-work materials. This makes it possible to greatly contribute to expanding the scope of application.

[Brief explanation of drawings]

1 and 2 are conceptual explanatory diagrams of a rolling machine used in an embodiment of the present invention, in which FIG. 1 is a front cross-sectional view of the main part thereof, and FIG. 2 is a cross-sectional view taken along ■-■ of FIG. 1. , FIG. 3 is a front cross-section 1 of a side guide according to an embodiment of the present invention. (1) - Upper roll, (2) - Lower roll, (3
)(3')--Side guide, (4)-Enclosed heater,
(5) - Rolled material.

Claims (1)

[Claims] A feature of rolling is that both widthwise sides of the lower part of the material to be rolled that are pressed by the rolls are restrained by a pair of side guides that have heating means installed in the lower part of the material to be rolled and the area corresponding to the area near the rolled part. A constant temperature rolling method.