JPS58125384A - Manufacture of bimetal - Google Patents

Abstract

PURPOSE:To suppress oxidation of a metal at the time of hot press-sticking, and to elevate a manufacturing yield, by welding 2 sheets of metals one of which is ''Invar '', by an electronic beam, and subsequently, executing hot rolling by heating at a specified temperature. CONSTITUTION:As a base material, to a low expansion side metal, an invar, that is to say, the first metal 1 consisting of an iron alloy containing 35-37% nickel is clad, and to a high expansion side metal, the second metal 2 whose coefficient of thermal expansion is larger than Invar is clad. The junction boundary part of both sides in the longitudinal direction of both the clad metals 1, 2 is welded by performing electronic beam welding. Subsequently, the welded metals 1, 2 are heated at a temperature of 900-1,000 deg.C, are made to pass through between rolling rollers, and hot rolling is executed. By this hot rolling, the metals 1, 2 are rolled together since the junction boundary part is welded in advance, and at the same time, as for the metals 1, 2, each junction surface is press-stuck to each other. Subsequently, the oxide film is removed by sandblast, and they are finished to prescribed dimensions by cold rolling.

Description

[Detailed description of the invention] Technical field of invention The present invention relates to a method for manufacturing bimetals.

TECHNICAL BACKGROUND OF THE INVENTION In general, as a bimetal, a bimetal using an amper, that is, an iron alloy containing 35 to 37 kg of Kel as the low expansion metal, is widely used.

This is because the amplifier has an extremely small coefficient of thermal expansion.

As a method for manufacturing bimetals, there are two methods: hot compression bonding and cold compression bonding of a high expansion metal and a low expansion metal.

In the cold crimping method, the two metals are individually hot-rolled and cold-rolled before being crimped, which requires a large amount of process and equipment.
Since the two metals are hot rolled and crimped as they are in a stacked state, and then cold rolled, the process and equipment are simple.

Problems with the Background Art In the method of manufacturing bimetal by hot press bonding,
In order to make both metals with different coefficients of thermal expansion expand at the same time, the two metals are stacked and fixed by welding at the joint boundary, and in this state hot rolling is performed to bond the two metals together. I have to.

Conventionally, MIG welding (Inertops Metal Arc II) has been used to weld the two metals together. However, when hot rolling (crimping) is performed, the deformability of the two metals is different, so the joint surface is subjected to stress. However, MIG
Since the contact depth of the welded part is small, it is difficult to withstand shearing force, and there is a risk that the two metals will separate. Therefore, in the past, the heating temperature during hot rolling was set at 1100 to 1200°C in order to prevent shearing force from acting on the joint between the two metals.
It is necessary to raise the temperature to

However, when both metals are heated to such high temperatures, an oxide film is formed on the metal surface, and in the case of ampers in particular, in addition to surface oxidation, selective oxidation causes an oxide layer to be formed even inside the metal. . Ninth, there is no need for a process to remove the oxide film on both metals, and machining, sandblasting, etc. are used as this process. However, such processing work is difficult and increases the number of man-hours.
In addition to this, the metal is thin due to the oxide film, so the thickness cannot reach the standard thickness and the product becomes unusable, so bimetal preparation is required.
< , or it is necessary to prepare a thick metal with the oxide film thickness taken into account in advance, resulting in a problem of increased material cost.

This tendency is particularly noticeable in bimetals using ampers which have a high degree of oxidation.

Purpose of the Invention The present invention manufactures bimetals using an amper by hot press bonding, suppresses metal oxidation during hot press bonding, thereby improving manufacturing yield and reducing material cost. The purpose of the present invention is to provide a method for manufacturing a bimetal that aims to reduce the .

Summary of the Invention The method for manufacturing a bimetal of the present invention involves stacking two metals, one of which is inmber, and welding the joint boundary by electron beam welding, thereby applying heat to the joint boundary of both metals. It has sufficient strength to withstand the shearing force during rolling, and then heats both metals at a low temperature of 900 to 1000°C and hot-rolls them to suppress the formation of an oxide film on the metals. be.

Embodiments of the Invention The basic steps of the method for manufacturing a bimetal according to the present invention will be explained.

First, the material is an amper on the low-expansion side metal, that is, two
A first metal 1 made of an iron alloy containing 35 to 37% of Kel, and a second metal 2 made of a nickel-chromium-iron alloy with a large thermal expansion coefficient, for example, are prepared as a high expansion metal. .

Note that each of these metals 1 and 2 is a plate-shaped material.

Next, as shown in the drawing, the first metal 1 and the second metal 2 are
The two metals are stacked one on top of the other, and the two stacked metals are welded by electron beam welding at the joint boundaries on both sides in the longitudinal direction. A characteristic of electron beam welding is that the welded part 3 at the joint boundary between the metals 1 and 2 welded by electron beam welding is formed deep inside the joint boundary along the joint surface.For this reason, the welded part 3 The welding strength of metals 1 and 2 in is extremely high.

Then 900-100 for welded metals 1 and 2
The material is heated at a temperature of 0.degree. C. and passed through a rolling row 2 for hot rolling. As a result of this hot rolling, metals 1 and 2 are rolled together as the joint boundary is welded, and at the same time metals 1 and 2 are rolled together.
2, the joint surfaces are crimped together. Therefore, the strength of the welded part 3 at the joint boundary between the metals 1 and 2 that has been electron beam welded is large, and is strong enough to withstand the joint surface of the two metals 1 and 2 during hot rolling (crimping). Therefore, metal 1.2 does not peel off due to shear force during hot rolling. Therefore, it is no longer necessary to heat the metals 1 and 2 at a high temperature of 1,100 to 1,200°C to prevent shearing stress from occurring during hot rolling.
Hot rolling can be performed well without peeling. Therefore, the degree of oxidation of the metals 1 and 2 during hot rolling is small, and the oxide film formed on the surface is thin. In particular, the first metal 1 made of umber has only a thin oxide film formed on the surface and no oxide layer inside.

Next, the hexavalent oxide film formed on the surface of the metals 1 and 20 during hot rolling is removed by sandblasting. This operation is very simple since the oxide film is only small.

Next, the gold Jgl was pressed by hot rolling.

2 is subjected to cold rolling to finish it into a predetermined product size.

In this way, a hot-pressed bimetal is manufactured.

However, in this bimetal manufacturing method, the oxide film formed on metals 1 and 2 during hot rolling is much thinner than in the conventional case, so the machining allowance for removing the oxide film is The thickness of the metal plate after the oxide film is removed is very small, and the thickness of the metal plate is hardly reduced.Therefore, the rate of generation of unnecessary bimetal products due to the removal of the oxide film can be significantly reduced. In addition, unlike conventional methods, it is not necessary to use a metal 1.2 mm thick with a large allowance for machining of the oxide film in advance, but instead of using 1g1.
2 can be used.

Here, by the manufacturing method of the present invention, metal 1 made of an iron alloy containing 36% bimetal, 23% nickel, 5% chromium,
qb, metal 2 consisting of the remainder iron is prepared. These metals 1
The wood dimensions of , 2 are length 1500 x width 300 x wall thickness 60. After overlapping these metals 1 and 2 and welding their joint boundaries by electron beam welding,
Hot rolling was performed by heating at a temperature of 000° C. to perform compression bonding.

The oxide films of metals 1 and 2 were removed from the thus obtained bimetal by sandblasting, but the thickness of the oxide film at this time was 0.05mm, and it was impossible to remove it sufficiently by sandblasting. It was thick. In addition, as a conventional example, metals 1.2 and 1.2 are combined. After performing MIG bath welding, hot compression bonding was performed at a temperature of 1200° C. to obtain a bimetal. Metal 1.2 in this conventional bimetal
A process (sandblasting) was performed to remove the oxide film, but the thickness of the oxide film at this time was 0.1 wm or more.
The oxide film could not be removed sufficiently by sandblasting. As a result, the production method of the present invention can provide an excellent yield.

Effects of the Invention The bimetal manufacturing method of the present invention can economically manufacture a bimetal using an amper for one metal with a high yield by hot compression bonding.

[Brief explanation of the drawing]

The drawing is an explanatory diagram showing a state in which metal is bath-welded in the manufacturing method of the present invention. 1.2...Metal, 3...Welding Department Applicant Representative Patent Attorney Takehiko Suzue 3゛3

Claims (1)

[Claims] A step of preparing a first metal made of an iron alloy containing 35 to 37% of nickel by weight and a second metal having a higher coefficient of thermal expansion than the first metal; Overlap them and electron beam melt the joint boundary.
a step of welding the welded first and second
A method for producing a bimetal comprising the steps of: heating the metal to a temperature of 900 to 1000°C, hot rolling, and pressing the two together.