JPH01306546A - Continuous manufacture of phosphor bronze stock - Google Patents

Abstract

PURPOSE:To continuously and inexpensively manufacture phosphor bronze stocks excellent in cold workability by drawing out molten phosphor bronze in the form of a continuously cast slab or billet in a horizontal direction by means of a horizontal continuous casting machine and then passing the above slab or billet through a rolling mill and heat treatment equipment provided on a continuous casting line to continuously carry out the refining of crystalline grains and the homogenization of material. CONSTITUTION:A continuously cast slab or billet 5 of phosphor bronze is drawn out in a horizontal direction from a horizontal mold having a cooling device 3 and provided to the side wall of a holding furnace 1 for molten phosphor bronze. The above continuously cast slab or billet 5 is rolled by means of a rolling mill 7 at 2-4% draft to undergo the refining of the crystalline grains of the continuously cast slab or billet 5 and is successively heated in a heating furnace 8 provided on the same line to 700-800 deg.C for 15-20min and cooled by means of a cooling device 9 to undergo the remelting of segregation phase and the homogenization of structure, and then, the plate stock, rod stock, bar stock, wire rod, etc., of phosphor bronze excellent in workability are continuously drawn out by means of a drawing device 6.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a method for continuously manufacturing a phosphor bronze material having excellent cold workability.

[Conventional technology and its issues]

Phosphor bronze material has excellent properties such as strength, springiness, and corrosion resistance, and is widely used as a member for electrical and electronic devices. Generally, in the cast structure of phosphor bronze, eutectoid crystals (α+δ) are segregated in the α phase, which is mainly composed of Cu and has excellent workability, and the α phase and the δ phase, which is a Sn-rich phase and inhibits workability. In this state, the workability for rolling etc. is poor, so a heat treatment is used to re-dissolve the δ component in the α phase (homogenization heat treatment), and this heat treatment is usually performed at 600 to 650°C for 30 minutes.
This will be done for about an hour.

In addition, it is desirable to make the ingot crystal grains finer in order to improve workability, and by electromagnetic stirring casting method, mechanical rotational stirring casting method, etc., dendrites, which are the solid-liquid interface morphology during the solidification process in the mold, are mainly produced. A generally known method is to crush dendrite crystals produced by growth to crystallize a fine primary α phase.

However, since the above-mentioned homogenization heat treatment and crystal grain refinement have been performed independently in separate processes, there is a problem of reduced productivity due to long heating times in the homogenization heat treatment, and crystal grain refinement due to the stirring casting method. The grain refining method has the problem of variations in workability due to the irregular shape of the primary crystals after solidification of the ingot.

(Problems to be Solved by the Invention) The present invention has been made as a result of studies on the above problems, and it combines the refinement of crystal grains to improve workability and the heat treatment to homogenize the segregated phase into a casting line. We have developed a continuous manufacturing method for phosphor bronze materials that can be carried out continuously on the same line to increase productivity and obtain materials with good properties.

[Means and effects for solving the problems] The present invention cools and solidifies phosphor bronze molten metal in a mold of a horizontal continuous casting machine that is directly connected to the side wall of a molten metal holding furnace, and then horizontally transports the solidified ingot from inside the mold by a drawing device. After pulling out the caster, it is rolled at a processing rate of 2 to 4% using a rolling mill placed on the continuous casting machine line, and then heat treated for 15 to 25 minutes at a temperature of 700 to 800°C in a heating furnace on the same line. This is a continuous manufacturing method of phosphor bronze material characterized by applying.

That is, the present invention uses a production line in which, for example, a horizontal continuous casting machine, a rolling mill, a heating furnace, and a drawing device are arranged in a straight line on the same line to continuously perform the steps of casting, rolling, and heat treatment to produce phosphor bronze material. It is manufactured. For example, as shown in Figure 1, a mold (2) is placed on the side wall of a molten metal holding furnace (1).
A horizontal continuous casting machine (
The phosphor bronze ingot (5) cast in step 4) is pulled out horizontally by the ingot drawing device (6) and rolled on the same line @
(71), followed by heat treatment by passing through a heating furnace (8), and cooling by a cooling device (9) to produce a long plate material.

However, in the present invention, the ingot is rolled at a processing rate of 2 to 4% using the above-mentioned rolling mill to refine the crystal grains of the ingot and thereby improve workability. If the processing rate is less than 2%, the effect of refining the ingot crystal grains will not be sufficiently obtained even if the subsequent heating homogenization treatment is performed, and if the processing rate is about 4%, the effect of refining the ingot crystal grains will not be obtained. saturates, and once this is exceeded, the degree of stress concentration on the grain boundaries of the ingot becomes larger (the difference between the surface layer and the center of the ingot becomes large), and the ductility at the point when the stress is relaxed by later heating increases. Differences occur due to recovery and intergranular cracks occur.

In addition, after the above-mentioned rolling process, heat treatment is performed in a heating furnace at a temperature of 700 to 800'C for 15 to 25 minutes to redissolve the segregated phase and homogenize the Mi texture, but the temperature is 700C.
If it is less than 800°C, it will take a long time to homogenize, and if it exceeds 800°C, hot embrittlement will appear in the ingot segregation and intergranular cracking will likely occur.

Furthermore, the reason why the heating time is set to 15 to 25 minutes is that sufficient homogenization cannot be achieved if the heating time is shorter than 15 minutes, and the effect is the same even if the heating time exceeds 25 minutes, which is not economical or efficient.

As described above, the present invention continuously applies working strain to the ingot that has come out of the mold to refine the crystal grains, and then heats it through a heating furnace to alleviate the working strain and refine the recrystallization. At the same time, redissolution of the segregated phase and homogenization are carried out continuously, and the phosphor bronze material produced by this method has good workability and bending properties.

In addition, since casting, rolling, and heat treatment are performed on the same line,
This makes it possible to save 111 times in the manufacturing process.

In addition, in the present invention, the above-mentioned phosphorus blue! r! In addition to board materials,
Various materials such as strips and rods can be manufactured.

〔Example〕

An embodiment of the present invention will be described below.

Phosphor bronze consisting of S n 8.0%, PO, 12%, balance Cu and unavoidable impurities, thickness 16ffiI11, width 4
An ingot with a cross section of 00 m1 was cast by the Heltley type horizontal continuous casting fi (41) shown in Fig. (7), the processing rate is 0.2.3.4%
700° in a heating furnace (8).
Heat treatment was performed at C for 25 minutes, at 750°C for 20 minutes, and at SO'C for 15 minutes. Next, this was cut into a length of 1 m, and after sulfurizing it from 16 m + 8 to 15 + u[I and confirming that there were no defects, a 6 m thick phosphor bronze plate was produced by cold rolling at a processing rate of 60%. Regarding this sample, the relationship between rolling reduction rate and grain size was investigated.

The results are shown in Table 1.

As is clear from Table 1, samples Nos. 1 to 3 of the present invention all have a very fine average grain size, and a defect-free plate material can be obtained even when cold rolled. In contrast, according to the conventional method, 4. No. 5 had a large grain size, and slight cracks occurred even during cold rolling.

In addition, 60 mm x 300 mm samples were taken from the conventional material NQ4 with a processing rate of 0% and the inventive material Nα3 with a processing rate of 4%, and the relationship between the bending radius R and the load was investigated using the bending test method shown in Figure 2. . The results are shown in FIG. As is clear from FIG. 3, it is recognized that the material of the present invention exhibits superior properties in terms of bending workability compared to the conventional material.

〔effect〕

As explained above, according to the present invention, phosphor bronze material with excellent workability can be manufactured continuously on the same line, so that the manufacturing process can be greatly reduced, which has a significant industrial effect. It is.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram illustrating a manufacturing method according to an embodiment of the present invention, FIG. 2 is a perspective view showing a bending test method used in an embodiment of the present invention, and FIG. 3 is an embodiment of the present invention. FIG. 3 is a diagram showing the bending properties of an example material. 1... Molten metal holding furnace, 2... Mold, 3... sh
Mold cooling device, 4... Horizontal continuous casting machine, 5... Ingot, 6... Ingot drawing device, 7... Rolling machine, 8
... Heating furnace, 9... Cooling device, lO... Bending sample, 11... Bending test stand.

Claims (2)

[Claims] (1) The phosphor bronze molten metal is cooled and solidified in the mold of a horizontal continuous casting machine that is directly connected to the side wall of the molten metal holding furnace. After the solidified ingot is pulled out horizontally from the mold by a drawing device, it is placed on the continuous casting machine line. Rolling is performed at a processing rate of 2 to 4% using a rolling mill, and then rolling is performed at a processing rate of 700 to 800% using a heating furnace on the same line.
1. A method for continuously producing phosphor bronze material, which comprises performing heat treatment at a temperature of 15 to 25 minutes at a temperature of .degree. (2) The method for continuously manufacturing a phosphor bronze material according to claim 1, wherein the phosphor bronze material is a plate material, a strip material, a bar material, a wire material, or the like.