JP2002220607A - Sintering bonding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To recycle cast iron chips by bonding the cast iron chips to a steel material while sintering them. SOLUTION: This method comprises arranging the cast iron chips uniformly on the steel material with interposing non-chilling elements such as Ni and Cu in between, sintering the cast iron chips, and bonding the sintered compact to the steel material, by causing discharge between the cast iron chips 13 and the steel material 12 along with applying pressure between them.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sintering joining method for joining a steel material and a sintered body of cast iron chips.

[0002]

2. Description of the Related Art Joining of dissimilar metal materials is considered to be difficult. In particular, joining of cast iron (including powder) and other metals is difficult to achieve by fusion joining using electricity or gas. There is no practical example because it occurs and the bonding surface becomes brittle.

[0003] Among the joining techniques for metal materials, it is known that joining different kinds of metal materials having different types and structures basically improves the productivity and improves the functions of products.

[0004] On the other hand, a recycling technique for sintering cast iron chips generated during cutting of a cast iron workpiece and reusing the same as a structure is the most demanded today. Conventionally, a method of promoting diffusion bonding between particles by keeping the particles in a high-temperature reducing atmosphere (H ₂ or the like) for a long time has been used, but a more efficient method is required.

[0005] Further, the joining between the metal sintered body and the steel material is as follows.
Conventionally, a method such as brazing, which has been considered difficult and has a low bonding force, has been used as a mass production technique, but this method is not applicable to parts requiring high strength bonding force.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and provides a sintered body of cast iron chips and joining the sintered body to a steel material so that the two can be solidified in a short cycle and firmly. It is an object of the present invention to provide a sintering bonding method that can be bonded to a metal.

[0007]

Means for Solving the Problems In order to achieve the above object, a sintering bonding method according to the present invention is to uniformly cast iron chips into a steel material by interposing a non-tilting element such as Ni or Cu. And pressurize the cast iron chips to the steel material to discharge them, thereby sintering the cast iron chips and joining the sintered body to the steel material side.

Further, in the sinter joining method according to the present invention, a cast iron chip is placed in a molding die on a steel material with a non-tilting element such as Ni or Cu interposed therebetween. While a pulse current is being input during this time, the cast iron chips are pressed against the steel material, and the sintered body is joined to the steel material while sintering the cast iron chips.

Further, another sintering joining method according to the present invention comprises:
A non-chilling element such as Ni or Cu is interposed between the cast iron chips uniformly over the iron and steel material. The powder is sintered, and the sintered body is joined to the steel material.

[0010]

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

A sintered body was produced using cast iron (FC-200) chips, and the sintered body was bonded to an iron plate. The shape of the sintered body at this time is a disk having a thickness of 5 mm and a diameter of 30 mm. On the other hand, the iron plate is a 3 mm-thick ordinary steel plate (S
S330) was used.

FIG. 1 schematically shows a sintering and joining apparatus A for producing and joining the above sintered body using a pulse current.
In the figure, reference numeral 1 denotes a press installed in a vacuum chamber 2;
Reference numeral 3 denotes an upper stand, and 4 denotes a lower stand. A graphite jig 7 including a graphite piston 5 and a graphite cylinder 6 slidably fitted to the piston 5 is provided between the upper and lower stands 3 and 4 of the press device 1. Reference numeral 8 denotes an exhaust pump for maintaining the inside of the vacuum chamber 2 at a predetermined degree of vacuum. Reference numeral 9 denotes a transmitter for supplying a DC pulse current to the press device 1.
The temperature in the cylinder 6 of the press device 1 is the thermocouple 1 for the low temperature range.
0, and is detected by the high-temperature radiation thermometer 11.
This is fed back via a control device (not shown) or the like. Table 1 shows the specifications of the sintering apparatus A.

[0013]

[Table 1]

In FIG. 1, a steel plate 12 is set on the lower base 4 of the press device 1 and Ni powder as a non-chilling element is interposed between the steel plate 12 and the graphite jig 7. The cast iron chips 13 are set. At this time, the cast iron chips 13 move downward and are inserted into the inside of the cylinder 6 whose lower end is in contact with the steel plate 12.

In this state, a high current of a DC pulse is supplied from the transmitter 9 while the pressing device 1 is operated to apply a load to the cast iron chips 13 with the pressurizing piston 5. The electric current flows from the transmitter 9 through the graphite jig 7, and a large amount of discharge energy is generated at the powder particle contact of the cast iron chip 13, which is a workpiece in the graphite jig 7, and at the joint interface between the casting chip 13 and the steel plate 12. Release to a high temperature. The temperature control at this time is performed by feeding back the values detected by the thermometers 10 and 11 for the low temperature range and the high temperature range to the transmitter 9 and controlling the current from the transmitter 9. Table 2 shows an example of the implemented conditions.

[0016]

[Table 2]

In 170 seconds, the temperature of the workpiece reached 1100 ° C., and the fabrication was completed. That is, the cast iron chips 13 were sintered together by welding the powder particles to each other, and the sintered compact was welded and joined to the steel plate 12.

At the time of this sinter joining, Ni powder is mixed in the vicinity of the joining interface between the steel plate 12 and the cast iron chips 13, so that the joining strength between them is strengthened. This is because the Ni powder becomes active at the time of energy impact at the time of electric discharge, thereby promoting the sintering reaction and promoting the joining reaction between the steel structure and the sintered body. In particular, the latter reaction is significant, and a stronger bonding force can be obtained.

FIG. 2 is a photomicrograph at a magnification of 85 of the vicinity of the bonding interface of a sintered bonded body mixed with Ni powder at 1100 ° C. and processed at 900 ° C., respectively. As shown, the cast iron chips 13 on the steel plate 12 are sintered, and the sintered body is bonded to the steel plate 12 via the Ni layer 14. In any case, there is no chill layer that adversely affects the junction. These metal structures prove that the sintering has been performed well.

Table 3 shows the results of measuring the hardness of the joining members at this time. The hardness of the cast iron chip sintered body in the table is 206
A value of ２227 Hv is a proof that the sintering of the cast iron chips has been completely performed because the value is close to the value of the cast product of FC200.

[0021]

[Table 3]

FIG. 4 shows that, instead of Ni, Cu powder, which is a non-chilling element similar to Ni, is mixed in the vicinity of the bonding interface.
A micrograph at a magnification of 85 in the vicinity of the joint interface of the sintered joined body treated at 900 ° C. is shown in FIG.
Layer. In this case, the bonding effect was slightly inferior to that of Ni, probably because Cu had a smaller tendency to activate due to discharge energy, but the bonding was still good.

In this embodiment, the size of the sintered body of the cast iron cuttings to be sintered on the steel sheet is shown as a disk having a thickness of 5 mm and a diameter of 30 mm. It is arbitrarily determined according to the size and shape of the tool and the magnitude of the input energy.

The power source used at this time is a power source that generates a rectangular pulse of alternating current or direct current that applies discharge energy between two structures between the powder particles, and the pulse width, period, and set time of the pulse at this time. For example, conditions suitable for the material to be joined are set.

Further, as another embodiment of the present invention,
Instead of the pulse current in the above-described embodiment, high-frequency heating, the cast iron chips are heated and melted by an electron beam or the like, and are pressed together with them to form a sintered body, which is joined to a steel material. There is a sinter joining method.

[0026]

According to the present invention, cast iron chips can be bonded to a steel sheet in a sintered state, and a strong bond between a cast iron sintered alloy and a steel material, which has been considered difficult until now, can be obtained. became.

[0027] Thus, the cast iron chips, which were discarded as industrial waste as it is, can be diverted to the structure, and can be used as environmental technology and recycling technology.

Further, the sintering process, which conventionally required a long time, is shortened by using a pulse current, or by using high-frequency heating or an electron beam. In addition, since sintering and joining are performed in one step, productivity can be improved.

[Brief description of the drawings]

FIG. 1 is a configuration explanatory view schematically showing an apparatus for carrying out the method of the present invention.

FIG. 2 is a microscopic structure diagram of a rising surface joined by sintering by the method of the present invention.

FIG. 3 is a microscopic structure diagram of a bonding rising surface which is sintered and bonded by the method of the present invention.

FIG. 4 is a microscopic structure diagram of a bonding rising surface sintered and bonded by the method of the present invention.

[Explanation of symbols]

A: Sintering joining device, 1: Pressing device, 2: Vacuum chamber, 3: Upper stage, 4: Lower stage, 5: Piston, 6: Cylinder, 7: Graphite jig, 8: Exhaust pump, 9 ... Transmitter,
10 thermocouple for low temperature range, 11 radiation thermometer for high temperature range, 1
2 ... steel plate, 13 ... cast iron chips, 14 ... Ni layer, 15 ... Cu
layer.

Claims (3)

[Claims] Claims: 1. A cast iron chip is uniformly layered on a steel material with a non-chilled element such as Ni or Cu interposed therebetween, and the cast iron chip is discharged into the steel material while being compressed into a steel material. Sintering and joining the sintered body to the steel material side. 2. A cast iron chip is placed on a steel material in a state where a non-tilizing element such as Ni or Cu is interposed therebetween in a molding die. A sintering joining method characterized by joining the sintered body to a steel material while pressing the powder to a steel material and sintering the cast iron cuttings. 3. A cast iron chip is evenly layered on a steel material with a non-chilling element such as Ni or Cu interposed therebetween, and the two are heated by high frequency heating, an electron beam or the like while pressing the cast iron chip against the steel material. A sinter joining method characterized by heating to sinter cast iron chips and joining the sintered body to a steel material side.