JPS63235446A - Iron powder discharging apparatus - Google Patents

Abstract

PURPOSE:To prevent the development of wear and build-up and to execute stable production for a long time by arranging surface layer composed of Cr2O3- Al2O3 solid solution having the specific composition and metallic Cr, to which contact with iron powder in an iron powder discharging apparatus. CONSTITUTION:The iron powder for disposable body warmer, etc., supplied from a supplying hopper 1, is discharged through a discharging ring 3 fitted to a ring-fixed guide 2 and supplied to the necessary process through a discharging chute 4. In the iron powder discharging apparatus having the above constitution, the surface layer composing of >=97wt.% of 1:9-9:1 or Cr2O3-Al2O3 solid solution, <=0.5% metallic Cr and the balance inevitable impurities, is arranged on the contacting face with the iron powder having one face or more of inner face of the above hopper 1, discharging ring 3, discharging chute 4, etc. The above surface layer is formed by abutting or thermal-spraying a ceramic plate composing a ceramic plate composing of the above composite on the contacting face with iron powder. by this method, the coating layer having excellent wear resistance and build-up resistance, is formed and the above apparatus can stably be used for a long time.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention is a method for measuring so-called iron powder in order to measure iron powder in fixed amounts in production equipment for products 1 made from iron powder, such as disposable body warmers. This invention relates to an iron powder cutting device that has excellent wear resistance and prevents build-up.

(Prior Art) Manufacturing equipment for products using iron powder, such as disposable body warmers and oxygen absorbers, includes a step of measuring out a fixed amount of powdered iron powder together with other auxiliary raw materials.

Most of the weighing equipment used at this time is made of metal, but iron powder reacts with oxygen in the air and other auxiliary materials to form iron oxide, which adheres to the equipment and gradually grows (hereinafter, this production things are called build-ups).

Therefore, supply iron powder, measure a certain amount of iron powder from it,
The build-up on the surface of the iron powder cutting device that sends this iron powder to the next process reduces the internal volume of the device, making accurate measurement difficult, and the build-up on the surface of the cutting ring and the surface facing this ring. The surface of the flat plate provided with the plate is fixed due to build-up, making it difficult to move for cutting out, so it is necessary to remove the build-up each time.

Therefore, as a method to prevent this build-up, attempts have been made to coat the surface of the cutting device with a material that does not cause build-up, such as synthetic resin, but this causes severe wear and reduces the replacement cycle of the device. ,
This method has not been put into practical use because it causes a decline in productivity and an increase in maintenance costs. Applying tape to the surface of the equipment has been widely tried as a method to achieve the same effect, but the issue of wear has not been resolved, and production has been forced to take down time to reapply the tape each time. be.

(Problems to be Solved by the Invention) The present invention focuses on the composition and contaminant components of the coating layer made of Cr203-At203 solid solution, and provides an iron powder cutting device with excellent wear resistance and build-up resistance. be.

(Means for solving the problems) The present invention provides Cr2O3 with a weight ratio in the range of 1:9 to 9:1.
-fiJ, 203 Contains 97% by weight or more of a solid solution,
The present invention is an iron powder cutting device having a surface layer on the iron powder contact surface, in which the metal Cr is 0.5% by weight or less, and the remainder consists of unavoidable impurities.

The present invention will be explained in detail below.

Generally, At, o, (melting point 2045°C), Cr2O3
(melting point 2275℃) etc. have a high melting point and are reactive with metals.
It has high hardness and wear resistance.

Further, studies have been conducted focusing on the fact that Cr2O3 and M2O form a complete solid solution over the entire region.

First of all, we considered the peel bond between the base material and the coating layer, and investigated the composition without peeling.
By making it a solid solution of 90% by weight, it becomes thermally stable,
It was found that a coating layer without peeling could be formed.

Therefore, Cr203 with a weight ratio in the range of l:9 to 9:1
- Various coating layers made of At, 03 solid solution have been used on the iron powder contact surfaces of iron powder cutting devices, but in some cases, build-up occurs between each cutting device or between various parts of the iron powder contact surface. In some cases, it did not occur at all.

Therefore, as a result of intensive investigation into this build-up mechanism, we found that metal C
It has been found that build-up occurs when r is present in excess of 0.5%.

Next, Table 1 shows the results of the peel resistance test and Table 2 shows the results of the build-up test, which were used as the basis for the numerical limitations of the coating material according to the present invention.

In the peeling resistance test, a sample in which a coating layer of various Cr2O3-Al2O2 solid solutions was formed (sprayed) on the outermost surface of SCH22 cast steel of 30 x 50 x 5 crn was repeatedly immersed in water after heating at 1000°C for 30 minutes, and the number of peeling occurrences was determined. Peeling resistance was determined by investigating.

In the build-up test, iron oxide powder, which is the build-up raw material, is placed between two flat plates of the sample prepared using the same procedure as the peeling resistance test, and a load is applied on top of the two plates.
The build-up raw material and the two flat plates were rubbed together, heated in air at 1000° C. for 5 hours, and after cooling, the surface condition of the coating layer was observed to determine the build-up property.

As can be seen from this result, in the Cr2O, -M, O5 solid solution, the ratio of the solid solution is 1 = 9 as in N[L3~5.
It can be seen that in the range of ~9:1, durability is exhibited for 10 times or more, and peeling resistance is significantly improved.

In addition, the coating layer used in this test was Cr, O, -AE203
The composition other than the solid solution is Cr that has not been made into a solid solution,
O8, O20, and the inevitable impurity 8102,
TiO2, Cab.

MyO, Fe2O3, etc.

In addition, the composition of the Cr2O3-O203 solid solution is 1 by weight.
:9 to 9:1, it can be seen that when the Cr2O3-AJL203 solid solution is 97% by weight or more and the metal Cr content is 0.5% by weight or less, the buildup is less likely to occur.

(HIILlo, 11, 12, 15, 16.17.19
゜20.21) Among them, especially when the metal Cr content is 0.2% by weight or less, it becomes extremely small (Ugly 11, 12, l 6.
1'7°20.21'), and the metal Cr content is o, o
In the case of 1% or less, no buildup was observed in experiments.

Techniques for reducing Cr203-M2o and metallic Cr in the solid solution include, for example, oxidation treatment, pickling, etc. in the manufacturing process of the solid solution powder, and reduction of Cr2O3 using a non-reducing atmosphere during thermal spraying. There are ways to suppress this.

FIG. 1 shows an example of an iron powder cutting device to which the present invention is directed.

1 in the figure is an iron powder supply hopper, and below the supply hopper 1 there are cut-out rings 3 (a plurality of pieces) supported by a ring holding guide 2, and further below that there is a cut-out chute 4 (corresponding to the cut-out ring 3). ), and the iron powder is supplied from the cutting chute 4 to the required process.

The present invention is an iron powder cutting device of this kind, in which a ceramic plate made of the above composition is brought into contact with the iron powder contact surface or a surface layer is formed by thermal spraying.

The iron powder contact surface on which the surface layer made of the above composition is provided is as follows:
One or more surfaces selected from (1) the inner surface of the iron powder supply hopper 1, (2) the inner surface of the cutting ring 3, and (3) the inner surface of the cutting chute 4 can be selected as desired.

(Example) Na1l,l'' shown in Table 2 was applied to the surface of the stainless steel.

The coating layers 20 and 14 were formed by thermal spraying, polished to a surface smoothness of 100 μm or less, and applied to an iron powder cutting device. In addition, a stainless steel iron powder cutting device was prepared as a conventional product.

Table 3 shows the results of using the five types of iron powder cutting devices described above in a disposable warmer manufacturing facility for six months (operating 16 hours a day).

The parts to which the present invention is applied are the supply hole, <-1, the cutting ring 3, and the cutting chute 4.

As shown in Table 3, even after 6 months of use, no build-up or surface wear was observed in the product of the present invention.

(Effects of the Invention) As shown in the above examples, the coating layer having wear resistance and build-up resistance according to the present invention shows no wear or build-up even when used for a long time, and is stable for a long time. It contributes to production.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of an example of an iron powder cutting device of the present invention. Agent Patent Attorney Tate Chanogi Mistake 1 - Ichimon ■---F

Claims (1)

[Claims] Cr_2O_3-Al in the range of 1:9 to 9:1 by weight
Contains 97% by weight or more of _2O_3 solid solution and contains metal C
An iron powder cutting device characterized in that the iron powder contact surface has a surface layer in which r is 0.5% by weight or less and the remainder consists of unavoidable impurities.