JPH029585A - Manufacture of cast iron bond grinder element - Google Patents

Abstract

PURPOSE:To reduce the manufacturing cost and material cost of a grinder element by subjecting a base metal to total shape processing into a desired form, coating it uniformly with an admixture of abrasive grains and matrix powder, and performing the baking process as it is under the specified conditions. CONSTITUTION:A base metal 2 subjected to total shape processing is uniformly coated with an admixture of abrasive grains and matrix powder to form an abrasive layer 1. After drying for several minutes, it is baked at 1,100-1,400 deg.C for 30-40min for joining of the abrasive layer 1 and base metal 2 metallurgically, and thus desired cast iron bond grinder element is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for manufacturing a cast iron bonded grindstone, and more particularly to a method for manufacturing a cast iron bonded grindstone of any shape through simple steps.

[Prior Art] Conventionally, the following steps were taken to manufacture a cast iron bond grindstone.

1. Mixing of abrasive grains and matrix powder 2. Press molding (molding pressure 6-3 ton/Cm2) 3. Degreasing (500-600°C) 4. Sintering (1100-1140°C) 5. Processing of fitting part 6. Brazing Attachment 7, Truing, Dressing In addition, when manufacturing whetstones with particularly complex shapes, press forming has limitations on the shape, so first form the whetstone into a simple shape such as a cylinder, and then use the pre-made metal Electrical discharge machining was performed using a mold electrode to form the desired shape.

[Problems to be Solved by the Invention] However, the conventional method has the following problems, all of which lead to an increase in the cost of the grindstone.

1. Because the molding pressure is extremely high, a large press device is required, and the mold wear is severe due to abrasive particles.

2. In order to maintain the strength of the compact, a certain amount of wall thickness is required, and the abrasive grains in the parts that are not used during grinding are wasted.

3. Because it goes through the sintering process, distortion and variations due to shrinkage inevitably occur, making it impossible to form a stable sintered body and requiring machining at the fitting part with the base metal.

4. In the case of a grindstone with a complicated shape, electric discharge machining is required, which takes time and the abrasive grains in the cut portion are completely wasted.

The present invention was made in order to solve the above-mentioned problems, and it simplifies the manufacturing process even for products with complex shapes, reduces the machining allowance by full-form truing, and reduces the amount of abrasive grain in parts not used for grinding. The purpose is to reduce manufacturing costs and material costs for grinding wheels by minimizing waste.

[Means for Solving the Problems] In order to achieve this object, the method for manufacturing a cast iron bonded grindstone of the present invention includes forming a base metal into a desired shape in advance, and then mixing abrasive grains and matrix powder thereon. The body is coated uniformly and fired under the specified conditions.

[Example] Hereinafter, an example embodying the present invention will be described with reference to the drawings.

The raw material for the grindstone of the present invention consists of diamond abrasive grains with a particle size of about 100 μm and matrix powder.

Matrix powder is usually made by crushing cast iron and has a particle size of 50~
A mixed powder of about 100 μm thick powder and carbonyl iron powder with a particle size of about 1 to 5 μm is used, but in this case, press forming is not performed, so a powder with a width of about 5 μm is used based on carbonyl iron powder with good sinterability. It is desirable to use one to which a predetermined amount of graphite powder is added. If the amount of graphite powder added is about 2.5 to 5% by weight, there will be no problem in terms of strength, and no wear of the diamond abrasive grains will be observed during sintering.

Wet-mix the above mixed powder with a volatile solvent such as ethyl alcohol, and apply it uniformly to a thickness of about 500 to 11,000p, depending on conditions such as tool life, on a base metal that has been processed into a desired shape in advance. do. Then, after drying for several minutes, it is fired in a furnace in a reducing atmosphere. The condition is 1100-1
Preferably, the temperature is 140°C for 30 to 40 minutes.

FIG. 1 is an explanatory diagram of the coating state.

An abrasive grain layer 1 is uniformly applied on a base metal 2 which has been processed into a full shape. The abrasive grain layer and the base metal part are metallurgically joined at the same time as sintering. If the base metal is made of tool steel (SKD or 5KS), the bonding condition will be good. This is thought to be because the steel contains a large amount of carbon, which facilitates atomic diffusion.

Figures 2 and 3 are structural photographs of the boundary area magnified 400 times when 5KD-11 is used as the base metal, and 300
These are electron micrographs enlarged twice (in each photo, the upper side is the matrix part and the lower side is the base metal part).

Moreover, FIG. 4 is an electron micrograph showing the state in which diamond abrasive grains are held. From these photographs, it can be seen that the bonding state between the base metal and the abrasive grain layer and the retention state of the abrasive grains are good.

The present invention is not limited to the embodiments detailed above, and various changes can be made without departing from the spirit thereof. For example, it is possible to use cubic boron nitride (CBN) instead of diamond abrasive grains, or add a small amount of Cu (approximately 5% by weight) to the matrix powder to increase matrix strength and abrasive grain retention. It is.

C Effects of the Invention] As is clear from the detailed description above, according to the present invention, the steps of press molding, degreasing, fitting part processing, and brazing can be omitted all at once, resulting in a significant reduction in manufacturing costs. This eliminates the need for press machines, molds, and other equipment.

In addition, in the case of complex shapes, since the total machining allowance is small, less wasted abrasive grains are removed, and the truing time can be shortened.Furthermore, since the thickness of the abrasive grain layer can be changed freely, the life of the abrasive wheel can be improved. It is possible to adjust it according to the purpose and avoid wasting abrasive grains. Even if the abrasive grain layer is gone, the base metal can be reused. That is, according to the method of the present invention, the cost for manufacturing a grindstone can be significantly reduced compared to the conventional method.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the coating state, FIG. 2 is a microstructure photograph showing the boundary, FIG. 3 is an electron micrograph of the boundary, and FIG. 4 is an electron micrograph showing the abrasive grain retention state. In the figure, 1 is an abrasive grain layer, and 2 is a base metal.

Claims (1)

[Claims] 1. Shank or base metal (2
) A method for manufacturing a bonded cast iron grindstone, characterized in that a mixture of abrasive grains and matrix powder is applied onto the shank or the base metal (2), and at the same time, an abrasive layer (1) is formed on the shank or base metal (2).