JPS60257963A - Production of mud pump liner - Google Patents

Abstract

PURPOSE:To improve the reliability of a mud pump liner while decreasing the man- hour for working and to prevent the decrease in the wear resistance thereof by forming an inside cylinder by centrifugal casting of a wear resistant metal and heating the cylinder then installing the cylinder into a casting mold which is an outside cylinder and casting a tough metallic material into the mold at the point of the time when a limited temp. is attained to insert-cast the inside cylinder thereby forming an integral composite cylinder. CONSTITUTION:The inside cylinder 1 is made of a high-chromium cast iron by centrifugal casting. The outside surface of the inside cylinder is then roughly finished or is as cast and shot-blasted. After the cylinder 1 is heated to 700-900 deg.C, the cylinder is installed in the casting mold 10 which is the outside cylinder. The melt of a carbon steel or low alloy steel is poured into the spacing between the outside surface of the inside cylinder and the inside surface of the casting mold at the point of the time when the cylinde4 1 is at 400-600 deg.C to cast the cylinder 2. The casting consisting of the cylinder 1 embedded by casting in the cylinder 2 is taken out of the mold 10. The runner is removed and the inside surface of the cylinder 1, the outside surface of the cylinder 2 and both end faces are finished to prescribed sizes. The casting is subjected to a heat treatment if necessary.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a matsubon liner configured as a composite pipe.

During oil drilling, in order to cool and lubricate the tip of the bit and transport the cuttings to the ground or sea, they are discharged from the ground or sea through a drilling pipe and from the bit nozzle to the bottom of the pit, and the inside of the mine outside the drilling pipe is raised. A piston pump is used as a mud pump to circulate muddy water, but the pump liner is subject to high internal pressure, and the fluid handled is mud mixed with sand. ,
A composite pipe is used in which an inner tube 1 made of a material with excellent wear resistance such as high chromium cast iron and an outer tube 2 made of a highly tough material such as ordinary cast steel or forged steel are brought into close contact with each other. ing.

The mud pump liner with the above-mentioned composite tube structure has conventionally been manufactured by a shrink fit method or a double centrifugal casting method.

In the shrink fit method, the inner cylinder is made by centrifugal casting, the outer cylinder is made of carbon steel forging or steel pipe, and both are machined to the required precision dimensions and integrated by shrink fit. However, it has the drawbacks of strict dimensional accuracy, a large number of machining operations, and a large proportion of machining costs.

In the double centrifugal casting method, the 9♀ through-cast steel that will become the outer cylinder is first cast by centrifugal casting, and before it solidifies, the high chromium cast iron that will become the inner cylinder is centrifugally cast to form an integrated composite pipe. However, the heat builds up in the outer cylinder, which delays the solidification and cooling of the inner cylinder.
The disadvantage is that the structure becomes coarser, resulting in lower wear resistance.

The present invention is a mud pump liner that solves the problems described in (-) of mud pump liners using the shrink fit method and double centrifugal casting method. The purpose is to provide a manufacturing method for.

The manufacturing method of the mud pump liner according to the present invention solves the double problem.The inner cylinder is made by centrifugal casting, and the IJ[
After heating, the outer cylinder is placed in a mold, and when the inner cylinder is between 4000 and 600°C, ordinary steel or low alloy steel is cast between the inner surface of the mold and the outer surface of the inner cylinder to form the inner cylinder. It is characterized by an integrated casting.

Embodiment FIG. 1 is a diagram showing an embodiment of the method for manufacturing a mud pump liner according to the present invention in the order of steps.

(a) The inner cylinder 1 is made of high chromium cast iron by centrifugal casting. The outer surface is rough finished] or as-cast shot blasted.

(b) After heating the above inner cylinder 1 to an appropriate temperature, the outer cylinder mold 1
The inner cylinder is installed between the outer surface of the inner cylinder and the inner surface of the mold.
Molten carbon steel or low alloy steel is poured at a temperature of 00°C to 600°C, and the outer cylinder 2 is cast.

(c) Remove the casting from the mold. The inner cylinder 1 is cast into the outer cylinder 2.

(d) Remove the runner and finish the inner surface of the inner tube 1, the outer surface and both end surfaces of the outer tube 2 to predetermined dimensions. In addition, if necessary,
Heat treatment is applied to obtain the required strength.

121 Eh. ,,, 11, □, 4□, etc. . -1 F) shows a cross-sectional view of '. The main mold 7 is molded using a flask 11 and an outer cylinder = 3-, and a lower mold 8 and an upper mold 9 are molded using other flasks 12 and 13.

Before installing the inner cylinder 1, put the hanging tool 3 inside and tighten the lower part by about 5cm.
Fix Qmm with magnesia 4. On top of that, fill the inner cylinder 1 with coarse sand 5 up to the end face, put it in a heating furnace, and heat it to 700°.
C to 900°C for about 1 hour, then taken out from the heating furnace,
It is placed in the main mold 7 set on the lower mold 8, and the core 6 is placed on it.
- Cover with the L-type 9, and when the inner cylinder is at 400° to 600°C, pour carbon steel or low alloy steel molten metal from the runner and cast for a predetermined time.

In the manufacturing method of the present invention described above, when the outer cylinder 2 is cast, the inner cylinder 1
Since it has already solidified, even if it comes into contact with the molten metal of the outer cylinder and is heated, the structure will not become coarse, and therefore the wear resistance will not deteriorate. In addition, since the inner cylinder 1 is cast around the outer cylinder 2 to bring the outer surface of the inner cylinder into close contact with the inner surface of the outer cylinder, strict dimensional accuracy is not required as in the case of the shrink fitting method, and it may be as-cast. , the number of machining operations can be significantly reduced.

Moreover, due to the contraction of the outer cylinder due to solidification, the inner cylinder 14- is tightened by the outer cylinder 2, thereby preventing the inner cylinder from coming off from the outer cylinder during use when attached to the pump.

Also, since the inner cylinder is given stress in the direction of shrinking its diameter by the outer cylinder, when internal pressure is applied due to pump operation, the stress decreases by offsetting the stress in the direction of expanding the diameter due to the internal pressure. This is advantageous in terms of strength.

As can be seen from the above, according to the present invention, a mud pump liner configured as a composite pipe can be manufactured by significantly reducing the number of machining operations and without causing a decrease in wear resistance, resulting in cost reduction. This has a significant effect on increasing service life and improving reliability.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram illustrating an embodiment of the mud pump manufacturing method of the present invention in the order of steps, Fig. 2 is a sectional view showing an example of an outer cylinder casting mold in the method, and Fig. 3 is a general mud pump liner. FIG. 1...Inner cylinder 2...Outer cylinder 7.8.9...Mold-
Confirmed to Low

Claims (1)

[Claims] Manufacture of a mud pump liner that is composed of an inner cylinder made of a wear-resistant metal and an outer cylinder made of a tough metal, the outer surface of the former and the inner surface of the latter being brought into close contact with each other to form a composite pipe. In the method, an inner cylinder is cast by a centrifugal casting method, heated to an appropriate temperature, placed in an outer cylinder mold, and a metal material forming an outer cylinder is placed between the inner surface of the mold and the outer surface of the inner cylinder. A method for producing a mud pump liner, characterized in that the cylinder is cast at a temperature of 400° to 600°C, and the inner cylinder is integrated with the casting.