CN115015395A - Method for manufacturing hard alloy long transverse hole for ultrasonic detection - Google Patents

Abstract

The invention discloses a method for making a cemented carbide long transverse hole for ultrasonic detection, which includes the following steps: S1, blank production: according to the shrinkage coefficient of the blank and the diameter and depth of the developed long transverse hole, calculating the long transverse hole to be machined in the blank S2, long horizontal hole production: open a long horizontal hole on the side of the blank in step S1; S3, core rod production: select the same material as the blank, use this material to make a cylindrical core rod, the core The diameter of the rod is smaller than the diameter of the long horizontal hole; S4, paint spraying: in step S3, the side surface of the mandrel rod is sprayed with paint, and air-dried, so that the diameter of the mandrel rod after spraying is the same as the diameter of the long horizontal hole; S5, blank sintering; S6, Long horizontal hole reprocessing; by spraying a layer of paint on the core rod, the diameter of the sprayed core rod is the same as the diameter of the long horizontal hole, so as to prevent deformation of the long horizontal hole during sintering, and the coating makes the sintered long horizontal hole and the core rod. There is a gap between them to facilitate the extraction of the core rod.

Description

Method for making long transverse holes in cemented carbide for ultrasonic testing

technical field

The invention relates to the technical field of ultrasonic flaw detection, in particular to a method for making long transverse holes of cemented carbide for ultrasonic detection.

Background technique

Ultrasonic testing is currently one of the most effective methods to detect internal defects in cemented carbide. Ultrasonic testing is a comparative test, and a test block must be compared. The role of the test block: ultrasonic detector calibration, sensitivity setting, and detection of cemented carbide. Comparison of internal defect sizes. Ultrasonic transverse wave testing method is another important method of ultrasonic testing. It can detect defects that cannot be detected by ultrasonic longitudinal wave method, so it is very important. The long horizontal hole test block is a commonly used comparison test block in the ultrasonic shear wave detection process. It is used to set the detection initial sensitivity and compare the size of the detected defect during the detection process. Therefore, the long horizontal hole in the long horizontal hole test block is made. It must be standardized. In the steel industry, the national flaw detection standard clearly stipulates that the long horizontal hole test block is made by machining.

Cemented carbide is difficult to machine due to its high density. At present, metal holes generally use three methods: machining, laser, and electric spark. Mechanical processing generally increases the diameter of more than 2mm, and the process is cumbersome, low efficiency, and small diameter holes are difficult to process. Laser drilling generally punches through holes, and it is easy to destroy the cemented carbide structure. EDM drilling will also destroy the alloy structure of the hole, and with the depth of the hole, the verticality of the hole will become worse, especially when drilling a hole with a small diameter, the electrode wire is easy to break, and it is difficult to punch.

A method for making a flat-bottom hole test block for ultrasonic testing of SiC/Al composite materials was inquired. The application number is CN111060602A. Considering the use of clearance fit, the SiC/Al block cylinder is inserted into the prepared hole to prevent the hole from being deformed during the sintering process. As well as maintaining the physical properties of the pores of the sintered block. According to the analysis, because the sintering mechanism of cemented carbide is different from that of SiC/Al composite material, the factors affecting the material of the developed hole in the sintering process are completely different, so the means to prevent the influence of these factors are different. The body is completely adhered to the inner wall of the hole; the defect detection rate of cemented carbide is not an order of magnitude with its size, so the aperture size developed in this project is much smaller than it, and the diameter of the inserted mandrel is required to be small, which is very difficult to pull out.

In the actual inspection process, it is found that the long and transverse holes with small diameters are necessary in the ultrasonic testing of cemented carbides. Therefore, it is necessary to study the long and transverse holes with small diameters in the ultrasonic testing of cemented carbides. The invention relates to a method for making long transverse holes for ultrasonic testing of alloys or related literatures and reports. It is of great significance to study the fabrication method of small-diameter long-horizontal holes for ultrasonic testing of cemented carbide.

Aiming at the above shortcomings, the present invention provides a method for manufacturing a long transverse hole for ultrasonic detection of cemented carbide.

SUMMARY OF THE INVENTION

In order to overcome the above-mentioned technical problems, the object of the present invention is to provide a method for making a cemented carbide long transverse hole of ultrasonic detection, by spraying a layer of paint on the core rod, so that the diameter of the core rod after spraying is the same as the diameter of the long transverse hole, The diameter of the core rod after spraying is the same as the diameter of the long horizontal hole, which can ensure that the core rod is filled with the long horizontal hole and prevent deformation during the sintering process of the long horizontal hole. The change of the rod and the blank is the same. After the high temperature treatment of the core rod, the sprayed coating on the side of the core rod will form powder, so that there is a gap between the sintered long horizontal hole and the core rod, which is convenient for the extraction of the core rod. , it can process long horizontal holes with a diameter of 0.5mm to 1.0mm, and realize the production of smaller long and horizontal holes in cemented carbide.

The object of the present invention can be realized through the following technical solutions:

The method for making long transverse holes of cemented carbide detected by ultrasonic comprises the following steps:

S1. Blank production: According to the shrinkage coefficient of the blank and the diameter and depth of the developed long horizontal hole, calculate the diameter and depth of the long horizontal hole to be machined in the blank;

S2, production of long horizontal holes: in step S1, a long horizontal hole is opened on the side of the blank;

S3. Mandrel production: Select the same material as the blank, and use this material to make a cylindrical mandrel. According to the actual operation, the length of the mandrel exceeds the length of the long horizontal hole to facilitate clamping, and the diameter of the mandrel is smaller than the long horizontal hole. diameter, so that there is a gap between the mandrel and the long horizontal hole, which is convenient for the extraction of the mandrel after the sintering of the blank is completed;

S4, paint spraying: in step S3, spray paint on the side of the mandrel and air dry, so that the diameter of the mandrel after spraying is the same as the diameter of the long horizontal hole, and the diameter of the mandrel after spraying is the same as the diameter of the long horizontal hole, which can ensure the mandrel Filled with long horizontal holes to prevent deformation of long horizontal holes during sintering;

S5, blank sintering: insert the mandrel rod in step S4 into the long horizontal hole on the side of the blank, and then sinter, and pull out the mandrel rod after the sintering is completed;

S6. Reprocessing of long horizontal holes: Finally, select a cemented carbide twist drill with the same inner diameter as the long horizontal hole to process the inner wall roughness of the horizontal hole based on the central axis of the long horizontal hole. After the hole is processed, use a laser to test the diameter of the hole. and verticality;

The diameter error of the long horizontal hole prepared by the above method is not more than 0.05mm, the depth error of the long horizontal hole is not more than 0.3mm, the verticality tolerance is not more than 0.1mm, and the roughness of the inner wall of the hole is Ra 3.2μm.

As a further solution of the present invention: in the step S2, the diameter of the long horizontal hole is 0.5 mm to 1.0 mm, and the depth of the long horizontal hole is 30 mm to 50 mm.

As a further solution of the present invention: in the step S3, the thickness of the paint sprayed on the side of the core rod is 0.05mm to 0.10mm, and the length of the core rod is 30mm to 50mm.

As a further scheme of the present invention: the coating of the core rod in the step S3 needs to be polished to control the thickness of the coating, and the polishing of the coating includes the following steps:

Y1. Fixing the mandrel: fix both ends of the mandrel by the rotating roller, the rotating roller is driven by the motor, and a grinding blade with adjustable position is set on one side of the rotating roller;

Y2. Spray paint: adjust the motor to a low speed, drive the mandrel to rotate, then spray the paint on the side of the mandrel and air dry;

Y3. Grinding paint: measure the actual diameter R of the long horizontal hole, adjust the distance between the grinding blade and the center of the roller to 0.5R, and adjust the motor to a high speed to ensure that the grinding blade can grind the paint on the side of the core rod.

As a further solution of the present invention: the coating is Al2O3, the core rod covered by Al2O3 will not adhere to the inner wall of the long horizontal hole during the sintering process, and the Al2O3 forms powder after sintering, The physical properties of the pores are not affected during the sintering process.

As a further solution of the present invention: the low speed range of the motor is 60r/min to 120r/min, and the high speed range of the motor is 500r/min to 800r/min.

As a further scheme of the present invention: the calculation formula of the shrinkage coefficient in the step S1 is:

D=[(V1-V2)/V2]*100%;

V2=V1/(D+1);

In the formula, D is the alloy shrinkage coefficient corresponding to the blank, V1 is the volume of the blank before shrinkage, and V2 is the volume of the blank after shrinkage.

The beneficial effects of the invention are as follows: by spraying a layer of paint on the core rod, the diameter of the core rod after spraying is the same as the diameter of the long horizontal hole, and the diameter of the core rod after spraying is the same as the diameter of the long horizontal hole, which can ensure that the core rod is filled with the long horizontal hole. hole, to prevent deformation during the sintering process of long and horizontal holes, and the material of the core rod is the same as that of the blank, to ensure that the changes of the core rod and the blank are consistent during the sintering process of the blank. , it will form powder, so that there is a gap between the sintered long horizontal hole and the core rod, which is convenient for the extraction of the core rod. Through the above-mentioned core rod, long and horizontal holes with a diameter of 0.5mm to 1.0mm can be processed to achieve smaller hardness. Manufacture of long and horizontal holes in solid alloys.

Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings.

Fig. 1 is the production method flow chart of the present invention;

Fig. 2 is the real picture of ultrasonic detection small aperture long transverse hole test block of the present invention;

Fig. 3 is the diffraction image of the long transverse hole made by the laser test of the present invention;

Fig. 4 is the aperture diagram of the embodiment 1 of the present invention utilizing the laser scanning method to test the long transverse hole of cemented carbide;

Fig. 5 is the aperture diagram of the embodiment 2 of the present invention utilizing the laser scanning method to test the long horizontal hole of cemented carbide;

FIG. 6 is a diagram showing that the core rod of the present invention is not sprayed with adhesive paint, and the cemented carbide is tested and bonded to the core rod by means of laser scanning during the sintering process.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

Example 1:

As shown in Fig. 1-Fig. 6, the manufacturing method of the cemented carbide long horizontal hole detected by ultrasonic is to develop a long horizontal hole with a diameter of 50mm and a depth. The specific manufacturing process includes the following steps:

S1. The production of the long and horizontal hole test block for pressing the blank: according to the shrinkage coefficient of the material, press a 125*1250*62.5mm ³ cuboid plate blank;

S2. Process three long horizontal holes on one side of the blank, the diameters of the three long horizontal holes are 0.625mm, 0.875mm and 1.25mm respectively, and the hole depths are all 62.5mm;

S3. Make three core rods with a height of 50mm and a flat end cylinder, and the diameters of the three core rods are 0.450mm, 0.750mm and 0.950mm;

S4. Fix the two ends of the mandrel by the rotating roller, the rotating roller is driven by the motor, set a grinding blade with an adjustable position on one side of the rotating roller, adjust the motor to a low speed, drive the mandrel to rotate, and then spray the paint on the The side of the mandrel is air-dried, and the distance between the grinding blade and the center of the roller is adjusted to three levels of 0.5m, 0.8mm and 1.0mm, corresponding to three mandrels respectively. Adjust the motor to a high speed to ensure that the grinding blade can touch the mandrel. The paint on the side is polished, the low speed range of the motor is 60r/min, the high speed range of the motor is 500r/min, and the paint is aluminum oxide;

S5. Insert the polished mandrel into the long horizontal hole, and then place the blank and the mandrel in the boiler for simultaneous sintering. After the sintering is completed, pull out the mandrel;

S6. For reprocessing of long horizontal holes, the inner wall of long horizontal holes with a diameter of 0.625 mm is processed by a flat bottom hole drill with a diameter of 0.5 mm of cemented carbide, so that a diameter of 0.496 mm, a depth of 50 mm and a verticality tolerance of 0.1 can be obtained. mm, the roughness of the inner wall of the hole Ra 3.2μm long and horizontal hole rectangular solid carbide ultrasonic testing test block, the same is the case for the long horizontal hole with a diameter of 0.875mm and the long horizontal hole with a diameter of 1.25mm;

The calculation formula of the shrinkage coefficient in step S1 is:

D=[(V1-V2)/V2]*100%;

V2=V1/(D+1);

In the formula, D is the alloy shrinkage coefficient corresponding to the blank, V1 is the volume of the blank before shrinkage, V2 is the volume of the blank after shrinkage, and the alloy shrinkage coefficient D of this blank is 0.2.

Measure the processed three long horizontal holes, and get the following data:

1 2 3 Hole depth(mm) 50.04 49.96 50.05 Aperture(mm) 0.496 0.976 1.030

Example 2:

To develop a long horizontal hole with a diameter of 30mm and a depth of 30mm, the specific production process includes the following steps:

S1. The production of the long and horizontal hole test block for pressing the blank: according to the shrinkage coefficient of the material, press a 125*1250*62.5mm ³ cuboid plate blank;

S2. Process three long horizontal holes on one side of the blank, the diameters of the three long horizontal holes are 0.625mm, 0.875mm and 1.25mm respectively, and the hole depths are all 37.5mm;

S3. Make three core rods with a height of 30mm and a flat end cylinder, and the diameters of the three core rods are 0.450mm, 0.750mm and 0.950mm;

S4. Fix the two ends of the mandrel by the rotating roller, the rotating roller is driven by the motor, set a grinding blade with an adjustable position on one side of the rotating roller, adjust the motor to a low speed, drive the mandrel to rotate, and then spray the paint on the The side of the mandrel is air-dried, and the distance between the grinding blade and the center of the roller is adjusted to three levels of 0.5m, 0.8mm and 1.0mm, corresponding to three mandrels respectively. Adjust the motor to a high speed to ensure that the grinding blade can touch the mandrel. The paint on the side is polished, the low speed range of the motor is 60r/min, the high speed range of the motor is 500r/min, and the paint is aluminum oxide;

S5. Insert the polished mandrel into the long horizontal hole, and then place the blank and the mandrel in the boiler for simultaneous sintering. After the sintering is completed, pull out the mandrel;

S6. Reprocessing the long horizontal hole. Use a cemented carbide flat-bottom hole drill with a diameter of 0.5mm to process the inner wall of a long horizontal hole with a diameter of 0.625mm. In this way, a diameter of 0.496mm, a depth of 30mm, and a verticality tolerance of 0.1 can be obtained. mm, the roughness of the inner wall of the hole Ra 3.2μm long and horizontal hole rectangular solid carbide ultrasonic testing test block, the same is the case for the long horizontal hole with a diameter of 0.875mm and the long horizontal hole with a diameter of 1.25mm;

The calculation formula of the shrinkage coefficient in step S1 is:

D=[(V1-V2)/V2]*100%;

V2=V1/(D+1);

In the formula, D is the alloy shrinkage coefficient corresponding to the blank, V1 is the volume of the blank before shrinkage, V2 is the volume of the blank after shrinkage, and the alloy shrinkage coefficient D of this blank is 0.2.

Measure the processed three long horizontal holes, and get the following data:

1 2 3 Hole depth(mm) 30.09 29.96 29.97 Aperture(mm) 0.504 0.796 1.045

To sum up, by spraying a layer of paint on the side of the mandrel, the diameter of the mandrel after spraying is the same as the diameter of the long horizontal hole, and the diameter of the mandrel after spraying is the same as the diameter of the long horizontal hole, which can ensure that the mandrel is full of long holes. The horizontal hole prevents deformation during the sintering process of the long horizontal hole, and the material of the core rod is the same as that of the blank, which ensures that the change of the core rod and the blank is the same during the sintering process of the blank. After sintering, powder will be formed, so that there is a gap between the sintered long horizontal hole and the mandrel, which is convenient for the extraction of the mandrel. Through the above mandrel, the diameter of 0.5mm to 1.0mm, the verticality tolerance of 0.1mm, A long horizontal hole with a roughness Ra of the inner wall of the hole of 3.2 μm.

An embodiment of the present invention has been described in detail above, but the content is only a preferred embodiment of the present invention, and cannot be considered to limit the scope of the present invention. All equivalent changes and improvements made according to the scope of the application of the present invention should still belong to the scope of the patent of the present invention.

Claims (6)

1. The method for manufacturing the hard alloy long transverse hole for ultrasonic detection is characterized by comprising the following steps of:

s1, blank preparation: calculating the aperture and the depth of the long transverse hole to be processed in the blank according to the shrinkage coefficient of the blank and the diameter and the depth of the developed long transverse hole;

s2, manufacturing a long transverse hole: forming a long transverse hole on the side surface of the blank in the step S1;

s3, manufacturing a core rod: selecting the same material as the blank, and manufacturing a cylindrical core rod by using the material, wherein the diameter of the core rod is smaller than that of the long transverse hole;

s4, spraying the paint: spraying paint on the side surface of the core rod in the step S3, and air-drying to make the diameter of the sprayed core rod the same as that of the long transverse hole;

s5, blank sintering: inserting the core rod in the step S4 into the long transverse hole on the side surface of the blank, then sintering, and pulling out the core rod after sintering is completed;

s6, reprocessing of the long transverse hole: and finally, selecting a hard alloy twist drill with the same inner diameter as the long transverse hole to process the thickness of the inner wall of the transverse hole by taking the central axis of the long transverse hole as a reference, and testing the aperture and the verticality by using a laser instrument after the hole is processed.

2. The method of claim 1, wherein the diameter of the long transverse hole in step S2 is 0.5mm to 1.0mm, and the depth of the long transverse hole is 30mm to 50 mm.

3. The method for manufacturing a cemented carbide long transverse hole for ultrasonic testing according to claim 1, wherein the thickness of the coating sprayed on the side surface of the core rod in the step S3 is 0.05mm to 0.10mm, and the length of the core rod is 30mm to 50 mm.

4. The method for manufacturing the cemented carbide long transverse hole for ultrasonic testing according to claim 3, wherein the coating of the core rod in the step S3 needs to be polished to control the thickness of the coating, and the polishing of the coating comprises the following steps:

y1, fixing the core bar: fixing two ends of the core bar through a rotating roller, driving the rotating roller by a motor, and arranging a polishing blade with an adjustable position on one side of the rotating roller;

y2, spray coating: adjusting the motor to a low rotating speed to drive the core rod to rotate, then spraying the coating on the side surface of the core rod, and air-drying;

y3, grinding coating: the actual diameter R of the long transverse hole is measured, the distance between the polishing blade and the circle center of the rotary roller is adjusted to be 0.5R, the motor is adjusted to be at a high rotating speed, and the polishing blade can polish the coating on the side face of the core rod.

5. The method for manufacturing the long transverse hole of the hard alloy for ultrasonic testing according to claim 1, wherein the coating is aluminum oxide.

6. The method for manufacturing the long transverse hole of the hard alloy for ultrasonic testing according to claim 4, wherein the low rotating speed range of the motor is 60r/min to 120r/min, and the high rotating speed range of the motor is 500r/min to 800 r/min.

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