Method for repairing superficial crack damage of end face of casting shell of 1Cr17Ni3 gear pump

Abstract

The invention relates to the technical field of remanufacturing, in particular to a 1Cr17Ni3 gear pump casting shell end face superficial crack damage repairing method which comprises the steps that cleaning is conducted, and defect positions are determined; marking the defect position, then extending in a polyline form to form two rings, and connecting the two rings by using a line segment; polishing to form an outer ring groove, an inner ring groove and a line segment groove for connecting the inner ring and the outer ring; demagnetization is carried out; carrying out laser cladding repair; liquid nitrogen treatment; carrying out cladding repair and liquid nitrogen treatment on the test block to verify the hardness performance; the end face subjected to cladding repair is polished; and cleaning and carrying out penetrant flaw detection, and if no defect exists, successfully repairing. Local repair of a small area of the end face is avoided, local deformation is avoided, and the sealing performance is enhanced; the restoration quality deterioration caused by heat accumulation is avoided; the equal-hardness cladding repair is realized; the problem that after the shell has magnetism, the repairing quality is reduced due to the fact that powder adheres to the end face continuously in the cladding process is solved.

Description

Technical Field

[0001] The invention relates to the technical field of remanufacturing, and in particular to a method for repairing superficial crack damage on the end face of a 1Cr17Ni3 gear pump casting housing. Background Art

[0002] 1Cr17Ni3 martensitic stainless steel is an excellent casting material widely used in the manufacture of pump housings in hydraulic systems. After a long period of service, the end faces of the housings will produce small cracks on the surface due to stress corrosion, affecting the sealing performance. At present, conventional welding repair methods will have problems such as low compatibility between the repair layer and the base material, easy to produce defects such as pores, cracks, inclusions, or local hardness mismatch, which will affect the sealing performance. Summary of the invention

[0003] In order to solve the above technical problems, the present invention proposes a method for repairing superficial crack damage on the end face of a 1Cr17Ni3 gear pump casting housing.

[0004] The technical problem to be solved by the present invention is achieved by adopting the following technical solutions:

[0005] A method for repairing shallow crack damage on the end face of a 1Cr17Ni3 gear pump casting housing comprises the following steps:

[0006] Step 1, using acetone to clean the surface of the 1Cr17Ni3 gear pump casting housing, and then conducting magnetic particle testing on the end face of the 1Cr17Ni3 gear pump casting housing to determine the defect position of the end face of the 1Cr17Ni3 gear pump casting housing;

[0007] Step 2: Use a marker pen to mark the defect position on the end surface of the 1Cr17Ni3 gear pump casting housing, and then extend it on the end surface of the 1Cr17Ni3 gear pump casting housing in the form of a multi-segment line to form two rings, and the two rings are connected by a line segment;

[0008] Step 3: Use a small manual grinder to grind the line segment marked by the marker pen to remove the shallow surface defects on the end face of the 1Cr17Ni3 gear pump casting housing, and form an outer ring groove, an inner ring groove, and a line segment groove connecting the inner ring and the outer ring;

[0009] Step 4: Demagnetize the 1Cr17Ni3 gear pump casting shell by using an AC coil passing method, and use a magnetometer to detect the residual magnetism of the end surface of the 1Cr17Ni3 gear pump casting shell. If the residual magnetism is greater than 0.25mT, repeat the AC coil passing method to demagnetize the 1Cr17Ni3 gear pump casting shell;

[0010] Step 5: Perform laser cladding repair on the end surface of the 1Cr17Ni3 gear pump casting housing:

[0011] Step 51, select a particle size of 53-150 μm, a fluidity of less than 17s / 50g, and a chemical composition by weight percentage: C: 0.01-0.03%, Cr: 12.0-14.0%, Ni: 8.0-10.0%, Mo: 3-5%, Co: 5-6%, Si: <0.5%, Mn: <0.5%, P: <0.005%, S: <0.005%, O: <0.03%, N: <0. 015%, H: <0.003%, the balance is Fe and unavoidable impurities in the cladding powder, select high-purity argon as the shielding gas and the shielding gas flow rate is 10-20L / min, set the process parameters: powder feeding gas flow rate is 2-5L / min, powder feeding disk speed is 1.2-1.5rpm, powder output time is at least 8s, laser spot diameter is 1.5-3mm, laser power is 1200-1600W, moving speed is 10mm / s;

[0012] Step 52, firstly, cladding the polished outer ring groove, and the cladding repair of the outer ring groove is in a clockwise direction. The laser cladding is performed in sections, and the sections of the laser cladding process are consistent with the sections of the line segments drawn by the marker pen in step 2;

[0013] Step 53, each cladding process is to first move the cladding head to a safe point, then turn on the powder feeding switch, and after the powder flow is stable, turn on the protective gas, and move the cladding head to 7-10 mm above the starting point of the area to be repaired, turn on the laser, and move the cladding head along the set path. When it moves to the end point, turn off the laser and powder feeding, stay at this position for 8-20 seconds, continue to output the protective gas to protect the molten pool and the first cladding area, and then move the cladding head to a safe point, and the cladding of this section is completed;

[0014] Step 54, repeat the above segmented cladding process until the outer ring cladding is completed, and then clad the polished inner ring groove. The inner ring groove cladding repair is carried out in a counterclockwise direction. The laser cladding is carried out in segments, and each segment of the cladding process follows the outer ring segment of the cladding process.

[0015] Step 55, finally cladding the line segment groove connecting the inner ring and the outer ring, the laser cladding is performed in sections, and each section of the cladding process follows the cladding process of each section of the outer ring;

[0016] Step 6, placing the 1Cr17Ni3 gear pump casting housing after cladding repair in liquid nitrogen for 1 to 3 hours and then taking it out;

[0017] Step 7, using the same cladding process as step 5, a cladding repair test is performed on a 1Cr17Ni3 test block in the same heat treatment state as the 1Cr17Ni3 gear pump casting housing, the cladding test block is placed in liquid nitrogen for 1 to 3 hours and then taken out, and the hardness performance of the test block after cladding is detected. It is detected that the hardness of the cladding layer of the test block is 320 to 340 HV, and the hardness of the substrate is 320 to 340 HV, achieving equal hardness cladding repair;

[0018] Step 8, use a high-precision horizontal axis and rectangular table surface grinder to grind the end surface of the 1Cr17Ni3 gear pump casting housing after cladding repair, use a height meter to detect the change in the height of the 1Cr17Ni3 gear pump casting housing after grinding compared with the height of the 1Cr17Ni3 gear pump casting housing before repair, and use a roughness meter to detect the roughness of the end surface of the 1Cr17Ni3 gear pump casting housing;

[0019] Step 9: Clean the surface of the 1Cr17Ni3 gear pump casting housing with acetone, and then conduct penetrant testing on the end face of the 1Cr17Ni3 gear pump casting housing to detect and repair the rear end face defects. If there are no defects, it is determined that the end face of the 1Cr17Ni3 gear pump casting housing has been repaired successfully.

[0020] As a further improvement of the present invention, the magnetization method in step 1 is selected as the current supply method.

[0021] As a further improvement of the present invention, the width of the pen tip of the marker in step 2 is 1-4 mm, and the length of each line segment is 1-2 cm.

[0022] As a further improvement of the present invention, in step 3, the grinding head of the small manual grinder is selected to be 2-6 mm, and the grinding depth is 0.5-2 mm.

[0023] As a further improvement of the present invention, the height of the safety point in step 53 should be at least 200 mm away from the part to be repaired.

[0024] As a further improvement of the present invention, the grinding process in step 8 is as follows:

[0025] The initial vertical feed rate is controlled between 0.1 and 0.5 mm / min until the portion of the cladding layer higher than the initial end face of the 1Cr17Ni3 gear pump casting housing is almost completely polished away, and then a step-by-step polishing method is adopted, with the vertical feed rate controlled at 0.002 to 0.005 mm each time, until the end face is completely free of the unevenness caused by the cladding process, and a complete end face is obtained.

[0026] As a further improvement of the present invention, in step 8, the height reduction value of the 1Cr17Ni3 gear pump casting housing is required to be less than 0.03 mm.

[0027] As a further improvement of the present invention, in step 8, the roughness Ra of the end surface of the 1Cr17Ni3 gear pump casting housing is required to be less than 0.8 μm.

[0028] The beneficial effects of the present invention are:

[0029] 1. The present invention forms an outer ring groove, an inner ring groove and a line segment groove connecting the inner ring and the outer ring by grinding defects, and performs cladding and material addition on the groove formed by grinding, thereby avoiding local repair of a small area of ​​the end face and avoiding local deformation. After the repair, the rear end face has two annular repair areas, the inner ring and the outer ring, thereby enhancing the sealing performance;

[0030] 2. Laser cladding is carried out in sections, with each section length of 1 to 2 cm. When the cladding head reaches the end point, the laser and powder feeding are turned off, and the area is kept at this position for 8 to 20 seconds. The protective gas is continuously discharged to protect the molten pool and the first cladding area, which protects the entire cladding section. The surface of the cladding section is bright white and basically unoxidized, with high cladding quality. The continuous blowing at the end point also plays a cooling role, so that each section is at room temperature during the initial cladding, avoiding the deterioration of the repair quality caused by heat accumulation;

[0031] 3. Use special cladding powder, the chemical composition by weight percentage is: C: 0.01-0.03%, Cr: 12.0-14.0%, Ni: 8.0-10.0%, Mo: 3-5%, Co: 5-6%, Si: <0.5%, Mn: <0.5%, P: <0.005%, S: <0.005%, O: <0.03%, N: <0.015%, H: <0.003%, the balance is Fe and unavoidable impurities. After cladding repair, the hardness of the cladding layer is 320-340HV, and the hardness of the substrate is 320-340HV, achieving equal hardness cladding repair;

[0032] 4. After magnetic particle testing, the defective area is marked with a marker pen, and the line segment marked with the marker pen is polished with a small manual grinder. The cast shell is demagnetized using the AC coil method, eliminating the magnetism incidental to magnetic particle testing and mechanical polishing, and avoiding the problem of reduced repair quality caused by continuous powder sticking to the end face during the cladding process after the shell has magnetism;

[0033] 5. Place the clad parts in liquid nitrogen for 1 to 3 hours and then take them out to ensure that the metastable residual austenite after cladding is transformed into martensite, eliminate the metastable structure of the cladding layer, and ensure the dimensional stability of the shell during use, that is, to ensure the sealing effect of the shell;

[0034] 6. Use a high-precision horizontal axis and rectangular table surface grinder to grind the shell cladding repair end face. When the cladding layer is almost completely removed and the unrepaired part of the shell end face is removed, use a step-by-step grinding method, and control the vertical feed amount at 0.002-0.005mm each time until the end face is completely free of the unevenness caused by the cladding process and obtain a complete end face. This is conducive to reducing the height loss of the shell parts after repair. The height reduction value after the shell is repaired is less than 0.03mm, and the parts still meet the use tolerance after repair;

[0035] 7. Magnetic particle inspection is used before repair, which has higher accuracy, while penetrant inspection is used after repair. This avoids the abnormal magnetic trace phenomenon caused by the different magnetic properties of the cladding layer formed by heterogeneous powder cladding repair and the substrate during the magnetic particle inspection process, which is conducive to more accurately displaying the repair quality of the parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The present invention is further described below in conjunction with the accompanying drawings and embodiments:

[0037] Figure 1 Schematic diagram of shell end surface defects;

[0038] Figure 2 Schematic diagram of using a marker pen to mark end face defects and extend to form outer rings, inner rings and connecting sections. DETAILED DESCRIPTION

[0039] In order to make the technical means, creative features, objectives and effects achieved by the present invention easier to understand, the present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0040] A method for repairing shallow crack damage on the end face of a 1Cr17Ni3 gear pump casting housing comprises the following steps:

[0041] Step 1: Use acetone to clean the surface of the 1Cr17Ni3 gear pump casting shell, and then carry out magnetic particle inspection on the end face of the 1Cr17Ni3 gear pump casting shell. The magnetization method is the power-on method. After magnetization, the magnetic suspension is poured on the end face of the shell, and then the magnetic marks on the end face of the shell are observed to determine the defect position of the end face of the 1Cr17Ni3 gear pump casting shell, such as Figure 1 shown.

[0042] Step 2: Use a marker with a 1-4mm tip width to mark the defect position on the end face of the 1Cr17Ni3 gear pump casting housing, and then extend it on the end face of the 1Cr17Ni3 gear pump casting housing in the form of a multi-segment line to form two rings, which are connected by a line segment. The length of each line segment is 1 to 2 cm. Figure 2 shown.

[0043] In this embodiment, specifically, a marker pen with a pen tip width of 34 mm is used, and the length of each line segment is 1 cm.

[0044] Step 3: Use a small manual grinder to grind the line segments marked by the marker pen. Select a 2-6mm grinding head and a grinding depth of 0.5 to 2mm to remove shallow surface defects on the end face of the 1Cr17Ni3 gear pump casting housing to form an outer ring groove, an inner ring groove, and a line segment groove connecting the inner ring and the outer ring.

[0045] In this embodiment, specifically, the grinding head is selected to be 3 mm, and the grinding depth is 1 mm.

[0046] Step 4: Demagnetize the 1Cr17Ni3 gear pump casting shell by using the AC coil passing method, and use a magnetometer to detect the residual magnetism of the end face of the 1Cr17Ni3 gear pump casting shell. If the residual magnetism is greater than 0.25mT, repeat the AC coil passing method to demagnetize the 1Cr17Ni3 gear pump casting shell.

[0047] The demagnetization operation in this step is to eliminate the magnetism of the Cr17Ni3 gear pump casting shell, so as to avoid the reduction of repair quality caused by the magnetic adhesion of powder to the end face of the Cr17Ni3 gear pump casting shell during the cladding process.

[0048] Step 5: Perform laser cladding repair on the end surface of the 1Cr17Ni3 gear pump casting housing:

[0049] Step 51, select a particle size of 53-150 μm, a fluidity of less than 17s / 50g, and a chemical composition by weight percentage: C: 0.01-0.03%, Cr: 12.0-14.0%, Ni: 8.0-10.0%, Mo: 3-5%, Co: 5-6%, Si: <0.5%, Mn: <0.5%, P: <0.005%, S: <0.005%, O: <0.03%, N: <0. 015%, H: <0.003%, the balance is Fe and unavoidable impurities in the cladding powder, select high-purity argon as the shielding gas and the shielding gas flow rate is 10-20L / min, set the process parameters: powder feeding gas flow rate is 2-5L / min, powder feeding disk speed is 1.2-1.5rpm, powder output time is at least 8s, laser spot diameter is 1.5-3mm, laser power is 1200-1600W, and moving speed is 10mm / s.

[0050] In this embodiment, specifically, the chemical composition of the cladding powder is as follows by weight: C: 0.01%, Cr: 13%, Ni: 8%, Mo: 3.5%, Co: 5%, Si: 0.2%, Mn: 0.2%, P: 0.0005%, S; 0.0005%, O: 0.02%, N: 0.008%, H: 0.001%, and the balance is Fe and unavoidable impurities. The fluidity is 16s / 50g, and the cladding powder is prepared by plasma rotating electrode atomization powder making method.

[0051] The protective gas flow rate is 12L / min, the powder feeding gas flow rate is 2.5L / min, the powder feeding disk speed is 1.2rpm, the powder output time is 10s, the laser spot diameter is 2mm, and the laser power is 1500W.

[0052] Step 52, first cladding the polished outer ring groove, the outer ring groove cladding repair is along the clockwise direction, the laser cladding is performed in segments, the segmentation of the laser cladding process is consistent with the segmentation of the line segments drawn by the marker pen in step 2, and the length of each line segment is 1 to 2 cm.

[0053] In this embodiment, specifically, the length of each line segment is 1 cm.

[0054] Step 53, in each cladding process, the cladding head is first moved to a safe point. The height of the safe point should be at least 200 mm away from the part to be repaired. Then, the powder feeding switch is turned on. After the powder flow is stable, the protective gas is turned on, and the cladding head is moved to 7-10 mm above the starting point of the area to be repaired. The laser is turned on and the cladding head moves along the set path. When it moves to the end point, the laser and powder feeding are turned off. The cladding head stays at this position for 8-20 seconds, and the protective gas is continuously discharged to protect the molten pool and the first cladding area, and at the same time, it has a cooling effect. Finally, the cladding head is moved to a safe point, and the cladding of this section is completed.

[0055] Since each cladding section is short, continuous air blowing at the end position protects the entire cladding section. The surface of the cladding section is bright white and basically unoxidized, with high cladding quality. Continuous air blowing at the end position also has a cooling effect, so that the temperature of each section is lower than 60°C during the initial cladding, avoiding the deterioration of repair quality caused by heat accumulation.

[0056] In this embodiment, specifically, the height of the safety point should be 250 mm from the part to be repaired; the cladding head moves to 9 mm above the starting point of the area to be repaired; and stays at this part for 12 seconds.

[0057] Step 54, repeat the above segmented cladding process until the outer ring cladding is completed, and then clad the polished inner ring groove. The inner ring groove cladding repair is carried out in a counterclockwise direction. The laser cladding is carried out in segments, and each segment of the cladding process follows the outer ring segment of the cladding process.

[0058] Step 55, finally cladding the line segment groove connecting the inner ring and the outer ring, the laser cladding is performed in sections, and each section of the cladding process follows the cladding process of each section of the outer ring.

[0059] Step 6: Place the 1Cr17Ni3 gear pump casting housing after cladding repair in liquid nitrogen for 1 to 3 hours and then take it out to ensure that the metastable residual austenite after cladding is transformed into martensite. This step eliminates the metastable structure of the cladding layer and ensures the dimensional stability of the housing during use, that is, ensures the sealing effect of the housing.

[0060] In this embodiment, specifically, the temperature is kept warm for 2 hours.

[0061] Step 7. Use the same cladding process as step 5 to carry out a cladding repair test on a 1Cr17Ni3 test block in the same heat treatment state as the 1Cr17Ni3 gear pump casting housing. Place the clad test block in liquid nitrogen for 1 to 3 hours and then take it out to test the hardness of the test block after cladding. It was found that the hardness of the cladding layer of the test block was 320 to 340 HV and the hardness of the substrate was 320 to 340 HV, achieving equal hardness cladding repair.

[0062] In this embodiment, specifically, after 2 hours of insulation, the detected hardness of the cladding layer is 330HV, 328HV, 335HV, 332HV, and 338HV, and the hardness of the substrate is 325, 328H, 333H, 331H, and 334HV, achieving equal hardness cladding repair.

[0063] Step 8. Use a high-precision horizontal axis and rectangular table surface grinder to grind the end face of the 1Cr17Ni3 gear pump casting housing after cladding repair. The initial vertical feed rate is controlled between 0.1 and 0.5 mm / min until the part of the cladding layer higher than the initial end face of the 1Cr17Ni3 gear pump casting housing is almost completely polished away. Then use a step-by-step grinding method, and control the vertical feed rate at 0.002 to 0.005 mm each time until the end face is completely free of the unevenness caused by the cladding process to obtain a complete end face.

[0064] A height meter was used to detect the change in the height of the 1Cr17Ni3 gear pump casting housing after grinding compared with the height of the 1Cr17Ni3 gear pump casting housing before repair. The height reduction of the 1Cr17Ni3 gear pump casting housing was less than 0.03mm. A roughness meter was used to detect the end surface roughness of the 1Cr17Ni3 gear pump casting housing. The end surface roughness Ra of the 1Cr17Ni3 gear pump casting housing was less than 0.8μm.

[0065] In this embodiment, specifically, the initial vertical feed amount is controlled at 0.2 mm / min, each vertical feed amount is controlled at 0.003 mm, the height reduction value of the 1Cr17Ni3 gear pump casting housing is 0.02 mm, and the end surface roughness Ra of the 1Cr17Ni3 gear pump casting housing is 0.4 μm.

[0066] Step 9: Use acetone to clean the surface of the 1Cr17Ni3 gear pump casting housing, and then conduct penetrant testing on the end face of the 1Cr17Ni3 gear pump casting housing to detect the defects on the rear face after repair. If there are no defects, it is determined that the end face of the 1Cr17Ni3 gear pump casting housing has been repaired successfully. If magnetic particle testing is still used after repair, the cladding layer formed by the heterogeneous powder cladding repair will have different magnetic properties from the substrate, which will form abnormal magnetic traces and affect the judgment of defects. The use of penetrant testing effectively avoids this problem.

[0067] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions only describe the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for repairing shallow crack damage on the end face of a 1Cr17Ni3 gear pump casting housing, characterized in that: The following steps are involved: Step 1, using acetone to clean the surface of the 1Cr17Ni3 gear pump casting housing, and then conducting magnetic particle testing on the end face of the 1Cr17Ni3 gear pump casting housing to determine the defect position of the end face of the 1Cr17Ni3 gear pump casting housing; Step 2: Use a marker pen to mark the defect position on the end surface of the 1Cr17Ni3 gear pump casting housing, and then extend it on the end surface of the 1Cr17Ni3 gear pump casting housing in the form of a multi-segment line to form two rings, and the two rings are connected by a line segment; Step 3: Use a small manual grinder to grind the line segment marked by the marker pen to remove the shallow surface defects on the end face of the 1Cr17Ni3 gear pump casting housing, and form an outer ring groove, an inner ring groove, and a line segment groove connecting the inner ring and the outer ring; Step 4: Demagnetize the 1Cr17Ni3 gear pump casting shell by using an AC coil passing method, and use a magnetometer to detect the residual magnetism of the end surface of the 1Cr17Ni3 gear pump casting shell. If the residual magnetism is greater than 0.25mT, repeat the AC coil passing method to demagnetize the 1Cr17Ni3 gear pump casting shell; Step 5: Perform laser cladding repair on the end surface of the 1Cr17Ni3 gear pump casting housing: Step 51, select a particle size of 53-150 μm, a fluidity of less than 17s / 50g, and a chemical composition by weight percentage: C: 0.01-0.03%, Cr: 12.0-14.0%, Ni: 8.0-10.0%, Mo: 3-5%, Co: 5-6%, Si: <0.5%, Mn: <0.5%, P: <0.005%, S: <0.005%, O: <0.03%, N: <0. 015%, H: <0.003%, the balance is Fe and unavoidable impurities in the cladding powder, select high-purity argon as the shielding gas and the shielding gas flow rate is 10-20L / min, set the process parameters: powder feeding gas flow rate is 2-5L / min, powder feeding disk speed is 1.2-1.5rpm, powder output time is at least 8s, laser spot diameter is 1.5-3mm, laser power is 1200-1600W, moving speed is 10mm / s; Step 52, firstly, cladding the polished outer ring groove, and the cladding repair of the outer ring groove is in a clockwise direction. The laser cladding is performed in sections, and the sections of the laser cladding process are consistent with the sections of the line segments drawn by the marker pen in step 2; Step 53, each cladding process is to first move the cladding head to a safe point, then turn on the powder feeding switch, and after the powder flow is stable, turn on the protective gas, and move the cladding head to 7-10 mm above the starting point of the area to be repaired, turn on the laser, and move the cladding head along the set path. When it moves to the end point, turn off the laser and powder feeding, stay at this position for 8-20 seconds, continue to output the protective gas to protect the molten pool and the first cladding area, and then move the cladding head to a safe point, and the cladding of this section is completed; Step 54, repeat the above segmented cladding process until the outer ring cladding is completed, and then clad the polished inner ring groove. The inner ring groove cladding repair is carried out in a counterclockwise direction. The laser cladding is carried out in segments, and each segment of the cladding process follows the outer ring segment of the cladding process. Step 55, finally cladding the line segment groove connecting the inner ring and the outer ring, the laser cladding is performed in sections, and each section of the cladding process follows the cladding process of each section of the outer ring; Step 6, placing the 1Cr17Ni3 gear pump casting housing after cladding repair in liquid nitrogen for 1 to 3 hours and then taking it out; Step 7, using the same cladding process as step 5, a cladding repair test is performed on a 1Cr17Ni3 test block in the same heat treatment state as the 1Cr17Ni3 gear pump casting housing, the cladding test block is placed in liquid nitrogen for 1 to 3 hours and then taken out, and the hardness performance of the test block after cladding is detected. It is detected that the hardness of the cladding layer of the test block is 320 to 340 HV, and the hardness of the substrate is 320 to 340 HV, achieving equal hardness cladding repair; Step 8, use a high-precision horizontal axis and rectangular table surface grinder to grind the end surface of the 1Cr17Ni3 gear pump casting housing after cladding repair, use a height meter to detect the change in the height of the 1Cr17Ni3 gear pump casting housing after grinding compared with the height of the 1Cr17Ni3 gear pump casting housing before repair, and use a roughness meter to detect the roughness of the end surface of the 1Cr17Ni3 gear pump casting housing; Step 9: Clean the surface of the 1Cr17Ni3 gear pump casting housing with acetone, and then conduct penetrant testing on the end face of the 1Cr17Ni3 gear pump casting housing to detect and repair the rear end face defects. If there are no defects, it is determined that the end face of the 1Cr17Ni3 gear pump casting housing has been repaired successfully.

2. A method for repairing shallow crack damage on the end face of a 1Cr17Ni3 gear pump casting housing according to claim 1, characterized in that: In step 1, the magnetization method is selected as the power-on method.

3. The method for repairing shallow crack damage on the end face of a 1Cr17Ni3 gear pump casting housing according to claim 1 is characterized in that: In step 2, the width of the marker pen tip is 1-4 mm, and the length of each line segment is 1 to 2 cm.

4. The method for repairing shallow crack damage on the end face of a 1Cr17Ni3 gear pump casting housing according to claim 1 is characterized in that: Step 3: For small and medium-sized manual grinders, select a grinding head of 2-6 mm and a grinding depth of 0.5 to 2 mm.

5. The method for repairing shallow crack damage on the end face of a 1Cr17Ni3 gear pump casting housing according to claim 1, characterized in that: In step 53, the height of the safety point should be at least 200 mm from the part to be repaired.

6. A method for repairing shallow crack damage on the end face of a 1Cr17Ni3 gear pump casting housing according to claim 1, characterized in that: The grinding process in step 8 is as follows: The initial vertical feed rate is controlled between 0.1 and 0.5 mm / min until the portion of the cladding layer higher than the initial end face of the 1Cr17Ni3 gear pump casting housing is almost completely polished away, and then a step-by-step polishing method is adopted, with the vertical feed rate controlled at 0.002 to 0.005 mm each time, until the end face is completely free of the unevenness caused by the cladding process, and a complete end face is obtained.

7. The method for repairing shallow crack damage on the end face of a 1Cr17Ni3 gear pump casting housing according to claim 1, characterized in that: In step 8, it is required that the height reduction value of the 1Cr17Ni3 gear pump casting housing is less than 0.03mm.

8. The method for repairing shallow crack damage on the end face of a 1Cr17Ni3 gear pump casting housing according to claim 1, characterized in that: In step 8, the end surface roughness Ra of the 1Cr17Ni3 gear pump casting housing is required to be less than 0.8 μm.

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