A surfacing wire for a B-doped Fe-Cr-C series scraper and its preparation method and application

Abstract

The present invention discloses a surfacing welding wire for a B-doped Fe-Cr-C series scraper and its preparation method and application, including a flux-cored wire and a welding skin, characterized in that: the flux-cored wire comprises the following components by mass percentage: C powder 0.8-1.0%, Si powder 1.2-1.5%, Mn powder 3.2-3.8%, Cr powder 60-65%, B powder 5-8%, ZiC powder 2.5-3%, vanadium nitride iron powder 2-5%, and the balance is Fe powder, and the sum of the mass percentages of the above components is 100%. A preparation method of a surfacing welding wire for a B-doped Fe-Cr-C series scraper is: mixing the above alloy powders, drying them, and then wrapping them with low-carbon steel strips and drawing to obtain. The present invention develops a surfacing welding wire matching the scraper base material, forms a firmly bonded surfacing layer, and strengthens the surfacing layer metal through multi-element alloys to meet its continued service requirements, which has important engineering practical significance.

Description

Technical Field

[0001] The present invention belongs to the field of metal materials, and particularly relates to a surfacing welding wire for a scraper of a B-doped Fe-Cr-C system, a preparation method of the surfacing welding wire, and an application of the surfacing welding wire. Background Art

[0002] With the progress of technology, the demand for mineral resources is continuously increasing, and the research and innovation of mining machinery are also vigorously promoted. Among mining mechanical equipment, scraper conveyors, transfer machines, coal plows, etc. as important mining transportation equipment have developed towards the direction of heavy load, long distance, and long service life. However, the use environment of mining machinery is relatively harsh, and during service, the structure often fails due to reasons such as friction and wear, particle impact, and medium corrosion. If it is not remanufactured and repaired but directly discarded, it will cause a great waste of resources.

[0003] The important characteristics of the remanufacture of mining machinery are that the quality and performance of remanufactured products can reach or even exceed those of new products, while the cost is only about 50% of that of new products, the energy-saving effect reaches about 60%, and the material saving is more than 70%, with remarkable social and economic benefits. The wear of the structure of mining scrapers is inevitable, and the number of them to be repaired is huge. Surfacing welding is an important manufacturing method in the remanufacturing industry. Due to the high bonding strength between the surfacing layer and the base body, it can significantly improve the service life of workpieces. And the quality of the surfacing layer is mainly determined by the welding wire used for surfacing. Therefore, it has important engineering practical significance to develop a surfacing welding wire that matches the base material of the scraper, form a firmly bonded surfacing layer, and strengthen the surfacing layer metal through multi-element alloys to meet its continued service requirements. Summary of the Invention

[0004] The purpose of the present invention is to provide a surfacing welding wire for a scraper of a B-doped Fe-Cr-C system, which is specifically used for the arc surfacing repair and remanufacture of mining scrapers, can meet the requirements of continued service, and thus reduce production costs.

[0005] Another purpose of the present invention is to provide a preparation method of a surfacing welding wire for a scraper of a B-doped Fe-Cr-C system.

[0006] Still another purpose of the present invention is to provide a preparation method of a surfacing layer for a scraper of a B-doped Fe-Cr-C system.

[0007] The present invention is implemented by the following technical solutions:

[0008] A surfacing welding wire for a B-doped Fe-Cr-C series scraper, comprising a flux-cored wire and a welding skin, characterized in that: the flux-cored wire comprises the following components by mass percentage: C powder 0.8-1.0%, Si powder 1.2-1.5%, Mn powder 3.2-3.8%, Cr powder 60-65%, B powder 5-8%, ZiC powder 2.5-3%, vanadium nitride iron powder 2-5%, and the balance is Fe powder, and the sum of the mass percentages of the above components is 100%.

[0009] Further, the particle size of the powder is 75-150 μm, and the purity of the powder is ≥99.90%.

[0010] Further, the material of the welding skin is low-carbon steel strip.

[0011] Further, the thickness of the welding skin is 0.3 mm and the width is 7 mm.

[0012] Further, the powder filling rate of the flux-cored wire is controlled at 30-35%.

[0013] A preparation method of a surfacing welding wire for a B-doped Fe-Cr-C series scraper, the specific steps are as follows:

[0014] Step 1: Weigh the powder C powder, Si powder, Mn powder, Cr powder, B powder, ZiC powder, vanadium nitride iron powder and the balance is Fe powder respectively according to the mass percentage of Claim 1, and the sum of the mass percentages of the above components is 100%;

[0015] Step 2: Place the powder weighed in Step 1 in a vacuum heating furnace for heating, the heating temperature is 150-180 °C, and the heat preservation time is 2-3 h to remove the crystal water in the powder; the dried powder is placed in a powder mixer for sufficient mixing, and the mixing time is 2-3 h;

[0016] Step 3: Use alcohol to remove the grease on the surface of the welding skin belt, and wrap the powder prepared in Step 2 in the welding skin belt through a flux-cored wire drawing device to form a thick wire;

[0017] Step 4: The thick wire prepared in Step 3 is finally drawn to a preset diameter range through multiple drawings;

[0018] Step 5: After the flux-cored wire is drawn, it is wound on a wire reel by a wire winding machine and finally sealed in a vacuum packaging bag of the flux-cored wire for standby.

[0019] Further, in Step 4, the aperture of the first drawing die is 2.6 mm. After the first drawing process is completed, the apertures of the second to the Nth dies are sequentially reduced, N≥2, and finally a flux-cored wire with a diameter of 1.2 mm is obtained.

[0020] Furthermore, a method for preparing a B-doped Fe-Cr-C series surfacing layer for a scraper comprises the following specific steps:

[0021] (1) Use a grinding wheel to polish the area to be repaired on the surface of the failed scraper to expose the metallic luster, and use alcohol to remove the oil stains on the surface.

[0022] (2) Preheat the scraper to 280 - 300 °C with an oxyacetylene flame.

[0023] (3) Use the surfacing welding wire for the scraper to carry out surfacing welding on the surface of the scraper.

[0024] (4) Wrap the scraper with heat-insulating cotton after the surfacing welding is completed.

[0025] Furthermore, for a method for preparing a B-doped Fe-Cr-C series surfacing layer for a scraper, the welding current is 180 - 200 A, the welding voltage is 20 - 25 V, the welding speed is 40 cm / min, the surfacing layer lap rate is 20%, and the shielding gas is a mixed gas of 80% Ar + 20% CO 2 。

[0026] Furthermore, the interlayer temperature during surfacing welding is controlled at 250 - 270 °C.

[0027] Regarding the surfacing welding wire for the scraper, the preparation method of the surfacing welding wire for the scraper, and the preparation method of the surfacing layer for the scraper of the present invention, the wear of the mining scraper structure is inevitable, and the number of scrapers to be repaired is huge; the present invention develops a surfacing welding wire matching the scraper base material, forms a firmly bonded surfacing layer, and strengthens the surfacing layer metal through multi-element alloying to meet its continued service requirements, which has important engineering practical significance. The beneficial effects of the present invention are:

[0028] (1) The present invention adds element B to the Fe-Cr-C alloy system to achieve the doping of B into (Cr,Fe) 7 C 3 carbide, thereby improving the stability of the carbide.

[0029] (2) The present invention adds ZrC hard powder, and the addition of this powder forms a dispersion of hard phases in the cladding metal, thereby improving the wear resistance of the surfacing layer.

[0030] (3) The present invention adds vanadium nitride iron powder, which contains elements V, N, C, and Fe and is a new type of alloy additive. The addition of V is beneficial to the formation of VC and strengthens the surfacing alloy. N partially replaces element C, reduces C in the steel, refines the microstructure, and improves the yield strength and tensile strength; in addition, N can also improve the abrasive wear performance of the surfacing layer by precipitating carbonitrides.

[0031] (4) When applying surfacing welding to the surface of the scraper, preheat before welding, slow cool after welding, and select a lower heat input to suppress cracking of the surfacing layer. Description of the Drawings

[0032] Figure 1 It is a macroscopic morphology diagram of the surfacing layer on the surface of the scraper prepared in Example 2 of the method of the present invention.

[0033] Figure 2 It is a metallographic structure diagram of the surfacing layer of the scraper prepared in Example 2 of the method of the present invention.

[0034] Figure 3 It is a friction and wear morphology diagram of the surfacing layer on the surface of the scraper prepared in Example 2 of the present invention. Detailed Description of the Invention

[0035] The present invention will be described in detail below in conjunction with the drawings and specific embodiments.

[0036] The present invention provides a surfacing welding wire for a B-doped Fe-Cr-C series scraper, including a flux-cored wire and a welding skin. The flux-cored wire is composed of the following components by mass percentage: 0.8-1.0% of C powder, 1.2-1.5% of Si powder, 3.2-3.8% of Mn powder, 60-65% of Cr powder, 5-8% of B powder, 2.5-3% of ZiC powder, 2-5% of vanadium nitride iron powder, and the rest is Fe powder. The sum of the mass percentages of the above components is 100%.

[0037] The preparation method of the above-mentioned surfacing welding wire for a B-doped Fe-Cr-C series scraper is as follows:

[0038] Step 1: Weigh the powder by mass percentage respectively: 0.8-1.0% of C powder, 1.2-1.5% of Si powder, 3.2-3.8% of Mn powder, 60-65% of Cr powder, 5-8% of B powder, 2.5-3% of ZiC powder, 2-5% of vanadium nitride iron powder, and the rest is Fe powder. The sum of the mass percentages of the above components is 100%.

[0039] Step 2: Place the powder weighed in Step 1 in a vacuum heating furnace for heating. The heating temperature is 150-180°C, and the holding time is 2-3 hours to remove the crystal water in the powder; the dried powder is placed in a powder mixer for sufficient mixing, and the mixing time is 2-3 hours;

[0040] Step 3: Use low-carbon steel strip as the welding skin, remove the grease on the surface of the low-carbon steel strip with alcohol, and wrap the powder prepared in Step 2 in the low-carbon steel strip through a flux-cored wire drawing device. The aperture of the first drawing die is 2.6 mm;

[0041] Step 4: After the first-pass drawing is completed, gradually reduce the die aperture until a flux-cored wire with a diameter of 1.2 mm is finally obtained.

[0042] Step 5: After the flux-cored wire drawing is completed, wind it on a wire spool by a wire winding machine and finally seal it in a vacuum packaging bag of the flux-cored wire for standby.

[0043] In Step 1, the particle size of the weighed powder is 200 - 300 mesh, and the purity of the powder is ≥99.90%.

[0044] In Step 1, in the ferrovanadium nitride powder, the content of V element is 45%, the content of N element is 10%, the content of C element is 0.4%, and the rest is Fe element.

[0045] In Step 3, the welding skin is a low-carbon steel strip with a thickness of 0.3 mm and a width of 7 mm.

[0046] In Step 3, the filling amount of the flux-cored wire is controlled at 33 - 35 wt%.

[0047] The functions and roles of each alloy component in this flux-cored wire are as follows:

[0048] (1) C element: C can effectively improve the strength and hardness of the surfacing layer and is an economical additive element.

[0049] (2) Cr element: The addition of Cr helps to improve the strength of the surfacing layer. Cr is an element that stabilizes the α-phase region structure. In this invention, a high Cr content is adopted, which can fully ensure the martensite structure characteristics of the surfacing layer. The martensite structure has the characteristic of high strength, meeting the application requirements of the surfacing layer. Cr can also form (Cr,Fe) 7 C 3 , further improving the strength and wear resistance of the surfacing layer.

[0050] (3) B element: B is dissolved into (Cr,Fe) 7 C 3 to improve the high-temperature oxidation characteristics of carbides. In addition, after B is dissolved, the covalent bond strength between Cr, Fe elements and C element is enhanced, thus improving the stability of (Cr,Fe) 7 C 3 . Since this carbide is the main strengthening way of the surfacing alloy, the improvement of its stability also effectively improves the wear resistance of the surfacing layer.

[0051] (4) ZiC powder: ZiC is added as a hard phase, belonging to the dispersion strengthening principle. The melting point of ZiC is relatively high. Fine-sized ZiC can be used as the nucleation particles of the surfacing alloy, refining the surfacing layer structure, refining the martensite lath bundle and spacing, thereby improving the performance of the surfacing layer.

[0052] (5) N element: N is added in the form of vanadium nitride iron powder. N can replace a part of C, refine the martensite lath bundle, and improve its strength. In addition, the compound formed by N and C precipitates in the surfacing metal, which can effectively improve the abrasive wear resistance of the surfacing layer.

[0053] (6) V element: V is added in the form of vanadium nitride iron powder. On the one hand, V can dissolve into α-Fe to improve the mechanical properties of the surfacing layer through solid solution strengthening. On the other hand, V forms VC and precipitates in the surfacing layer to further improve its wear resistance.

[0054] (7) Si and Mn elements: The addition of these two elements can, on the one hand, improve the strength and toughness of the surfacing layer, and on the other hand, play a role in deoxidation. However, in the weld with a high C content, the content of these two elements should be limited, so the content of them is limited in the present invention.

[0055] The present invention also provides a preparation method for a B-doped Fe-Cr-C series scraper surfacing layer, and the specific steps are as follows:

[0056] (1) Use a grinding wheel to polish the area to be repaired on the surface of the failed scraper to make it show metallic luster; use alcohol to remove the oil stain on the surface.

[0057] (2) Preheat the scraper to 280 - 300 °C with an oxyacetylene flame;

[0058] (3) Use the welding wire of the present invention to carry out surfacing on the surface of the scraper, with a welding current of 180 - 200 A, a welding voltage of 20 - 25 V, a welding speed of 40 cm / min, a surfacing layer overlap rate of 20%, and a shielding gas of 80% Ar + 20% CO 2 , and the interlayer temperature during surfacing is controlled at 250 - 270 °C.

[0059] (4) Wrap the scraper with heat-insulating cotton after the surfacing is completed.

[0060] Example 1

[0061] Step 1: Weigh the powder by mass percentage respectively: 0.8% C powder, 1.2% Si powder, 3.2% Mn powder, 60% Cr powder, 5% B powder, 2.5% ZiC powder, 2% vanadium nitride iron powder, and the rest is Fe powder. The sum of the mass percentages of the above components is 100%.

[0062] Step 2: Place the powder weighed in Step 1 in a vacuum heating furnace for heating. The heating temperature is 150 °C and the holding time is 2 h to remove the crystal water in the powder; the dried powder is placed in a powder mixer for sufficient mixing, and the mixing time is 2 h;

[0063] Step 3: Use low-carbon steel strip as the welding skin, remove the grease on the surface of the low-carbon steel strip with alcohol, and wrap the powder prepared in Step 2 in the low-carbon steel strip through a flux-cored wire drawing device. The aperture of the first drawing die is 2.6 mm;

[0064] Step 4: After the first process of drawing is completed, gradually reduce the aperture of the die, and finally obtain a flux-cored wire with a diameter of 1.2 mm;

[0065] Step 5: After the flux-cored wire drawing is completed, wind it on a wire spool by a wire winding machine, and finally seal it in a vacuum packaging bag of the flux-cored wire for standby.

[0066] Use the welding wire prepared in Example 1 to prepare the surfacing layer of the mining scraper. The specific steps are as follows:

[0067] (1) Use a grinding machine to grind the area to be repaired on the surface of the failed scraper to expose the metallic luster; remove the oil stain on the surface with alcohol.

[0068] (2) Preheat the scraper to 280 °C with an oxyacetylene flame;

[0069] (3) Use the welding wire of the present invention to perform surfacing on the surface of the scraper. The welding current is 180 - 200 A, the welding voltage is 20 - 25 V, the welding speed is 40 cm / min, the surfacing layer lap rate is 20%, and the shielding gas is a mixture of 80% Ar + 20% CO 2 , and the interlayer temperature during surfacing is controlled at 250 °C.

[0070] (4) Wrap the scraper with heat-insulating cotton after the surfacing is completed.

[0071] After testing, the hardness of the surfacing layer on the surface of the scraper is 56 HRC; the bending strength of the surfacing layer is 214 MPa; the bonding strength of the surfacing layer is 285 MPa; the friction and wear mechanism of the surfacing layer is adhesive wear.

[0072] Example 2

[0073] Step 1: Weigh the powder by mass percentage respectively: 1.0% C powder, 1.5% Si powder, 3.8% Mn powder, 65% Cr powder, 8% B powder, 3% ZiC powder, 5% vanadium nitride iron powder, and the rest is Fe powder. The sum of the mass percentages of the above components is 100%.

[0074] Step 2: Place the powder weighed in Step 1 in a vacuum heating furnace for heating. The heating temperature is 180 °C, and the holding time is 3 h to remove the crystal water in the powder; the dried powder is placed in a powder mixer for sufficient mixing, and the mixing time is 3 h;

[0075] Step 3: Use low-carbon steel strip as the welding skin, remove the grease on the surface of the low-carbon steel strip with alcohol, and wrap the powder prepared in Step 2 in the low-carbon steel strip through a flux-cored wire drawing device. The aperture of the first drawing die is 2.6 mm;

[0076] Step 4: After the first-pass drawing is completed, gradually reduce the aperture of the die, and finally obtain a flux-cored wire with a diameter of 1.2 mm;

[0077] Step 5: After the flux-cored wire drawing is completed, wind it on a wire spool by a wire winding machine, and finally seal it in a vacuum packaging bag of the flux-cored wire for standby.

[0078] Use the welding wire prepared in Example 2 to prepare the surfacing layer of the mining scraper. The specific steps are as follows:

[0079] (1) Use a grinding wheel to polish the area to be repaired on the surface of the failed scraper to make it show a metallic luster; remove the oil stain on the surface with alcohol.

[0080] (2) Preheat the scraper to 300 °C with an oxyacetylene flame;

[0081] (3) Use the welding wire of the present invention to perform surfacing on the surface of the scraper. The welding current is 180 - 200 A, the welding voltage is 20 - 25 V, the welding speed is 40 cm / min, the surfacing layer lap rate is 20%, and the shielding gas is a mixed gas of 80% Ar + 20% CO 2 , and the interlayer temperature during surfacing is controlled at 270 °C.

[0082] (4) Wrap the scraper with heat-insulating cotton after the surfacing is completed.

[0083] After testing, the hardness of the surfacing layer on the surface of the scraper is 55 HRC; the bending strength of the surfacing layer is 223 MPa; the bonding strength of the surfacing layer is 280 MPa; the friction and wear mechanism of the surfacing layer is adhesive wear.

[0084] Figure 1 This is the macroscopic morphology diagram of the surfacing layer on the surface of the scraper prepared in Example 2 of the method of the present invention. It can be seen from the figure that the surfacing layer has a beautiful shape, less spatter, and no crack defects.

[0085] Figure 2 This is the metallographic structure diagram of the surfacing layer of the scraper prepared in Example 2 of the method of the present invention. It can be seen from the figure that the surfacing layer is mainly composed of martensite structure, the lath bundles are clearly visible, the lath bundles are relatively fine, and the lath bundle spacing is also small.

[0086] Figure 3 This is the friction and wear morphology diagram of the surfacing layer on the surface of the scraper prepared in Example 2 of the present invention. It can be seen from the figure that the surfacing layer has excellent wear resistance and less wear.

[0087] Example 3

[0088] Step 1: Weigh the powder by mass percentage respectively: 0.9% of C powder, 1.4% of Si powder, 3.5% of Mn powder, 63% of Cr powder, 7% of B powder, 2.8% of ZiC powder, 3.5% of ferrovanadium nitride powder, and the rest is Fe powder. The sum of the mass percentages of the above components is 100%.

[0089] Step 2: Place the powder weighed in Step 1 in a vacuum heating furnace for heating. The heating temperature is 160°C and the holding time is 2.5 h to remove the crystal water in the powder. The dried powder is placed in a powder mixer for sufficient mixing, and the mixing time is 2.5 h.

[0090] Step 3: Use low-carbon steel strip as the welding skin, remove the grease on the surface of the low-carbon steel strip with alcohol, and wrap the powder prepared in Step 2 in the low-carbon steel strip through the flux-cored wire drawing equipment. The aperture of the first drawing die is 2.6 mm.

[0091] Step 4: After the first process of drawing is completed, gradually reduce the aperture of the die, and finally obtain a flux-cored wire with a diameter of 1.2 mm.

[0092] Step 5: After the flux-cored wire drawing is completed, wind it on a wire spool by a wire winding machine, and finally seal it in a vacuum packaging bag of the flux-cored wire for standby.

[0093] Use the wire prepared in Example 3 to prepare the surfacing layer of the mining scraper. The specific steps are as follows:

[0094] (1) Use a grinding wheel to polish the area to be repaired on the surface of the failed scraper to make it show a metallic luster; remove the oil stain on the surface with alcohol.

[0095] (2) Preheat the scraper to 290°C with an oxyacetylene flame.

[0096] (3) Use the wire of the present invention to carry out surfacing on the surface of the scraper. The welding current is 180 - 200 A, the welding voltage is 20 - 25 V, the welding speed is 40 cm / min, the surfacing layer lap rate is 20%, and the shielding gas is a mixed gas of 80% Ar + 20% CO 2 , and the interlayer temperature is controlled at 260°C during surfacing.

[0097] (4) Wrap the scraper with heat-insulating cotton after the surfacing is completed.

[0098] After testing, the hardness of the surfacing layer on the surface of the scraper is 54 HRC; the bending strength of the surfacing layer is 250 MPa; the bonding strength of the surfacing layer is 290 MPa; the friction and wear mechanism of the surfacing layer is adhesive wear.

[0099] Example 4

[0100] Step 1: Weigh the powder by mass percentage respectively: C powder 0.88%, Si powder 1.3%, Mn powder 3.4%, Cr powder 62%, B powder 6%, ZiC powder 2.7%, ferrovanadium nitride powder 3%, and the rest is Fe powder. The sum of the mass percentages of the above components is 100%.

[0101] Step 2: Place the powder weighed in Step 1 in a vacuum heating furnace for heating. The heating temperature is 155 °C and the holding time is 2.3 h to remove the crystal water in the powder. The dried powder is placed in a powder mixer for sufficient mixing, and the mixing time is 2.3 h.

[0102] Step 3: Use low-carbon steel strip as the welding skin, remove the grease on the surface of the low-carbon steel strip with alcohol, and wrap the powder prepared in Step 2 in the low-carbon steel strip through a flux-cored wire drawing device. The aperture of the first drawing die is 2.6 mm.

[0103] Step 4: After the first process of drawing is completed, gradually reduce the aperture of the die, and finally obtain a flux-cored wire with a diameter of 1.2 mm.

[0104] Step 5: After the flux-cored wire drawing is completed, wind it on a wire reel through a wire winding machine, and finally seal it in a vacuum packaging bag of the flux-cored wire for standby.

[0105] Use the wire prepared in Example 4 to prepare the surfacing layer of the mining scraper. The specific steps are as follows:

[0106] (1) Use a grinding wheel to polish the area to be repaired on the surface of the failed scraper to make it show metallic luster; remove the oil stain on the surface with alcohol.

[0107] (2) Preheat the scraper to 285 °C with an oxyacetylene flame.

[0108] (3) Use the wire of the present invention to perform surfacing on the surface of the scraper. The welding current is 180 - 200 A, the welding voltage is 20 - 25 V, the welding speed is 40 cm / min, the surfacing layer lap rate is 20%, and the shielding gas is a mixed gas of 80% Ar + 20% CO 2 , and the interlayer temperature during surfacing is controlled at 255 °C.

[0109] (4) Wrap the scraper with heat-insulating cotton after the surfacing is completed.

[0110] After testing, the hardness of the surfacing layer on the surface of the scraper is 51 HRC; the bending strength of the surfacing layer is 240 MPa; the bonding strength of the surfacing layer is 270 MPa; the friction and wear mechanism of the surfacing layer is adhesive wear.

[0111] Example 5

[0112] Step 1: Weigh the powder by mass percentage respectively: C powder 0.81%, Si powder 1.3%, Mn powder 3.3%, Cr powder 61%, B powder 7.5%, ZiC powder 2.9%, ferrovanadium nitride powder 4.5%, and the rest is Fe powder. The sum of the mass percentages of the above components is 100%.

[0113] Step 2: Place the powder weighed in Step 1 in a vacuum heating furnace for heating. The heating temperature is 175°C and the holding time is 2.1 h to remove the crystal water in the powder. The dried powder is placed in a powder mixer for sufficient mixing, and the mixing time is 2.1 h.

[0114] Step 3: Use low-carbon steel strip as the welding skin, remove the grease on the surface of the low-carbon steel strip with alcohol, and wrap the powder prepared in Step 2 in the low-carbon steel strip through a flux-cored wire drawing device. The aperture of the first drawing die is 2.6 mm.

[0115] Step 4: After the first pass of drawing is completed, gradually reduce the aperture of the die, and finally obtain a flux-cored wire with a diameter of 1.2 mm.

[0116] Step 5: After the flux-cored wire drawing is completed, wind it on a wire spool by a wire winding machine and finally seal it in a vacuum packaging bag of the flux-cored wire for standby.

[0117] Use the wire prepared in Example 5 to prepare a surfacing layer for a mining scraper. The specific steps are as follows:

[0118] (1) Use a grinding wheel to polish the area to be repaired on the surface of the failed scraper to expose the metallic luster; remove the oil stain on the surface with alcohol.

[0119] (2) Preheat the scraper to 295°C with an oxyacetylene flame.

[0120] (3) Use the wire of the present invention to perform surfacing on the surface of the scraper. The welding current is 180 - 200 A, the welding voltage is 20 - 25 V, the welding speed is 40 cm / min, the surfacing layer lap rate is 20%, and the shielding gas is a mixed gas of 80% Ar + 20% CO 2 , and the interlayer temperature is controlled at 244°C during surfacing.

[0121] (4) Wrap the scraper with heat-insulating cotton after surfacing.

[0122] After testing, the hardness of the surfacing layer on the surface of the scraper is 52 HRC; the bending strength of the surfacing layer is 233 MPa; the bonding strength of the surfacing layer is 274 MPa; the friction and wear mechanism of the surfacing layer is adhesive wear.

Claims

1. A surfacing welding wire for a B-doped Fe-Cr-C series scraper, comprising a flux-cored wire and a welding skin, characterized in that, the flux-cored wire comprises the following components by mass percentage: C powder 0.8 - 1.0%, Si powder 1.2 - 1.5%, Mn powder 3.2 - 3.8%, Cr powder 60 - 65% B powder 5 - 8%, ZiC powder 2.5 - 3%, vanadium nitride iron powder 2 - 5%, and the rest is Fe powder, and the sum of the mass percentages of the above components is 100%; the particle size of the powder is 75 - 150 μm, and the purity of the powder is ≥99.90%; the material of the welding skin is low-carbon steel strip; the thickness of the welding skin is 0.3 mm, and the width is 7 mm.

2. A surfacing welding wire for a B-doped Fe-Cr-C series scraper according to claim 1, characterized in that, the powder filling rate of the flux-cored wire is controlled at 30 - 35%.

3. A preparation method of a surfacing welding wire for a B-doped Fe-Cr-C series scraper according to claim 1 or 2, characterized in that, the specific steps are as follows: Step 1: Weigh the powder C powder, Si powder, Mn powder, Cr powder, B powder, ZiC powder, vanadium nitride iron powder, and the rest is Fe powder respectively according to the mass percentage described in claim 1, and the sum of the mass percentages of the above components is 100%; Step 2: Place the powder weighed in Step 1 in a vacuum heating furnace for heating, the heating temperature is 150 - 180 °C, and the heat preservation time is 2 - 3 h to remove the crystal water in the powder; the dried powder is placed in a powder mixer for sufficient mixing, and the mixing time is 2 - 3 h; Step 3: Use alcohol to remove the grease on the surface of the welding skin belt, and wrap the powder prepared in Step 2 in the welding skin belt through a flux-cored wire drawing device to form a thick wire; Step 4: The thick wire prepared in Step 3 is finally drawn to a preset diameter range through multiple draws; Step 5: After the flux-cored wire drawing is completed, it is wound on a wire reel by a wire winding machine and finally sealed in a vacuum packaging bag of the flux-cored wire for standby.

4. A preparation method of a surfacing welding wire for a B-doped Fe-Cr-C series scraper according to claim 3, characterized in that, in the said Step 4, the aperture of the first drawing die is 2.6 mm. After the first drawing process is completed, the apertures of the second to the Nth dies are sequentially reduced, N is greater than or equal to 2, and finally a flux-cored wire with a diameter of 1.2 mm is obtained.

5. A preparation method of a surfacing layer for a B-doped Fe-Cr-C series scraper, which uses the surfacing welding wire for a B-doped Fe-Cr-C series scraper prepared in claim 3, characterized in that, the specific steps are as follows: (1) Use a grinding wheel to polish the area to be repaired on the surface of the failed scraper to make it show a metallic luster, and use alcohol to remove the oil stain; (2) Preheat the scraper to 280 - 300 °C with an oxyacetylene flame; (3) Use the said surfacing welding wire for the scraper to carry out surfacing on the surface of the scraper; (4) Wrap the scraper with heat preservation cotton after the surfacing is completed.

6. A preparation method of a surfacing layer for a B-doped Fe-Cr-C series scraper according to claim 5, characterized in that, The welding current is 180 - 200 A, the welding voltage is 20 - 25 V, the welding speed is 40 cm / min, the surfacing layer overlap rate is 20%, and the shielding gas is a mixture of 80% Ar + 20% CO 2 .

7. A method for preparing a B-doped Fe-Cr-C system surfacing layer for a scraper according to claim 5 or 6, characterized in that, the interlayer temperature during surfacing is controlled at 250 to 270 °C.

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