Impact-wear-resistant flux-cored wire for welding high-manganese steel lining plate and surfacing method

Abstract

The invention discloses an impact-wear-resistant flux-cored wire for welding a high-manganese steel lining plate and a surfacing method, belongs to the technical field of surface engineering, and aims to solve the problems that a traditional high-manganese steel lining plate is embrittled, a surfacing layer is peeled off and deformed and the like. A flux core of the flux-cored wire comprises high-carbon ferrochrome powder, micro-carbon ferrochrome powder, graphite powder, ferrosilicon powder, ferromanganese powder, ferrotitanium powder, ferromolybdenum powder, ferrovanadium powder, ferroboron powder, calcium fluoride powder and nickel powder; the balance is iron powder; the outer skin is a low-carbon cold-rolled steel strip, the diameter is 2.4-3.2 mm, and the filling rate is 42-50%; the surfacing method comprises the steps that pretreatment and drying are conducted, plasma arc automatic surfacing is adopted, the current ranges from 135 A to 180 A, the welding speed ranges from 350 mm / min to 650 mm / min, the wire feeding speed ranges from 1800 mm / min to 2200 mm / min, compressed gas and protective gas are both argon, and the surface temperature of the high manganese steel lining plate is controlled; through solid solution of the nickel powder and weak self-protection of the calcium fluoride powder, the surfacing layer is high in hardness, high in wear resistance, small in matrix deformation and free of interface cracking.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of surface engineering, and particularly relates to a flux-cored wire for impact and wear resistance of a welded high manganese steel lining plate and a surfacing method. BACKGROUND

[0002] As a key equipment in the mining and metallurgical industries, the cylinder inner wall of a ball mill is subjected to strong impact and abrasive wear of steel balls, materials and slurry. The traditional high manganese steel lining plate, such as Mn13, has a thickness of 50-130 mm, excellent toughness, impact toughness ≥ 150 J / cm2, and strong work hardening capacity, and the hardness after work hardening can reach HB500. However, the impact and wear of the lining plate caused by the insufficient hardness are extremely rapid and severe in the initial stage of the ball mill, which leads to the premature reduction of the outer size of the lining plate and the failure to meet the requirements of the lifting amount, thereby further reducing the efficiency of the ball mill and causing the ball mill to run significantly out of the standard, and thus the lining plate of the ball mill needs to be frequently replaced.

[0003] When the existing open arc automatic surfacing technology and submerged arc surfacing technology are used for high manganese steel surfacing, the carbonization of the high manganese steel heat affected zone is often caused, the impact toughness is reduced to <50 J / cm2, the risk of brittle fracture is extremely high, and the surfacing layer is also prone to large-scale cracking and peeling due to the excessively high welding stress. In addition, due to the large heat input, generally greater than 1.5 kJ / mm, the deformation of the substrate is very serious and difficult to control. Furthermore, the existing surfacing materials mainly focus on single wear resistance or impact resistance, and it is difficult to meet the collaborative requirements of the lining plate of the ball mill for a "high toughness substrate + hardening wear-resistant layer".

[0004] The plasma surfacing technology has the advantages of strong controllability of melting depth, fast cladding speed, high production efficiency, high bonding strength between the substrate material and the surfacing layer in a metallurgical bonding state, and easy mechanization and automation in the surfacing process. However, there are few studies on the plasma surfacing technology for the lining plate of the ball mill, and the traditional Fe-Cr-C alloy system material is still used to prepare the wear-resistant coating, ignoring the problem of interface cracking between the high manganese steel substrate and the surfacing layer. Patent CN119057304A discloses a plasma surfacing flux-cored wire for high stress impact and wear resistance and a preparation method thereof. Although the prepared surfacing alloy has high impact and wear resistance, the influence of the surfacing process on the deformation of the high manganese steel lining plate and the interface cracking between the coating and the substrate is not concerned. In addition, although the plasma surfacing process uses full argon protection without self-protection, the large protection gas pressure often hinders the floating of the deoxidation products from the molten pool in actual production, resulting in an increase in pores. Therefore, a small amount of calcium fluoride can be used to play a weak self-protection effect to offset the influence of part of the external gas pressure. SUMMARY

[0005] The present application aims to provide a flux-cored wire for welding high manganese steel lining plate and a surfacing method, which can realize low dilution rate, no spalling and micro-deformation surfacing of the impact wear-resistant coating of the high manganese steel lining plate, and overcome the problems of brittle cracking of the high manganese steel heat-affected zone and the difficulty of floating the deoxidation products of the surfacing layer from the molten pool.

[0006] To achieve the above-mentioned purpose, the present application realizes the following technical solutions:

[0007] A flux-cored wire for welding high manganese steel lining plate, comprising an outer skin and a core, the core is composed of the following raw materials in weight percentage, the sum of the weight percentage of all raw materials is 100wt%: high-carbon chromium iron powder 10-18wt%, micro-carbon chromium iron powder 25-38wt%, graphite powder 0.5-2wt%, silicon iron powder 1-2wt%, manganese iron powder 1-4wt%, titanium iron powder 1.5-3wt%, molybdenum iron powder 1-5wt%, vanadium iron powder 1-4wt%, boron iron powder 0.5-5wt%, calcium fluoride powder 0.3-1wt%, nickel powder 0.5-2wt%, and the rest is reduced iron powder.

[0008] Further, the outer skin is a low-carbon cold-rolled steel strip, and the wire is made by wrapping the core with the outer skin through cold rolling and drawing.

[0009] Further, the diameter is 2.4-3.2mm, and the filling rate is 42-50%.

[0010] A surfacing method for welding high manganese steel lining plate, which uses the above-mentioned flux-cored wire for welding high manganese steel lining plate.

[0011] Step 1: pretreat the surface of the high manganese steel lining plate to remove oil stains and rust on the surface of the workpiece;

[0012] Step 2: place the above-mentioned flux-cored wire in a heating furnace for drying and dehumidifying;

[0013] Step 3: use a plasma arc automatic surfacing machine as the welding equipment, and the welding process parameters include: welding current 135-180A, welding speed 350-650mm / min, and wire feeding speed 1800-2200mm / min; the wire feeding mode is side-shaft wire feeding;

[0014] Step 4: during the plasma cladding process, the surface temperature of the high manganese steel lining plate at a distance of 5cm from the molten pool needs to be controlled in the range of 150-280℃.

[0015] Further, in step 3, the compressed gas and the protective gas both use argon with a purity of ≥99.99%, the flow rate of the compressed gas is 3-7L / min, and the flow rate of the selected protective gas is 5-12L / min.

[0016] Further, in step 2, the above-mentioned flux-cored wire is placed in a heating furnace at 150-250℃ for 1-2h for drying and moisture removal.

[0017] Further, the microstructure of the high manganese steel backing plate after plasma surfacing is composed of an iron-based solid solution and a plurality of component strengthening phases uniformly distributed therein.

[0018] Further, the hardness of the surfacing layer of the high manganese steel backing plate after plasma surfacing reaches 55-62HRC, and the impact wear resistance is 1.44-1.88 times that of the high manganese steel backing plate.

[0019] The present application aims at the interface adaptation problem between the high manganese steel backing plate and the surfacing layer, and introduces 0.5-2wt% nickel powder for solid solution strengthening. The nickel atoms are solid-solved in the γ-Fe matrix, which can effectively reduce the linear expansion coefficient of the surfacing layer itself, relieve the interface stress generated in the cooling process due to the difference in thermal expansion between the coating and the substrate, and thus inhibit the interface cracking tendency. However, too much nickel powder will increase the manufacturing cost and result in low hardness of the surfacing layer. In addition, 0.3-1wt% calcium fluoride powder is added to the flux, which decomposes to produce a small amount of active gas at high temperature during plasma surfacing, forms a weak self-protection effect, partially offsets the hindering effect of the external argon protection pressure on the upward floating of the deoxidation products in the molten pool, ensures the smooth escape of Si and Mn deoxidation products, and reduces the porosity of the surfacing layer to 0.5-0.8%. The microstructure of the surfacing layer is composed of an iron-based solid solution and a plurality of component strengthening phases uniformly distributed therein, which produces good impact wear resistance. By controlling the surfacing heat input, the surface temperature of the high manganese steel backing plate 5cm away from the molten pool is controlled at 150-280℃, the surfacing layer and the substrate are metallurgically bonded, and the interface is crack-free, the overall deformation of the high manganese steel backing plate is ≤2mm, and the unity of the impact wear resistance improvement of more than 1.4 times and the structural integrity is realized.

[0020] Compared with the prior art, the present application has the following beneficial effects:

[0021] 1. The present application provides a flux-cored wire for welding high manganese steel backing plate for impact wear resistance, which can fully play the role of Fe and Ni solid solution strengthening, and effectively relieve the cracking of the coating / substrate interface caused by the difference in linear expansion coefficient.

[0022] 2. The present application adds a small amount of calcium fluoride powder (≤1wt%) to the flux-cored wire to achieve a weak self-protection effect, which can generate a protective gas in the molten pool to offset part of the external protection gas pressure and ensure the normal floating of deoxidation products from the molten pool, and effectively avoid the porosity of the molten pool exceeding 1%.

[0023] 3. The present application controls the surfacing process to ensure a low deformation (≤2mm) of the high manganese steel substrate, which is convenient for subsequent installation in the ball mill cylinder.

[0024] 4. The single layer (thickness about 3mm) plasma surfacing coating prepared by the present application has good metallurgical bonding state with the base, the coating hardness reaches 55-62HRC, and the impact wear resistance of the liner material is improved. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 The microstructure diagram of the impact wear resistant coating surface prepared by the plasma surfacing of the example 1 of the present application.

[0026] Figure 2 The microstructure diagram of the impact wear resistant coating / base interface prepared by the plasma surfacing of the example 2 of the present application.

[0027] Figure 3 The weight loss comparison diagram of the high manganese steel liner with the impact wear resistant coating of the example 3 of the present application and the original high manganese steel liner.

[0028] Figure 4 The longitudinal deformation amount picture of the high manganese steel liner after the plasma surfacing of the example 5 of the present application.

[0029] Figure 5 The longitudinal deformation amount picture of the high manganese steel liner after the plasma surfacing of the comparative example 1 of the present application.

[0030] Figure 6 The picture of the high manganese steel liner before the plasma surfacing.

[0031] Figure 7 The metallographic structure diagram of the impact wear resistant coating without adding calcium fluoride powder of the comparative example 4.

[0032] Figure 8 The metallographic structure diagram of the impact wear resistant coating with excessive calcium fluoride powder of the comparative example 5.

[0033] Figure 9 The metallographic structure diagram of the impact wear resistant coating of the example 4.

[0034] Figure 10 The microstructure diagram of the impact wear resistant coating without adding nickel powder of the comparative example 6. DETAILED DESCRIPTION

[0035] The present application will be further described in detail below in combination with the drawings of the specification. It should be understood that the specific examples described herein are only used to explain the present application, and are not used to limit the present application.

[0036] The raw materials used in the present application are as follows:

[0037] The high manganese steel liner is ZGMn13 high manganese steel, and the high manganese steel liner before the plasma surfacing is warped upward by 20.0mm from the horizontal line at the corner;

[0038] High carbon ferrochrome contains 7-9% C, and ≥60% Cr, with a powder particle size range of 60-325 mesh;

[0039] Micro-carbon ferrochrome contains 3-6% C, and ≥55% Cr, with a powder particle size range of 60-325 mesh;

[0040] Graphite powder contains ≥98% C, with a powder particle size range of 60-200 mesh;

[0041] Silicon iron powder contains ≥72% Si, with a powder particle size range of 60-200 mesh;

[0042] Manganese iron powder contains 65-72% Mn, and 1-1.5% C, with a powder particle size range of 60-200 mesh;

[0043] Titanium iron powder contains 35-45% Ti, and ≤8% Al, with a powder particle size range of 60-200 mesh;

[0044] Molybdenum iron powder contains ≥60% Mo, with a powder particle size range of 60-200 mesh;

[0045] Vanadium iron powder contains 40-55% V, with a powder particle size range of 60-200 mesh;

[0046] Boron iron powder contains 9-25% B, and ≤0.1% C, with a powder particle size range of 60-200 mesh;

[0047] Nickel powder contains ≥98% Ni, with a powder particle size range of 60-200 mesh;

[0048] Calcium fluoride powder contains ≥96% CaF2, with a powder particle size range of 60-200 mesh;

[0049] Reduced iron powder contains ≥98% Fe, with a powder particle size range of 60-325 mesh.

[0050] Example 1

[0051] An impact-resistant and wear-resistant flux-cored wire for welding high-manganese steel lining plate, comprising a low-carbon cold-rolled steel strip sheath and a flux core powder, wherein the flux core components and their proportions are as follows: high-carbon ferrochrome powder 12.3wt%, micro-carbon ferrochrome powder 28.5wt%, graphite powder 1.3wt%, silicon iron powder 1.2wt%, manganese iron powder 2.5wt%, titanium iron powder 1.6wt%, molybdenum iron powder 2.7wt%, vanadium iron powder 1.4wt%, boron iron powder 0.8wt%, nickel powder 1.1wt%, calcium fluoride powder 0.8wt%, and the balance is reduced iron powder. The flux-cored wire prepared by the cold rolling and drawing process has a diameter of 2.4mm and a filling rate of 43%.

[0052] A surfacing method of welding high manganese steel liner, the flux-cored wire is placed in a heating furnace at 150℃ for 2h to dry and remove moisture.

[0053] The surface of the high manganese steel liner is pretreated (angle grinder polishing or sand blasting) to remove oil stains and rust on the surface of the workpiece.

[0054] The flux-cored wire is used for plasma surfacing on the high manganese steel liner, the welding current is 140A, the welding speed is 380mm / min, the wire feeding speed is 1850mm / min; the wire feeding mode is side shaft wire feeding; the purity of the compressed gas and the protective gas is 99.99%, the selected compressed gas flow is 4L / min, and the selected protective gas flow is 8L / min; the surface temperature of the high manganese steel liner at a distance of 5cm from the molten pool is 169℃.

[0055] As shown in Figure 1 , the microstructure of the impact and wear resistant coating prepared by plasma surfacing, the hard phase in various forms is uniformly distributed on the iron base, which plays a key role in improving wear resistance, and the porosity is 0.8%.

[0056] The longitudinal deformation amount before and after plasma surfacing is 1.4mm.

[0057] The coating hardness measured by a Rockwell hardness tester is 56.2 HRC.

[0058] An impact and wear test is carried out by using an MLD-10 impact and wear tester, the impact hammer mass is 10kg, the impact load is 5J, the counterpart is 45 steel, the test sample is loaded on the impact hammer head and impacted downward, the impact frequency is 200 times / min, the counterpart rotation speed is 200r / min; at the same time, refined quartz sand (particle size 1.50-2.36mm) is added as abrasive, the abrasive flow is 40kg / h; the impact and wear time is 5h. The mass loss of the test sample before and after wear is measured by using an analytical balance with an accuracy of 0.1mg, the results are that the impact and wear loss of the high manganese steel liner is 1.1273g, the impact and wear loss of the high manganese steel liner with surfacing layer is only 0.7831g, and the impact and wear resistance of the high manganese steel liner is 1.44 times that of the high manganese steel liner of the embodiment.

[0059] Example 2

[0060] The invention discloses a flux-cored wire for welding high manganese steel liner plate, which comprises a low-carbon cold-rolled steel belt sheath and a flux core powder, wherein the flux core components and their proportions are as follows: high-carbon chromium iron powder 14.2wt%, micro-carbon chromium iron powder 30.1wt%, graphite powder 1.7wt%, silicon iron powder 1.5wt%, manganese iron powder 3.1wt%, titanium iron powder 2.2wt%, molybdenum iron powder 4.5wt%, vanadium iron powder 2.5wt%, boron iron powder 1.6wt%, nickel powder 0.7wt%, calcium fluoride powder 0.5wt%, and the rest is reduced iron powder. The diameter of the flux-cored wire prepared by a cold rolling and drawing process is 2.4mm, and the filling rate is 45%.

[0061] A surfacing method for welding high manganese steel liner plate, the above-mentioned flux-cored wire is placed in a heating furnace at 175℃ for 1.75h to dry and dehumidify.

[0062] The surface of the high manganese steel liner plate is pretreated (angle grinder polishing or sand blasting) to remove oil stains and rust on the surface of the workpiece.

[0063] The flux-cored wire is used for plasma surfacing on the high manganese steel liner plate, the welding current is 160A, the welding speed is 420mm / min, the wire feeding speed is 1890mm / min, the wire feeding mode is side-shaft wire feeding, the purity of the compressed gas and the protective gas is 99.99%, the selected compressed gas flow is 5L / min, the selected protective gas flow is 10L / min, and the surface temperature of the high manganese steel liner plate at a distance of 5cm from the molten pool is 183℃.

[0064] The interface between the plasma surfacing coating and the substrate is in a good metallurgical bonding state, and no cracking occurs at the interface, as shown in Figure 2 .

[0065] The longitudinal deformation amount before and after the plasma surfacing is 1.5mm.

[0066] The coating hardness measured by using a Rockwell hardness tester is 57.8 HRC, and the porosity is 0.7%.

[0067] The impact wear test is the same as that in Example 1, the results are that the impact wear loss of the high manganese steel liner plate is 1.1090g, the impact wear loss of the high manganese steel liner plate with the surfacing layer is only 0.7165g, and the impact wear resistance of the high manganese steel liner plate in this embodiment is 1.55 times that of the high manganese steel liner plate.

[0068] Example 3

[0069] The invention discloses a flux-cored wire for welding high manganese steel liner plate, which comprises a low-carbon cold-rolled steel belt sheath and a flux core powder, wherein the flux core components and their proportions are as follows: high-carbon chromium iron powder 15.8 wt%, micro-carbon chromium iron powder 32.2 wt%, graphite powder 0.8 wt%, silicon iron powder 1.2 wt%, manganese iron powder 3.6 wt%, titanium iron powder 2.5 wt%, molybdenum iron powder 3.7 wt%, vanadium iron powder 3.2 wt%, boron iron powder 2.5 wt%, nickel powder 1.1 wt%, calcium fluoride powder 0.9 wt%, and the rest is reduced iron powder. The diameter of the flux-cored wire prepared by a cold rolling and drawing process is 2.8 mm, and the filling rate is 47%.

[0070] A surfacing method for welding high manganese steel liner plate, the above-mentioned flux-cored wire is placed in a heating furnace at 200℃ for 1.5h to dry and dehumidify.

[0071] The surface of the high manganese steel liner plate is pretreated (angle grinder polishing or sand blasting) to remove oil stains and rust on the surface of the workpiece.

[0072] The flux-cored wire is used for plasma surfacing on the high manganese steel liner plate, the welding current is 165A, the welding speed is 480mm / min, the wire feeding speed is 2020mm / min, the wire feeding mode is side shaft wire feeding, the compressed gas and the protective gas are both argon with a purity of 99.999%, the selected compressed gas flow is 6L / min, the selected protective gas flow is 8L / min, and the surface temperature of the high manganese steel liner plate at a distance of 5cm from the molten pool is 212℃.

[0073] The longitudinal deformation amount before and after plasma surfacing is 1.7mm.

[0074] The coating hardness measured by a Rockwell hardness tester is 59.4 HRC, and the porosity is 0.6%.

[0075] The impact wear experiment is the same as that in Example 1, the results are that the impact wear weight loss of the high manganese steel liner plate is 1.0895g, the impact wear weight loss of the high manganese steel liner plate with the surfacing layer is only 0.6042g, the impact wear resistance of the high manganese steel liner plate in this embodiment is 1.80 times that of the high manganese steel liner plate without the surfacing layer, and the impact wear weight loss of the two is as follows Figure 3 .

[0076] Example 4

[0077] The invention discloses a flux-cored wire for welding high manganese steel liner plate, which comprises a low-carbon cold-rolled steel belt sheath and a flux core powder, wherein the flux core components and their proportions are as follows: high-carbon chromium iron powder 16.5 wt%, micro-carbon chromium iron powder 35.5 wt%, graphite powder 1.4 wt%, silicon iron powder 1.5 wt%, manganese iron powder 1.8 wt%, titanium iron powder 1.8 wt%, molybdenum iron powder 2.1 wt%, vanadium iron powder 1.3 wt%, boron iron powder 4.6 wt%, nickel powder 1.5 wt%, calcium fluoride powder 0.7 wt%, and the rest is reduced iron powder. The diameter of the flux-cored wire prepared by a cold rolling and drawing process is 2.8 mm, and the filling rate is 48%.

[0078] A surfacing method for welding high manganese steel liner plate, the above-mentioned flux-cored wire is placed in a heating furnace at 225℃ for 1.25h to dry and dehumidify.

[0079] The surface of the high manganese steel liner plate is pretreated (angle grinder polishing or sand blasting) to remove oil stains and rust on the surface of the workpiece.

[0080] The flux-cored wire is used for plasma surfacing on the high manganese steel liner plate, the welding current is 170A, the welding speed is 520mm / min, the wire feeding speed is 2050mm / min, the wire feeding mode is side-shaft wire feeding, the compressed gas and the protective gas are both argon with a purity of 99.999%, the selected compressed gas flow is 6L / min, the selected protective gas flow is 8L / min, and the surface temperature of the high manganese steel liner plate at a distance of 5cm from the molten pool is 256℃.

[0081] The longitudinal deformation amount before and after the plasma surfacing is 1.8mm.

[0082] The coating hardness measured by a Rockwell hardness tester is 60.5 HRC, and the porosity is 0.5%, as shown in Figure 9 .

[0083] The impact wear experiment is the same as that in Example 1, and the results are that the impact wear weight loss of the high manganese steel liner plate is 1.1141g, the impact wear weight loss of the high manganese steel liner plate with the surfacing layer is only 0.5986g, and the impact wear resistance of the high manganese steel liner plate in this embodiment is 1.86 times that of the high manganese steel liner plate.

[0084] Example 5

[0085] The invention discloses a flux-cored wire for welding high manganese steel liner plate, which comprises a low-carbon cold-rolled steel belt sheath and a core powder, wherein the core components and their proportions are as follows: high-carbon chromium iron powder 17.3wt%, micro-carbon chromium iron powder 37.2wt%, graphite powder 1.8wt%, silicon-iron powder 1.7wt%, manganese-iron powder 2.8wt%, titanium-iron powder 1.8wt%, molybdenum-iron powder 4.4wt%, vanadium-iron powder 3.8wt%, boron-iron powder 4.1wt%, nickel powder 0.9wt%, calcium fluoride powder 0.5wt%, and the rest is reduced iron powder. The diameter of the flux-cored wire prepared by a cold rolling and drawing process is 3.2mm, and the filling rate is 49%.

[0086] A surfacing method for welding high manganese steel liner plate is provided, wherein the above flux-cored wire is placed in a heating furnace at 250℃ for 1h to dry and dehumidify.

[0087] The surface of the high manganese steel liner plate is pretreated (angle grinder polishing or sand blasting) to remove oil stains and rust on the surface of the workpiece.

[0088] The flux-cored wire is used for plasma surfacing on the high manganese steel liner plate, the welding current is 175A, the welding speed is 580mm / min, the wire feeding speed is 2130mm / min, the wire feeding mode is side-shaft wire feeding, the compressed gas and the protective gas are both argon with a purity of 99.999%, the selected compressed gas flow is 6L / min, the selected protective gas flow is 7L / min, and the surface temperature of the high manganese steel liner plate at a distance of 5cm from the molten pool is 271℃.

[0089] The longitudinal deformation amount before and after the plasma surfacing is 1.9mm.

[0090] The coating hardness measured by a Rockwell hardness tester is 61.4 HRC, and the porosity is 0.5%.

[0091] The impact and wear experiment is the same as that in Example 1, the results show that the impact and wear weight loss of the high manganese steel liner plate is 1.0764g, the impact and wear weight loss of the high manganese steel liner plate with the surfacing layer is only 0.5739g, and the impact and wear resistance of the high manganese steel liner plate in this embodiment is 1.88 times that of the high manganese steel liner plate.

[0092] Example 6

[0093] The invention discloses a flux-cored wire for welding high manganese steel liner plate, which comprises a low-carbon cold-rolled steel belt sheath and a core powder, wherein the core components and their proportions are as follows: high-carbon chromium iron powder 17.3wt%, micro-carbon chromium iron powder 37.2wt%, graphite powder 1.8wt%, silicon-iron powder 1.7wt%, manganese-iron powder 2.8wt%, titanium-iron powder 1.8wt%, molybdenum-iron powder 4.4wt%, vanadium-iron powder 3.8wt%, boron-iron powder 4.1wt%, nickel powder 0.9wt%, calcium fluoride powder 0.5wt%, and the rest is reduced iron powder. The diameter of the flux-cored wire prepared by a cold rolling and drawing process is 3.2mm, and the filling rate is 49%.

[0094] A surfacing method for welding high manganese steel liner, the above flux-cored wire is placed in a heating furnace at 250℃ for 1h for drying and dehumidifying.

[0095] The surface of the high manganese steel liner is pretreated (angle grinder polishing or sand blasting) to remove oil stains and rust on the surface of the workpiece.

[0096] The flux-cored wire is used for plasma surfacing on the high manganese steel liner, the welding current is 155A, the welding speed is 550mm / min, the wire feeding speed is 2060mm / min; the wire feeding mode is side shaft wire feeding; the compressed gas and the protective gas are both argon with a purity of 99.999%, the selected compressed gas flow is 5L / min, and the selected protective gas flow is 8L / min; the surface temperature of the high manganese steel liner at a distance of 5cm from the molten pool is 252℃.

[0097] Example 7

[0098] A flux-cored wire for welding high manganese steel liner for impact and wear resistance, comprising a low-carbon cold-rolled steel strip sheath and a core powder, wherein the core composition and proportion are as follows: high-carbon chromium iron powder 18.1wt%, micro-carbon chromium iron powder 24.8wt%, graphite powder 2.2wt%, silicon iron powder 0.9wt%, manganese iron powder 4.1wt%, titanium iron powder 1.5wt%, molybdenum iron powder 5.1wt%, vanadium iron powder 0.9wt%, boron iron powder 4.9wt%, nickel powder 0.5wt%, calcium fluoride powder 0.6wt%, and the balance is reduced iron powder. The diameter of the flux-cored wire prepared by cold rolling and drawing process is 3.2mm, and the filling rate is 49%.

[0099] A surfacing method for welding high manganese steel liner, the above flux-cored wire is placed in a heating furnace at 200℃ for 1.5h for drying and dehumidifying.

[0100] The surface of the high manganese steel liner is pretreated (angle grinder polishing or sand blasting) to remove oil stains and rust on the surface of the workpiece.

[0101] The flux-cored wire is used for plasma surfacing on the high manganese steel liner, the welding current is 175A, the welding speed is 500mm / min, the wire feeding speed is 2100mm / min; the wire feeding mode is side shaft wire feeding; the compressed gas and the protective gas are both argon with a purity of 99.999%, the selected compressed gas flow is 6L / min, and the selected protective gas flow is 9L / min; the surface temperature of the high manganese steel liner at a distance of 5cm from the molten pool is 231℃.

[0102] Comparative Example

[0103] Three comparative experiments were carried out, namely Comparative Example 1, Comparative Example 2 and Comparative Example 3, using the welding wire formula of Example 5 to verify the influence of welding current, wire feeding speed and high manganese steel liner surface temperature control on the process of the application. Generally, the wire feeding speed is positively correlated with the welding speed, that is, the wire feeding speed is large, and the welding speed will also be large, so the welding speed is not listed, and the rest is the same as Example 5. The comparison effect is shown in the following table:

[0104] As shown in Figure 4 and Figure 5 , the longitudinal deformation of the high manganese steel liner before and after plasma surfacing of Example 5 and Comparative Example 1 is shown. The deformation amount of Comparative Example 1 is larger. The original high manganese steel liner before plasma surfacing is curved upward by 20.0 mm from the horizontal line, as shown in Figure 6 .

[0105] Comparative Example 4

[0106] No calcium fluoride powder is added, and the rest is the same as Example 1.

[0107] The longitudinal deformation amount before and after plasma surfacing is 1.4 mm.

[0108] The coating hardness measured by a Rockwell hardness tester is 53.2 HRC.

[0109] As shown in Figure 7 , the porosity in the surfacing layer is 2.7%.

[0110] The impact wear experiment is the same as Example 1, and the results are that the impact wear loss of the high manganese steel liner is 1.1198 g, and the impact wear loss of the high manganese steel liner with the surfacing layer is 0.8875 g. The impact wear resistance is only 1.26 times that of the original, which is because the matrix around the pores in the surfacing layer is more susceptible to the influence of abrasive particles and peeling during wear.

[0111] Comparative Example 5

[0112] 2.8wt% calcium fluoride powder is added, and the rest is the same as Example 1.

[0113] The longitudinal deformation amount before and after plasma surfacing is 1.4 mm.

[0114] The coating hardness measured by a Rockwell hardness tester is 54.7 HRC.

[0115] As shown in Figure 8 , the porosity in the surfacing layer is 2.3%.

[0116] The impact wear test is the same as that of Example 1, and the results are that the high manganese steel liner plate has an impact wear loss of 1.1207 g, and the high manganese steel liner plate with the surfacing layer has an impact wear loss of 0.8336 g, and the impact wear resistance is only 1.34 times that of the original.

[0117] Comparative Example 6

[0118] No nickel powder is added, and the rest is the same as that of Example 2. As shown in Figure 10 the surfacing layer / base interface bonding of Comparative Example 6, it can be seen that the interface cracks, which is in sharp contrast to the surfacing layer / base interface bonding of Example 2 shown in Figure 2 , which also confirms the effectiveness of adding nickel powder.

[0119] Through the above comparative experiments, it is proved that the surfacing process provided by the present application has beneficial effects in the field of high manganese steel liner plate in preparing a well-formed coating and controlling the deformation of the high manganese steel liner plate.

[0120] The above examples are only preferred embodiments of the present application, and it should be pointed out that the present application is not limited to the above examples, and various changes can be made according to the purposes of the present application without departing from the technical principles of the present application. Any changes, modifications, substitutions, combinations and simplifications made in accordance with the spirit and principles of the technical solutions of the present application shall be regarded as equivalent replacement methods, and these changes also belong to the protection scope of the present application.

Claims

1. An impact and abrasion resistant flux cored welding wire for welding high manganese steel liner plates, characterized by, The drug core is composed of the following raw materials in percentage by weight: high-carbon chromium iron powder 10-18 wt%, micro-carbon chromium iron powder 25-38 wt%, graphite powder 0.5-2 wt%, silicon iron powder 1-2 wt%, manganese iron powder 1-4 wt%, titanium iron powder 1.5-3 wt%, molybdenum iron powder 1-5 wt%, vanadium iron powder 1-4 wt%, boron iron powder 0.5-5 wt%, calcium fluoride powder 0.3-1 wt%, nickel powder 0.5-2 wt%, and the rest is reduced iron powder.

2. The flux cored wire for welding high manganese steel liner plate for impact and abrasion resistance according to claim 1, characterized by The outer skin is a low-carbon cold-rolled steel strip, and the welding wire is made by wrapping the outer skin around the drug core through cold rolling and drawing.

3. The flux cored wire for welding high manganese steel liner plates for impact and abrasion resistance according to claim 2, characterized by, The diameter is 2.4-3.2 mm, and the filling rate is 42-50%.

4. A surfacing method for welding a high-manganese steel liner plate, using the impact and wear resistant flux-cored wire for welding a high-manganese steel liner plate according to claim 1, characterized in that, Step 1: pretreating the surface of the high-manganese steel liner plate; Step 2: drying and dehumidifying the flux-cored wire; Step 3: using a plasma arc automatic surfacing machine as the welding equipment, and the welding process parameters include: welding current 135-180 A, welding speed 350-650 mm / min, wire feeding speed 1800-2200 mm / min, and side-shaft wire feeding mode; Step 4: during the plasma cladding process, the temperature of the high-manganese steel liner plate surface 5 cm away from the molten pool needs to be controlled in the range of 150-280℃.

5. The method of welding a high manganese steel liner as defined in claim 4, wherein, In step 3, both the compressed gas and the protective gas are argon with a purity of ≥99.99%, the compressed gas flow rate is 3-7 L / min, and the selected protective gas flow rate is 5-12 L / min.

6. The method of welding a high manganese steel liner as defined in claim 4, wherein, In step 2, the flux-cored wire is placed in a heating furnace at 150-250℃ for 1-2 h for drying and dehumidifying.

7. The method of welding a high manganese steel liner as defined in claim 4, wherein The microstructure of the high-manganese steel liner plate after plasma surfacing is composed of an iron-based solid solution and uniformly distributed multi-component strengthening phases.

8. The method of welding a high manganese steel liner as defined in claim 4, wherein, The hardness of the surfacing layer of the high-manganese steel liner plate after plasma surfacing reaches 55-62 HRC, and the impact and wear resistance is 1.44-1.88 times that of the high-manganese steel liner plate.

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