A seamless flux-cored welding wire for 10CrNiCu steel for ships

Abstract

The invention discloses a seamless flux-cored welding wire for 10CrNiCu steel for ships, which is used for welding continuous casting 907A steel for main hull, and is composed of a low-carbon steel outer skin and a flux core. The diameter of the welding wire is 1.0-1.4 mm, and the filling rate of the flux core powder is 14-16%. The flux core contains rutile, aluminum oxide, ferroboron, zircon sand, quartz, bismuth oxide, potassium titanate, sodium fluoride, electrolytic manganese, ferrotitanium, magnesium powder, manganese silicon alloy, nickel powder, metal chromium, copper powder and iron powder in terms of the mass percentage of the flux core welding wire. The seamless flux-cored welding wire for 10CrNiCu steel for ships of the invention has the advantages of good welding processability, stable mechanical properties, good crack resistance, low diffusible hydrogen, strong moisture absorption resistance, excellent rust resistance, etc., which is helpful to promote the upgrading of flux-cored welding wire for ship steel welding in my country and improve the quality of ship construction.

Description

Technical Field

[0001] The invention belongs to the technical field of welding materials, and in particular relates to a seamless flux-cored welding wire for 10CrNiCu steel for ships. Background Art

[0002] 10CrNiCu steel (907A steel) is a hull structural material suitable for 390MPa class ships. 10CrNiCu steel is a 390MPa class ship main hull structural steel improved by reducing Si, increasing Mn and micro-alloying on the basis of the original 907 steel. Due to its good comprehensive mechanical properties and seawater corrosion resistance, it is the main hull steel for submarine non-pressure hulls, new missile frigates and other small and medium-sized ships. At present, the welding materials used in the continuous casting 907A steel welding construction used in surface ships are mainly 907A flux-cored welding wire, TH907A welding rod and 907A submerged arc welding wire with 705-ch flux.

[0003] The 10CrNiCu flux-cored welding wires currently used in shipyards are all seamed flux-cored welding wires. According to the technical conditions for the supply of 10CrNiCu steel flux-cored welding wires, the diffusible hydrogen is required to be less than 6ml / 100g (mercury method or gas chromatography method), but the existing seamed 10CrNiCu flux-cored welding wires often fail to meet the diffusible hydrogen standards during the supply process, thus affecting the supply progress. At the same time, the existing seamed 10CrNiCu flux-cored welding wires are almost all vacuum-packed to prevent the welding wires from absorbing moisture. During transportation, the vacuum bags are often damaged due to road bumps or mutual friction between the welding wire reels. The seamed flux-cored welding wires that are unpacked or vacuum-packed during use are easy to absorb moisture and rust, resulting in an increase in the diffusible hydrogen content in the weld metal and an increase in the tendency to crack. At the same time, the flux-cored welding wires that have absorbed moisture have increased porosity sensitivity during welding, which ultimately leads to a decrease in welding quality and the mechanical properties of the welded joints. At present, some manufacturers use 5kg / reel flux-cored wire to supply shipyards in order to reduce the moisture absorption problem of the seamed 10CrNiCu flux-cored wire during long exposure and moisture absorption when not fully used. However, the use of 5kg / reel flux-cored wire will increase the number of wire reels to replace, thereby reducing the work efficiency of welders. In other words, the use of small reels is not a fundamental solution to the moisture absorption and high diffusible hydrogen of the seamed 10CrNiCu flux-cored wire.

[0004] At present, some countries have begun to use seamless flux-cored wire for welding hull steel, such as HY-80 steel and HY-100 steel used in the hull structure of American submarines and aircraft carriers. Seamless flux-cored wire is also widely used in other high-strength steel welding projects, such as marine engineering, bridges, etc.

[0005] The advantages of seamless flux-cored welding wire over traditional seamless flux-cored welding wire are: ① Ultra-low diffusible hydrogen, the diffusible hydrogen content is generally less than 3.5ml / 100g. Ultra-low diffusible hydrogen can effectively reduce the crack incidence of weld metal and has high porosity resistance. This is because the seamless flux-cored welding wire can be subjected to high-temperature dehydrogenation treatment during production, which can reduce the moisture (one of the sources of hydrogen) in the flux-cored powder and attached to the outer steel strip; ② Strong moisture absorption resistance. After the seamless flux-cored welding wire is formed, since the outer steel strip is a seamless structure without gaps, moisture absorption of the flux-cored powder inside the welding wire will not occur at all. Therefore, the seamless flux-cored welding wire has a strong moisture absorption resistance, and even long-term storage in a humid environment does not require re-drying; ③ The surface of the welding wire can be copper-plated, so the wire feeding performance is excellent, the wear of the conductive nozzle is small, copper plating can improve the current transmission capacity, and the wire after copper plating has excellent rust resistance; ④ There is no gap in the outer steel strip, the cross-sectional shape of the welding wire is uniform and rigid, the welding wire is not twisted and deformed when used, the wire feeding performance and welding wire alignment are excellent, the arc is more stable, and it can be used for fully automatic welding of robots (manipulators) with a higher degree of mechanization, which can significantly improve welding efficiency and save comprehensive costs. Therefore, seamless flux-cored welding wire can fundamentally solve the problems of moisture absorption and high diffusible hydrogen.

[0006] With the implementation of China's maritime power plan and the intensification of maritime territorial disputes, the number of Chinese ships built has also increased unreasonably. Among them, the use of flux-cored welding wire matching 10CrNiCu steel has also gradually increased. At the same time, the development of welding technology has also put forward higher requirements on the quality and quality of flux-cored welding wire matching 10CrNiCu steel. Summary of the invention

[0007] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a seamless flux-cored welding wire for ship 10CrNiCu steel, which is used for welding the main hull 10CrNiCu steel. It has the advantages of good welding processability, stable mechanical properties, good crack resistance, low diffusible hydrogen, strong moisture absorption resistance, and excellent rust resistance. It is helpful to promote the upgrading of flux-cored welding wire for ship steel welding in my country and improve the quality of ship construction.

[0008] In order to solve the above technical problems, the present invention provides a seamless flux-cored welding wire for 10CrNiCu steel for ships, which is composed of a low-carbon steel outer skin and a flux core. The contents of the components in the flux core are as follows, measured by the mass percentage of the flux-cored welding wire: 37-42% rutile, 1-2% alumina, 0.2-0.5% ferroboron, 1-3% zircon sand, 2-5% quartz, 0.2-0.4% bismuth oxide, 2-5% potassium titanate, 3-5% sodium fluoride, 2-5% electrolytic manganese, 1-3% ferrotitanium, 4-7% magnesium powder, 10-15% manganese silicon alloy, 7-10% nickel powder, 0.2-0.5% metallic chromium, 0.5-1% copper powder, and the rest is iron powder.

[0009] The present invention adopts a titanium-base type flux-cored welding wire slag system, TiO 2 The solidification temperature of the slag is high and can adapt to all-position welding. Rutile is the main slag-forming agent and arc stabilizer, which can adjust the melting point and viscosity of the slag and improve the formation and slag removal of the weld. Alumina can adjust the viscosity of molten iron and slag, which is conducive to all-position welding, but too much addition will cause increased smoke and spatter, so the amount of alumina added should be controlled between 1 and 2%. Boron and titanium can form Ti-B compounds in the weld metal, promote the formation of acicular ferrite in the weld metal, and improve the impact toughness of the weld metal. Boron is a low-melting-point substance. If too much is added, it is easy to precipitate at the grain boundary and cause thermal cracks. Therefore, the amount of ferroboron added should be 0.2-0.5%. Zircon sand and quartz can adjust the melting point and viscosity of slag, making it suitable for all-position welding. Quartz can also improve the spreadability of slag, which is conducive to weld formation. However, excessive amount will reduce the melting point of welding slag, which is not conducive to forming during vertical welding. Therefore, the addition amount of zircon sand should be 1-3%, and the addition amount of quartz should be 2-5%. The addition of bismuth oxide is conducive to slag removal during flux-cored wire welding and forming a smooth weld. Bismuth is a low-melting-point substance. If too much is added, it is easy to precipitate at the grain boundary and cause thermal cracks. The addition amount of bismuth oxide is preferably 0.2-0.4%. During welding, potassium ions of potassium titanate can stabilize the arc, but too much addition will cause an increase in smoke. Therefore, the addition amount of potassium titanate should be controlled between 2 and 5%. Sodium fluoride can shrink the arc during welding, improve arc penetration and penetration, thereby preventing incomplete penetration. In addition, the fluoride ions decomposed by sodium fluoride at high temperature can dehydrogenate and reduce the content of diffuse hydrogen in the weld metal. However, too much addition will cause increased spatter, so the amount of sodium fluoride added should be controlled between 3 and 5%. Electrolytic manganese and manganese silicon alloy neutralize manganese and silicon elements, which can improve the tensile strength and toughness of the weld metal while deoxidizing. Too low content will lead to too low strength of the weld metal, and too high content will lead to too high strength of the weld metal and reduced toughness. Therefore, the amount of electrolytic manganese added is 2-5%, and the amount of manganese silicon alloy added is 10-15%. The main purpose of adding titanium iron is to deoxidize. In addition, titanium oxide can act as a strong hydrogen trap, which can solidify a large amount of hydrogen, thereby effectively reducing the content of diffuse hydrogen in the deposited metal. Due to the great affinity of Ti with oxygen, Ti in the weld is in the form of tiny particle oxides (TiO, TiO2, TiO3, TiO4, TiO2 ... 2 O 3 、TiO 2) is dispersed in the weld and is very easy to become the nucleation core of acicular ferrite, which is conducive to the formation of acicular ferrite structure, thereby improving the toughness of the weld metal. The amount of titanium iron added should be controlled at 1-3%. The main purpose of adding magnesium powder is also deoxidation. At the same time, the deoxidation product entering the deposited metal can improve the tensile strength of the weld metal, because a very small part of magnesium oxide can enter the weld metal in the form of inclusions, improving the hardness and strength of the steel. Most of the deoxidation products of magnesium enter the slag, which can increase the melting point of the slag and make the welding wire suitable for all-position welding. When the amount added is too low, insufficient deoxidation is easy to produce pores, but when the content is too high, it will cause an increase in smoke during welding, resulting in poor welding processability. Therefore, the amount of magnesium powder added is controlled at 4-7%. The main purpose of adding nickel powder is to improve the impact toughness of the weld metal. The amount of nickel powder added is 7-10%. Chromium powder is mainly used to reduce the tough-to-brittle transition temperature of the welded joint. At the same time, the addition of chromium can improve the strength of the welded joint. Too little addition will cause the tough-to-brittle transition temperature of the welded joint to be too high. Too much addition will cause the strength of the welded joint to be too high, which is not conducive to improving the toughness of the welded joint. The addition of chromium powder is preferably 0.2-0.5%. Copper has a precipitation strengthening effect, but excessive copper is prone to increase the tendency of liquefaction cracks. An appropriate amount of Cu can improve the strength, toughness and corrosion resistance of the weld. When the Cu content of the deposited metal is less than 1.0%, the weld strength is improved by solid solution strengthening and the content of acicular ferrite is increased. When the Cu content is greater than 1.0%, the weld is strengthened by precipitation, but it is not conducive to the toughness of the weld. Therefore, the copper powder content in the flux core component is controlled between 0.5 and 1%.

[0010] Compared with the existing seamless flux-cored welding wire, the ship 10CrNiCu steel seamless flux-cored welding wire of the present invention has the following main advantages: it can be used for welding 10CrNiCu steel, has a lower diffusible hydrogen content, and the diffusible hydrogen content of the deposited metal of the 10CrNiCu steel seamless flux-cored welding wire is 2.46ml / 100g; the welded joint has good seawater corrosion resistance, and the stable corrosion potential of the sample is -713mV. It has good welding crack resistance, and the drop hammer test measured that the 1.2mm 10CrNiCu steel welding wire weld NDT is -55℃ (P-3 sample). The welding process is good, all-position welding can be performed, the arc is stable, the slag is easy to remove, and the spatter is small.

[0011] Specifically, the diameter of the seamless flux-cored welding wire for continuous casting 907A steel of the present invention is 1.0-1.4 mm, and the filling rate of the flux-cored powder is 14-16%.

[0012] The preparation process of the seamless flux-cored welding wire for 10CrNiCu steel for ships described in the present invention is: preparation of flux powder; storage, unloading, cleaning, drying, leveling of steel strips, and roller forming; online synchronous addition of flux-cored powder; online welding; manufacturing and annealing of coarse wire rods; manufacturing and annealing of fine wire rods; drawing and reducing the diameter of the welding wire; copper plating and polishing of the welding wire; batching and testing of the welding wire to prepare the finished welding wire.

[0013] Compared with the existing manufacturing method of seamless flux-cored welding wire for ship 10CrNiCu steel, the preparation method of the present invention has the following advantages: using thick and wide steel strips, higher production efficiency and lower cost; using online high-frequency welding, high welding quality; using online detection technology, accurate welding quality detection.

[0014] The seamless flux-cored welding wire for 10CrNiCu steel for ships of the present invention is used for welding 10CrNiCu steel for the main hull and has good welding processability, stable mechanical properties, good crack resistance, low diffusible hydrogen, strong moisture absorption resistance and excellent rust resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is the manufacturing process flow chart of seamless flux-cored welding wire for 10CrNiCu steel for ships.

[0016] Figure 2 This is the morphology of the flat welding weld of seamless flux-cored wire for 10CrNiCu steel for ships.

[0017] Figure 3 Metallographic structure of seamless flux-cored wire welded joint for 10CrNiCu steel for ships.

[0018] Figure 4 This is the corrosion potential-time curve of the seamless flux-cored wire welded joint of 10CrNiCu steel for ships. DETAILED DESCRIPTION

[0019] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0020] Embodiment 1:

[0021] A seamless flux-cored welding wire for 10CrNiCu steel for ships, consisting of a low-carbon steel sheath and a flux core, with a welding wire diameter of 1.4 mm, a flux core powder filling rate of 15%, and the contents of the components in the flux core as a percentage of the mass of the flux-cored welding wire are as follows: 40% rutile, 1.5% alumina, 0.5% ferroboron, 1% zircon sand, 2% quartz, 0.4% bismuth oxide, 3% potassium titanate, 5% sodium fluoride, 5% electrolytic manganese, 2% ferrotitanium, 5% magnesium powder, 13% manganese silicon alloy, 10% nickel powder, 0.5% metallic chromium, 1% copper powder, and the remainder iron powder.

[0022] Manufacturing process, such as Figure 1As shown, the following steps are included:

[0023] (1) Preparation of drug powder:

[0024] ① Powder mixing should be done with a calibrated and valid scale before use. According to the amount of raw materials added, scales with different ranges and accuracy levels should be used for weighing. In principle, a scale with a range greater than and close to the weight of the powder to be mixed should be used, and the accuracy level of the scale should be higher than ○Ⅲ level.

[0025] ② Prepare powder according to welding wire formula and check total weight. The weight of single barrel of powder shall not exceed 30kg. The total weight deviation shall not exceed ±0.5% of theoretical weight of powder. Powder beyond the deviation range shall not be put into use.

[0026] ③Put the qualified core powder into a suitable mixer for mixing. The mixing time should be no less than 60 minutes. It is recommended to use a V-type mixer with a capacity suitable for the powder weight for mixing.

[0027] ④Put the evenly mixed powder into the hopper and dry it in an oven at a temperature of 120-150°C for no less than 120 minutes (the powder that is not put into production after drying should be kept warm in the oven for later use. Powder that is not mixed can also be kept warm in the oven for mixing). The hopper should be marked with information such as the brand, powder weight, and date of the welding wire produced.

[0028] (2) Storing, unloading, cleaning, drying, leveling and rolling of steel strips:

[0029] ① Before unwinding the steel strip, check whether there is rust on each surface and side. If there is rust, use a grinder to grind and polish it, otherwise it cannot be put into production. Each roll of steel strip is welded with an argon arc welder and then driven into the loop storage tray. The recommended welding current is 200±10A, and the argon gas flow rate is 10~20L / min. The steel strip enters the cleaning device through the storage and unwinding device.

[0030] ② After the steel strip enters the cleaning device, ultrasonic cleaning is used to remove oil, dust, water and other impurities on the surface of the steel strip.

[0031] ③After cleaning, the steel strip enters the drying device and is dried by blast.

[0032] ④The dried steel strip enters the leveling device to make it flat.

[0033] ⑤The leveled steel strip is rolled into a "U" shape.

[0034] (3) Online simultaneous addition of core powder:

[0035] ① Input the actual measured steel strip width and thickness values ​​into the steel strip size parameter column in the powder feeder operation interface, and set the powder filling rate to 15%.

[0036] ② When the equipment is running stably, start the powder adding device to produce coarse wire rod. The working condition of each equipment should be monitored at all times during production.

[0037] ③ During the production process, the amount of powder in the V-shaped hopper of the powder feeder should be no less than 20 kg. Vibration should be avoided when adding powder to avoid affecting the filling rate.

[0038] (4) Online welding:

[0039] ①Welding power 2.0kW, steel strip running speed 0.08m / s, extrusion volume 3mm.

[0040] ②Online eddy current flaw detection is used to detect the welding quality, and it should be ensured that the weld is firmly welded and the internal and external burrs do not affect the subsequent wire drawing.

[0041] (5) Coarse wire rod manufacturing and annealing:

[0042] ① Each roll of unannealed thick wire rod produced should be marked with the wire brand and nominal wire rod specifications. Status (cold rolled), weight, production date, coil number, etc.

[0043] ② Each coil of wire rod should be sampled at the beginning and end to test the filling rate. When two adjacent coils of wire rod are connected end to end, a filling rate test sample can be taken at the connection point, and the sampling length is 130-160 mm. A balance with a maximum range of 200g and a graduation value of 0.1g should be used for the filling rate test. The test results should be recorded in the corresponding production process record card, and the record should correspond to the coil number of the wire rod. When the filling rate of the wire rod meets the technical index requirements, it can be transferred to subsequent processing. If the filling rate of the wire rod does not meet the requirements, it shall not be transferred to subsequent production. The unannealed coarse wire rod is inspected coil by coil by visual inspection. If no cracking is found, it is qualified. For cracked wire rods, the cracked part should be removed.

[0044] ③ The small coiled thick wire rods that have passed the inspection should be annealed in an annealing furnace with atmosphere protection (normal purity nitrogen). Annealing system: the furnace temperature is not higher than 200℃, the heating time is 120min, the insulation temperature is 650±10℃, and the insulation time is determined according to the annealing equipment, the furnace load, etc. (60 to 240min is recommended when the furnace load is less than 2.5 tons). After the annealing is completed, the thick wire rods are cooled with the furnace to below 300℃ before they can be taken out of the furnace for air cooling.

[0045] ④ The wire brand and nominal wire rod specifications should be marked on the annealed thick wire rod. Status (annealed state), weight, production date, coil number (the same as the coil number of unannealed rough wire rod), etc.

[0046] (6) Manufacturing and annealing of thin wire rods:

[0047] ① Use a fine reducing mill to roll the annealed thick wire rod (temperature not higher than 60°C). After rolling, a fine wire rod with a nominal diameter of Ф6.5㎜ or Ф5.5㎜ is obtained.

[0048] ② Use visual inspection to inspect each roll of thin wire rod. If no cracks or other defects that affect subsequent production are found, it is qualified. Otherwise, it should be rejected. Hang a label on each roll of qualified thin wire rod to indicate the roll number (consistent with the roll number of the thick wire rod) and weight and other information.

[0049] ③ The fine wire rods that have passed the inspection should be annealed in an annealing furnace with atmosphere protection (normal purity nitrogen). Annealing system: furnace temperature is not higher than 200℃, heating time: 120min, insulation temperature: 650±10℃, insulation time: determined according to annealing equipment, furnace loading, etc. (60~360min is recommended when the furnace loading is less than 2.5 tons). After annealing, the fine wire rods should be cooled with the furnace to below 300℃ before being air-cooled.

[0050] ④ After annealing, the thin wire rod should be labeled with information such as wire brand, specification, state (annealed state), weight, date, coil number (consistent with the coil number before annealing), etc.

[0051] (7) Wire drawing and reducing, wire copper plating and polishing:

[0052] ① If the annealed thin wire rod has oxide scale on the surface after long-term storage, pickling or mechanical methods should be used to remove the surface oxide scale. Hydrochloric acid, sulfuric acid or a mixed acid composed of the two acids can be used for pickling. In order to improve the pickling effect or efficiency, the acid solution can be heated or the electrolysis process can be added. If the acid solution contains hydrochloric acid, the acid solution heating temperature shall not exceed 60°C to prevent the generation of a large amount of acid mist. The pickling time depends on the surface oxide scale of the wire rod. After pickling, the residual acid on the surface of the wire rod should be rinsed off with clean water. If some oxide scale still remains, you can choose to pickle or polish it again according to the amount of residue to ensure that there is no oxide scale residue on the surface of the wire rod. The wire rod that has passed the pickling should be coated in time, and the coating can be made of borax or saponified liquid. When applying borax, the solution temperature should be kept at 80-100°C, and the solution specific gravity range is: 1.15-1.30g / cm 3 The wire rod should be dried promptly after coating to prevent rust or affect subsequent drawing lubrication.

[0053] ② Drawing and reducing diameter: When drawing the welding wire, polycrystalline diamond dies are recommended for the finished product pass and the pass before the finished product, and carbide dies are recommended for other passes. When drawing the welding wire, sodium soap drawing powder should be used as a lubricant. The welding wire drawing process can be appropriately adjusted according to the changes in equipment and dies.

[0054] ③Welding wire copper plating polishing

[0055] Welding wire copper plating process: mechanical degreasing → hot water scrubbing → electrolytic alkaline washing → hot water scrubbing → water washing → electrolytic pickling → activated pickling → water washing → copper plating → neutralization water washing → hot water rinsing → drying → polishing and sizing.

[0056] (8) After the welding wire is batched and inspected, the seamless flux-cored welding wire is obtained:

[0057] ① Each batch of welding wire should be made of the same size, same batch number of steel strips, same batch number of main flux core raw materials, with the same formula and manufacturing process. The maximum weight of each batch of welding wire is 50t. One reel of each batch of welding wire can be selected for inspection.

[0058] ② The inner packaging of welding wire is sealed with heat shrinkable plastic film, and the outer packaging is packed in paper box. The outer packaging of each welding wire and the side edge of the welding wire reel should be marked with: standard number, welding wire model or brand; trademark and manufacturer name; specification and net weight; batch number and inspection number; production date, etc.

[0059] Embodiment 2:

[0060] A seamless flux-cored welding wire for 10CrNiCu steel for ships, consisting of a low-carbon steel sheath and a flux core, with a welding wire diameter of 1.0 mm, a flux core powder filling rate of 14%, and the contents of the components in the flux core as a percentage of the mass of the flux-cored welding wire are as follows: 37% rutile, 1% alumina, 0.2% ferroboron, 3% zircon sand, 5% quartz, 0.3% bismuth oxide, 2% potassium titanate, 3% sodium fluoride, 3.5% electrolytic manganese, 3% ferrotitanium, 4% magnesium powder, 15% manganese silicon alloy, 7% nickel powder, 0.3% metallic chromium, 0.7% copper powder, and the balance iron powder.

[0061] Manufacturing process, such as Figure 1 As shown, the following steps are included:

[0062] (1) Preparation of drug powder:

[0063] ① Powder mixing should be calibrated with qualified and valid scales before use. Scales with different ranges and accuracy levels should be used for weighing according to the amount of raw materials added. In principle, a scale with a range greater than and close to the weight of the powder to be mixed should be used, and the accuracy level of the scale should be higher than ○Ⅲ level.

[0064] ② Prepare powder according to welding wire formula and check total weight. The weight of single barrel of powder shall not exceed 30kg. The total weight deviation shall not exceed ±0.5% of theoretical weight of powder. Powder beyond the deviation range shall not be put into use.

[0065] ③Put the qualified core powder into a suitable mixer for mixing. The mixing time should be no less than 60 minutes.

[0066] It is recommended to use a V-type mixer with a capacity suitable for the powder weight to mix the powder.

[0067] ④Put the evenly mixed powder into the hopper and dry it in an oven at a temperature of 120-150°C for no less than 120 minutes (the powder that is not put into production after drying should be kept warm in the oven for later use. Powder that is not mixed can also be kept warm in the oven for mixing). The hopper should be marked with information such as the brand, powder weight, and date of the welding wire produced.

[0068] (2) Storing, unloading, cleaning, drying, leveling and roller forming of steel strips:

[0069] ① Before unwinding the steel strip, check whether there is rust on each surface and side. If there is rust, use a grinder to grind and polish it, otherwise it cannot be put into production. Each roll of steel strip is welded with an argon arc welder and then driven into the loop storage tray. The recommended welding current is 200±10A, and the argon gas flow rate is 10~20L / min. The steel strip enters the cleaning device through the storage and unwinding device.

[0070] ② After the steel strip enters the cleaning device, ultrasonic cleaning is used to remove oil, dust, water and other impurities on the surface of the steel strip.

[0071] ③After cleaning, the steel strip enters the drying device and is dried by blast.

[0072] ④The dried steel strip enters the leveling device to make it flat.

[0073] ⑤The leveled steel strip is rolled into a "U" shape.

[0074] (3) Online simultaneous addition of core powder:

[0075] ① Input the actual measured steel strip width and thickness values ​​into the steel strip size parameter column in the powder feeder operation interface, and set the powder filling rate to 14%.

[0076] ② When the equipment is running stably, start the powder adding device to produce coarse wire rods. The working conditions of each equipment should be monitored at all times during production.

[0077] ③ During the production process, the amount of powder in the V-shaped hopper of the powder feeder should be no less than 20 kg. Vibration should be avoided when adding powder to avoid affecting the filling rate.

[0078] (4) Online welding:

[0079] ①Welding power 2.7kW, steel strip running speed 0.15m / s, extrusion volume 3mm.

[0080] ②Online eddy current flaw detection is used to detect the welding quality, and it should be ensured that the weld is firmly welded and the internal and external burrs do not affect the subsequent wire drawing.

[0081] (5) Coarse wire rod manufacturing and annealing:

[0082] ① Each roll of unannealed thick wire rod produced should be marked with the wire brand and nominal wire rod specifications. Status (cold rolled), weight, production date, coil number, etc.

[0083] ② Each coil of wire rod should be sampled at the beginning and end to test the filling rate. When two adjacent coils of wire rod are connected end to end, a filling rate test sample can be taken at the connection point, and the sampling length is 130-160 mm. A balance with a maximum range of 200g and a graduation value of 0.1g should be used for the filling rate test. The test results should be recorded in the corresponding production process record card, and the record should correspond to the coil number of the wire rod. When the filling rate of the wire rod meets the technical index requirements, it can be transferred to subsequent processing. If the filling rate of the wire rod does not meet the requirements, it shall not be transferred to subsequent production. The unannealed coarse wire rod is inspected coil by coil by visual inspection. If no cracking is found, it is qualified. For cracked wire rods, the cracked part should be removed.

[0084] ③ The small coiled thick wire rods that have passed the inspection should be annealed in an annealing furnace with atmosphere protection (normal purity nitrogen). Annealing system: the furnace temperature is not higher than 200℃, the heating time is 120min, the insulation temperature is 650±10℃, and the insulation time is determined according to the annealing equipment, the furnace load, etc. (60 to 240min is recommended when the furnace load is less than 2.5 tons). After the annealing is completed, the thick wire rods are cooled with the furnace to below 300℃ before they can be taken out of the furnace for air cooling.

[0085] ④ The wire brand and nominal wire rod specifications should be marked on the annealed thick wire rod. Status (annealed state), weight, production date, coil number (the same as the coil number of unannealed rough wire rod), etc.

[0086] (6) Manufacturing and annealing of thin wire rods:

[0087] ① Use a fine reducing mill to roll the annealed thick wire rod (temperature not higher than 60°C). After rolling, a fine wire rod with a nominal diameter of Ф6.5㎜ or Ф5.5㎜ is obtained.

[0088] ② Use visual inspection to inspect each roll of thin wire rod. If no cracks or other defects that affect subsequent production are found, it is qualified. Otherwise, it should be rejected. Hang a label on each roll of qualified thin wire rod to indicate the roll number (consistent with the roll number of the thick wire rod) and weight and other information.

[0089] ③ The fine wire rods that have passed the inspection should be annealed in an annealing furnace with atmosphere protection (normal purity nitrogen). Annealing system: furnace temperature is not higher than 200℃, heating time: 120min, insulation temperature: 650±10℃, insulation time: determined according to annealing equipment, furnace loading, etc. (60~360min is recommended when the furnace loading is less than 2.5 tons). After annealing, the fine wire rods should be cooled with the furnace to below 300℃ before being air-cooled.

[0090] ④ After annealing, the thin wire rod should be labeled with information such as wire brand, specification, state (annealed state), weight, date, coil number (consistent with the coil number before annealing), etc.

[0091] (7) Wire drawing and reducing, wire copper plating and polishing:

[0092] ① If the annealed thin wire rod has oxide scale on the surface after long-term storage, pickling or mechanical methods should be used to remove the surface oxide scale. Hydrochloric acid, sulfuric acid or a mixed acid composed of the two acids can be used for pickling. In order to improve the pickling effect or efficiency, the acid solution can be heated or the electrolysis process can be added. If the acid solution contains hydrochloric acid, the acid solution heating temperature shall not exceed 60°C to prevent the generation of a large amount of acid mist. The pickling time depends on the surface oxide scale of the wire rod. After pickling, the residual acid on the surface of the wire rod should be rinsed off with clean water. If some oxide scale still remains, you can choose to pickle or polish it again according to the amount of residue to ensure that there is no oxide scale residue on the surface of the wire rod. The wire rod that has passed the pickling should be coated in time, and the coating can be made of borax or saponified liquid. When applying borax, the solution temperature should be kept at 80-100°C, and the solution specific gravity range is: 1.15-1.30g / cm 3 The wire rod should be dried promptly after coating to prevent rust or affect subsequent drawing lubrication.

[0093] ② Drawing and reducing diameter: When drawing the welding wire, polycrystalline diamond dies are recommended for the finished product pass and the pass before the finished product, and carbide dies are recommended for other passes. When drawing the welding wire, sodium soap drawing powder should be used as a lubricant. The welding wire drawing process can be appropriately adjusted according to the changes in equipment and dies.

[0094] ③Welding wire copper plating polishing

[0095] Welding wire copper plating process: mechanical degreasing → hot water scrubbing → electrolytic alkaline washing → hot water scrubbing → water washing → electrolytic pickling → activated pickling → water washing → copper plating → neutralization water washing → hot water rinsing → drying → polishing and sizing.

[0096] (8) After the welding wire is batched and inspected, the seamless flux-cored welding wire is obtained:

[0097] ① Each batch of welding wire should be made of the same size, same batch number of steel strips, same batch number of main flux core raw materials, with the same formula and manufacturing process. The maximum weight of each batch of welding wire is 50t. One reel of each batch of welding wire can be selected for inspection.

[0098] ② The inner packaging of welding wire is sealed with heat shrinkable plastic film, and the outer packaging is packed in paper box. The outer packaging of each welding wire and the side edge of the welding wire reel should be marked with: standard number, welding wire model or brand; trademark and manufacturer name; specification and net weight; batch number and inspection number; production date, etc.

[0099] Embodiment 3:

[0100] A seamless flux-cored welding wire for 10CrNiCu steel for ships, composed of a low-carbon steel sheath and a flux core, with a welding wire diameter of 1.2 mm, a flux core powder filling rate of 16%, and the contents of the components in the flux core as a percentage of the mass of the flux-cored welding wire are as follows: 42% rutile, 2% alumina, 0.3% ferroboron, 2% zircon sand, 4% quartz, 0.2% bismuth oxide, 5% potassium titanate, 4% sodium fluoride, 2% electrolytic manganese, 1% ferrotitanium, 7% magnesium powder, 10% manganese silicon alloy, 9% nickel powder, 0.2% metal chromium, 0.5% copper powder, and the balance iron powder

[0101] Manufacturing process, such as Figure 1 As shown, the following steps are included:

[0102] (1) Preparation of drug powder:

[0103] ① Powder mixing should be calibrated with qualified and valid scales before use. Scales with different ranges and accuracy levels should be used for weighing according to the amount of raw materials added. In principle, a scale with a range greater than and close to the weight of the powder to be mixed should be used, and the accuracy level of the scale should be higher than ○Ⅲ level.

[0104] ② Prepare powder according to welding wire formula and check total weight. The weight of single barrel of powder shall not exceed 30kg. The total weight deviation shall not exceed ±0.5% of theoretical weight of powder. Powder beyond the deviation range shall not be put into use.

[0105] ③Put the qualified core powder into a suitable mixer for mixing. The mixing time should be no less than 60 minutes.

[0106] It is recommended to use a V-type mixer with a capacity suitable for the powder weight to mix the powder.

[0107] ④Put the evenly mixed powder into the hopper and dry it in an oven at a temperature of 120-150°C for no less than 120 minutes (the powder that is not put into production after drying should be kept warm in the oven for later use. Powder that is not mixed can also be kept warm in the oven for mixing). The hopper should be marked with information such as the brand, powder weight, and date of the welding wire produced.

[0108] (2) Storing, unloading, cleaning, drying, leveling and rolling of steel strips:

[0109] ① Before unwinding the steel strip, check whether there is rust on each surface and side. If there is rust, use a grinder to grind and polish it, otherwise it cannot be put into production. Each roll of steel strip is welded with an argon arc welder and then driven into the loop storage tray. The recommended welding current is 200±10A, and the argon gas flow rate is 10~20L / min. The steel strip enters the cleaning device through the storage and unwinding device.

[0110] ② After the steel strip enters the cleaning device, ultrasonic cleaning is used to remove oil, dust, water and other impurities on the surface of the steel strip.

[0111] ③After cleaning, the steel strip enters the drying device and is dried by blast.

[0112] ④The dried steel strip enters the leveling device to make it flat.

[0113] ⑤The leveled steel strip is rolled into a "U" shape.

[0114] (3) Online simultaneous addition of core powder:

[0115] ① Input the actual measured steel strip width and thickness values ​​into the steel strip size parameter column in the powder feeder operation interface, and set the powder filling rate to 16%.

[0116] ② When the equipment is running stably, start the powder adding device to produce coarse wire rod. The working condition of each equipment should be monitored at all times during production.

[0117] ③ During the production process, the amount of powder in the V-shaped hopper of the powder feeder should be no less than 20 kg. Vibration should be avoided when adding powder to avoid affecting the filling rate.

[0118] (4) Online welding:

[0119] ①Welding power 2.5kW, steel strip running speed 0.15m / s, extrusion volume 3mm.

[0120] ②Online eddy current flaw detection is used to detect the welding quality, and it should be ensured that the weld is firmly welded and the internal and external burrs do not affect the subsequent wire drawing.

[0121] (5) Coarse wire rod manufacturing and annealing:

[0122] ① Each roll of unannealed thick wire rod produced should be marked with the wire brand and nominal wire rod specifications. Status (cold rolled), weight, production date, coil number, etc.

[0123] ② Each coil of wire rod should be sampled at the beginning and end to test the filling rate. When two adjacent coils of wire rod are connected end to end, a filling rate test sample can be taken at the connection point, and the sampling length is 130-160 mm. A balance with a maximum range of 200g and a graduation value of 0.1g should be used for the filling rate test. The test results should be recorded in the corresponding production process record card, and the record should correspond to the coil number of the wire rod. When the filling rate of the wire rod meets the technical index requirements, it can be transferred to subsequent processing. If the filling rate of the wire rod does not meet the requirements, it shall not be transferred to subsequent production. The unannealed coarse wire rod is inspected coil by coil by visual inspection. If no cracking is found, it is qualified. For cracked wire rods, the cracked part should be removed.

[0124] ③ The small coiled thick wire rods that have passed the inspection should be annealed in an annealing furnace with atmosphere protection (normal purity nitrogen). Annealing system: the furnace temperature is not higher than 200℃, the heating time is 120min, the insulation temperature is 650±10℃, and the insulation time is determined according to the annealing equipment, the furnace load, etc. (60 to 240min is recommended when the furnace load is less than 2.5 tons). After the annealing is completed, the thick wire rods are cooled with the furnace to below 300℃ before they can be taken out of the furnace for air cooling.

[0125] ④ The wire brand and nominal wire rod specifications should be marked on the annealed thick wire rod. Status (annealed state), weight, production date, coil number (the same as the coil number of unannealed rough wire rod), etc.

[0126] (6) Manufacturing and annealing of thin wire rods:

[0127] ① Use a fine reducing mill to roll the annealed thick wire rod (temperature not higher than 60°C). After rolling, a fine wire rod with a nominal diameter of Ф6.5㎜ or Ф5.5㎜ is obtained.

[0128] ② Use visual inspection to inspect each roll of thin wire rod. If no cracks or other defects that affect subsequent production are found, it is qualified. Otherwise, it should be rejected. Hang a label on each roll of qualified thin wire rod to indicate the roll number (consistent with the roll number of the thick wire rod) and weight and other information.

[0129] ③ The fine wire rods that have passed the inspection should be annealed in an annealing furnace with atmosphere protection (normal purity nitrogen). Annealing system: furnace temperature is not higher than 200℃, heating time: 120min, insulation temperature: 650±10℃, insulation time: determined according to annealing equipment, furnace loading, etc. (60~360min is recommended when the furnace loading is less than 2.5 tons). After annealing, the fine wire rods should be cooled with the furnace to below 300℃ before being air-cooled.

[0130] ④ After annealing, the thin wire rod should be labeled with information such as wire brand, specification, state (annealed state), weight, date, coil number (consistent with the coil number before annealing), etc.

[0131] (7) Wire drawing and reducing, wire copper plating and polishing:

[0132] ① If the annealed thin wire rod has oxide scale on the surface after long-term storage, pickling or mechanical methods should be used to remove the surface oxide scale. Hydrochloric acid, sulfuric acid or a mixed acid composed of the two acids can be used for pickling. In order to improve the pickling effect or efficiency, the acid solution can be heated or the electrolysis process can be added. If the acid solution contains hydrochloric acid, the acid solution heating temperature shall not exceed 60°C to prevent the generation of a large amount of acid mist. The pickling time depends on the surface oxide scale of the wire rod. After pickling, the residual acid on the surface of the wire rod should be rinsed off with clean water. If some oxide scale still remains, you can choose to pickle or polish it again according to the amount of residue to ensure that there is no oxide scale residue on the surface of the wire rod. The wire rod that has passed the pickling should be coated in time, and the coating can be made of borax or saponified liquid. When applying borax, the solution temperature should be kept at 80-100°C, and the solution specific gravity range is: 1.15-1.30g / cm 3 The wire rod should be dried promptly after coating to prevent rust or affect subsequent drawing lubrication.

[0133] ② Drawing and reducing diameter: When drawing the welding wire, polycrystalline diamond dies are recommended for the finished product pass and the pass before the finished product, and carbide dies are recommended for other passes. When drawing the welding wire, sodium soap drawing powder should be used as a lubricant. The welding wire drawing process can be appropriately adjusted according to the changes in equipment and dies.

[0134] ③Welding wire copper plating polishing

[0135] Welding wire copper plating process: mechanical degreasing → hot water scrubbing → electrolytic alkaline washing → hot water scrubbing → water washing → electrolytic pickling → activated pickling → water washing → copper plating → neutralization water washing → hot water rinsing → drying → polishing and sizing.

[0136] (8) After the welding wire is batched and inspected, the seamless flux-cored welding wire is obtained:

[0137] ① Each batch of welding wire should be made of the same size, same batch number of steel strips, same batch number of main flux core raw materials, with the same formula and manufacturing process. The maximum weight of each batch of welding wire is 50t. One reel of each batch of welding wire can be selected for inspection.

[0138] ② The inner packaging of welding wire is sealed with heat shrinkable plastic film, and the outer packaging is packed in paper box. The outer packaging of each welding wire and the side edge of the welding wire reel should be marked with: standard number, welding wire model or brand; trademark and manufacturer name; specification and net weight; batch number and inspection number; production date, etc.

[0139] The outer skin of the seamless flux-cored welding wire for 10CrNiCu steel for ships of the present invention is selected from ordinary low-carbon steel strips, and the chemical composition and properties are shown in Tables 1 and 2. The chemical composition and mechanical properties of the deposited metal of the welding wire are shown in Tables 3 and 4. The diffusible hydrogen content of the deposited metal is shown in Table 5.

[0140] Table 1

[0141]

[0142] Table 2

[0143]

[0144] Table 3

[0145] C Si Mn S P Ni Cr Cu Example 1 0.063 0.287 1.03 0.0057 0.024 1.25 0.044 0.132 Example 2 0.051 0.237 1.15 0.0044 0.017 1.27 0.055 0.143 Example 3 0.049 0.262 1.01 0.0051 0.019 1.19 0.058 0.130

[0146] Table 4

[0147]

[0148] Table 5

[0149] Diffusible hydrogen content (ml / 100g) Example 1 2.78 Example 2 2.21 Example 3 2.38

[0150] Figure 2 This is the morphology of the flat welding bead of seamless flux-cored welding wire for 10CrNiCu steel for ships (the picture has been grayed). From the weld morphology photo, it can be seen that the welding wire has good welding processability, easy slag removal and small spatter. Figure 3 This is the metallographic structure of the welded joint of 10CrNiCu steel seamless flux-cored wire for ships. From the metallographic diagram, it can be seen that the welded joint is mainly composed of acicular ferrite structure, indicating that the welded joint has good impact toughness. Figure 4 This is the corrosion potential-time curve of the seamless flux-cored wire welded joint of 10CrNiCu steel for ships. It can be seen from the curve that the stable corrosion potential of the sample is -713mV, and it has good seawater corrosion resistance.

[0151] The above is only the best embodiment of the present invention. It should be noted that, for ordinary technicians in this field, several modifications or equivalent substitutions can be made to the technical solution of the present invention without departing from the principle of the present invention, which should also be regarded as falling within the protection scope of the present invention.

Claims

1. A seamless flux-cored welding wire for ship 10CrNiCu steel, consisting of a low-carbon steel sheath and a flux core. Features: Calculated as a percentage of the mass of the flux-cored welding wire, the contents of each component in the flux core are as follows: 37-42% rutile, 1-2% alumina, 0.2-0.5% ferroboron, 1-3% zircon sand, 2-5% quartz, 0.2-0.4% bismuth oxide, 2-5% potassium titanate, 3-5% sodium fluoride, 2-5% electrolytic manganese, 1-3% ferrotitanium, 4-7% magnesium powder, 10-15% manganese silicon alloy, 7-10% nickel powder, 0.2-0.5% metallic chromium, 0.5-1% copper powder, and the rest is iron powder.

2. The seamless flux-cored welding wire for 10CrNiCu steel for ships according to claim 1, Features: The diameter of the welding wire is 1.0-1.4 mm, and the filling rate of the flux core powder is 14-16%.

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