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CN-122007706-A - High-cobalt martensitic stainless steel submerged-arc welding flux-cored wire and BD roller and preparation method thereof

CN122007706ACN 122007706 ACN122007706 ACN 122007706ACN-122007706-A

Abstract

The invention discloses a high-cobalt martensitic stainless steel submerged arc welding flux-cored wire and a BD roller and a preparation method thereof, and relates to the technical field of welding materials and surfacing. The flux-cored wire comprises 50-80% of wire sheath and 20-50% of flux core by mass, wherein the flux core comprises graphite, JCr-A, cobalt powder, metallic nickel, feMo55-A, tungsten powder, feV75-A, FNb-3, FTD1 or FTD2, high aluminum, feB22C0.1, metallic titanium, caF 2 and rutile, and the balance of atomized iron powder. The invention also discloses a BD roller and a preparation method. The flux-cored wire can not only remarkably improve the red hardness and wear resistance of the roller, but also maintain and ensure the stability of the high-temperature strength, the high-temperature hardness and the cold-hot fatigue resistance of the roller, has higher heat resistance, and is more suitable for overlaying of the hot-rolled pass roller.

Inventors

  • ZOU HONGJUN
  • LUO BIAO
  • ZHOU YING
  • AN FEI
  • DU CHAO
  • Qing Guangyang

Assignees

  • 四川国鑫机械制造有限公司

Dates

Publication Date
20260512
Application Date
20260320

Claims (10)

  1. 1. The submerged arc welding flux-cored wire for the high-cobalt martensitic stainless steel is characterized by comprising 50-80% of wire outer skin and 20-50% of flux core by mass percent; The flux core comprises, by mass, 0.2-0.5% of graphite, JCr 99-A1.2-3.0% of cobalt powder 16.4-41.0%, metallic nickel 6.4-16%, feMo 55-A10.9-27.3%, tungsten powder 0.32-0.8%, feV 75-A0.06-0.16%, FNB-3:0.02-0.05%, FTD1 or FTD2 0.1-0.25%, high aluminum 1.2-3.0%, feB22C 0.1.04-0.1%, metallic titanium 0.01-0.03%, caF 2 0.4-1.0% and rutile 0.25-0.63%, and the balance of atomized iron powder.
  2. 2. The high cobalt martensitic stainless steel submerged arc welding flux-cored wire of claim 1, wherein the wire sheath is a stainless steel strip.
  3. 3. The high cobalt martensitic stainless steel submerged arc welding flux-cored wire of claim 1, wherein the particle size of each component of the flux-cored wire is 80-150 mesh.
  4. 4. The high-cobalt martensitic stainless steel submerged arc welding flux-cored wire of claim 1, wherein the flux-cored wire has an O-shaped or E-shaped cross section and a wire diameter of 2.5-4.0 mm.
  5. 5. The method for preparing the high-cobalt martensitic stainless steel submerged arc welding flux-cored wire, which is characterized by comprising the following steps: (1) The raw materials of the medicine core are mixed according to the formula amount to obtain a mixture; (2) Rolling the pretreated welding wire outer skin into a U shape, filling the mixture into the U-shaped welding wire outer skin, and rolling into a shape.
  6. 6. A BD roller, characterized in that a working layer is welded on the surface of the roller, and the working layer is obtained by overlaying the submerged arc flux-cored wire of any one of claims 1 to 4.
  7. 7. The method for manufacturing a BD roll according to claim 6, comprising the steps of: (1) The pretreatment, namely arranging a build-up welding forming space at the steel passing position of the roll surface of the roller, wherein the effective thickness of all steel passing surfaces is 7-15 mm; (2) Preheating before overlaying, namely preheating after flaw detection of the roller treated in the step (1), wherein the flaw detection is coloring flaw detection and/or ultrasonic flaw detection; (3) Hoisting the preheated roller to a special machine for surfacing, installing the roller body in a special heat-preserving cover, respectively assembling the two ends of the roller with a headstock and a tailstock, then carrying out submerged arc automatic surfacing to form a surfacing layer, and reserving turning allowance to obtain the surfacing layer; (4) And performing post-weld heat treatment, namely performing post-weld heat treatment on the roller subjected to the post-weld treatment for ensuring the plasticity and toughness of weld metal, and performing subsequent turning to obtain the BD roller.
  8. 8. The BD roll manufacturing method of claim 7, wherein in step (3), the submerged arc automatic overlaying parameters include: The polarity of the power supply is that the direct current is reversely connected; 300-450A of welding current; The welding voltage is 28-32V; the welding speed is 300-450 mm/min; dry elongation of 20-30 mm; the eccentricity is 25-40 mm; the overlap joint amount is 55-60%, and adjacent welding beads overlap joint; The interlayer temperature is 320-360 ℃.
  9. 9. The BD roll manufacturing method according to claim 7, wherein in the step (4), the heat treatment specifically comprises the steps of heating to 440-460 ℃ at a heating rate of less than or equal to 60 ℃ per hour, then keeping the temperature for 3-5 hours, heating to 560 ℃ at a heating rate of less than or equal to 40 ℃ per hour, then keeping the temperature for 5-7 hours, heating to 595-600 ℃ at a heating rate of less than or equal to 20 ℃ per hour, then keeping the temperature for a period of time equal to the maximum roll diameter divided by 100, the unit of the obtained heat-preserving time is in millimeters, and after the heat preservation is finished, cooling to 500 ℃ at a cooling rate of less than or equal to 20 ℃ per hour, discharging the furnace, and cooling to room temperature for turning.
  10. 10. The BD roll manufacturing method of claim 7, wherein in step (4), the hardness of the BD roll after manufacturing is 50-53 HRC.

Description

High-cobalt martensitic stainless steel submerged-arc welding flux-cored wire and BD roller and preparation method thereof Technical Field The invention relates to the technical field of welding materials and surfacing, in particular to a high-cobalt martensitic stainless steel submerged arc welding flux-cored wire and a BD roller and a preparation method thereof. Background When rolling various steel rails, H-shaped steel, I-shaped steel, B-shaped steel and other sectional materials, the steel mill is provided with two blooming rolling mills, namely a BD1 rolling mill and a BD2 rolling mill, which are two-roller reversible housing rolling mills, the rolling tools correspondingly used are BD1 rollers (60 CrMnMo forged steel or 60CrNiMo cast steel) and BD2 rollers (alloy cast iron), and 3-6 grooved channels are formed in the roller surfaces so as to meet the rolling requirements of different products, wherein the quality requirements of hundred-meter heavy rails are the strictest. The blanks of the products before rolling are continuous casting billets, the billets are heated to about 1150 ℃ and are qualified after being discharged from the furnace for rolling, a large amount of water is used for cooling, and the working conditions are very harsh. Under normal conditions, a set of BD new rollers can be started from the maximum size to the minimum size (namely the scrapped size) for 6-7 times, and the BD new rollers are started according to the hole-shaped size after the BD new rollers are started every time, so that the workload for preparing the BD new rollers is extremely large, and the BD new rollers occupy extremely large funds and cost. During rolling, the blank is firstly processed through each hole pattern of the BD1 roller in sequence to form a blank of the product, and then the blank is processed again through each hole pattern of the BD2 roller in sequence to form a blank of the rolled product for subsequent procedures. Therefore, in the process of changing the blank into the product 'embryonic' profile, the rolling condition of the BD2 roller is more severe than that of the BD1 roller, firstly, the hole type is more complex, the deformation amount is larger, the asymmetry of the hole type is stronger, secondly, the temperature of the rolled piece is reduced, the rolling force is larger, the failure is scrapped faster, and more consumption is caused, thirdly, the length of the rolled piece passing through the BD2 roller is longer than that of the rolled piece passing through the BD1 roller, and the steel passing time of each hole of the BD2 roller is longer when rolling, namely the continuous rolling force and the high-temperature acting time are longer. The failure mode of the BD roller is mainly characterized by the problems of steel sticking, cracking of the roller surface, serious uneven abrasion, easy generation of myoma with different sizes and shapes at the steel passing part due to plastic deformation, and the like, and people can repair and grind when the rolling quality requirement is not met in one rolling period, and the machine can be started when the labor cannot repair and grind. It is for these reasons that the single pass of the rolls has low rolling capacity, frequent roll replacement, high roll consumption and high cost per ton of steel. In order to prolong the service life or rolling quantity of the roller, and with the progress of materials, equipment, technology and other technologies, the prior unit in China carries out submerged arc surfacing on the BD1 roller by using medium and high carbon high alloy steel with Cr5 percent or martensitic steel with Cr5 percent to obtain satisfactory effects, on the BD1 roller for rolling 38kg/m, 60kg/m and 75kg/m hundred meter heavy rails, the rolling quantity of the surfacing roller (called surfacing roller hereinafter) on a single machine is 3 times or more than that of the original roller, and the technology has the advantages of greatly reducing the cost of ton steel, high comprehensive cost performance and the like. In order to solve the problem that the BD2 alloy cast iron roller cannot be subjected to overlaying repair, the material of the BD2 roller is changed into the same material as that of the BD1 roller, the BD2 roller is subjected to overlaying reinforcement according to the scheme, and the 'sticky steel' of the BD2 roller is more serious than that of the BD1 roller when the BD2 alloy cast iron roller is used. The method has the main problems that the rolling roll is stuck with steel, the surface of a rolled piece is scratched to different degrees once the steel is stuck, the surface of the rolled piece is scratched seriously by a large amount of stuck steel, the surface of the rolled piece still has defects such as 'scab', 'line' and the like after finish rolling after subsequent rolling, the product cannot meet the quality requirement, more waste products are produced, the wear of each hole pattern and each working