CN114535805A - 980DP cold-rolled high-strength steel with yield strength of 700Mpa grade and splicing method - Google Patents

980DP cold-rolled high-strength steel with yield strength of 700Mpa grade and splicing method Download PDF

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CN114535805A
CN114535805A CN202210361265.9A CN202210361265A CN114535805A CN 114535805 A CN114535805 A CN 114535805A CN 202210361265 A CN202210361265 A CN 202210361265A CN 114535805 A CN114535805 A CN 114535805A
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welding
equal
steel
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余灿生
苏冠侨
常智渊
郑之旺
郑昊青
王敏莉
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Pangang Group Panzhihua Iron and Steel Research Institute Co Ltd
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Pangang Group Panzhihua Iron and Steel Research Institute Co Ltd
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
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    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/14—Working by laser beam, e.g. welding, cutting or boring using a fluid stream, e.g. a jet of gas, in conjunction with the laser beam; Nozzles therefor
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
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    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/60—Preliminary treatment
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
    • B23K35/22—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by the composition or nature of the material
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    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
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    • C22C38/00—Ferrous alloys, e.g. steel alloys
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    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
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    • C22C38/28—Ferrous alloys, e.g. steel alloys containing chromium with titanium or zirconium
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    • C22C38/38—Ferrous alloys, e.g. steel alloys containing chromium with more than 1.5% by weight of manganese
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Abstract

The invention discloses 980DP cold-rolled high-strength steel with yield strength of 700Mpa and a splicing method, belonging to the technical field of steel rolling production processes. The 980DP cold-rolled high-strength steel with the yield strength of 700MPa and capable of ensuring stable and efficient production of an acid rolling process and the splicing method are provided. The 980DP cold-rolled high-strength steel is dual-phase steel comprising the following components in parts by weight, wherein the components in parts by weight at least comprise C: 0.06% -0.14%, Si: 0.15 to 0.60%, Mn: 1.50-2.20%, P is less than or equal to 0.015%, S is less than or equal to 0.010%, Als: 0.010-0.080%, N is less than or equal to 0.008%, Cr: 0.30-0.90%, Ti: 0.01 to 0.06 percent, Nb: 0.01% -0.050%, Mo: 0.10 to 0.50 percent of the total weight of the alloy, less than or equal to 0.005 percent of B, and the balance of Fe and inevitable impurities. The splicing method comprises the steps of taking a plurality of cold-rolled high-strength steel coils with mutually adaptive widths and thicknesses as splicing objects, trimming the ends of the cold-rolled high-strength steel coils to be spliced, and connecting the cold-rolled high-strength steel coils in a pairwise opposite mode along the length direction into an integrated ultra-long continuous steel belt in a laser welding mode.

Description

980DP cold-rolled high-strength steel with yield strength of 700Mpa grade and splicing method
Technical Field
The invention relates to 980DP cold-rolled high-strength steel, in particular to 980DP cold-rolled high-strength steel with yield strength of 700MPa, and belongs to the technical field of steel rolling production processes. The invention also relates to a splicing method for the 980DP cold-rolled high-strength steel acid rolling process.
Background
The welding equipment is used for welding the front steel coil and the rear steel coil to realize continuous production of iron and steel enterprises, and the method is an important technological means for improving the production efficiency and reducing the production cost. Is widely applied to an acid rolling combined unit, a continuous annealing/galvanizing unit and the like to realize continuous and efficient production. Laser welding is a method of welding by the heat generated by a focused laser beam as an energy source to bombard a weldment. Because the laser has optical properties of refraction, focusing and the like, the laser welding has the characteristics of low heat input, small welding deformation, no electromagnetic field influence and the like, and is widely applied to welding raw materials of the acid rolling combined unit. Because 780MPa grade continuous annealing high-forming dual-phase steel has high alloy content, and has stronger hardenability and hardenability, the weldability is poorer, the strip breakage accident along the welding line is easy to occur in the acid washing and cold rolling processes, the continuous production is not facilitated, the production efficiency and the production safety are seriously influenced, the detailed research on the production rhythm, transition materials, welding key processes and the like is required, so that good welding quality is obtained, and the continuous and efficient production is promoted. Through the inquiry of relevant patents, the similar patents of the acid rolling process and other processes are realized by using a laser welder as follows:
CN 112025081A discloses a method for welding QP980 and above ultra-high strength steel by a laser welding machine, which comprises the following steps: 1) adjusting the working process of the laser welding machine, namely adjusting the inlet section, the outlet section and the middle section; 2) adjusting the position of a protective gas nozzle; 3) adjusting the transverse blowing air pressure; 4) selecting a transition material; 5) cooling by a water cooling device; 6) optimizing welding parameters; 7) monitoring the quality of the welding seam in real time by adopting a QCDS welding seam detection system; 8) optimizing a preheating and annealing device; 9) equipment maintenance before production and welding realizes the production of QP980 with carbon equivalent of more than 0.575% and poor weldability. But introduces production rhythm, transition material selection basis, raw material requirements, strip head/tail treatment, gas protection, weld joint quality evaluation and the like, is not beneficial to guidance of the whole welding process, and is not beneficial to popularization of producing cold rolling 980DP with yield strength exceeding 700MPa by the same type of equipment at home and abroad.
CN104842056A discloses a weld joint plasticizing device and process for an ultrahigh-strength dual-phase steel laser tailor-welded blank, wherein the weld joint of the ultrahigh-strength dual-phase steel tailor-welded blank is arranged between a heat conduction material and a cooling plate, so that the flatness of a welded plate is ensured, and meanwhile, an electromagnetic chuck is adopted for accurately positioning to assemble the material; switching on a high-frequency heating coil to adjust the output power, ensuring the output temperature to be 800-850 ℃, keeping the temperature for 3-5 min, and austenitizing the welded seam tissue; rapidly cooling the welding line of the ultrahigh-strength dual-phase steel tailor-welded blank by adopting a cooling plate filled with cooling liquid; adjusting the output power of the high-frequency heating coil, ensuring the output temperature to be 250-300 ℃, and preserving the heat for 5-30 s; reducing the flow rate of the cooling liquid, improving the output power of the high-frequency heating coil, ensuring the output temperature to be 300-380 ℃, keeping the temperature for 10-90 s, and performing a local distribution process on the welding seams; reducing the output power of the high-frequency heating coil to zero; and (3) rapidly cooling the welding line of the ultrahigh-strength dual-phase steel tailor-welded blank to room temperature by adopting the cooling plate filled with cooling liquid. The average size of the obtained weld grains is 1.5-4.0 mu m, the cupping value of the dual-phase steel tailor-welded blank with the ultra-high strength steel is 7.3-9.9 mm, and the cupping value of the tailor-welded blank is improved by 43%. The production rhythm, the selection basis of transition materials, the requirements of raw materials, the treatment of the head/tail of the strip, the key welding process parameters (welding wires, laser power, welding speed, wire feeding process and the like) and the like are not detailed, and the equipment is specially modified, so that the equipment is not beneficial to finishing the welding of the raw materials of the cold-rolled 980DP acid-rolled process welding method with the acid-rolled yield strength of more than 700MPa by using a conventional machine set.
CN 113118630A discloses a method for preparing a laser tailor-welded blank with different thicknesses, which comprises the steps of purifying two DP steel plates with different thicknesses (the thickness difference is less than or equal to 0.5mm, the C content difference is less than or equal to 0.03%, and the Mn content difference is less than or equal to 0.4%), cooling, air-drying and placing on a welding workbench. The horizontal gap of the DP steel plate is 0mm, the gap in the vertical direction is 0.05-0.08 mm, and the defocusing amount is 0.2-1.0 mm in the welding process; the laser power is 3.7-4.2 kW; the welding speed is 5.0-8.0 m/min; the laser offset is 0.4-0.7 mm, a protective gas side blowing device is adopted to blow gas, and the distance between a gas blowing port and a welding line is 20-28 mm; and a 30-60-degree protective gas between the blowing opening of the blowing measuring device and the DP steel plate to be welded is argon, the gas flow is 900-1000L/H, and the 590DP and 780DP finished products are welded. The welding method provides guidance for welding the cold-rolled 980DP acid-rolled raw materials of the welding method in the cold-rolled 980DP acid-rolling process with yield strength exceeding 700MPa, and provides basis for selecting a production rhythm and a transition material for welding a finished product.
Disclosure of Invention
The technical problem to be solved by the invention is as follows: the invention provides 980DP cold-rolled high-strength steel with yield strength of 700Mpa grade, which can ensure stable and efficient production of an acid rolling process, and the invention also provides a splicing method for the acid rolling process of the 980DP cold-rolled high-strength steel.
The technical scheme adopted for solving the technical problems is as follows: the 980DP cold-rolled high-strength steel with the yield strength of 700Mpa is dual-phase steel comprising the following components in parts by weight,
the components in parts by weight at least comprise C: 0.06% -0.14%, Si: 0.15 to 0.60%, Mn: 1.50-2.20%, P is less than or equal to 0.015%, S is less than or equal to 0.010%, Als: 0.010-0.080%, N is less than or equal to 0.008%, Cr: 0.30-0.90%, Ti: 0.01 to 0.06 percent, Nb: 0.01% -0.050%, Mo: 0.10 to 0.50 percent of the total weight of the alloy, less than or equal to 0.005 percent of B, and the balance of Fe and inevitable impurities.
Further, the components in parts by weight also comprise Al: 0.025-0.065 percent and less than or equal to 0.004 percent of N; c: 0.07 to 0.13%, Si: 0.25 to 0.55%, Mn: 1.60-2.20%, Cr: 0.53 to 0.65%, Nb: 0.015% -0.040%, Mo: 0.25% -0.45%, B: 0.0008% -0.0020%, Ti: 0.015-0.045%, P is less than or equal to 0.010%, S is less than or equal to 0.005%.
The splicing method for the 980DP cold-rolled high-strength steel acid rolling process is characterized in that a plurality of cold-rolled high-strength steel coils with mutually adaptive widths and thicknesses are used as splicing objects, the ends of the cold-rolled high-strength steel coils to be spliced are trimmed, then the cold-rolled high-strength steel coils are connected into an integral ultra-long continuous steel strip in a laser welding mode in a pairwise opposite mode along the length direction,
wherein the yield strength of the strip steel with higher strength in the two steel coils before and after welding is less than 1.2 times of the yield strength of the strip steel with lower strength,
and before laser welding, modified filler wires are added among welding seams and are melted simultaneously in the welding process to complete the welding work of the splicing seams,
the carbon equivalent of two adjacent cold-rolled high-strength steel coils to be welded is controlled within the range of 0.30-0.90 according to the numerical value calculated by the following formula, wherein the carbon equivalent is Ceq ═ C + Mn/6+ Si/24+ Ni/40+ Cr/5+ Mo/4+ V/14 (%).
In the preferable mode of the scheme, the chemical components of the added modified filler wire are controlled according to the following requirements,
c: 0.02-0.15%, Si: 0.55-1.10%, Mn: 1.35-1.90%, P is less than or equal to 0.030%, S is less than or equal to 0.030%, Cu is less than or equal to 0.50%, Ti + Zr: 0.02-0.30%, Al: 0.10 to 0.50 percent, and the balance of Fe and inevitable impurities,
wherein the modified filler wire has a diameter of no more than 1.2 mm.
Furthermore, double-cutting shears are adopted for trimming the end of each 980DP cold-rolled high-strength steel coil needing to be spliced, in the shearing process, the inclination angle of the shear blade and the steel strip is controlled at not more than 2.3 degrees, the gap between the shear blades is controlled at 0.30-0.65 mm,
the control of the shear blade gap is determined according to the steel strip thickness according to the following requirements, when the steel strip thickness is less than or equal to 2.5mm, the shear blade gap is 0.30mm, and the shear blade gap is increased by 0.05mm when the steel strip thickness is increased by 0.5 mm; the replacement period of the shear blade is less than or equal to 6000t or the shearing frequency is less than or equal to 10000 times, the side clearance of the shear blade is calibrated after the shear blade is replaced every time, the shearing cross section and the longitudinal direction of the strip steel form 90 degrees, and the defects of smooth and straight shearing end face, no burr, layering and the like need to be ensured.
The preferable mode of the proposal is that when the end of each 980DP cold-rolled high-strength steel coil needing to be spliced is trimmed, the trimming length of the end of each steel coil is controlled according to the following requirements,
when the thickness t of the steel strip is less than 2.75mm, the cutting amount is not less than 7.0m, when the thickness t of the steel strip is more than or equal to 2.75mm and less than 4.0mm, the cutting amount is not less than 6.1m, when the thickness t of the steel strip is more than or equal to 4.0mm, the cutting amount is not less than 5.2m, the defects of the head and the tail of the strip can be completely cut, and the welding quality cannot be deteriorated.
Furthermore, when the end of each 980DP cold-rolled high-strength steel coil needing to be spliced is trimmed, the geometric shape of the strip steel is required to be checked, and the specific requirements are that,
the surface flatness of the strip steel is less than or equal to 225um, the camber is less than or equal to 20mm/10m, the convexity of hc-h40 is less than or equal to 125 mu m,
the thickness difference of two adjacent splicing steel belts is less than or equal to 1.3H1, the width difference is less than or equal to 260mm, when the lateral deviation is less than or equal to 120mm during splicing,
wherein H1 is the thickness of the thinner steel strip, and the unit is mm; hc is the thickness of the middle part of the strip steel, and the unit is mum; the thickness of the h40 steel strip at a distance of 40mm from the edge is measured in mum.
The preferable mode of the proposal is that the laser welding is gas shielded laser welding, the gas shielded laser welding at least comprises a plurality of welding parameters of laser power, welding speed and wire feeding speed, each parameter is respectively controlled according to the following requirements,
the laser power is controlled to be 12 +/-0.8 KW, the welding speed is controlled to be 1.9-4.2 +/-0.3 m/min according to the thickness of a steel strip, the wire feeding speed is controlled to be 2.1-4.2 m/min according to the thickness of the steel strip, a rolling wheel is used for cleaning a welding seam after welding is finished, the pressure of the rolling wheel is less than or equal to 60KN, the height of the rolling wheel is 0-7.5 mm,
wherein when the thickness of the steel strip is less than or equal to 2.5mm, the welding speed is controlled to be 4.2 +/-0.3 m/min, the welding speed is reduced by 0.3m/min when the thickness is increased by 0.5mm, and the compensation range of the welding speed is 0-15%; when the thickness of the steel strip is less than or equal to 2.5mm, the wire feeding speed is 2.1 +/-0.3 m/min, the speed is increased by 0.3m/min when the thickness is increased by 0.5mm, the compensation range of the wire feeding speed is 0-15%,
the protective gas of the gas-shielded laser welding is He accounting for 45-51 NL/h + N2Mixed gas accounting for 8.0-12.0 NL/h and CO accounting for 1.8-2.3 NL/h, wherein the dew point of the mixed gas is less than or equal to minus 50 ℃, the pressure value is 0.4-0.7 MPa, the temperature is 5-50 ℃,
the auxiliary gas during welding is He, the pressure value is 0.4-0.7 MPa, the flow rate is 90-160 NL/min, and the temperature is 5-50 ℃.
Further, after welding is finished, the welding line needs to be subjected to heat treatment through thermal circulation in real time, in the specific process, the heat treatment power is 40kW, the frequency is 30kHz, the current compensation amount of the welding line heat treatment is 0-15%, the heating speed is less than or equal to 20 ℃/s in the heating process of the welding line heat treatment, and the welding line is cooled to below 300 ℃ at the cooling speed of less than or equal to 15 ℃/s during cooling.
Furthermore, the welded seam is required to be subjected to quality control according to the following requirements,
the thickness t1 of the welding seam is 1.02-1.15 times of the thickness of the original steel strip;
performing a cupping test on the weld seam sampling, wherein the number of sampling points is at least 3, the left point and the right point are taken within a range of 100-200 mm from the edge, the 3 rd point is the middle part of the strip steel, the hole diameter of the punched hole is 15mm, and the punched hole is 100mm away from the weld seam;
the cupping test requirement is that if the gap is in the heat affected zone and the gap is perpendicular to the direction of the welding seam, the welding seam is judged to be qualified; if the split is coincident with the weld, the weld quality is judged to be unqualified, and if two welds are not allowed in one large coil, the weld quality is judged to be unqualified,
if the welding is a width jump type splicing welding seam, a crescent punching bending experiment is required, and the specific requirements are that,
1) punching at the welding seam, wherein the punching amount is 30mm relative to the width of the narrow strip steel,
2) in the case of narrow and wide, punching was performed twice at a position deviated from the weld to the inlet side by 240mm and at the weld,
3) in the case of narrowing the width, punching was performed twice at a position deviated from the weld toward the outlet by 240mm and at the weld,
after the test, the transition of the width jump steel coil can be carried out without problems.
The invention has the beneficial effects that: the technical scheme provided by the application is that components of 980DP cold-rolled high-strength steel are as follows: 0.06% -0.14%, Si: 0.15 to 0.60%, Mn: 1.50-2.20%, P is less than or equal to 0.015%, S is less than or equal to 0.010%, Als: 0.010-0.080%, N is not more than 0.008%, Cr: 0.30-0.90%, Ti: 0.01 to 0.06 percent, Nb: 0.01% -0.050%, Mo: 0.10 to 0.50 percent of steel, less than or equal to 0.005 percent of B, and the balance of Fe and inevitable impurities, and splicing the steel coils before acid rolling according to the following method, namely, taking a plurality of cold-rolled high-strength steel coils with mutually adaptive width and thickness as splicing objects, trimming the end of each cold-rolled high-strength steel coil needing to be spliced, then connecting each cold-rolled high-strength steel coil into an integral ultra-long continuous steel strip in a laser welding mode in a pairwise opposite manner along the length direction, wherein the yield strength of the steel strip with higher strength in the two steel coils before and after welding is lower than the yield strength of the steel strip with lower strength, adding a modified filler wire between welding seams before laser welding, melting the modified filler wire simultaneously in the welding process to complete the welding work of the splicing seams, controlling the carbon equivalent of the two adjacent welded cold-rolled high-strength steel coils within the range of 0.30 to 0.90 according to the numerical value calculated by the following formula, the carbon equivalent calculation formula is Ceq ═ C + Mn/6+ Si/24+ Ni/40+ Cr/5+ Mo/4+ V/14 (%). Therefore, the technical problems of instability and low production efficiency in the production process in the prior art are effectively solved, and the purpose of ensuring stable and efficient production of the 980DP cold-rolled high-strength steel acid rolling process is achieved.
Detailed Description
In order to solve the technical problems in the prior art, the invention provides 980DP cold-rolled high-strength steel with yield strength of 700MPa, which can ensure stable and efficient production of an acid rolling process, and a splicing method for the acid rolling process of the 980DP cold-rolled high-strength steel. The 980DP cold-rolled high-strength steel is dual-phase steel comprising the following components in parts by weight,
the components in parts by weight at least comprise C: 0.06% -0.14%, Si: 0.15 to 0.60%, Mn: 1.50-2.20%, P is less than or equal to 0.015%, S is less than or equal to 0.010%, Als: 0.010-0.080%, N is less than or equal to 0.008%, Cr: 0.30-0.90%, Ti: 0.01% -0.06%, Nb: 0.01% -0.050%, Mo: 0.10 to 0.50 percent of the total weight of the alloy, less than or equal to 0.005 percent of B, and the balance of Fe and inevitable impurities. The splicing method takes a plurality of cold-rolled high-strength steel coils with mutually adaptive width and thickness as splicing objects, firstly trimming the end of each cold-rolled high-strength steel coil to be spliced, then all the cold-rolled high-strength steel coils are oppositely connected into an integrated ultra-long continuous steel strip in pairs along the length direction by adopting a laser welding mode, wherein the yield strength of the strip steel with higher strength in the two steel coils before and after welding is less than 1.2 times of the yield strength of the strip steel with lower strength, and before laser welding, a modified filler wire is added between welding seams and is melted simultaneously in the welding process to complete the welding work of splicing seams, the carbon equivalent of two adjacent welded cold-rolled high-strength steel coils is controlled within the range of 0.30-0.90 according to the numerical value calculated by the following formula, the carbon equivalent calculation formula is Ceq ═ C + Mn/6+ Si/24+ Ni/40+ Cr/5+ Mo/4+ V/14 (%). By adopting the technical scheme provided by the application, the technical problems of instability and low production efficiency in the production process in the prior art are effectively solved, and the purpose of stable and efficient production of 980DP cold-rolled high-strength steel acid rolling process can be ensured.
In the above embodiment, the components in parts by weight described herein further include, as required: 0.025-0.065 percent and less than or equal to 0.004 percent of N; accordingly, C: 0.07 to 0.13%, Si: 0.25 to 0.55%, Mn: 1.60-2.20%, Cr: 0.53 to 0.65%, Nb: 0.015% -0.040%, Mo: 0.25% -0.45%, B: 0.0008% -0.0020%, Ti: 0.015-0.045%, P less than or equal to 0.010% and S less than or equal to 0.005%. Correspondingly, the chemical components of the modified filler wire added in the application are controlled according to the following requirements, C: 0.02-0.15%, Si: 0.55-1.10%, Mn: 1.35-1.90%, P is less than or equal to 0.030%, S is less than or equal to 0.030%, Cu is less than or equal to 0.50%, Ti + Zr: 0.02-0.30%, Al: 0.10-0.50%, and the balance of Fe and inevitable impurities, wherein the diameter of the modified filler wire is not more than 1.2 mm. When the end of each 980DP cold-rolled high-strength steel coil needing to be spliced is trimmed, in order to ensure the trimming quality and guarantee the subsequent welding, double-cutting shears are adopted for trimming, in the shearing process, the inclination angle of a shear blade and the steel strip is controlled according to 2.3 degrees or less, the gap between the shear blade is controlled according to 0.30-0.65 mm, the control of the gap between the shear blade is determined according to the following requirements on the thickness of the steel strip, when the thickness of the steel strip is less than or equal to 2.5mm, the gap between the shear blade is 0.30mm, and when the thickness of the steel strip is increased by 0.5mm, the gap between the shear blade is increased by 0.05 mm; the replacement period of the shear blade is less than or equal to 6000t or the shearing frequency is less than or equal to 10000 times, the side clearance of the shear blade is calibrated after the shear blade is replaced every time, the shearing cross section and the longitudinal direction of the strip steel form 90 degrees, and the defects of smooth and straight shearing end face, no burr, layering and the like need to be ensured. Correspondingly, in order to ensure stable and efficient production of subsequent acid rolling engineering, when the end required to be spliced of each 980DP cold-rolled high-strength steel coil is trimmed, the trimming length of the end of each steel coil is controlled according to the following requirement, the cutting amount is not less than 7.0m when the thickness t of the steel strip is less than 2.75mm, the cutting amount is not less than 6.1m when the thickness t of the steel strip is not less than 2.75mm and less than 4.0mm, and the cutting amount is not less than 5.2m when the thickness t of the steel strip is not less than 4.0mm, so that the defects of the head and the tail of the strip can be completely cut, and the welding quality cannot be deteriorated. When the end of each 980DP cold-rolled high-strength steel coil needing to be spliced is trimmed, the geometric shape of the strip steel is also required to be checked, the specific requirements are that the surface flatness of the strip steel is less than or equal to 225um, the camber is less than or equal to 20mm/10m, the convexity of hc-H40 is less than or equal to 125 um, the thickness difference of two adjacent spliced steel strips is less than or equal to 1.3H1, the width difference is less than or equal to 260mm, and when the lateral deviation is not more than 120mm during splicing, wherein H1 is the thickness of a thinner steel strip, and the unit is mm; hc is the thickness of the middle part of the strip steel, and the unit is mum; the thickness of the h40 steel strip at a distance of 40mm from the edge is measured in mum.
Further, the laser welding is gas shielded laser welding, the gas shielded laser welding at least comprises a plurality of welding parameters including laser power, welding speed and wire feeding speed, each parameter is controlled according to the following requirements, the laser power is controlled to be 12 +/-0.8 KW, the welding speed is controlled to be 1.9-4.2 +/-0.3 m/min according to the thickness of a steel strip, the wire feeding speed is controlled to be 2.1-4.2 m/min according to the thickness of the steel strip, a rolling wheel is applied to clean the weld after the welding is finished, the pressure of the rolling wheel is less than or equal to 60KN, the height of the rolling wheel is 0-7.5 mm, when the thickness of the steel strip is less than or equal to 2.5mm, the welding speed is controlled to be 4.2 +/-0.3 m/min, the speed is reduced by 0.3m/min when the thickness is increased by 0.5mm, and the compensation range of the welding speed is 0-15%; when the thickness of the steel strip is less than or equal to 2.5mm, the wire feeding speed is 2.1 +/-0.3 m/min, the speed is increased by 0.3m/min when the thickness is increased by 0.5mm, the compensation range of the wire feeding speed is 0-15%, and the protective gas of gas shielded laser welding is He accounting for 45-51 NL/h + N2The mixed gas accounts for 8.0-12.0 NL/h + CO accounts for 1.8-2.3 NL/h, the dew point of the mixed gas is less than or equal to minus 50 ℃, the pressure value is 0.4-0.7 MPa, the temperature is 5-50 ℃, the auxiliary gas in welding is He, the pressure value is 0.4-0.7 MPa, the flow rate is 90-160 NL/min, and the temperature is 5-50 ℃.
Meanwhile, after welding is finished, the welding seam needs to be subjected to heat treatment through thermal circulation in real time, in the specific process, the heat treatment power is 40kW, the frequency is 30kHz, the current compensation amount of the welding seam heat treatment is 0-15%, the heating speed is less than or equal to 20 ℃/s in the heating process of the welding seam heat treatment, and the welding seam is cooled to below 300 ℃ at the cooling speed of less than or equal to 15 ℃/s during cooling. Correspondingly, the quality of the welded seam needs to be controlled according to the following requirements, and the thickness t1 of the welded seam is 1.02-1.15 times of the thickness of the original steel strip. The specific requirements or the process of each test are that the cupping test is carried out on the welding seam sampling, the number of sampling points is at least 3, the left point and the right point are taken within a range of 100-200 mm from the edge, the 3 rd point is the middle part of the strip steel, the hole diameter of a punched hole is 15mm, and the distance between the punched hole and the welding seam is 100 mm;
the cupping test requirement is that if the gap is in the heat affected zone and the gap is perpendicular to the direction of the welding seam, the welding seam is judged to be qualified; if the split is coincident with the weld, the weld quality is judged to be unqualified, and if two welds are not allowed in one large coil, the weld quality is judged to be unqualified,
if the welding is a width jump type splicing welding seam, a crescent punching bending experiment is required, and the specific requirements are that,
1) punching at the welding seam, wherein the punching amount is 30mm relative to the width of the narrow strip steel,
2) in the case of narrow and wide, punching was performed twice at a position deviated from the weld to the inlet side by 240mm and at the weld,
3) in the case of narrowing the width, punching was performed twice at a position deviated from the weld toward the outlet by 240mm and at the weld,
after the test, the transition of the width jump steel coil can be carried out without problems.
In summary, the above technical solutions provided by the present application also have the following advantages,
the method has the advantages that the smooth and crack-free surface is obtained through regulating and controlling the material quality (temperature, straightness, camber and convexity), thickness/width transition, good surface quality, shearing process and quality and key welding process (welding wire components, laser power, welding speed, wire feeding speed and welding seam heat treatment energy), the defects of inclusion, incomplete penetration, misalignment and the like do not exist in a welding seam area, and the good-quality welding seam is confirmed after the detection of the welding seam thickness and the cup convexity test, so that the stable and efficient production of an acid rolling procedure is ensured, and the method provides guidance for producing the dual-phase steel by internal and external similar units.
DETAILED DESCRIPTION OF EMBODIMENT (S) OF INVENTION
1) The invention aims to provide a cold-rolled 980DP acid-rolled welding method with yield strength exceeding 700MPa, which is characterized in that good weld joint quality is obtained by regulating and controlling the material quality (temperature, straightness, camber and convexity), thickness/width transition, good surface quality, shearing process and quality and key welding process (welding wire selection, laser power, welding speed, wire feeding speed and weld joint heat treatment energy) of a connecting material, so that stable and efficient production of an acid-rolled procedure is ensured, and guidance is provided for producing dual-phase steel by using similar machines at home and abroad.
2) The technical scheme of the invention is as follows: a cold rolling 980DP acid rolling process welding method with yield strength exceeding 700MPa comprises the following chemical component ranges: c: 0.06% -0.14%, Si: 0.15 to 0.60%, Mn: 1.50-2.20%, P is less than or equal to 0.015%, S is less than or equal to 0.010%, Als: 0.010-0.080%, N is less than or equal to 0.008%, Cr: 0.30-0.90%, Ti: 0.01 to 0.06 percent, Nb: 0.01% -0.050%, Mo: 0.10 to 0.50 percent of the total weight of the alloy, less than or equal to 0.005 percent of B and the balance of Fe and inevitable impurities.
3) In the preferred cold-rolled 980DP acid rolling process welding method with yield strength of over 700MPa, the chemical components are as follows by weight percent: c: 0.07 to 0.13%, Si: 0.25 to 0.55%, Mn: 1.60-2.20%, Cr: 0.53 to 0.65%, Nb: 0.015% -0.040%, Mo: 0.25% -0.45%, B: 0.0008% -0.0020%, Ti: 0.015% -0.045%, Al: 0.025-0.065%, P is less than or equal to 0.010%, S is less than or equal to 0.005%, N is less than or equal to 0.004%, and the balance of Fe and unavoidable impurities.
4) Wherein, the carbon content of the selected connecting material of the cold rolling 980DP acid rolling process welding method with the yield strength exceeding 700MPa is controlled within a certain range (the carbon equivalent formula is as follows: ceq is C + Mn/6+ Si/24+ Ni/40+ Cr/5+ Mo/4+ V/14 (%)), and the yield strength of the strip steel with higher strength in the two steel coils before and after welding needs to be ensured to be less than 1.2 times of the yield strength of the softer strip steel; the raw materials can be welded after being cooled to less than or equal to 60 ℃. The surface of the hot rolling raw material is required to be a hot rolling iron scale which is normal to eyes, has no out-of-standard defect and can not have accumulated water, and simultaneously requires good plate shape. The thickness range of the hot rolling raw material for welding is 2.2-6.0 mm, and the width range is 850-1500 mm.
5) According to the procedure 4), the carbon equivalent of the connecting material is within the range of 0.30-0.90, the surface flatness of the strip steel is less than or equal to 225umit, the camber is less than or equal to 20mm/10m, and the convexity (hc-h40) is less than or equal to 125 mu m. The welder of claim 4, wherein the jump range of the thickness of the welder is less than or equal to 1.3H1(H1 is the thickness of thin steel strip in mm), and the jump of the width is less than or equal to 260mm (each side is less than or equal to 130 mm).
6) The inclination angle of the cutting edge and the steel strip is 2 degrees, the tail part of the previous steel strip and the tail part of the next steel strip need to be cut by double cutting to remove a certain length before welding to ensure the strip shape and the welding quality can be ensured, wherein when the thickness t of the raw material is less than 2.75mm, the cutting amount is 7.0mm, when the thickness t of the raw material is less than or equal to 2.75mm and less than 4.0mm, the cutting amount is 6.1mm, when the thickness is more than or equal to 4.0mm, the cutting amount is 5.2m, and an operator needs to set the cutting length according to the actual situation of the supplied materials to ensure that the defects of the head and the tail of the strip can be completely cut without deteriorating the welding quality.
7) According to the sequence 6), the range of the shear blade gap is 0.30-0.65 mm, the shear blade gap is 0.30mm when the thickness of the raw material is less than or equal to 2.5mm, and the shear blade gap is increased by 0.05mm when the thickness of the raw material is increased by 0.5 mm. The shearing edge period is required to be less than or equal to 6000t or the shearing frequency is required to be less than or equal to 10000 times, the side clearance of the shearing edge is calibrated after the shearing edge is replaced every time, the shearing cross section and the longitudinal direction of the strip steel form 90 degrees, and the defects of smooth and straight shearing end face, no burr, layering and the like need to be ensured.
8) The strip weld faces should be aligned and in a horizontal plane. The welding spot focused by the laser beam to be proper can be determined by adopting a focusing position (the height adjusting range is 0-9.0mm, the Z-axis control precision is +/-0.05 mm) or a spot position (the adjusting range is +/-1.5 mm, and the X-axis control precision is +/-0.05 mm).
9) Because the yield strength exceeds 700MPa, the welding performance is poor due to the fact that the alloy content is high in the cold rolling 980DP acid rolling process welding method, welding wires need to be added to weld for assisting welding, and the diameter of the welding wires is 0.9 mm; the material quality of the welding wire is determined to be YGW13 (the chemical compositions are C: 0.02-0.15%, Si: 0.55-1.10%, Mn: 1.35-1.90%, P < 0.030%, S < 0.030%, Cu < 0.50%, Ti + Zr: 0.02-0.30%, Al: 0.10-0.50%) by referring to the JIS Z3312 standard, not only can fill the part of the welding line lower than the strip steel, improve the performance of the special steel welding line area, but also can eliminate the blank area between the gaps.
10) The welding key process parameters including laser power, welding speed, wire feeding speed, welding seam heat treatment power and welding seam heat treatment frequency are respectively as follows: 12 +/-0.8 KW, 1.9-4.2 +/-0.3 m/min (the welding speed is 4.2 +/-0.3 m/min when the thickness of the raw material is less than or equal to 2.5mm, the speed is reduced by 0.3m/min when the thickness is increased by 0.5 mm; the compensation range of the welding speed is 0-15%) and 2.1-4.2 m/min (the welding speed is 2.1 +/-0.3 m/min when the thickness of the raw material is less than or equal to 2.5mm, the speed is increased by 0.3m/min when the thickness is increased by 0.5mm, and the compensation range of the wire feeding speed is 0-15%). After welding, the welding seam needs to be cleaned by a rolling wheel, the pressure of the rolling wheel is less than or equal to 60KN, the height of the rolling wheel is 0-7.5 mm, and the welding seam needs to be subjected to heat treatment to improve the welding seam quality due to the fact that the alloy content of the cold-rolled 980DP acid-rolling process welding method with the cold-rolled yield strength exceeding 700MPa is high.
11) Gas protection is required in the whole process of the welding process, wherein the laser protection gas is He (45-51 NL/h) + N2(8.0-12.0 NL/h) + CO (1.8-2.3 NL/h) (dew point is less than or equal to-50 ℃, pressure is 0.4-0.7 MPa, and temperature is 5-50 ℃); the auxiliary gas during welding is He (pressure 0.4-0.7 MPa, flow 90-160 NL/min, temperature 5-50 ℃).
12) According to the sequence 10), after welding, performing heat treatment on the welding seam through thermal circulation, wherein the power is 40kW, the frequency is 30kHz, the current compensation amount of the welding seam heat treatment is 0-15%, the heating speed is required to be less than or equal to 20 ℃/s in the heating process of the welding seam heat treatment, and the welding seam is cooled to below 300 ℃ at the cooling speed of less than or equal to 15 ℃/s for air cooling.
13) After the welded welding seam is annealed and polished after welding, the surface is required to be smooth and free of cracks, the welding seam area cannot have the defects of inclusion, incomplete penetration, misalignment and the like, and in addition, the welding seam quality needs to be checked through the welding seam thickness and the cup-convex test.
14) According to the sequence 13), the thickness (t1) of the welding seam is 1.02-1.15 times of the thickness of the raw material (t1 is more than or equal to 1.02t and less than or equal to 1.15t, wherein t is the thickness of the raw material); when a weld joint is sampled to perform a cupping test, at least 3 points are tested, the left point and the right point are taken within a range of 100-200 mm from the edge part, the 3 rd point is the middle part of the strip steel, the hole diameter of the punched hole is 15mm, and the distance between the punched hole and the weld joint is 100 mm. If the crack is vertical to the direction of the welding seam in the heat affected zone and the crack is vertical to the direction of the welding seam, the welding seam is judged to be qualified; and if the crack is coincident with the welding seam, determining that the welding seam quality is unqualified. In addition, two welding seams are not allowed in a large roll, and otherwise the roll is judged to be unqualified. Need carry out towards the curved experiment of crescent when carrying out width jump linking, require: (1) punching at the welding seam, wherein the punching amount is 30mm relative to the width of the narrow strip steel; (2) in the case of narrow and wide, punching is performed twice at a position (wide side) deviated from the weld to the entrance side by 240mm and at the weld; (3) in the case of narrowing the width, punching was performed twice at a position (wide side) deviated from the weld toward the exit by 240mm and at the weld. After the test, the transition of the width jump steel coil can be carried out without problems.
Example one
1) After the tail of a cold-rolled 980DP acid-rolled steel coil is sheared by 6.2mm by a cold-rolled 980DP acid-rolled welding method (chemical components of 0.09% C, 0.35% Si, 1.85% Mn, 0.009% P, 0.002% S, 0.043% Als, 0.62% Cr, 0.025% Nb, 0.031% Ti, 0.32% Mo, 0.0015% B, and a carbon equivalent of 0.53) with a steel coil temperature of 45 ℃ and a yield strength of 3.50mm × 1330mm exceeding 700MPa, the cold-rolled 980DP acid-rolled welding method (0.11% C, 0.031% Si, 1.90% Mn, 0.012% P, 0.002% S, 0.046% Als, 0.63% Cr, 0.028% Nb, 0.031% Ti, 0.35% Mo, 0.008% B, 0.015% P, 0.015% S, 0.015% C, 0.04% C/2% S, and a welding wire with a steel coil temperature of 47 ℃ and a yield strength of 3.30mm × 1300mm exceeding 700MPa are blended by a welding wire with a welding speed of a welding wire of a welding speed of 0.04 mm, 0.010% Cu, Ti: 0.035%, 0.18% Al) and welding was performed at a speed of 3.3 m/min. The welding seam welded by the welding process is flat and smooth, has no nodules, craters and welding penetration, has no cracks along the welding seam and good effect of punching crescent in a cup-convex test, and has no strip breakage accident caused by the welding seam in the pickling and cold rolling processes.
2) After a steel coil is sheared at a tail of 5.6mm by a cold-rolled 980DP acid-rolling process (chemical composition of 0.107% C, 0.36% Si, 1.83% Mn, 0.007% P, 0.002% S, 0.052% Als, 0.026% Nb, 0.032% Ti, 0.33% Mo, 0.0016% B, and carbon equivalent of 0.54) with a yield strength of over 700MPa at a steel coil temperature of 40 ℃ and a gauge of 3.30mm × 1270mm, a steel coil head of 780DP (0.11% C, 0.27% Si, 1.76% Mn, 0.011% P, 0.004% S, 0.042% Als, 0.52% Cr, 0.26% Mo, and carbon equivalent of 0.57) at a temperature of 42 ℃ and a gauge of 3.50 × 1315.3 mm is hot-dip galvanized with a steel coil head of 5.3mm at a welding current of 12.3% C, 2.018 min, 0.018% Si, 0.15% P, 0.15% Al, and a wire rate of 10.15% P. The welding seam welded by the welding process is flat and smooth, has no nodules, craters and welding penetration, has no cracks along the welding seam and good effect of punching crescent in a cup-convex test, and has no strip breakage accident caused by the welding seam in the pickling and cold rolling processes.
3) After cutting the tail of a cold-rolled 980DP steel coil 6.2mm by an acid rolling process (chemical components of 0.095% C, 0.37% Si, 1.91% Mn, 0.006% P, 0.002% S, 0.041% Als, 0.0.095% Nb, 0.58% Cr, 0.032% Ti, 0.35% Mo, 0.0012% B, and 0.54 carbon equivalent) having a steel coil temperature of 53 ℃ and a gauge of 3.65mm × 1300mm and a yield strength of more than 700MPa, the tail of the steel coil is cut by a wire cutting method (chemical components of 0.095% C, 0.02% Si, 0.14% Mn, 0.010% P, 0.006% S, 0.044% Als, 0.060% Ti, and 0.014% Cu) by a wire cutting the head of a steel coil having a steel coil temperature of 60 ℃ and a gauge of 4.5mm × Ti 1220mm (chemical components of 0.0030% C, 0.02% Si, 0.14% Mn, 0.010% P, 0.006% S, 0.044% Als, 0.060% Ti, and 0.010% Cu, 0.010% C, 0.015% S, and a wire cutting wire by a wire cutting method using a wire cutting method (wire cutting a wire cutting method) at a wire cutting speed of 60% Cu: 0.025%) and welding was performed at a speed of 5.5 m/min. The welding seam welded by the welding process has poor quality, the cup bulge test has no crack along the welding seam, and the production is carried out after the connecting material is changed.

Claims (10)

1. A980 DP cold-rolled high-strength steel with the yield strength of 700Mpa grade is characterized in that: the 980DP cold-rolled high-strength steel is dual-phase steel comprising the following components in parts by weight,
the components in parts by weight at least comprise C: 0.06% -0.14%, Si: 0.15 to 0.60%, Mn: 1.50-2.20%, P is less than or equal to 0.015%, S is less than or equal to 0.010%, Als: 0.010-0.080%, N is less than or equal to 0.008%, Cr: 0.30-0.90%, Ti: 0.01 to 0.06 percent, Nb: 0.01% -0.050%, Mo: 0.10 to 0.50 percent of the total weight of the alloy, less than or equal to 0.005 percent of B, and the balance of Fe and inevitable impurities.
2. The 980DP cold rolled high strength steel with a yield strength of 700Mpa grade according to claim 1, characterized in that: the components in parts by weight also comprise Al: 0.025-0.065 percent and less than or equal to 0.004 percent of N; c: 0.07 to 0.13%, Si: 0.25 to 0.55%, Mn: 1.60-2.20%, Cr: 0.53 to 0.65%, Nb: 0.015% -0.040%, Mo: 0.25% -0.45%, B: 0.0008% -0.0020%, Ti: 0.015-0.045%, P less than or equal to 0.010% and S less than or equal to 0.005%.
3. The splicing method for the acid rolling process of 980DP cold-rolled high-strength steel of claim 2 is characterized in that: the splicing method takes a plurality of cold-rolled high-strength steel coils with mutually adaptive width and thickness as splicing objects, firstly, the ends of the cold-rolled high-strength steel coils to be spliced are trimmed, then, the cold-rolled high-strength steel coils are connected into an integrated ultra-long continuous steel strip in a laser welding mode in a pairwise opposite manner along the length direction,
wherein the yield strength of the strip steel with higher strength in the two steel coils before and after welding is less than 1.2 times of the yield strength of the strip steel with lower strength,
and before laser welding, modified filler wires are added among welding seams and are melted simultaneously in the welding process to complete the welding work of the splicing seams,
the carbon equivalent of two adjacent cold-rolled high-strength steel coils to be welded is controlled within the range of 0.30-0.90 according to the numerical value calculated by the following formula, wherein the carbon equivalent is Ceq ═ C + Mn/6+ Si/24+ Ni/40+ Cr/5+ Mo/4+ V/14 (%).
4. Splicing method according to claim 3, characterized in that: the chemical components of the added modified filler wire are controlled according to the following requirements,
c: 0.02-0.15%, Si: 0.55-1.10%, Mn: 1.35-1.90%, P is less than or equal to 0.030%, S is less than or equal to 0.030%, Cu is less than or equal to 0.50%, Ti + Zr: 0.02-0.30%, Al: 0.10 to 0.50 percent, and the balance of Fe and inevitable impurities,
wherein the modified filler wire has a diameter of no more than 1.2 mm.
5. Splicing method according to claim 3 or 4, characterized in that: the end of each 980DP cold-rolled high-strength steel coil needing to be spliced is trimmed by adopting double-cutting shears, the inclination angle of a cutting edge and the steel strip is controlled within 2.3 degrees in the shearing process, the gap between the cutting edges is controlled according to 0.30-0.65 mm,
the control of the shear blade gap is determined according to the following requirements on the basis of the thickness of the steel strip, when the thickness of the steel strip is less than or equal to 2.5mm, the shear blade gap is 0.30mm, and the shear blade gap is increased by 0.05mm when the thickness of the steel strip is increased by 0.5 mm; the replacement period of the shear blade is less than or equal to 6000t or the shearing frequency is less than or equal to 10000 times, the side clearance of the shear blade is calibrated after the shear blade is replaced every time, the shearing cross section and the longitudinal direction of the strip steel form 90 degrees, and the defects of smooth and straight shearing end face, no burr, layering and the like need to be ensured.
6. Splicing method according to claim 5, characterized in that: when the end of each 980DP cold-rolled high-strength steel coil needing to be spliced is trimmed, the trimming length of the end of each steel coil is controlled according to the following requirements,
when the thickness t of the steel strip is less than 2.75mm, the cutting amount is not less than 7.0m, when the thickness t of the steel strip is more than or equal to 2.75mm and less than 4.0mm, the cutting amount is not less than 6.1m, when the thickness t of the steel strip is more than or equal to 4.0mm, the cutting amount is not less than 5.2m, the defects of the head and the tail of the strip can be completely cut, and the welding quality cannot be deteriorated.
7. Splicing method according to claim 6, characterized in that: when the end of each 980DP cold-rolled high-strength steel coil needing to be spliced is trimmed, the geometric shape of the strip steel is required to be checked, and the specific requirements are that,
the surface flatness of the strip steel is less than or equal to 225um, the camber is less than or equal to 20mm/10m, the convexity of hc-h40 is less than or equal to 125 mu m,
the thickness difference of two adjacent splicing steel belts is less than or equal to 1.3H1, the width difference is less than or equal to 260mm, when the lateral deviation is less than or equal to 120mm during splicing,
wherein H1 is the thickness of the thinner steel strip, and the unit is mm; hc is the thickness of the middle part of the strip steel, and the unit is mum; the thickness of the h40 steel strip at a distance of 40mm from the edge is measured in mum.
8. Splicing method according to claim 7, characterized in that: the laser welding is gas shielded laser welding which at least comprises a plurality of welding parameters of laser power, welding speed and wire feeding speed, each parameter is respectively controlled according to the following requirements,
the laser power is controlled to be 12 +/-0.8 KW, the welding speed is controlled to be 1.9-4.2 +/-0.3 m/min according to the thickness of a steel strip, the wire feeding speed is controlled to be 2.1-4.2 m/min according to the thickness of the steel strip, a rolling wheel is used for cleaning a welding seam after welding is finished, the pressure of the rolling wheel is less than or equal to 60KN, the height of the rolling wheel is 0-7.5 mm,
wherein when the thickness of the steel strip is less than or equal to 2.5mm, the welding speed is controlled to be 4.2 +/-0.3 m/min, the welding speed is reduced by 0.3m/min when the thickness is increased by 0.5mm, and the compensation range of the welding speed is 0-15%; when the thickness of the steel strip is less than or equal to 2.5mm, the wire feeding speed is 2.1 +/-0.3 m/min, the speed is increased by 0.3m/min when the thickness is increased by 0.5mm, the compensation range of the wire feeding speed is 0-15%,
the protective gas of the gas-shielded laser welding is He accounting for 45-51 NL/h + N2Mixed gas accounting for 8.0-12.0 NL/h and CO accounting for 1.8-2.3 NL/h, wherein the dew point of the mixed gas is less than or equal to minus 50 ℃, the pressure value is 0.4-0.7 MPa, the temperature is 5-50 ℃,
the auxiliary gas during welding is He, the pressure value is 0.4-0.7 MPa, the flow rate is 90-160 NL/min, and the temperature is 5-50 ℃.
9. Splicing method according to claim 8, characterized in that: after welding, the welding seam needs to be subjected to heat treatment through thermal circulation in real time, in the specific process, the heat treatment power is 40kW, the frequency is 30kHz, the current compensation amount of the welding seam heat treatment is 0-15%, the heating speed is less than or equal to 20 ℃/s in the heating process of the welding seam heat treatment, and the welding seam is cooled to below 300 ℃ at the cooling speed of less than or equal to 15 ℃/s during cooling.
10. Splicing method according to claim 8, characterized in that: the welded seam is required to be subjected to quality control according to the following requirements,
the thickness t1 of the welding seam is 1.02-1.15 times of the thickness of the original steel strip;
performing a cupping test on the weld seam sampling, wherein the number of sampling points is at least 3, the left point and the right point are taken within a range of 100-200 mm from the edge, the 3 rd point is the middle part of the strip steel, the hole diameter of the punched hole is 15mm, and the punched hole is 100mm away from the weld seam;
the cupping test requirement is that if the gap is in the heat affected zone and the gap is perpendicular to the direction of the welding seam, the welding seam is judged to be qualified; if the split is coincident with the weld, the weld quality is judged to be unqualified, and if two welds are not allowed in one large coil, the weld quality is judged to be unqualified,
if the welding is a width jump type splicing welding seam, a crescent punching bending experiment is required, and the specific requirements are that,
1) punching at the welding seam, wherein the punching amount is 30mm relative to the width of the narrow strip steel,
2) in the case of narrow and wide, punching was performed twice at a position deviated from the weld to the inlet side by 240mm and at the weld,
3) in the case of narrowing the width, punching was performed twice at a position deviated from the weld toward the outlet by 240mm and at the weld,
after the test, the transition of the width jump steel coil can be carried out without problems.
CN202210361265.9A 2022-04-07 2022-04-07 980DP cold-rolled high-strength steel with yield strength of 700Mpa grade and splicing method Pending CN114535805A (en)

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Publication number Priority date Publication date Assignee Title
DE10124345A1 (en) * 2001-05-18 2002-11-21 Linde Ag Laser welding comprises using a protective gas containing molecular gases as well as argon and/or helium or molecular gases mixed with the protective gases
CN105132818A (en) * 2015-09-30 2015-12-09 河南理工大学 Structural steel with yield strength being over 630 MPa for buildings and preparing method of structural steel
CN110640340A (en) * 2018-06-27 2020-01-03 宝山钢铁股份有限公司 Laser welding method for realizing rapid splicing of high-strength steel
CN112593154A (en) * 2020-11-30 2021-04-02 攀钢集团攀枝花钢铁研究院有限公司 980 MPa-grade cold-rolled dual-phase steel with yield strength exceeding 700MPa and production method thereof

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DE10124345A1 (en) * 2001-05-18 2002-11-21 Linde Ag Laser welding comprises using a protective gas containing molecular gases as well as argon and/or helium or molecular gases mixed with the protective gases
CN105132818A (en) * 2015-09-30 2015-12-09 河南理工大学 Structural steel with yield strength being over 630 MPa for buildings and preparing method of structural steel
CN110640340A (en) * 2018-06-27 2020-01-03 宝山钢铁股份有限公司 Laser welding method for realizing rapid splicing of high-strength steel
CN112593154A (en) * 2020-11-30 2021-04-02 攀钢集团攀枝花钢铁研究院有限公司 980 MPa-grade cold-rolled dual-phase steel with yield strength exceeding 700MPa and production method thereof

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