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CN-122007595-A - Welding and rolling method for welding seams of thin non-oriented silicon steel

CN122007595ACN 122007595 ACN122007595 ACN 122007595ACN-122007595-A

Abstract

The invention belongs to the technical field of non-oriented silicon steel laser welding, and relates to a method for welding and rolling a welding line of thin non-oriented silicon steel. According to the method, the head and the tail of the thin-specification large-grain non-oriented silicon steel substrate with the width of 1000-1200 mm are welded through an effective welding process, and the hard plate is rolled by five-frame acid continuous rolling smoothly.

Inventors

  • ZHU RUI
  • LU JIADONG
  • ZHANG JIANLEI
  • YUE ZHONGXIANG
  • LI HUALONG

Assignees

  • 张家港中美超薄带科技有限公司
  • 江苏省沙钢钢铁研究院有限公司
  • 江苏沙钢集团有限公司
  • 江苏沙钢钢铁有限公司

Dates

Publication Date
20260512
Application Date
20260210

Claims (13)

  1. 1. A method for welding and rolling a weld of thin gauge non-oriented silicon steel, the method comprising the steps of: (1) Preparing welding raw materials, namely producing a non-oriented silicon steel substrate through steelmaking and casting, wherein the chemical components of the non-oriented silicon steel substrate are ：C≤0.0025%,S≤0.0025%,Si：1.50~2.10%,Al：0.7%,Mn：0.5%,P≤0.020%,Nb≤0.0015%,Cu≤0.03%,Ti≤0.0015%,Ni≤0.003%,Cr≤0.03%,N≤0.002%, mass percent of Fe and unavoidable impurities, and the width of the non-oriented silicon steel substrate is 1000-1200 mm and the thickness of the non-oriented silicon steel substrate is 1.3-1.5 mm; (2) The preparation before welding of the non-oriented silicon steel substrate comprises uncoiling the non-oriented silicon steel substrate at a cold rolling procedure inlet feeding machine, and cutting the non-oriented silicon steel substrate to form a neat section without tearing or burrs and uniform burrs after cutting, wherein the width of the non-oriented silicon steel substrate is 1000-1200 mm and the thickness of the non-oriented silicon steel substrate is 1.3-1.5 mm, and the width of the non-oriented silicon steel substrate adopts positive deviation of 0-2 mm and the thickness tolerance of +/-0.01 mm; (3) The method comprises the steps of performing front-back butt joint of the non-oriented silicon steel substrates, namely butt joint of two rolls of non-oriented silicon steel substrates which are similar in composition and same in thickness and width, removing surface iron scales between two layers of steel plates, and clamping the steel plates to a welding machine position, wherein the clamping plates of the welding machine are clamped to keep 0-5 degrees parallel to the non-oriented silicon steel substrates, and the edges are 5-10 mm; (4) Welding, namely welding the well-butted substrates, wherein the welding power of the welding process is laser steady-state power, the chemical components of the welding wire are, by mass, less than or equal to 0.15% of C, less than or equal to 0.03% of S, 0.55-1.10% of Si, 1.25-1.90% of Mn, less than or equal to 0.003% of P, less than or equal to 0.5% of Cu, and the diameter of the welding wire is 0.8-1.0 mm; (5) Checking the quality of the welding seam, namely checking the welding seam, and passing through a next procedure after the checking is qualified; (6) The rolling process is optimized, namely when the welding seam is at the inlet of the rolling mill, the five racks are subjected to acid continuous rolling under equal-proportion light pressure, and the welding seam is subjected to rack-by-rack reduction after the welding seam is at the outlet of the rolling mill.
  2. 2. The method for welding and rolling a weld of thin gauge non-oriented silicon steel as set forth in claim 1 wherein: Unlike the previous steelmaking, continuous casting, hot rolling, normalizing and cold rolling processes, the non-oriented silicon steel substrate is produced by the steelmaking, cast rolling and cold rolling processes.
  3. 3. The method for welding and rolling a weld of thin gauge non-oriented silicon steel as set forth in claim 1 wherein: the grain size of the non-oriented silicon steel substrate is 500-700 mu m.
  4. 4. The method for welding and rolling a weld of thin gauge non-oriented silicon steel as set forth in claim 1 wherein: The wedge shape of the non-oriented silicon steel substrate is less than or equal to 60 mu m, the convexity is 40-60 mm, the camber is not more than 5mm/m, and the wave shape is not more than 30mm/m.
  5. 5. The method for welding and rolling a weld of thin gauge non-oriented silicon steel as set forth in claim 1 wherein: in the step (3), the deviation of each component of the two rolls of non-oriented silicon steel substrates is less than or equal to 0.30% of DeltaSi, less than or equal to 0.30% of DeltaAl, less than or equal to 0.30% of DeltaMn and less than or equal to 0.03% of DeltaP.
  6. 6. The method for welding and rolling a weld of thin gauge non-oriented silicon steel as set forth in claim 1 wherein: in the step (2), two uncoilers are arranged, one uncoiler is opened after uncoiling, and the other uncoiler is opened again to weld the tail part of one coil with the head part of the other coil.
  7. 7. The method for welding and rolling a weld of thin gauge non-oriented silicon steel as set forth in claim 1 wherein: in the step (2), a gate type plate shearing machine is used in the shearing process, the blade material is high-speed steel, and the hardness is 62-67 HRC.
  8. 8. The method for welding and rolling a thin gauge non-oriented silicon steel weld as set forth in claim 7 wherein: the clearance between the blades of the gate type plate shearing machine is 0.08-0.12 mm.
  9. 9. The method for welding and rolling a weld of thin gauge non-oriented silicon steel as set forth in claim 1 wherein: in the step (3), the pair of steel plates are clamped to a welding machine position, and a gap between the steel plates is 0.1mm.
  10. 10. The method for welding and rolling a weld of thin gauge non-oriented silicon steel as set forth in claim 1 wherein: in the step (3), the pair of steel plates is clamped to a welding machine position, and the clamping pressure is 80-120 KN.
  11. 11. The method for welding and rolling a weld of thin gauge non-oriented silicon steel as set forth in claim 1 wherein: In the step (4), the welding power of the welding process is 3.0-6.0 kW, the moving speed of the welding machine is 3.0-6.0 m/min, the gap between plates is 0.1-0.2 mm, and the wire filling speed is 3.0-4.0 m/min.
  12. 12. The method for welding and rolling a weld of thin gauge non-oriented silicon steel as set forth in claim 1 wherein: in the step (5), the X-ray moving speed and the welding head moving speed are 3.5m/min to the welding line when welding is carried out.
  13. 13. The method for welding and rolling a weld of thin gauge non-oriented silicon steel as set forth in claim 1 wherein: in the step (6), the welding seam is lightly pressed in an equal proportion of 60-80% under the condition of acid continuous rolling five frames.

Description

Welding and rolling method for welding seams of thin non-oriented silicon steel Technical Field The invention belongs to the technical field of non-oriented silicon steel laser welding, and relates to a method for welding and rolling a welding line of thin non-oriented silicon steel. Background The large grain size and thin thickness of thin gauge non-oriented silicon steel are significant challenges for their welding. According to a Hall-Peltier formula, sigma y=σ0+kd-1/2 is adopted, wherein sigma y is yield strength, mpa, sigma 0 is single crystal material strength, MPa, k is material constant, mpa μm 1/2, and d is grain size. It can be seen that the yield strength is inversely proportional to the grain size, and that as the grain size d increases, the term kd -1/2 decreases, resulting in a decrease in yield strength σy. The increased grain size reduces the toughness of the material itself, while the reduced thickness of the substrate makes heat input control, deformation control, and quality control during the soldering process exceptionally difficult. The two conditions are overlapped, so that the risks of cracks, burn-through and deformation in the welding process and the risks of product incapable of being continuously produced are obviously increased, and the welding becomes very difficult and the quality of the welding seam is difficult to ensure. On the other hand, the crystal grain size is large, so that the number of crystal boundaries under the same specification is drastically reduced, the impurity segregation is more concentrated, the thermal cracking is more easily generated due to the segregation and the stress concentration of the crystal boundaries in the welding cooling process, the stress is more difficult to disperse through the crystal boundaries, and the residual stress is higher. For acid tandem rolling, the welding seam is required to pass through a plurality of procedures such as acid washing, a tension roller, a straightening roller, a looper, a rolling mill and the like, and the welding seam is required to pass through bending, stretching and pressing for a plurality of times, so that a great challenge is brought to welding quality. Based on the characteristics of thin thickness and large grain size of the non-oriented silicon steel substrate, the heat input is reduced, coarsening and deformation of the grains are reduced, and the most direct problem of the increase of the grain size is that the coarsening trend at the high temperature of welding is increased, and larger deformation is easy to generate. Therefore, reducing the overall heat input is of primary concern. According to a heat input formula, Q=P/(vd), wherein Q is heat input, J/mm 2, P is welding power, W, v is welding speed, m/min, and d is material thickness, mm. As can be seen, the material thickness is reduced, requiring a corresponding reduction in welding power. Second, the process is tuned to optimize the tissue to maintain as much strength as possible while avoiding further brittleness. The heat input Q is proportional to the heat conductivity k of the material, and k=k 0 +A/D is calculated according to the heat conductivity equation, wherein k 0 is lattice intrinsic heat conductivity, A is material constant, and D is grain size, and mm. It can be seen that the increase in grain size and the decrease in thermal conductivity. Third, it is desirable to stabilize the bath by adjusting parameters to reduce defects. According to the theory of a mass balance equation in a welding process, kbhv 0=d2 vf pi/4, K is a filling coefficient (5.0-7.0), b is a welding gap, mm, h is a plate thickness, mm, v 0 is a welding speed, m/min is d is a welding wire diameter, mm, and v f is a welding wire speed, m/min. It can be seen that the front and rear process parameters are required to meet the weld mass balance conditions in order to maintain the weld puddle stable. In order to solve the problems of high breakage rate of a welding line and unstable welding quality caused by the differences of chemical compositions, plate shapes and thicknesses of materials in the traditional laser welding process, the related patent optimizes the welding process. For example, chinese patent application publication No. CN107378239a discloses an improved method for welding low grade non-oriented silicon steel by a laser welder, which improves the toe cross-section size by optimizing the welding process, adding a new secondary shearing step (shearing value is 0.5 mm), and adjusting the laser focal length to-3 mm to increase the weld width. The welding speed is set in a grading mode according to the thickness of the silicon steel, wherein 4.5m/min is adopted for 2.0-2.5 mm, 3.75m/min is adopted for 3.0-3.5 mm, 3m/min is adopted for 4.0-6.0 mm, and the heat affected zone is reduced through reducing the speed, so that the welding seam is softened and the toughness is improved. The method combines auxiliary processes such as pre-preheating, post-heatin