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CN-119347048-B - Nickel-iron alloy large-size stringer die welding method

CN119347048BCN 119347048 BCN119347048 BCN 119347048BCN-119347048-B

Abstract

The invention belongs to the technical field of welding, and relates to a welding method of a nickel-iron alloy large-size stringer die, which comprises the following steps of firstly, preparing each plate of the die; clamping the prepared plates on a machine tool, milling grooves at the lap joint positions of the plates, lap-jointing the plates into die body blanks, welding the lap joint positions of the plates in a layered and split way, annealing the welded die body blanks, carrying out numerical control machining on the die body blanks after annealing, and detecting the machined dies.

Inventors

  • CHEN XIANGDONG
  • HE DIANJUN
  • CHEN XIAOGUAN
  • WANG BO
  • DANG YU

Assignees

  • 陕西飞机工业有限责任公司

Dates

Publication Date
20260505
Application Date
20241009

Claims (6)

  1. 1. A welding method of a nickel-iron alloy large-size stringer die is characterized by comprising the following steps: 1. the method comprises the steps of preparing each plate of a die, dividing the die into eight plates, namely a top plate, a bottom plate, a left vertical plate, a right inclined plate, a front vertical plate, a rear inclined plate, a rear vertical plate and a plurality of reinforcing rib plates, wherein each plate is a flat plate without bending; 2. Clamping each prepared plate on a machine tool, and milling grooves at the lap joint positions of the plates, wherein the groove angle is 30 degrees, and the lap joint positions of two adjacent plates form a V-shaped groove of 60 degrees; 3. The method comprises the steps of overlapping all the plates into die body blanks, welding overlapping parts of all the plates in a layered and lane-dividing mode, dividing a V-shaped groove into multiple layers according to the depth direction during welding, welding the layers from the bottom layer to the upper layer, welding the next layer, completely cooling, welding the upper layer, polishing welded seams of all the layers, performing argon arc welding on the bottom layer, and performing segment welding on other layers every 200mm along the length direction; 4. Annealing the welded die body blank; 5. performing numerical control processing on the die body blank subjected to annealing treatment; 6. And detecting the processed die.
  2. 2. The method of claim 1, wherein in II, The reserved length of the blunt edge is 2mm, and the clearance of the blunt edge is 0.5mm.
  3. 3. The method of claim 2, wherein in III, The argon arc welding parameters are as follows, the rated current range is 200A, the argon flow is 20L/min, and the welding wire is INVAR M93 mm; The carbon dioxide gas shielded welding parameters are as follows, the rated current range is 200A, the protective gas flow is 20L/min, and the welding wire is INVAR M93.2 mm.
  4. 4. The method of claim 3, wherein the number of the first layer of welding beads is 1, and the number of welding beads of each upper layer is increased by 1 layer; And resting for 5min after continuously welding for 10 min.
  5. 5. The method according to claim 1, wherein the annealing treatment mode is that the furnace feeding temperature is more than or equal to 100 ℃, the temperature is raised to 820-850 ℃, the temperature raising rate is less than or equal to 100 ℃ per hour, the heat preservation time is more than or equal to 2H, the furnace is cooled to 200 ℃ along with the furnace, and the cooling rate is less than or equal to 80 ℃ per hour.
  6. 6. The method of claim 1, wherein detecting comprises: the profile of the molded surface is not more than +/-0.1 mm; the vacuumized leakage rate of the molded surface is not more than 0.017MPa/5min.

Description

Nickel-iron alloy large-size stringer die welding method Technical Field The invention belongs to the technical field of welding, and relates to a welding method for a nickel-iron alloy large-size stringer die. Background The large-size stringer mold disclosed by the invention is a mold with the external length dimension of a movable and fixed mold part of the stringer being larger than 3000mm, and is used for meeting the requirements of dimensional stability and air tightness of a composite material component in the autoclave molding process under the technological conditions of heating (180 ℃), pressurizing (0.8 MPa), vacuumizing (vacuum leakage rate is not more than 0.017MPa/5 min) and the like. The forming die made of the nickel-iron alloy has similar thermal expansion coefficient with the composite material component, effectively solves the problem of out-of-tolerance of the dimensional precision of the molded surface caused by the difference of the thermal expansion coefficients of common steel, aluminum and the composite material in the past, and has good structural stability and vacuum property. The nickel-iron alloy domestic material with the brand of 4J36 mainly comprises 36% of nickel, 63.8% of iron, 0.2% of carbon and poor heat conduction performance, is easy to adhere to a cutter in the mechanical processing, has poor metal fluidity in the welding process, and is easy to generate deformation, air holes, cracks and undercut, and belongs to a difficult-to-process material. Fig. 1 shows a schematic view of a movable mold of a stringer forming mold, the mold material being 4J36, Because the overall appearance of the die body is slender and a plurality of lightening holes are distributed, deformation is easy to generate in the processing. At present, the industry aims at the die body processing of a large-size stringer die, a sheet combination welding process method is generally adopted, namely, a 4J36 steel plate with the thickness of 20mm is divided into N layers along the height dimension of a movable die by cutting equipment, then assembly welding is carried out, the appearance is cut together with a plurality of lightening holes in the middle, after cutting, the connecting part of N layers of plate materials is mechanically milled with a V-shaped groove, and then layer-by-layer overlapped welding is carried out. Therefore, the welding deformation control of the large-size stringer die is the primary problem to be solved, and is the main research direction of the invention. Disclosure of Invention The invention aims to provide a welding method for a nickel-iron alloy large-size stringer mould, which reduces residual internal stress, effectively reduces welding deformation and defects, ensures that the molding surface of the large-size stringer molding mould made of a 4J36 material has good air tightness, and enables a carbon fiber composite material component to be molded into a qualified product in a heating and pressurizing state of an autoclave. Technical proposal A welding method of a nickel-iron alloy large-size stringer die comprises the following steps: 1. Preparing each plate of the die; 2. clamping each prepared plate on a machine tool, and milling grooves at the lap joint positions of each plate; 3. Overlapping each plate into a die body blank, and welding overlapping positions of each plate in a layered and lane-dividing mode; 4. Annealing the welded die body blank; 5. performing numerical control processing on the die body blank subjected to annealing treatment; 6. And detecting the processed die. Further, in one embodiment, the mold is divided into a plurality of plates, each of which is a flat plate without bending. Further, the mold is divided into eight kinds of plates, namely a top plate, a bottom plate, a left vertical plate, a right inclined plate, a front vertical plate, a rear inclined plate, a rear vertical plate and a plurality of reinforcing rib plates. In the second step, the bevel angle is 30 degrees, and the overlapping part of two adjacent plates forms a V-shaped bevel of 60 degrees; The reserved length of the blunt edge is 2mm, and the clearance of the blunt edge is 0.5mm. Further, in the third step, a technological method of argon arc welding bottoming and gas shield welding sealing is adopted, The argon arc welding parameters are as follows, the rated current range is 200A, the argon flow is 20L/min, and the welding wire is INVAR M93 mm; The carbon dioxide gas shielded welding parameters are as follows, the rated current range is 200A, the protective gas flow is 20L/min, and the welding wire is INVAR M93.2 mm. And in the third step, the V-shaped groove is divided into multiple layers according to the depth direction during welding, the thickness of a single layer is 2 mm-3 mm, the layers are welded from the bottom layer to the upper layer, the next layer is welded and is completely cooled, the upper layer is welded, and the welded seam of each layer is polished. Fu