Welding wire for laser butt welding of Al-Si coated plates formed by hot-stamping and butt welding method

Abstract

The invention provides a welding wire for laser butt welding of Al-Si coated plates formed by hot-stamping and a butt welding method. The welding wire comprises no more than 0.30% of C, 1.0%-1.5% of Mn, no more than 0.005% of S, no more than 0.010% of P, 0.030-0.050% of Als, no more than 0.001% of Si, 5.0%-9.0% of Ni, 0.21%-0.50% of Cr, 0.010%-0.020% of Nb, 0.010%-0.020% of Ti, no more than 0.0030% of N, and the balance Fe and inevitable impurities. The butt welding method comprises the steps that two Al-Si coated plates are fixed through a welding clamp, wherein a gap is reserved between thetwo Al-Si coated plates; the diameter of the welding wire is determined according to the size of the gap; laser butt welding is conducted; and then, hot-stamping formation is conducted. By the adoption of the welding wire, pretreatment of a coating is not needed; and the laser butt welding method is simple, and the performance of welds is better than that of parent metal.

Description

technical field [0001] The invention belongs to the field of welding technology, and in particular relates to a welding wire for laser tailor welding of a hot stamping formed Al-Si coating plate and a tailor welding method. Background technique [0002] As an effective energy-saving means, automobile lightweight has become one of the important development directions of the automobile industry. Hot stamping high-strength steel has attracted widespread attention in the automobile industry due to its dual advantages of light weight and safety. It is widely used in parts, such as B-pillar, middle channel, etc., and the strength level of the product has reached more than 1800MPa. Generally, the process of making parts with hot stamping steel is: blanking → heating in the furnace (generally above 900 °C, heating time not less than 5 minutes) → transferring the sheet from the furnace to the press → die stamping. For the thermoformed plate without coating protection, due to the lon...

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Problems solved by technology

[0005] CN 106475683 A, a patent application for the invention of a laser tailor welding method with Al-Si coated thermoformed steel sheets, discloses that the weld structure after laser welding can be achieved by pre-placing a certain thickness of Ni or Cr foil in the butt weld Complete martensite, but it is difficult to achieve industrial production and unequal thickness tailor-welded blanks, and the cost is high and the production efficiency is low. Moreover, the thickness of Ni or Cr foil used for different coating thicknesses is not easy to control, and it cannot be used in industrialization. Application in production

[0006] CN 106392328 A, a patent application for a laser tailor welding method for hot-formed steel with Al-Si coating discloses the use of adjusting the composition and ratio of shielding gas in laser welding to achieve Al burning in the coating to form Al 2 o 3 However, the oxidizing gas will not only oxidize the metal Al in the coating, but also oxidize the Fe element in the molten pool, and finally cause the weld to contain a lot of Slag inclusion or inclusion, that is, the cleanliness of the weld is poor, which is not conducive to the fatigue performance of the weld or component and its dynamic mechanical properties

[0007] The invention patent application with the publication number CN106232285A discloses a steel welded part with aluminum or aluminum alloy coating and its manufacturing method. layer, this kind of stripping method not only needs to invest in the construction of equipment, but also has low efficiency, which is unfavorable for use in industrial production

[0008] The invention patent application with the application number of 201380001259 discloses a tailor welded blank and its manufacturing method, as well as a hot stamping part using the tailor welded blank, which uses filler wire (the content of C is 0.1-0.8wt% higher than that of the base material, and the content of Mn is higher than that of the base material. 1.5-7.0 wt% of the base material) to suppress the occurrence of ferrite transformation in the weld zone, realize direct laser tailor welding without removing the Al-Si coating, and can obtain high-quality different materials and thicknesses Tailored welded blanks, the above composition can obtain martensitic structure welds, but the toughness of the welds is not good, especially for automotive structural parts under high-speed collision conditions

[0009] In addition, there is also a method of mechanical removal before welding, but the efficiency is too low to be used in industrial production; there is also a laser method that burns the Al-Si coating before welding and then welds, etc. etc. These methods are laborious and inefficient, and should not be popularized.

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