Dwinauto Alloy Welding CO2 Vision Marking Machine

Date:2022/4/28 9:16:13 / Read: / Source:本站

Dwinauto Alloy Welding CO2 Vision Marking Machine

1) When different grades of superalloys are combined for welding, the selection principle of welding wire is: in the case of meeting the performance requirements of the joint, first select the coal wire with good weldability and low cost in the combined welding alloy, and when the crack resistance cannot be satisfied, You can choose Ni-Cr-Mo welding wire.
2) Shielding gas Argon, helium or argon-helium mixed gas can be used as shielding gas for inert gas shielded arc welding of superalloys. Argon has low cost, high density and good protective effect, and is a commonly used protective gas. The purity of argon should meet the requirements of primary xenon specified in GB4842 "Argon". Adding less than 5% hydrogen into xenon gas has a reducing effect in the welding process, but it is only used for the welding of the first layer of weld bead or single bead, otherwise pores will be generated.
3) Tungsten electrodes Commonly used tungsten electrodes are thorium tungsten electrodes (WTh15) and cerium tungsten electrodes (WCe20). Cerium tungsten electrode has strong electron emission ability, low arc ignition voltage, good arc stability, large allowable welding current and low burning loss rate , so it is recommended to use cerium tungsten electrode. The diameter of tungsten electrode should be selected according to the welding current and processed into Conical electrodes. www.dwinauto.com

(2) Welding joint design When high-temperature alloy xenon arc welding is used, the fluidity of the molten pool is poor and the penetration depth is small. When designing the joint, it is required to increase the groove angle, reduce the height of the blunt edge, and increase the space between the roots. www.dwinauto.com

(3) Welding process Welded parts should be thoroughly cleaned of oxides, oil, etc. on the surface of welding and welding wire before assembly, tack welding and welding, and keep them clean. Tack welding should be carried out on the fixture to ensure the quality of the assembly. In order to rapidly cool the welding area, a chill block and a backing plate are often used, and the backing plate is provided with a forming groove of suitable size. The forming groove is generally arc-shaped, and there are evenly distributed small holes for the shielding gas in the groove to ensure that the back of the weld is well formed and protected. Chill blocks and backing plates are made of pure copper. When welding drill alloys, a pure copper backing plate with chrome Plating should be used. Because a small amount of copper contamination can lead to hot cracks after welding, both ends of the weld can be pre-installed with removable starter and end plates, and their material grades are the same as the ba se metal to avoid arc start and end defects. www.dwinauto.com

(4) DC current, positive polarity and high frequency arc ignition are used during welding, and the welding current can be controlled to increase and decrease. Typical welding process parameters are listed in Table 15-9. Under the condition of ensuring penetration, a Smaller welding heat input should be used. When multi-layer welding, the temperature between layers should be controlled. When welding alloys with high aging-strengthening and hot cracking susceptibility, the welding heat input should be strictly limited. It should be ensured that the arc burns steadily and the welding torch is kept in a nearly vertical position. The arc length should be as short as possible. When no welding wire is added, the arc length is less than 1.5mm; when welding wire is added, the arc length is similar to the diameter of the welding wire. When welding thin parts, the welding torch does not swing. In multi-layer welding, in order to fully fuse the deposited metal with the base metal and the front bea d, the welding torch can be properly oscillated. Thin-plate superalloy parts do not need preheating before welding, and it is recommended to weld in solution or annealed state. Thick plate parts (thickness greater than 4mm) can be properly preheated before welding due to the large degree of restraint. After welding, stress relief treatment should be carried out in time to prevent cracks. www.dwinauto.com


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