Wy25 excavator bucket teeth bucket and weld repair method - China USB Pen Disk - Ceramic USB Manufac

Published: 20th June 2011
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1. Bucket materials and welding WY25 type Excavator The fighting material as Q345, the weld is good. Bucket Teeth Material ZGMn13 (high manganese steel), the high temperature was austenite single phase, good toughness, impact loads in the surface layer due to work hardening and high wear resistance. But this is poor welding of steel: First, heat affected zone material embrittlement caused by precipitation of carbides; second weld hot cracking, especially in the production of liquefied cracks near the weld zone.



(1) heat affected zone of embrittlement caused by precipitation of carbides



ZGMn13 high manganese steel in the heat again, more than 250 may precipitate along the grain boundary carbides, and the material toughness declined significantly, serious damage to the excellent performance of high manganese steel. After analysis, when the high manganese steel, heating and cooling speed again when the first grain boundary carbide precipitation, with the residence time, grain boundary carbide particles by the discrete state into a mesh distribution, the brittleness increased significantly. Therefore, when the high manganese steel in Welding, or when heated after welding, heat affected zone will be in a section of carbide precipitation in different degrees, and may the martensite transformation, not only the material brittle, and will reduce the wear resistance and toughness. And, in the heat affected zone of carbide precipitation temperature range easily (650 so) the longer the stay, the more carbide precipitation.



To reduce carbide precipitation, to prevent loss of toughness and brittle materials, should take measures to speed up the cooling rate, that is, reduced residence time at high temperatures. Therefore, when welding with a short section of welding, intermittent welding, welding, etc. flood damage.



(2) welding hot cracking Way to prevent hot cracks is to reduce the basic metal or Welding materials In the S and P content; also available from the welding process on measures to minimize residual stresses, such as the use of a short section of welding, intermittent welding, welding and after welding, hammering dispersed so. Body in the bucket when the high manganese steel surfacing can be the first welding layer Cr-Ni, Cr-Ni-Mn or Cr-Mn austenitic steel weld for isolation to prevent cracks.



2. Bucket teeth bucket and welding technology



(1) welding preparation First body removed from the Big Dipper's bucket teeth have been worn, and then Angle grinder Department to install Tooth grinding clean, not that there Nigou, rust, and carefully check for cracks and other defects; in the bucket teeth to be carbon arc air welding Department Paokai a groove, and with the angle grinder to clean up.



(2) the weld first body in the bucket (bucket teeth and joints) with GBE309-15 electrode for welding, welding electrode is subject to 350 , 1? 5h drying, welding current should be relatively large, slightly slower welding speed to ensure the fusion zone of nickel content of 5% to 6%, to prevent the generation of the crack-sensitive martensite.



positioning welding. Tooth assembly is in place, with a diameter 3? 2mm of D266 electrodes were bilaterally symmetrical position welding, weld length of not more than 30mm. Water immediately after welding and hammering.



bottoming welding. With a diameter 3? 2mm of D266 were bottoming welding rod. With a small current, direct current reverse polarity, intermittent welding, a short section of solder. Welding should be stopped every time, water cooling, temperature control between the layers below 50 .



to fill welding. After the end of welding, use the D266 4mm diameter electrode for intermittent welding, welding current of 160A, a sub-electrode welding completed 3 to 4 times, each time stopping welding, the weld cooling water still in time to 50 below, and to hammer, to remove stress and to prevent carbide precipitation; each weld is completed for about two rotation welding seam welded to ensure the symmetry of up to 16mm up until the welding foot. Welded together with each completed Magnifier Check the crack situation, where crack is used to eliminate carbon arc gouging after welding.



Bucket teeth repaired by this method is used by more than a year, still a good weld. This method fixes Tooth efficient, low cost, good effect, there are some practical value.



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