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Use And Wear-resistant Welding Precautions

Oct 24, 2014

Hardfacing welding electrodes using methods and precautions: 1, the electrode can not be used for gold, silver, copper, aluminum casting metal material surfacing. 2, this electrode surfacing welding layer can machining, for processing or grinding wheel grinder available. Gas cutting can only be cut with a cutting machine. 3, before welding weldment remove rust, oil and other impurities. Such as impact resistance welding pieces need heating insulation. 4, try using a small current short-arc welding, to avoid burning of alloying elements. 5, high alloy welding metal content can be multi-surfacing, surfacing usually 1-3 layers. 6, when the multi-layer welding, hot welding finished one-time best hot into lime powder insulation, abrasion resistance constant, can increase its impact resistance. 7, again in the future if the welding, the welding can be welded to the beginning of finish grinding the original position of the solder layer, and a gradually finished welding is preferably a weldment, due to the solder layer so that the remaining original and the rapid heating and rapid cooling can be avoided to produce shedding phenomenon. 8, such as welding damp, solder layer on partial stomatal Chu now, so you can look electrode drying above 500 ℃ 1-2 hours of use is better. Surfacing at the edge of the workpiece surface or be deposited layer of wear, corrosion resistance, heat resistance welding performance metal layer. To repair and improve the life of the part, the rational use of materials, improve product performance, reduce costs and have significant economic benefits. 

Surfacing work and working conditions are very complicated, must be selected according to the different requirements of the appropriate electrodes when welding. Different workpiece and welding electrodes to different welding processes, in order to obtain a satisfactory welding results. 

Surfacing most frequently encountered problem is cracking, to prevent cracking of the main methods are: 

1, preheat, interpass temperature control, slow cooling after welding. 

2, stress relief heat treatment after welding. 

3, multi-layer surfacing avoid cracking when using low hydrogen welding electrodes. 

4, if necessary, surfacing transition between overlay and base metal (low carbon equivalent, high toughness electrodes). 

Cracking the workpiece and weld metal deposited carbon content, there is a direct relationship between the alloying elements, so the preheat temperature is generally based electrodes used to estimate carbon equivalent. 

Carbon equivalent formula is as follows: 

Ceq = C + 1 / 6Mn + 1 / 24Si + 1 / 5Cr + 1 / 4Mo + 1 / 15Ni 

This estimation formula is suitable for low, medium and high carbon and low alloy steel. 

Carbon equivalent (%) preheating temperature carbon equivalent (%) preheating temperature above ≤0.40 100 ℃ ≤0.70 250 ℃ more than ≤0.50 150 ℃ above ≤0.80 300 ℃ ≤0.60 200 ℃ more than ≤0.90 350 ℃ 

High manganese steel and austenitic stainless steel, from time to warm up. High alloy steel preheat temperature greater than 400 ℃. 

Surfacing effect refers to the solder layer hardness, wear resistance and heat resistance properties, the performance level of the following factors: 

1 welding current size, arc length. Current, arc length, alloying elements and easy burning, on the contrary, favorable alloying elements transition. 

2 preheat temperature, slow cooling conditions determine the quality of the surfacing layer. 

3 Some welding metal heat treatment in different ways to get different hardness. 

Hardness and chemical composition of the surfacing layer refers to three or more of welding metal surfacing the most important thing is to choose the right model, depending on the work environment and the need to choose a different base hardfacing welding 

  

Welding electrodes for use 

       Standard execution GB984-2001 

       Surfacing at the edge of the workpiece surface or be deposited layer of wear, corrosion resistance, heat resistance welding performance metal layer. To repair and improve the service life of parts, the rational use of materials, improve productivity 

   Product performance, reduce costs have significant economic benefits. 

       Surfacing work and working conditions are very complicated, must be selected according to the different requirements of the appropriate electrodes when welding. Different workpiece and welding electrodes to different welding processes, in order to obtain a satisfactory heap 

   Welding results. 

       Surfacing most frequently encountered problem is cracking, to prevent cracking of the main methods are: 

       1, preheat, interpass temperature control, slow cooling after welding. 

       2, stress relief heat treatment after welding. 

       3, multi-layer surfacing avoid cracking when using low hydrogen welding electrodes. 

       4, if necessary, surfacing transition between overlay and base metal (low carbon equivalent, high toughness electrodes). 

       Cracking the workpiece and weld metal deposited carbon content, there is a direct relationship between the alloying elements, so the preheat temperature is generally based electrodes used to estimate carbon equivalent. 

        Carbon equivalent formula is as follows: 

       Ceq = C + 1 / 6Mn + 1 / 24Si + 1 / 5Cr + 1 / 4Mo + 1 / 15Ni 

       This estimation formula is suitable for low, medium and high carbon and low alloy steel.