Introduction of hard-faced wear-resistant welding materials-covered welding rod
1.Suggestions for welding material selection：
AWS has relevant specifications for hard-faced welding materials, such as A5.13 hard-faced covered metal arc welding, A5.21 hard-faced bare welding wire and welding rod, to define materials. However, in general practical application, welding materials rarely define corresponding international specification class numbers. Therefore, in the selection of welding materials, the content of dissolved gold composition, hardness value and application occasions recommended by manufacturers are used as materials.
This kind of material attaches great importance to the design of welding procedure, that is, what kind of welding material to use, preheating temperature, inter-track temperature, number of welding layers, whether to do post-heating, whether to do post-heat treatment, whether there is a transition layer and other important factors will determine the success or failure and service life of a hard-surface welding workpiece.
①For various environments with different working attributes, the recommended hard surface welding materials are as follows：
Hard-faced welding material category
Reference wear rate(%)
Reference hardness value (HRC)
High carbon-high chromium, high special alloys (W, Nb, V, Co, etc.)
0.05 ~ 0.2
50 ~ 75
Medium friction + medium impact
Semi-Austenite, Austenite + Artensite, Artensite, Pearlite
0.2 ~ 8.0
20 ~ 60
Austenite, high manganese steel, medium carbon low alloy steel
6.0 ~ 20.0
5 ~ 55
②According to the classification of each hard surface welding material according to the organization type, the recommended application occasions are as follows：
Submerged arc welding material
Couplers for gears, shafts, rolls, rolling mills, automatic coupling machines for vehicles, foot peripheral fittings of bulldozers and track head surfaces, etc.
Rollers or sprockets of bulldozers, idlers or track shoes, digging edges, rollers, bucket end edges, mixing blades, cutting tools and shells of dredgers, etc.
High manganese Austenite series
Blade or roller of crusher, hammer of crusher, claw of excavator and track frog
High carbon-high chromium system
Coal pulverizer, coal pulverizer rotor, sand pump shell and pump blade, ghost tooth, receiving tooth, blast furnace cover, grinder, etc.
Tungsten carbide system
Blades of bulldozers, lining tools, relieving teeth, cutting tools, concrete cutters and earth drills, etc.
Cobalt-chromium-tungsten alloy system
Bushing of high-pressure pump, moving wheel sleeve, sliding surface of high-pressure valve, turbine blade and various cutters, cutting edge for paper industry, valve seat ring of internal combustion engine, high-temperature and high-pressure valve, injection eye mold, etc.
2.Key points of welding operation：
(1)Storage management of welding rod：
Suggestions for Carbon Steel Covered Welders.
(2)Precautions for welding：
①During the cooling process, high carbon-high chromium hard-faced welding materials are especially prone to weld bead cracking. In order to reduce the number of cracks and avoid weld bead peeling, preheating, wire temperature, post-heating control or transition layer as backing shall be carried out according to the manufacturer's recommendations.
②Most hard-faced welding materials have a certain amount of alloy. It is suggested to avoid high heat input during welding to reduce excessive burning loss of alloy and control the weaving amplitude within 3 times of the rod diameter.
③The rest shall be in accordance with the recommendations of carbon steel coated welders.