Because the wear-resistant composite plate production process is to use metallurgical surfacing welding and become, the welding current is in commonly 500 ~ 700 a, the welding arc temperature of 6000 ~ 7000 ℃, the moment of high temperature wire and the motherboard achieves melting point form molten pool (so-called bead), and added to molten pool of melting form surfacing welding alloy powder deposition layer. Surfacing welding process, the molten pool nearby motherboard temperature will reach 600 ~ 800 ℃, is even higher, because the motherboard is generally using common Q235 low carbon steel, wear-resisting layer of high carbon high chromium, so in the process of welding, each part of the motherboard temperature difference is very big, to produce highly uniform expansion, shrinkage and deformation, because the motherboard surrounded by linking piece firmly fastened, unable to free deformation, add wear-resisting layer is formed by a large number of alloy powder on the motherboard, surfacing welding wire for metallurgical formed a typical high hardness materials, because of the surfacing layer with the motherboard of the two thermal expansion coefficient difference is bigger, toughness good motherboard can withstand larger thermal deformation, and high hardness of surfacing welding layer under thermal deformation ability is almost zero, so the internal thermal stress greatly, the stress release if no immediate, in the later process (such as curly) likely to occur in the process of problem such as broken, split, wear-resisting layer falls off.
In the cooling process after hot deformation, for the release of the composite steel plate welding stress in welding, the welding layer surface is perpendicular to the direction of the weld can produce many sizes of crack, the crack is the result of the stress release, therefore, if there is no crack or few wear-resistant composite board surface crack, so is definitely not qualified products! These cracks look, it's easy to let people worry, afraid of wear-resistant composite steel plate in use crack spread into the motherboard, or even afraid to break or fall off, this for crack worry is redundant, wear-resistant composite steel plate welding process, belongs to the metallurgical combination, combining with the performance is very good. The crack will not fall off or fracture during use.