Boiler thermal power source. Of mill, Fan (collectively, the fans) is an important component in the boiler equipment. Of mill used to transport coal; induced draft fan is used to pump gas to make it through the chimney smoke. Boiler fan impeller units, in the course of their work, due to high speed (1 480 r / min or more), and withstand a certain wind, leaves and dust particles will be friction and corrosive effect of flue gas, generally run 7 month or so, it will be washed worn out leaves the phenomenon occurs, resulting in decreased life of the impeller, you need downtime. This will cause a corresponding boiler stop running, not only increases the labor intensity of the maintenance workers, increase the loading and unloading costs, spare parts and the corresponding amount of expenses, is more serious is the opportunity of stopping power generation, causing serious economic losses and Welding Electrodes .

Fan impeller structure and technical requirements
Boiler fan specification is generally not uniform, the impeller diameter (1 600 ~ 2 000) mm between.

The technical requirements of the impeller:
(1) after the disk roughness ≤ 0.5/100;
(2) at the end after the jump cylindrical disk error ≤ 4 mm;
(3) Disc diameter cylindrical jump at the deviation of ≤ 3 mm;
(4) at the end of tapered cylindrical disk before jumping deviation ≤ 6 mm;
(5) leaf exports in the face of the back plate is not vertical deviation ≤ 1 / 100;
(6) The static and dynamic balance correction.

Generally speaking, on the surface There are several ways to strengthen such as carburizing, plating, and plasma spraying. Conditions for the use of fans and the field conditions, the only feasible way to oxy-acetylene and electric arc spray welding.

Dilution rate of surfacing layer, reflecting the melting of base metal cladding layer into the percentage of the amount. Q235 wheel or base metal is generally 16 Mn. After melting the base metal from the dilution of wear-resistant alloys, alloy weld overlay will reduce the effectiveness, impact wear resistance.

After surfacing the impeller, the acceptance need not be static and dynamic balance test, the surface needs to size, shape and location to meet the bias requirements. Since surfacing uneven heating causes the impeller to produce welding stress, leading to welding deformation, it needs to take appropriate technical measures to control the deformation of the impeller within the tolerance range.

Power plant operation shows that the fan blade life after surfacing increased by 4 times, to avoid the impeller in a boiler overhaul period, due to wear and tear caused by leaf replacement or repair, ensure the normal operation of the unit, and achieved good economic and social benefits.

keywords:Nickel Alloy Welding Wire