1. Preparation of the segment: The segment has been arc-grinding, the oxide skin has been ground off on the welding surface, and the radian also meets the process requirements. The next work has two things: 1. Group according to the height of the segment, so that the welded saw blade is as round as possible. 2. Clean the segments with acetone or gasoline, etc. and dry them to ensure firm soldering.
2. Preparation of the base body: There are a lot of oil stains (anti-rust, grease) on the base body and even rust. It needs to be cleaned carefully, and the rust on the two planes is removed with an emery cloth. Grind the welding surface on a plate grinder to remove burrs and rust to ensure firm welding.
3. Preparation of welding sheet and flux: The welding sheet is generally rolled into strips, cut into strips with a width of about 0.5-1.0cm, and coiled into discs, which are convenient for automatic welding machines. The thickness is 0.1-0.5mm. If welding by hand, cut to size with scissors. In order to carry out the welding work smoothly, a layer of silver brazing flux is evenly coated on the welding contact surfaces (nodes, substrates and solder pieces), the purpose is to promote the reduction of oxides on the contact surfaces of the solder objects and promote the melting of the solder pieces, cover the fluidity of the solder tab melt, etc.
Selecting solder is important to work, the solder should meet the following requirements: 1. The melting temperature of the solder is lower than the hot pressing sintering temperature of the segment, generally 100-200 degrees Celsius lower. If this temperature difference is too small, it is possible to melt or volatilize the low melting point components in the segment matrix during welding, which will affect the welding quality and the quality of the segment. 2. The solder has better weldability to the segment and the steel matrix. 3. After the solder is melted, the fluidity should be good, and the surface tension should be small so that it can fill the welded part and make the welding firm. 4. Good economy and sufficient supply. 5. Meet environmental protection requirements
