It is not difficult to find that there are actually many types of castings, which can play different roles in different applications. For castings, welding is often used, but how to weld alloy steel castings to play a good role?
1. The weld formed by the welding process of alloy steel castings is that the welding rod and the base metal are melted by the current at high temperature to form the weld, and the welding rod and the base metal change from solid to liquid. High temperature liquid is thermal expansion, cooling to solid is shortening. Due to thermal expansion and cold contraction, stress occurs naturally in the welded layout. Some welding arrangements are inherently binding and rigid. The welding process is from solid to liquid, that is, solid to liquid, and then from liquid to solid, which also constitutes a weld.
2. The liquid state turns into a solid state, that is, molten steel turns into grains. The process of converting molten steel into grains is the crystallization process. Alloy steel casting negative pressure molding method: negative pressure molding is also called vacuum sealing molding. The sand box used in this method is equipped with a ventilating filter screen or a serpentine tube, which is connected with a vacuum pump through an exhaust pipe; the modeling material used is dry sand without moisture and binders.
3. When modeling, first cover a layer of plastic film on the template, pump air with a vacuum pump, so that the film is close to the template, then put on the sand box, and then fill the modeling material into the sand box. Cover the top surface of the sand box with a plastic film, connect the vacuum pump to suck out the air between the sand particles, so that a negative pressure is formed in the sand mold, and the vacuum of the template is canceled together, so that the plastic film is adsorbed on the inner cavity surface of the mold, and the sand mold depends on the pressure difference. Has a certain strength and hardness. After removing the mold, closing the box, pouring, and condensing and cooling, the negative pressure is cancelled, and the desired casting can be obtained.
In order to play a good role in welding, we need to weld alloy steel castings through the above methods, which can not only reduce some defects of the castings, but also use the above welding methods to keep the performance of the castings stable.
