1. The difference between forging and casting
(1) Casting: It is to turn a molten metal without shape into a solid with shape.
Casting is like you playing with wax. You bought wax (scrap steel, or pig iron) and then melted the wax into a liquid, put it in a mold, so you can get things of different shapes. (Solid-liquid-solid)
Forging is like the process of making bread. You knead the small dough and put it in a mold to make products of different shapes. Almost a solid at high temperature, the shape can change to other shapes (solid to solid).
The so-called casting is the process of casting molten metal into a model to obtain a casting. The casting profession focuses on the metal smelting process and the process control during the casting process.
forging is plastic forming in solid state, which is divided into hot working and cold working, such as extrusion, drawing, thickening, punching, etc. are all forging.
(2) Forging is slowly forming, casting is one-time forming
Casting: The molten liquid metal fills the cavity to cool. Pores are likely to occur in the middle of the workpiece.
Forging: It is mainly formed by extrusion at high temperature. Can refine the grains in the workpiece.
2. The difference between free forging and die forging
Free forging is a processing method that puts the heated metal blank on the forging equipment and applies impact force or pressure between the bottom irons to directly plastically deform the blank to obtain the required forging. Due to its simple shape and flexible operation, free forging is suitable for the production of single parts, small batches and heavy forgings. Free forging includes manual free forging and machine free forging. Manual free forging has low production efficiency and high labor intensity, and is only used for repair or simple, small, small batch forging production. In modern industrial production, machine free forging has become the main method of forging production. In heavy machinery manufacturing, it Has a particularly important role.
Die forging is called model forging, and the heated billet is placed in a forging die fixed on the die forging device and forged.
Die forging can be performed on a variety of equipment. In industrial production, most of the die forging on the hammer uses steam-air hammer, the tonnage is 5KN~300KN (0.5~30t). Hot forging presses are commonly used for die forging on presses, with a tonnage of 25000KN~63000KN.
The forging die structure of die forging includes single die forging die and multi-cavity forging die. As shown in Figure 3-13, it is a single-die hall forging die. It uses a dovetail groove and a diagonal wedge to fix the forging die to prevent it from falling out and moving left and right. The key and key slot are used to make the positioning of the forging die accurate and prevent forward and backward movement. The single die cavity is generally a final forging die cavity. Forging often requires an air hammer to make a blank, and then it is formed by multiple hammering of the final forging die cavity, and finally the forging is removed to remove the flash.
3. The difference between casting, forging, stamping and casting
(1) Casting is to melt raw materials and let them form naturally in the forming mold
Forging: heating raw materials to a certain temperature and then forging with tools.
Stamping: The raw materials are stamped and formed with a suitable stamping die.
Die casting: On the basis of casting, the melted raw material is injected into the mold using pressure to obtain a higher density or a more precise shape.
Casting: The molten liquid metal fills the cavity for cooling, and air holes are likely to occur in the middle of the parts.
(2) Forging: It is mainly formed by extrusion at high temperature. Can refine the grains in the workpiece.
The thickness of the parts is basically equivalent, suitable for stamping with sheet metal forming.
The thickness of the parts is very different, the shape is complex, and it is not heated. It is die-cast.
1. Casting is divided into two types: high-pressure casting and low-pressure casting. Simply put, after melting the metal, the pressure is different from that of the model, and the temperature of heating the metal is different from the machine used for casting.
2. Forging is also a casting method, the difference is that the temperature during forging is lower, and some can make the metal into a finished product in a semi-molten state.
3. Stamping is the process of making semi-finished products into finished products at room temperature by using machines such as punch presses.
4. Die-casting is also a method of high-temperature casting. When encountering castings with more complicated structure and greater difficulty, you can use a die-casting machine to heat the metal into a liquid state, press it into the mold, open the mold after cooling, and take out the product. Casting method.