1. Differences between Forging and Casting
(1) Casting:
It involves the transformation of shapeless liquid metal into a solid object with a specific shape.
Forging: Involves transforming a solid object from one shape into another shape.
Casting is similar to molding wax. You buy wax (scrap steel or pig iron), melt it until it forms a liquid, pour it into a mold and obtain objects of various shapes (solid-liquid-solid process).
Forging, on the other hand, is similar to making burgers out of dough. You knead small balls of dough, place them in a mold and create products of different shapes. Essentially, a solid at high temperatures can be remodeled (solid-solid process).
Casting refers to the process of pouring molten metal into a mold to obtain castings. The foundry specialty focuses on the process of melting metals and controlling the casting process.
Forging is solid-state plastic molding, with hot and cold processing. Operations such as extrusion, drawing, upsetting and punching are part of forging.
(2) Forging is gradual shaping, while casting is one-time shaping.
Casting: Molten liquid metal fills the mold cavity and cools. Easy to generate gas holes in the middle of the part.
Forging: Mainly uses the extrusion method to shape under high temperatures. It can refine the grain of the workpiece.
2. Differences between Free Forging and Die Forging
Free forging involves placing a heated metal blank between the upper and lower anvil of forging equipment, applying impact force or pressure, directly causing plastic deformation of the blank and obtaining the required forging.
Free forging is flexible in operation and suitable for single part production, small batches and heavy forgings due to its simple format. It is divided into manual free forging and machine free forging.
Manual free forging has low production efficiency and high labor intensity, and is only used for simple, small, small-batch repair or forging production.
In modern industrial production, machineless forging has become the main forging production method and plays a particularly important role in the manufacture of heavy machinery.
Die forging, also known as template forging, shapes the heated blank placed in the forging die fixed in the die forging equipment.
Forging can be carried out on various equipment. In industrial production, hammer forging mainly uses steam hammers, with tonnage ranging from 5KN to 300KN (0.5~30t). Forging on pressing machines generally uses hot forging presses, with a tonnage of 25,000 KN to 63,000 KN.
The forging die structure includes single-cavity forging die and multi-cavity forging die. The single-cavity forging die is shown in Figure 3-13. It uses a dovetail groove and wedge to keep the forging die fixed and prevent it from moving left and right.
The key and keyway are used to precisely position the forging die and prevent it from moving back and forth. The single cavity is generally the final forging die.
During forging, the pneumatic hammer is often used to make the blank, and then it is formed in one go by the multiple blows of the final forging die. The forged part is finally removed and the flash is cut off.
3. The differences between casting, forging, stamping and pressure casting
(1) Casting involves melting raw materials and letting them take shape naturally in a mold.
Forging involves heating raw materials to a specific temperature and then shaping them with the help of tools.
Stamping involves shaping raw materials using an appropriate stamping mold.
Die casting is based on casting; involves injecting molten material into a mold under pressure, achieving a higher density or more precise shape.
Casting: Molten liquid metal fills the mold cavity and cools. This process can result in gas pores within the part.
(2) Forging: Mainly shapes materials under high temperature through compression.
This process can refine the grains within the pieces.
Parts with relatively equal thickness are suitable for forming with sheet metal through stamping.
Parts with varying thicknesses, complex shapes and those that do not require heating are suitable for pressure casting.
1. Casting can be divided into two types: high pressure casting and low pressure casting. Simply put, after the metal is melted, the difference is in the pressure applied when injecting the metal into the mold, and the temperature of the heated metal and the casting machine used are also different.
2. Forging is a type of casting method, but it operates at a lower temperature, and some methods allow the metal to be shaped into a finished product in a semi-molten state.
3. Stamping is a process in which semi-finished products are shaped into finished products at room temperature using machines such as a punch press.
4. Die casting is a kind of high temperature casting method. When dealing with structurally complex and difficult-to-cast parts, a die casting machine can be used to melt metal to a liquid state, inject it into a mold, and then cool it. After cooling, the mold is opened to remove the product.
