Analisis perbandingan proses penempaan dan penggulungan untuk keluli acuan

As a key material in industrial manufacturing, the production process of mold steel directly affects the performance and quality of the final product. Forging and rolling, as the two main metal forming processes, have their own characteristics in the production of mold steel.

Process principles and core differences

Forging is a process that causes plastic deformation of metal billets in the solid state through pressure or impact force, mainly including three methods: free forging, die forging, and tire die forging. During the forging process, the metal undergoes three-dimensional plastic deformation and grain structure reorganization, which can effectively eliminate as cast structural defects and improve material strength and ductility. As an advanced form of forging, die forging involves placing heated metal billets into a fixed shaped forging die chamber and deforming them under pressure. It has the advantages of precise size, complex shape, and high production efficiency, but the mold cost is high, making it suitable for large-scale production.

Rolling is a process of continuous two-dimensional pressing of metal billets through rolling mills, which is divided into hot rolling and cold rolling. Hot rolling is carried out above the recrystallization temperature, which can significantly reduce energy consumption and costs, improve metal processing performance, break down coarse grains in the casting state, and reduce or eliminate casting defects. The rolling process has high efficiency and is suitable for large-scale mass production, but there may be problems such as uneven tissue distribution and coarse grain size.

Microstructure and mechanical properties

The improvement effect of forging process on the microstructure of mold steel is significantly better than that of rolling. During the forging process, the grain size of the metal raw material is refined and ordered, with no hidden defects such as pores or inclusions inside, forming a complete fiber streamline structure. Experimental data shows that the grain refinement of forged steel can reach 1.5 times that of rolled steel, and the internal defect welding rate is higher. Especially when using the three-way forging process, it can effectively break the carbide structure of the steel ingot center segregation, the original defects inside the welded material, and significantly improve the material's heat resistance and fatigue resistance.

Due to the limitation of deformation mode, rolled steel may exhibit delamination, resulting in non-metallic inclusions being compressed into thin sheets and affecting material properties. Forged parts have better isotropy, while rolled parts have significant directional differences, which is particularly critical in the application of molds that withstand complex stresses. In terms of mechanical properties, forged die steel is usually superior to rolled products in toughness, fatigue life, and other aspects, especially suitable for manufacturing dies that can withstand high impact loads.


Typical Defects and Quality Control

Common defects in forging process include large grain size, uneven grain size, cold hardening phenomenon, cracks, etc. Large grain size is usually caused by high initial forging temperature and insufficient deformation degree, which reduces the plasticity and toughness of forgings; Uneven grain size can significantly reduce the durability and fatigue performance of forgings; The phenomenon of cold hardening increases the strength and hardness of forgings, but reduces plasticity and toughness, and in severe cases may cause forging cracking.

The quality problems of rolling process are mainly manifested as uneven distribution of microstructure, coarse grain size, substandard material composition, and easy occurrence of defects such as cracks, sand holes, and pitting. After processing, deformation, cracking, or short service life of the mold may occur. Especially for thicker rolled plates, it is more difficult to ensure quality stability, and quality cannot be guaranteed above a thickness of 200mm.