Due to the globalization of technology brought about by economic globalization, domestic companies, foreign companies, and foreign companies have different levels of technology. Therefore, most of our situation today cannot be divided into domestic or foreign. The development of the mold industry must be viewed from the entire world. .
1. Development status of mold materials for automobile manufacturing
With the development of automobile manufacturing technology, the working conditions of molds are becoming more and more demanding, and the performance, quality and variety of molds are constantly raising higher requirements. New mold steel and cast iron adapted to different requirements, and have done a lot of work on variety, quality, production technology and production equipment, and made great progress.
1. Rapid development and serialization of die steel
Plastic mould steel can be divided into:
(1) Steel for small size molds, medium carbon quenched and tempered steel.
(2) Steel for large and medium-sized molds, pre-hardened medium-carbon low-alloy steel.
(3) Sulfur, lead and pre-hardened free-cutting die steel for improving cutting performance.
(4) Aging steel and maraging steel. Used to make complex, precise and clean molds.
(5) Cold work and hot work molds with high hardenability. It is used to manufacture the overall quenching mold.
(6) Carburized plastic mold.
(7) Corrosion-resistant plastic mold.
(8) Mirror polishing mold.
2. Developed advanced cold and hot work die steel
The general cold work die steel is divided into three categories: low alloy cold work die steel, such as 9CrWMnV, medium alloy cold work die steel Cr5Mo1V and high alloy cold work die steel Cr12Mo1V1, etc. In addition, the following new cold work die steels have been developed:
(1) High-tenacity, high-abrasion-resistant cold work die steel such as 8Cr8Mo2V2Si, Cr8Mo2VWSi in the United States, QCM8 (8Cr8Mo2VSi), DC53 (Cr8Mo2VSi), TCD (Cr8V2MoTi), etc. in Japan. This type of steel has many advantages. The carbides in the structure are fine and dispersed, the bending strength is high, the fracture toughness, wear resistance, machinability, grindability and tempering resistance are good, and the heat treatment deformation is small. Become a general-purpose mold steel.
(2) Flame quenching cold work die steel 7CrMnSiMoV is the most commonly used. In addition, there are SX5 (Cr8MoV) in Japan and CC # 1 in the United States. It is characterized by a wide quenching temperature range, high hardenability and easy and easy flame quenching.
(3) Powder metallurgy cold work die steel The powder metallurgy method can produce ultra-high carbon, high alloy (especially high vanadium content), high wear resistance die steel, and carbon-based titanium carbide that are difficult to produce by conventional processes. For example, the German X320CrVMo135, wC> 3%, wV> 5%, the area of fine, dispersed carbides reaches 50%, and its life is longer than that of cemented carbide molds.
The development of hot work die steel is also rapid. Three types of general-purpose hot work die steels are the most used: low alloy hot work die steels are 5CrNiMo and 5CrMnMo; medium alloy hot work die steels are 4Cr2MoVNi, H11 (4Cr5MoSiV), H13 (4Cr5MoSiV1), H12 (4Cr5MoWSiV) and H10 4Cr3Mo3SiV1); H21 (3Cr2W8V) is the most widely used high-alloy hot work die steel. In addition, a series of high-performance hot work die steels have been developed, mainly including the following:
(1) Base steel The chemical composition of the base steel is equivalent to the chemical composition of the base structure of the high-speed steel after quenching, so the amount of eutectic carbides remaining after quenching is small, and the carbides are fine and dispersed after tempering. The strength and toughness of the steel And thermal fatigue performance is good. Such as Vasco MA in the United States.