关于山东铝合金压铸粘模的那些东西，压铸粘模缺陷在实际生产中十分常见，直接影响产品的外观。如果严重，会导致铸件表面剥落、缺肉、应变和裂纹，特别是对有密封要求的铸件。粘模缺陷的实质是压铸合金与钢模具结合在一起，铸件材料粘在模具表面。在压铸过程中，金属液进入模具型腔，会对模具表面产生强烈的物理冲击，也会产生化学腐蚀。金属液对模具的物理化学作用会使模具表面产生小凹坑。每次注射都会引起模具表面的变化，模具表面的小凹坑会逐渐变大。随着时间的推移，凹坑会达到一定程度，使液态铝进入并与钢模结合。在模具表面会有一层致密的氧化层。当氧化层断裂并开始渗铝时，一种金属间化合物Al Fe Si开始形成。这些相以扩展的方式成长为钢，这种扩散受时间和温度的控制。此时出现粘铝缺陷。下面从四个方面分析粘铝因素及解决办法。
For those things of die casting die for aluminium alloy, the defect of die casting die is very common in actual production, which directly affects the appearance of products. If it is serious, it will lead to surface peeling, lack of meat, strain and crack, especially for the casting with sealing requirements. The essence of the sticking defect is that the die casting alloy is combined with the steel die, and the casting material is adhered to the surface of the die. In the process of die casting, the metal liquid entering the die cavity will have a strong physical impact on the surface of the die and also produce chemical corrosion. The physical and chemical action of liquid metal on the die will cause small pits on the surface of the die. Each injection will cause changes in the surface of the die, and the small pits on the surface of the die will gradually become larger. With the passage of time, the pit will reach a certain extent, so that liquid aluminium can enter and bond with the steel die. There will be a dense oxide layer on the surface of the die. When the oxide layer breaks and aluminizing begins, an intermetallic compound, Al-Fe-Si, begins to form. These phases grow into steel in an expanding manner, and this diffusion is controlled by time and temperature. At this time, sticky aluminium defect appears. The following four aspects are analyzed for the factors of sticking aluminium and the solutions.
1. Mould and Surface Coating
Adhesive aluminium is a complex process of mechanical wear and chemical reaction for the die. There are many damages on the surface of the die. If it is serious, it will lead to the failure of the die. Dies need to use good materials, reasonable surface treatment, can effectively reduce the adhesion of aluminum.
2. Mould material
对于铝合金压铸模具钢应具有:1)优良的高温强度和韧性;2)具有良好的高温耐磨性和热疲劳性能;3)良好的热处理和可加工性。如表1所示，常用的模具钢包括中国制造的4Cr5Mo Si V钢、瑞典yishengbai的8407钢、日本的SKD61钢和美国的H13钢。模具制造商应根据实际生产需要选择合适的模具材料。
For aluminium alloy die casting die steel, it should have: 1) excellent high temperature strength and toughness; 2) good high temperature wear resistance and thermal fatigue performance; 3) good heat treatment and machinability. As shown in Table 1, the commonly used die steels include 4Cr5Mo Si V steel made in China, 8407 steel made in Yishengbai, Sweden, SKD61 steel made in Japan and H13 steel made in the United States. The mould manufacturer should select the appropriate die material according to the actual production needs.
3. Hardness of Die Surface
The surface hardness of the die is not enough and the wear resistance is poor. Thermal fatigue failure, cracks and pitting corrosion will occur in the die, and then bonded aluminium will occur. If the surface hardness of the die is too high, brittle cracking will occur in the die. Therefore, it is necessary to choose a reasonable die surface hardness. For example, the optimum hardness of H13 steel after quenching is 44-48 hrc, and then different structural parts are refined. In order to improve toughness and avoid early cracking, the hardness of large holes can be reduced appropriately. The failure of core material is mainly caused by bending deformation, and the failure of crack is relatively rare, which can reduce the toughness of core material and improve the hardness of core material. For large size aluminum alloy castings or dies with complex shape and structure, heat treatment process is very difficult, and the hardness can be reduced appropriately. On the contrary, the hardness of small and medium-sized aluminium alloy die-casting dies can be improved appropriately.
4. Surface roughness of die
The surface of the die should have reasonable roughness. Too much roughness will cause great damage to the die, but the smaller the roughness, the better to avoid excessive polishing of the die surface. The surface of the die can be sandblasted, oxidized and polished with fine sand paper, which is beneficial to the uniform distribution of the release agent, and also can prevent the bonding between mirror die casting alloy and the die surface, and make the die surface produce pinholes. The recommended surface roughness of the die is shown in Table 2.
表面涂层对模具的保护非常重要。常用的处理方法有CVD涂层、PVD涂层、氧化、氮化和各种条件下的盐浴处理。渗氮处理可能是模具处理中最常用的处理方法。它对侵蚀也非常有效。然而，不当的处理可能会破坏耐热开裂性能。氧化处理也是一种常用的处理方法。第一次使用时稍微氧化模具。通常在空气或纯氧环境中加热到450 - 550 ?,保持1-2h,模具表面产生1 - 10微米氧化层、氧化层主要由C、硅和铁氧化物,研究已经证实,氧化层在模具有很大的保护作用,可以极大地抵抗腐蚀磨损。从第一阶段的研究结果来看，氧化层的产生和控制可能是未来模具表面处理的最重要方向。然而，考虑到模具失效的原因是多方面的，在模具加固过程中很难用单一的表面处理来抵抗各种形式的失效，许多研究已经开始考虑设计复合涂层系统。
Surface coating is very important for mould protection. Common treatment methods include CVD coating, PVD coating, oxidation, nitriding and salt bath treatment under various conditions. Nitriding treatment may be the most commonly used treatment method in die treatment. It is also very effective for erosion. However, improper treatment may damage the thermal cracking resistance. Oxidation treatment is also a common treatment method. The mould is slightly oxidized for the first time. Usually heated in air or pure oxygen environment to 450-550?, and maintained for 1-2 hours, the surface of the die produces 1-10 micron oxide layer, which is mainly composed of C, silicon and iron oxides. Research has confirmed that the oxide layer has a great protective effect on the die and can greatly resist corrosion and wear. From the research results of the first stage, the generation and control of oxide layer may be the most important direction of surface treatment of die in the future. However, considering that the causes of die failure are various, it is difficult to use a single surface treatment to resist various forms of failure in the process of die reinforcement. Many studies have begun to consider the design of composite coating system.
After the die is bonded with aluminium, the traditional method is polishing with grinding wheel and asphalt, which is easy to cause die damage. Sodium hydroxide solution can also be used for cleaning treatment, the damage to the die is relatively small, but it is not easy to be thoroughly treated, and the price is slightly higher.
There are many factors that cause the defect of bonded aluminium. This paper analyses the causes of sticky aluminium from four aspects, and puts forward corresponding countermeasures, which have certain reference value for die casting industry.