What should be paid attention to in the selection of two-color molds?

1) Wear resistance: When the blank is deformed in the mold cavity, it flows and slides along the surface of the mold cavity, resulting in severe friction between the surface of the mold cavity and the blank, resulting in the failure of the two-color mold due to wear. Therefore, the wear resistance of the two-color mold material is one of the most basic and important properties of the mold. Hardness is the main factor affecting wear resistance. Generally speaking, the higher the hardness of the two-color mold parts, the smaller the wear and the better the wear resistance. In addition, wear resistance is also related to the type, quantity, form, size and distribution of carbides in the material.

(2) Strong toughness: Most of the working conditions of two-color molds are very poor, and some often bear large impact loads, resulting in brittle fracture. In order to prevent the two-color mold parts from breaking suddenly during the working process, the two-color mold should have high strength and toughness. The toughness of the two-color mold mainly depends on the carbon content, particle size and organizational state of the material.

(3) Fatigue fracture performance: During the working process of the two-color mold, under the long-term action of cyclic stress, fatigue fracture is often caused. Its forms include small energy repeated impact fatigue fracture, tensile fatigue fracture, contact fatigue fracture and bending fatigue fracture. The fatigue fracture performance of the two-color mold mainly depends on its strength, toughness, hardness and the content of inclusions in the material.

(4) High temperature performance: When the working temperature of the two-color mold is high, the hardness and strength decrease, resulting in early wear or plastic deformation failure of the mold. Therefore, the two-color mold material should have high stability against tempering to ensure that the two-color mold has high hardness and strength at the working temperature.

(5) Resistance to cold and heat fatigue: Part of the two-color mold is in a state of repeated heating and cooling during the working process, pulling the surface of the cavity, pressure stress, causing surface cracking and peeling, increasing friction, hindering plastic deformation, reducing dimensional accuracy, and leading to failure of the two-color mold. Cold and heat fatigue is one of the main forms of thermal mold failure, and it should have high resistance to cold and heat fatigue.

(6) Corrosion resistance: when some two-color molds, such as plastic molds, are working, because the plastic contains elements such as chlorine and fluorine, they will decompose and analyze HCI, HF and other strong corrosive gases after heating to erode the surface of the two-color mold cavity and increase the surface roughness. , aggravating wear failure. Therefore, materials with excellent corrosion resistance must be selected for two-color mold processing.