Mold industry is known as the "mother of manufacturing". Over the past three decades, in the process of China's gradual transformation to a global manufacturing center, China's mold industry is booming; high-end mold production has become the development direction of many domestic mold enterprises, the choice of high-quality mold steel as raw materials to obtain mold design performance, one of the most common indicators of mold materials is "purity".

What is steel purity: describes the number, type, form, size and distribution of non-metallic inclusions contained in the steel. The "non-metallic inclusions" generally refers to the residual oxygen, sulfur, phosphorus, hydrogen, nitrogen and other harmful inclusions in the mold steel, the lower the percentage of these inclusions in the unit volume, the higher the purity of the mold steel. . . .

The effect of cleanliness on mold performance, the purity of cast steel (the content of non-metallic inclusions) on the strength, ductility, crack resistance, cutting resistance, fatigue strength, thermal embrittlement and corrosion resistance has a great impact steel.

Strength: The larger the inclusions particles in the mold steel, the worse the mold strength, the greater the possibility of tire corners and scratches.

Polishing: non-metallic inclusions, especially oxide inclusions, can significantly affect the surface finish of the mold cavity, affecting the level of polishing, and can even lead to the completion of the processing of the entire mold and the detection of scrap when polishing.

Ductility: An increase in band inclusions (mainly sulfides) will result in a significant reduction in cross-sectional shrinkage.

Toughness: Increased sulfide content will reduce the various toughness of steel, steel fracture toughness will decrease with the number or length of inclusions, resulting in a decrease in mold toughness and cracking, fracture or chip inside the chip will occur chip design.

Fatigue resistance: inclusions will reduce the fatigue resistance of the mold, generally brittle inclusions (type A) and large foreign oxide inclusions are more pronounced, resulting in premature mold failure.

Welding characteristics: Sulfide inclusions and large oxide inclusions reduce the welding characteristics of the mold.

Corrosion resistance: The presence of compound inclusions leads to die pitting.

Cutting ability: Inclusions of aluminum oxide, calcium oxide, manganese oxide and calcium aluminate oxide greatly reduce the cutting ability of the steel.