Nodulizer is an additive that can promote the crystallization of graphite in ductile iron into a spherical shape. It is generally used in the field of cast iron casting. So do you know what types it has? What are the quality criteria? Next, let’s learn about it together with Lishi Industrial.
Types of nodulizers
1. Pure magnesium: This is a nodularizing agent commonly used abroad, and it is rarely used in China. The advantages and disadvantages of nodular iron are also obvious by adding magnesium under pressure;
2. Copper-magnesium and nickel-magnesium: Nodulizers used in my country in the early stage, but the cost is high, and the accumulation of copper and nickel in the returned charge is difficult to control, resulting in a decrease in toughness;
3. Silicon-magnesium-iron alloy: Generally, the lowest magnesium content is 3.5-4.5%, and the highest is 10-15%. The commonly used alloys are 5-10% magnesium and 42-47% silicon. The recovery rate is higher, but the low-magnesium nodulizer increases the amount of silicon increase in molten iron. This nodulizer is used to treat molten iron with low content of sulfur and anti-spheroidizing elements, and cast castings with medium section thickness. Currently, it is used in domestic To manufacture ductile iron in large quantities will have certain contradictions with the production conditions and raw material procurement of foundry enterprises in China;
4. Rare-earth magnesium alloys: including rare-earth silicon-magnesium, rare-earth calcium-magnesium, rare-earth copper-magnesium and other alloys, which are rare-earth magnesium series alloy nodulizers developed by Chinese engineers and technicians based on the reality of China in the early 1960s. The advantages and disadvantages of various spheroidizing elements, especially the rare earth magnesium calcium alloy, which is the main nodularizing agent widely used in China at present, have opened up a road of nodular cast iron manufacturing technology suitable for China’s national conditions.
Quality Judgment Standards
1. The magnesium oxide content in the nodulizer is about 10% of the magnesium content;
2. The spheroidizing agent is dense, without segregation, shrinkage cavity, shrinkage porosity, and pulverization;
3. The particle size distribution of the nodulizer is uniform, no powdery alloy, obtuse angle and multi-deformed particles are better;
4. Spheroidizing elements have a strong ability to change the shape of graphite from flake to spherical;
5. The density and boiling point of the nodulizer are lower than that of molten iron. The density is small and can automatically float in molten iron. The boiling point is lower than the treatment temperature of molten iron. Magnesium can be converted into a gaseous state at this treatment temperature and has a self-stirring effect. Improve nodularization.
A qualified nodulizer, in addition to its dense appearance and no inclusions, is more important in the content and uniformity of its chemical composition. The above is the introduction of nodulizers by Lishi Industrial. Contact with us for more informations about nodulizers!