Application Of Rare Earth Elements In Cast Iron

Rare earth elements are widely used in steel welding materials, and their unique chemical and physical properties have a significant impact on the performance of welding materials.

1. Purifying welds and improving welding quality

Rare earth elements have strong chemical activity and can combine with impurities such as sulfur, oxygen, and nitrogen in steel to form stable rare earth inclusions, thereby reducing the harmful effects of these impurities and improving the purity of steel. Adding rare earth elements to the weld seam can have the effect of deoxidation and desulfurization, change the shape of sulfide inclusions, increase the resistance to crack propagation, thereby reducing the occurrence of hot cracks, improving the toughness, plasticity, and welding quality of the weld seam.

2. Refine grain size and improve microstructure

Rare earth elements can effectively refine the grain structure of steel, reduce the grain boundary area, and thus improve the strength and toughness of steel. This refining effect is mainly achieved through the reaction between rare earth elements and impurity elements in steel, forming rare earth inclusions that hinder grain growth during the crystallization process. In addition, rare earth elements can also promote the precipitation of harmful elements such as phosphorus and sulfur in steel in the form of rare earth inclusions, thereby reducing the adverse effects of these elements on the properties of steel.

3. Improve the performance of welded joints

Adding rare earth elements to welding rods can significantly improve the tensile strength, corrosion resistance, and plasticity of welded joints. Rare earth elements participate in a series of chemical reactions in welded joints, forming certain oxide films and phosphate films, thereby increasing the corrosion resistance of the joints. At the same time, rare earth elements can also introduce unique elements into steel structures, enhance intermolecular forces, and thus play a role in adjusting the structure and improving its plasticity before the critical plasticity of welded joints.

4. Improve welding performance

For steel structures that require high-power line energy welding, adding rare earth elements can enhance their welding performance. Rare earth elements can reduce the generation and propagation of cracks during the welding process, making the welded joint more stable and reliable. In addition, rare earth elements can improve the physical properties such as electromagnetic performance, thermal conductivity, and thermal expansion coefficient of welds, making them more suitable for various complex welding environments.