Molybdenum, a transition metal with a high melting point and excellent corrosion resistance, is widely used in various industries. However, molybdenum has a high thermal conductivity and a strong affinity for oxygen, nitrogen, and carbon, which makes it challenging to weld. In this article, we will introduce the step-by-step process of welding thin molybdenum plates.
Before welding, ensure that the surface of the molybdenum plates is clean and free of oxides, grease, and other impurities. Grind or sand the surfaces using sandpaper or a grinder to remove any loose material or oxides. Rinse the plates with acetone or alcohol to remove any remaining impurities.
Brazing is a process that uses a filler metal with a lower melting point than the base metal to join two pieces of metal. It is commonly used in molybdenum welding to create a strong joint. Apply a thin layer of brazing material to the edges of the molybdenum plates to be joined. Heat the plates to the brazing temperature, which is slightly higher than the melting point of the brazing material but lower than the melting point of molybdenum. Hold the plates together until the brazing material flows and completely fills the joint.
Once the brazing material has cooled and solidified, you can proceed with the welding process. Preheat the plates to about 100°C above the melting point of molybdenum to prevent cracking and ensure good weld penetration. Using a welding torch or an electron beam welder, apply heat to the edges of the plates where they meet. The molybdenum will begin to melt and fill the joint. Continue to apply heat until the molybdenum flows into the joint and forms a strong weld.
- Post-weld Heat Treatment
After welding, conduct a post-weld heat treatment to relieve residual stresses and improve the mechanical properties of the weld. Heat the welded assembly to about 600°C and hold for about 30 minutes. Slowly cool the assembly to room temperature. This heat treatment will help ensure that the weld is as strong and ductile as possible.
After heat treatment, grind or sand any excess weld material or irregularities on the surface of the welded assembly. Rinse with acetone or alcohol to remove any remaining impurities. The finished assembly can then be used in various applications where molybdenum thin plates are required.
In conclusion, welding thin molybdenum plates requires careful preparation, precise Brazing and welding techniques, and post-weld heat treatment to achieve strong, reliable joints. By following these step-by-step instructions, you can successfully weld molybdenum thin plates for various industrial applications that require high corrosion resistance and temperature tolerance.