Filler metal

About: Filler metal is a research topic. Over the lifetime, 11152 publications have been published within this topic receiving 86590 citations.

Infrared brazing of Ti-6Al-4V and 17-4 PH stainless steel with (Ni)/Cr barrier layer(s)

Abstract: Infrared brazing of Ti-6Al-4V and 17-4 PH stainless steel using the BAg-8 filler metal was performed in this study. A nickel barrier layer 10 µm thick was introduced on the 17-4 PH stainless steel before infrared brazing. For the specimen that was infrared brazed at 800 °C and 850 °C for less than 300 seconds, the Ni layer served as an effective barrier layer to prevent the formation of Ti-Fe intermetallics. Experimental results show that the average shear strength of the joint can be greatly improved for the specimen by Ni plating. Comparing the specimens with and without electroless-plated Ni film, the former has no Ti-Fe intermetallic compound, but interfacial CuNiTi and NiPTi phases are observed in the latter. The fractured location of the joint after the shear test is changed from the interfacial TiFe (without Ni plating) into the TiCu reaction layer (with Ni plating). The plated Ni layer is consumed for the specimen that was infrared brazed at 880 °C for 300 seconds, and its bonding strength is impaired. Consequently, a lower brazing temperature and/or time are still preferred even though a plated Ni barrier layer is applied.

Interlayer design for joining pressureless sintered sialon ceramic and 40Cr steel brazing with Ag57Cu38Ti5 filler metal

Abstract: An interlayer design and test was made to enhance the joining strength of the pressureless sintered sialon ceramic and 40Cr steel. Joining was performed by vacuum brazing using Ag57Cu38Ti5 filler metal. The joint strength was evaluated by four-point bending. A strong interfacial bond of the Ag57Cu38Ti5 filler metal on the sialon ceramic with formation of Ti2AIN, Ti5Si4 and TiAg was obtained at brazing temperatures over 1123 K, which could be weakened by a brazed metal such as Kovar or Ni-15Cr-15Co alloy. The joint strength of sialon ceramic with 40Cr steel can be improved by using a layer of soft interlayer such as Cu with a suitable thickness, particularly by the composite interlayer such as Cu/Nb alloy, Cu/Ta, Cu/Mo etc. The maximum strength of the ceramic/steel joint, 280 MPa, was obtained by using Cu/Nb alloy as interlayer and brazing at 1153 K for 5 min. Finally, we discuss how to design an interlayer in ceramic/metal joining.

Method and Apparatus for Repairing Damaged Tubes

Abstract: A laser welding apparatus (320) for clad welding the interior surface of a tube (20) is disclosed. The apparatus includes a rotating sleeve (324) positionable within the tube. Located within the rotating sleeve is a fiber optic cable (340) and a filler passage (386). The fiber optic cable receives laser energy from a laser (344). The filler passage receives filler material from a fillermetal delivery system (330) that synchronously moves with the rotating sleeve. Positioned at the end of the rotating sleeve is a welding head (322) which includes a head aperture (394) and a laser energy directional modification assembly (392). The laser energy from the fiber optic cable is transferred through the laser energy directional modification assembly and through the head aperture to a selected weld location on the interior surface of the tube. The filler metal from the filler metal delivery system is also conveyed through the head aperture and intersects with the laser energy at the selected weld location. The filler metal fuses with the interior surface of the tube to produce a clad weld.