Martensitic Stainless Steel Brazing by Using Ag-Cu- Ti as Active Filler Metal Alloys

Abstract

Brazing fillers for joining applications are essential to advanced material design and fabrication. Several types of brazing fillers have been developed in recent decades to join similar or different engineering materials. Important parts of automotive and aircraft components, including steel, are often joined by brazing. In this study, Similar samples of martensitic stainless steel were welded by the brazing method, using effective silver-based metal alloys. The brazing welding is done in inert gas atmosphere furnaces, by placing the samples in a special container filled with argon gas during the welding period and at a flow rate (10 to 15 minutes) inside a cylindrical furnace. Three types of metal alloys (silver, copper, and titanium) with different weight ratios of Ag, Cu, and Ti were used with a fixed welding time (10 minutes) at an appropriate temperature for each joint. A set of examinations and tests were conducted to find out the microscopic structure of the bonding site and the extent of the binder overlapping with the base material. Optical microscopy was used to study the microstructure of the weld joint. Optical and scanning electron microscopy (SEM) is used to study the joint microstructure. All joints of samples exhibited continuous bonding between the base metal and the filler metal, good wetting between the surfaces, and it was also noticed that the higher the proportion of titanium, the better the wetting between the surfaces., the greater the percentage of diffusion of the filler elements and the strength of the bonding with the base metal. The use of titanium-containing fillers in brazing is good for bonding in turbine blades of martensitic steel.

Keywords

• brazing
• filler metal
• microstructure
• bond phase