Cast high-temperature alloy and martensitic stainless steel diffusion welding method

Abstract

The invention discloses a cast high-temperature alloy and martensitic stainless steel diffusion welding method. According to percentage by mass: 55-60% of nickel powder, 25-30% of chromium powder and10-15% of molybdenum powder are uniformly mixed for ball milling, and then, are pressed as an intermediate layer; the intermediate layer is positioned between two welding base metals; the placed welding base metals and the intermediate layer are positioned between an upper pressing head and a lower pressing head of a vacuum hot pressing furnace; pre-pressure is applied to the welding base metals through the upper pressing head; the vacuumization is performed; after the temperature is increased to 980-1020 DEG C, the pressure is increased; the diffusion welding is performed after temperature and pressure maintenance by 1.5-2 h; then, the pressure is released; firstly, the slow cooling is performed; and then, the cooling along with a furnace is performed. The method is simple in process, high in operability and easy to popularize. The intermediate layer adopted by the welding method is the common component of the base metals; and the thermal expansion coefficient is within the base metalto achieve excellent transition between chemical properties and physical properties. After welding, the welding line compactness is high, the mechanical performance is excellent, and such defects ascracks and air holes are not generated.

Description

technical field [0001] The invention belongs to the field of solid-state connection of dissimilar materials, and relates to a method for diffusion welding of cast superalloy and martensitic stainless steel. Background technique [0002] Cast superalloys are metal structural materials that can work stably for a long time in high temperature and oxidative corrosion environments. The most important use in the aviation industry is to manufacture aeroengine turbine blades, guide vanes, turbine disks and other parts. Martensitic stainless steel has high thermal strength, not only high instantaneous strength at medium temperature, but also good medium temperature durability, creep resistance, stress corrosion resistance and cold and heat fatigue performance, suitable for manufacturing compressor blades, compressor discs, turbine shafts and other parts. [0003] The use of mechanical structures such as bolts and mortise teeth to connect the two materials increases the complexity of...

AI Technical Summary

Problems solved by technology

[0003] The use of mechanical structures such as bolts and mortise teeth to connect the two materials increases the complexity of the structure and processing costs, and at the same time increases the weight of the components and stress concentration; fusion welding methods such as electron beam welding and laser welding are prone to inclusions during the welding process , loose and thermal stress and other defects seriously reduce the mechanical properties of the joints; although friction welding can obtain better joints, the joint form is limited and cannot connect weldments with complex shapes; the joints obtained by brazing have low service temperature and low strength. It is difficult to take advantage of the advantages of steel and high-temperature alloys. In contrast, diffusion welding is an important way to obtain defect-free joints and complex component connections

However, there is currently no dissimilar material diffusion welding method suitable for casting superalloys and martensitic stainless steel. Research and development of the joining technology of these two materials has important practical value and broad prospects in the fields of aviation, aerospace, ships, and transportation.