Welding continued titanium alloys

Superabrasive tools, primarily PCBN, have been used to successfully weld ferritic steels, ferritic stainless steels, austenitic stainless steels, nickel-base superalloys. Invar, and Narloy-Z. Attempts to weld titanium with PCBN tools have been inconclusive. Tool life of 80 m (260 ft) has been demonstrated in FSW of 1018 steel, and very low tool wear has been reported on all other alloys. The primary concern in tool life continues to be fracture, and developments in PCBN grades continue to improve the fracture toughness of the FSW tools. The PCBN tools provide an extremely smooth finish when used for FSW or FSP. 

Type 409 stainless is an 11% chromium alloy stabilized with titanium. Its chemical composition will be foimd in Table 7.3. The material can be welded in the field, however, heat treatment improves corrosion resistance. It has a maximum allowable continuous operating temperature of 1300°F (705°C) with an intermittent operating temperature of 1500°F (815°C). It cannot be hardened by heat treatment. 

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