Joining precipitation-hardened nickel-base alloys by friction welding

Solid state deformation welding process, friction welding, has been developed for joining precipitation hardened nickel-base alloys and other gamma prime-strengthened materials which heretofore have been virtually unweldable. Method requires rotation of one of the parts to be welded, but where applicable, it is an ideal process for high volume production jobs

Production of hollow components for rolling element bearings by diffusion welding

A hollow rolling element for a bearing is fabricated by diffusion welding hollow shells together. The hollow shell halves are joined by faying surfaces and diffusion welding

Fabrication of hollow ball bearings by diffusion welding

Two steel hemispheres are diffusion welded in an atmosphere of 0.00002 torr at a temperature of 2130 degrees F for 4 hours with a pressure of 4 psi holding the hemispheres together. Weld is accomplished with only microdeformation

Diffusion welding of a directionally solidified gamma/gamma prime - delta eutectic alloy

Hot-press diffusion welding parameters were developed for a directionally solidified, gamma/gamma prime-delta eutectic alloy. Based on metallography, a good diffusion weld was achieved at 1100 C under 34.5 MPa (5 ksi) pressure for 1 hour. In addition, a dissimilar metal weld between gamma/gamma prime-delta and IN-100 was successfully made at 1100 C under 20.7 MPa (3 ksi) pressure for 1 hour

Solid state welding processes for an oxide dispersion strengthened nickel-chromium-aluminum alloy

Solid-state welding processes were evaluated for joining TD-NiCrAl (Ni-16Cr-4Al-2ThO2) alloy sheet. Both hot-press and resistance spot welding techniques were successfully applied in terms of achieving grain growth across the bond line. Less success was achieved with a resistance seam welding process. In stress-rupture shear and tensile shear tests of lap joints at 1100 C, most failures occurred in the parent material, which indicates that the weld quality was good and that the welds were not a plane of weakness. The overall weld quality was not as good as previously attained with TD-NiCr, probably because the presence of alumina at the faying surfaces and the developmental TD-NiCrAl sheet, which was not of the quality of the TD-NiCr sheet in terms of surface flatness and dimensional control

Financial liberalisation in India and a new test of the complementarity hypothesis

This paper reappraises the financial repression hypothesis for India in the light of the partial liberalisation of the financial sector in the early 1990s, using for the first time, state-of-art multivariate cointegration and vector error correction models (VECM). From this robust test we find that for the Indian economy over the sample period 1951-1999 money and capital are complementary, suggesting that higher real interest rates will raise the demand for money and lead to higher levels of investment. Furthermore, testing for a structural break in the early 1990s – to coincide with the liberalisation of the financial sector in India – suggests that these reforms have not significantly changed the complementary relationship between money and capital. The policy implication is that further financial liberalisation is required in India, to enhance investment and economic growth

An investigation into the sources of fluctuation in real and nominal wage rates in eight EU countries: A structural VAR approach

This paper uses the SVAR approach to assess the degree of labor market flexibility –measured as the responsiveness of real and nominal wages to permanent and temporary shocks - in eight EU member states (France, Italy, UK, Netherlands, Poland, Hungary, Slovakia and the Czech Republic) with a view to assessing their suitability for Euro-area membership. It is found that for Hungary and the Czech Republic real wages are more responsive to real (permanent) shocks than some current members of the Euro zone, such as Italy. On the other hand, in Poland and Slovakia, real wage flexibility seems to be extremely low, making higher unemployment more likely than other EU countries and early euro-area membership unadvisable

Solid state welding of dispersion-strengthened nickel alloys

Two-step solid state welding cycle applied to carefully prepared surfaces of an unrecrystallized alloy prevents loss of parent-metal strength at weld joint of dispersion-strengthened, nickel-chromium alloy