Showing papers on "Inconel published in 1971"

Some Problems in Welding Inconel 718 There are problems in welding Inconel 718—obtaining good penetration, micro-fissuring, and developing adequate impact strength and ductility—but these problems can be overcome by adequate control and selection of the proper solution heat treatments.

Abstract: Penetration In general, Inconel 718 has very good weldability. Welding tests were made using gas metal-arc (GMA) and gas tungsten arc (GTA) processes and satisfactory results were obtained. Welds were also made in the unaged and aged conditions and no major difficulties arose. The one problem always encountered was the difficulty of obtaining good penetration with the root pass. This is encountered in most nickel-base alloys and is due to the poor fluidity of the molten metal. It was therefore decided to study this aspect more closely and to try to

Carbide Sensitization and Intergranular Corrosloe of Nickel Base Alloys

Abstract: A thermodynamic theory has been used to predict the chromium content at equilibrium with chromium carbide particles and a matrix containing Ni-10Fe-16Cr for varying carbon contents and heat treatments Corrosion measurements and electron microscopic studies have been used to confirm the predictions made by the theory An important surface effect produced during the solution heat treatment is reported It is concluded that sensitization of Inconel 600 occurs by a chromium depletion mechanism similar to that which takes place in stainless steel

The effect of rapid thermal fluctuations on the creep rate in Inconel 718

Abstract: The creep properties of Inconel 718 under thermal cycling conditions were investigated. It was found that the creep rates under thermal cycling conditions are lower than the creep rates calculated from results of isothermal creep experiments. It was also found that an abrupt temperature decrease during steady-state creep is followed by a certain period of zero creep rate. It was shown that the decrease of strain rate during creep under cycling conditions is due to this stopping effect.

The rate of formation of intermetallic layers between aluminum and steel below 660°C

Abstract: The rate of formation of intermetallic compounds between aluminum and three ferritic steels, one austenitic steel, and Inconel has been determined by an electrolytic method. The steel was held at zero potential with respect to aluminum in a NaCl-AlCl3 melt, and the current measured. Comparison of measured thicknesses of intermetallic layers with those calculated from the integrated current gives an average deposition efficiency of 95 pct. For the Type 304 austenitic steel thickness \((mm) = k\sqrt {time}\) (min), andk is given by logk= −6400/T(0K) +4.469. The ferritic steels show a linear rate of growth of Al5Fe2, with an initial higher rate such that extrapolation of the linear curve back to zero time gives an intercept of 16±7 μm. The rate constants (mm min−1) may be represented by log (rate)=α/T+β, and the values of α and β are respectively −2650 and−0.788 for a plain carbon steel,−6580 and + 3.469 for a 1.3 pct Cr, 0.4 pct Mo steel, and−5950 and +2.466 for a 2.2 pct Cr, 0.9 pct Mo steel. The more highly alloyed steels are thus attacked, more slowly. Results for Inconel could not be fitted to any simple equation. With the ferritic steels growth is by aluminum diffusing inwards; with Inconel it is by nickel diffusing outward.

Effect of metallurgical reactions in INCONEL nickel-chromium-molybdenum alloy 625 on corrosion resistance in nitric acid

Abstract: Although INCONEL* nickel-chromium-molybdenum alloy 625 has good resistance to sensitization caused by carbide precipitation, some sampies of the material have been found to have less resistance than others. Laboratory studies of the precipitation reactions in the alloy give no indication that any particular phase is responsible for the increased corrosion rate. The studies do show, however, that the degree of sensitization is related to the total chromium content of the precipitates, and that control of processing, particularly annealing procedures, can produce material having maximum resistance to sensitization.

耐熱合金 Inconel 700のクリープ破断強度と疲労強度に及ぼす高温腐食ふん囲気の影響

Abstract: Hereunder is reported an experimental study made of the effect that the corrosive environment due to high temperature gives on the stress-rupture strength and the fatigue strength of Inconel 700 which is heat resisting Ni-base alloy.The experiments were carried out in such environments as residual fuel combustion gas, vanadium ash, mixture of vanadium ash and nickel sulfide and their combination at 700° and 750°C. The results are summarized as follows:(1) The strength of the alloy showed a remarkable declining tendency in sulfur-bearing environment.(2) The corrosive effect was found larger on the whole in the fatigue test than in the stress-rupture test. This is presumably due to the fact that the alloy is more sensitive to intergranular corrosion and notches under repeated stress than under static stress.(3) The estimation of the stress-rupture life of this alloy under gradually increasing stress caused by corrosion was investigated by using linear damage rule. The estimated life showed critical value when the corrosive environment is due to sulfur content.

Experimental Manufacture of Inconel Alloy 718 Compressor Rotor Blades from Metal Powder Preforms

Abstract: The objective of the program was to develop methods for making aircraft quality parts from forged Inconel Alloy 718 metal powder preforms. Aircraft quality parts were defined as those having room-temperature tensile and fatigue properties, and 1200 °F. tensile and 1300 °F. stress-rupture properties meeting aircraft specifications.