Feeding of high-nickel alloy castings

Abstract

Feeding of the nickel-based alloys CZ-100, M-35-1, and CW-12MW, as well as of the austenitic stainless steel CN-7M, is investigated, using a combination of casting experiments and simulation. Casting trials are performed at five foundries, to produce a total of 55 plates of varying lengths and radiographic soundness levels. In order to develop the property databases necessary to simulate the casting of these alloys, temperature data are recorded for each alloy during the casting trials. These measured data are used in conjunction with material property simulation to develop the necessary property data for each alloy, including the solidification path. These property data are used to simulate the casting trials. Good agreement between the simulation results and the radiographic testing (RT) results for the castings is obtained. A quantitative relation between the measured ASTM X-ray levels and the predicted minimum Niyama criterion value is established for all but the CZ-100 alloy, which does not appear to suffer from shrinkage defects. A large number of additional simulations are used to develop general feeding distance (FD) rules. The new rules are shown to provide accurate FDs for the casting trial plates. The FDs of the high-nickel alloys (except CZ-100) are found to be at least 25 pct shorter than those for typical low-alloy steels.