HOW the metallurgists of industry have been forced to develop virtually a new series of National Emergency (NE) steels because the original specifications were outmoded by the huge demand on molybdenum, is explained by the author, whose services as a member of the working committee, and whose company, have been in the forefront of this metallurgical wonder of all time.
Development work which would have ordinarily taken some 10 years was crowded into a space of a few weeks. A feature of the work was digging into old files which otherwise might have gathered dust until dumped into the ashcan. The interchange of information between users and steel makers set a new high for voluntary cooperation. But the author warns that the present level of knowledge is based only upon laboratory tests and must be proceeded upon with caution.
The NE 9420 appears to be satisfactory, Mr. Roush says, as a substitute gear steel for the former NE 4120, and may probably be used as a substitute for the NE 4620 specification. However, it does not appear to be warranted as a substitute for the NE 4320 or NE 4820. For these, he reported, the NE 8720 does appear to be satisfactory.
A great deal more work will have to be done before designers can be sure of the newest substitutes for substitute steels, he concludes, but counts this effort to save critical materials a factor in winning the war.
