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By way of contrast, steel-collar, which dates from approximately 1982, American Speech, Vol. 59, p. 68. shows signs of becoming a permanent part of the language; for robots "who" have been called steel-collar workers and a steel-collar workforce, appear to be the wave of the future where industry is concerned.
Robots have also been referred to as iron-collar workers, but I doubt that iron-collar will be able to compete successfully with steel-collar.