The Commerce Department on Friday took its broadest swipe yet at China’s supercomputing industry, imposing new export restrictions that effectively bar five major Chinese developers of next-generation, high-performance computing from obtaining U.S. technology.

Meanwhile, statistics reviewed by The Wall Street Journal show the Commerce Department has cut in half the number of licenses for U.S. tech companies to assign Chinese nationals to advanced engineering projects. The actions are the latest in a series of steps to keep...