Like steel bars going through a rolling mill, America's heavy industries are being squeezed into new shapes by the current recession.
One obvious and well-documented effect, say observers here in the nation's ''smokestack'' belt, is a substantial loss of manufacturing jobs.
But there is also evidence of a less visible but more positive result: a fundamental smoothing out of the historically rough relationship between labor and management.
Few expect this shift away from labor-management confrontations to be easy, or uninterrupted. There is still a strong strain of labor militancy in American industry, particulary among older workers who recall hard bargaining in the past.
And despite the threat of plant closings, workers are still willing at least to consider strikes - as today's (Oct. 26) balloting by United Automobile Workers (UAW) members at Chrysler Corporation demonstrates. Having voted down a tentative contract negotiated earlier by their own union leaders, Chrysler's 43, 200 hourly workers must now decide whether to strike on Nov. 1 or reopen negotiations after Christmas.
''You don't break down barriers that have been built up over 40 years overnight,'' says Gary Westwater, superintendent of employee relations at United States Steel's Irvin Works near Pittsburgh.
But so profound is the underlying shift in attitudes that some corporate executives are beginning to sound like union officials - and vice versa. For example:
* ''The relationship of management and labor must draw closer than ever before,'' says a personnel expert from Detroit. He adds that ''in too many cases , the quality of the product has not been put in the hands of those (hourly workers) who primarily deal with it.''
A union official? No. The words are from Alfred Warren, General Motors vice-president for industrial relations, who negotiates the company's labor contracts.
* On the other hand, an economist from Pittsburgh complains that too many rank-and-file workers are committed to a ''totally adversarial relationship'' between labor and management, adding that ''these ways of thinking are not competitive in the 1980s.''
A corporate manager? No, he's James Smith, assistant to the president and head of research for the United Steel Workers of America, the powerful industrywide union.
Speaking about labor-management relations to a conference at Indiana University of Pennsylvania, consultant -Robert Loekle emphasized that ''we're in a period of change.'' His point: ''We must learn to work out problems of the workplace as we work them out in the community'' - in other words, without antagonism and strikes.
These and other longtime observers of American industry foresee a drawing together of labor and management in the face of their common enemy: a worldwide market slump. America's steel industry is running between 40 and 45 percent capacity.And GM, says Mr. Warren, has already laid off 147,000 workers and is ''facing the greatest crisis we have ever faced.''
With further industrial plant closings a possibility, the unions would seem to have an obvious reason to moderate their demands. American workers have long been accused of being overpaid compared with their foreign counterparts (although union officials reply that lower-paid Japanese workers receive subsidized housing, utilities, and medical care).
The UAW, in particular, has already granted some concessions - notably at GM, where workers agreed this year to surrender some benefits to help the company remain competitive. And the Steelworkers' Mr. Smith, noting the large gap between his members' wages and those of other US workers, admits that ''we're going to have to make some adjustments.''
But the change in attitude is coming from management as well. In the past several years, Warren says he has sought much closer contacts with UAW leaders - and shared information with them in ways that 10 years ago would have been unthinkable.
He gives much of the credit to GM's widely admired ''quality of worklife'' program, which has solicited worker input on everything from the placement of water fountains to production schedules. As a result, he says approvingly, ''the fine line between what is management prerogative and what is union right is beginning to blur,'' and numerous decisions are now being made ''at the lowest possible level.''
In early November, he says, GM will announce an even more innovative step. Imitating a Japanese strategy, GM will announce the names of four plants in a project that guarantees workers lifetime employment.
Why is industry willing to go to such lengths?
Partly, say observers, for immediate financial gain - arising from the increased productivity of workers who feel they share in plant decisions. ''When you have a worker who's happy,'' says Mike Bonn, a burly, Serbian-speaking steelworker with a handlebar mustache, ''he produces a better product.''
Increased morale may also reduce absenteeism, which management and unions are working together to combat.
Corporate officials may also be jockeying for position in preparation for new waves of automation. GM now has 417 robots. By 1990, says Warren, it will have 14,000. Steven Miller of Carnegie-Mellon University estimates that there are about 2 million manufacturing jobs that could be ''robotized'' today. The introduction of new technology, however, worries union officials who fear further job losses.
But the real reason for changing attitudes may be that the old models of labor-management relations have been exhausted. ''I know of no other route left to us,'' says Warren, adding that ''this is a time for desperate measures - good desperate measures.