Up to 70 jobs at two British Steel sites in the north-east of England could be lost, the company has warned.
Plans for Skinningrove and Darlington are aimed at cutting costs and improving competitiveness, it said.
Peter Gate, managing director for special profiles - a steel shape with a specific cross section and composition - said the firm was "striving to become a global leader" in the product.
But it needed to be "more flexible and more efficient" to do so, he said.
This sector of the company was now making a profit but it "must become even more competitive" if the firm was to grow and win more orders, he said.
The Community union said it had received assurances there would be no compulsory redundancies.
Union national officer Steve McCool said it would "make sure this principle is upheld".
India's Tata Steel sold the sites last year, along with the Scunthorpe steelworks, to UK investment fund Greybull, which revived the British Steel name.