Moves by Corus to shut steelworks in Ebbw Vale, Llanwern and works in North-east England and Teesside will result in the loss of about 6000 jobs.
Industry members said they felt confident that the firm would not risk losing customers within construction, which accounts for about 30% of the company's output.
A steel industry source said: "I cannot imagine that anything as important to them as the construction market would be in any way left uncovered. They have made these moves after doing a very detailed assessment of the company and looking at it from every perspective." One source said: "The construction service centre that they set up last year went a long way to giving a better service to the industry. It used to be shambolic. I feel they are committed to construction, particularly as the market looks to be growing steadily."