Development History and Distribution of Domestic Mandrel Pipe Mill Lines

Described in the paper is the development history of the domestic mandrel pipe mills as from the early 2-roll full-floating mandrel mill to the 3-roll retained mandrel mill.Also detailed are the rolling process characteristics of different mandrel mill plants，and the main aspects of currently-used domestic mandrel mill lines，including quantity，capacities，product mixes and regional distribution，etc.It is regarded by the co-authors that development of domestic mandrel pipe mills is so fast that such type of pipe mill has been the leading one for production of seamless steel tube and pipes.As for the demand for seamless steel tubes from the domestic market，need for small-sized hot-rolled pipes with diameters under Ф180 mm is rather flourishing， whereas that for large-sized hot-rolled tubes with diameters over Ф460 mm is rather weak.Moreover，the regional distribution of the mandrel mill line is unbalanced，while surplus trend of capacities is developing，and the homogeneity competitions are so fierce，due to the hard market situation with poor demand.Finally，it is concluded that companies concerned have to try to identify their own niches to make efforts for improving development quality and profitability.