Features of structure formation during the decomposition of supercooled austenite of pipe steels with different chromium content

Abstract

The decomposition patterns of supercooled austenite in low-carbon pipe steels with variable chromium content (1-13%) and various alloying systems (Mn+Nb+V, Mo+Nb+V, Mn+Nb+Ti, Mo+Ni+Nb+V+Ti, Nb+V) were studied. Critical cooling rates and the structural components formed during these rates were determined. Based on the obtained data, metallographic principles for the production of seamless hot-rolled oil and gas pipeline and casing pipes were developed. Targeted setting of cooling temperature and rate parameters enables the achievement of the desired microstructure (bainitic-ferritic, bainitic-martensitic, martensitic-bainitic, or martensitic), which guarantees the achievement of strictly defined mechanical properties and operational reliability of finished pipe products with chromium content from 1 to 13%.