Furen XIAO
,
Mingchun ZHAO
,
Yiyin SHAN
,
Bo LIAO
,
Ke YANG
材料科学技术（英）
Acicular ferrite microstructure was achieved for an ultralow carbon pipeline steel through the improved thermomechanical control process (TMCP), which was based on the transformation process of deformed austenite of steel. Compared with commercial pipeline steels, the experimental ultralow carbon pipeline steel possessed the satisfied strength and toughness behaviors under the current improved TMCP, although it contained only approximately 0.025% C, which should mainly be attributed to the microstructural characteristics of acicular ferrite.
关键词:
Pipeline steel
,
null
,
null
Jinbo QU
,
Yiyin SHAN
,
Mingchun ZHAO
,
Ke YANG
材料科学技术（英）
The transformation behaviours and microstructural characteristics of three low carbon microalloyed steels were investigated. In particular, the effects of deformation and cooling conditions were studied by means of compression tests. It was found that at higher cooling rate (45℃/s), the transformation products was mainly granular bainite, the intragranular nucleated bainitic ferrite grew in different directions, and the second phase particles of M/A constituent uniformly distributed in the bainitic ferrite matrix. When the cooling rate was decreased to 25℃/s or 15℃/s, the resulting microstructure was converted to a mixture of polygonal hypoeutectoid ferrite and granular bainite, whose percentage was reduced. As the cooling rate was lowered to 8℃/s, the microstructure consisted chiefly of polygonal ferrite with a few amounts of M/A and pearlite.
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