Baoshan Iron & Steel Co., Ltd.

Leilei Sun

Guodong Xu

Lei Zheng

Hui Li

Jian Ming Liu

Bo Wang

Jian Liu

Chuanguo Zhang

Kougen Wu

Houjun Pang

Haisheng Xu

Mingzhuo Bai

Yong Zhang

Yan Shen

Shiqiang Xie

Steel for coiled tubing with a low yield ratio and ultra-high strength and a preparation method thereof, wherein the chemical composition of the steel in mass percentage is: C: 0.05-0.16%, Si: 0.1-0.9%, Mn: 1.25-2.5%, P&#x2264;0.015%, S&#x2264;0.005%, Cr: 0.51-1.30%, Nb: 0.005-0.019%, V: 0.010-0.079%, Ti: 0.01-0.03%, Mo: 0.10-0.55%, Cu: 0.31-0.60%, Ni: 0.31-0.60%, Ca: 0.0010-0.0040%, Al: 0.01-0.05%, N&#x2264;0.008%, and the rest being Fe and inevitable impurity elements. The chemical composition combines the technologies of low temperature finishing rolling and low temperature coiling to obtain an MA constituent+bainite+ferrite multiphase structure. The steel has a low yield ratio and ultra-high strength with the following specific properties: yield strength&#x2265;620 MPa, tensile strength&#x2265;750 MPa, elongation&#x2265;11%, and yield ratio&#x2264;0.83, and is suitable for manufacturing coiled tubing with ultra-high strength having a grade of 110 ksi or higher.

Steel for coiled tubing with low yield ratio and ultra-high strength and preparation method thereof

A X80 pipeline steel with good strain-aging performance comprises (wt. %): C: 0.02-0.05%; Mn: 1.30-1.70%; Ni: 0.35-0.60%: Ti: 0.005-0.020%; Nb: 0.06-0.09%; Si: 0.10-0.30%; Al: 0.01-0.04%; N&#x2264;0.008%; P&#x2264;0.012%; S&#x2264;0.006%; Ca: 0.001-0.003%, and balance iron and unavoidable impurities.

X80 pipeline steel with good strain-aging performance, pipeline tube and method for producing same

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Shanghai, China

Leilei Sun