US 12,467,560 B2
High-strength and high-toughness bainite geological drilling pipe and manufacturing method therefor
Wen Sun, Shanghai (CN); Yaoheng Liu, Shanghai (CN); Zhonghua Zhang, Shanghai (CN); Ping Hu, Shanghai (CN); and Yannan Ma, Shanghai (CN)
Assigned to BAOSHAN IRON & STEEL CO., LTD., Shanghai (CN)
Appl. No. 18/547,172
Filed by BAOSHAN IRON & STEEL CO., LTD., Shanghai (CN)
PCT Filed Feb. 25, 2022, PCT No. PCT/CN2022/077848
§ 371(c)(1), (2) Date Aug. 21, 2023,
PCT Pub. No. WO2022/179595, PCT Pub. Date Sep. 1, 2022.
Claims priority of application No. 202110213765.3 (CN), filed on Feb. 25, 2021.
Prior Publication US 2024/0133490 A1, Apr. 25, 2024
Prior Publication US 2024/0229979 A9, Jul. 11, 2024
Int. Cl. F16L 9/02 (2006.01); C21D 1/84 (2006.01); C21D 6/00 (2006.01); C21D 8/10 (2006.01); C21D 9/08 (2006.01); C22C 33/04 (2006.01); C22C 38/00 (2006.01); C22C 38/02 (2006.01); C22C 38/04 (2006.01); C22C 38/06 (2006.01); C22C 38/12 (2006.01)
CPC F16L 9/02 (2013.01) [C21D 1/84 (2013.01); C21D 6/005 (2013.01); C21D 6/008 (2013.01); C21D 8/105 (2013.01); C21D 9/085 (2013.01); C22C 33/04 (2013.01); C22C 38/001 (2013.01); C22C 38/002 (2013.01); C22C 38/02 (2013.01); C22C 38/04 (2013.01); C22C 38/06 (2013.01); C22C 38/12 (2013.01); C21D 2211/002 (2013.01)] 13 Claims
OG exemplary drawing
 
1. A bainite geological drilling pipe, comprising the following chemical elements in percentage by mass:
0.14-0.22% of C, 0.2-0.55% of Si, 2.1-2.9% of Mn, 0.01-0.04% of Nb, 0.015-0.04% of Al, 0.001-0.005% of B, 0<N≤0.007%, with the balance being Fe and inevitable impurities, wherein
a content ratio of Al to N is Al/N≥3,
wherein the bainite geological drilling pipe achieves the following properties without the need for quenching and tempering heat treatment: yield strength is greater than or equal to 750 MPa, tensile strength is greater than or equal to 1100 MPa, hardness is greater than or equal to 35 HRC, toughness is greater than or equal to 60 J, and residual stress is less than or equal to 40 MPa.