公开(公告)号：US20220025474A1

公开(公告)日：2022-01-27

申请号：US17130354

申请日：2020-12-22

Applicant: Northeastern University

Inventor： Qibin YE ,  Qinghai WANG ,  Cheng ZHOU ,  Yong TIAN ,  Zhaodong WANG

IPC: C21D8/02 ,  C21D6/00 ,  C22C38/50 ,  C22C38/46 ,  C22C38/48 ,  C22C38/44 ,  C22C38/42 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/00 ,  C22C38/54

Abstract: The present invention discloses a 785 MPa level extra-thick quenched and tempered rack steel plate for offshore platforms and a preparation method therefor, wherein chemical components of the steel plate by weight percentage are: 0.08%-0.15% of C, 0.60%-1.5% of Mn, 0.10%-0.50% of Si, 0.002%-0.005% of S, 0.005%-0.015% of P, 2.7%-4.0% of Ni, 0.40%-1.00% of Cr, 0.30%-0.70% of Mo, 0.10%-0.40% of Cu, 0%-0.080% of Nb, 0%-0.10% of V, 0%-0.08% of Ti, 0.02%-0.08% of Al, 0.0008%-0.0015% of B, and the balance of Fe and other unavoidable impurities. The present invention adopts a low C, high Ni—Cr—Mo alloying and Nb—V—Ti microalloying component system, has a yield strength of ≥795 MPa, a tensile strength of ≥865 MPa, a −60° C. Charpy V-notch impact energy of ≥140 J, a Z value of ≥35%, and a maximum thickness of 100 mm, and can be used to manufacture racks for offshore platforms.

公开(公告)号：US20210108279A1

公开(公告)日：2021-04-15

申请号：US16897950

申请日：2020-06-10

Applicant: Northeastern University

Inventor： Xiangtao DENG ,  Zhaodong WANG ,  Hao WU ,  Tianliang FU ,  Yong TIAN ,  Jiadong LI

IPC: C21D8/02 ,  C21D1/02 ,  C21D1/18 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/08 ,  C22C38/20 ,  C22C38/22 ,  C22C38/24 ,  C22C38/32

Abstract: An ultrahigh-strength ultrahigh-toughness and low-density dual-phase lamellar steel plate is disclosed. The steel plate comprises the following alloy components in percentage by mass: 0.200-0.320% of C, 0.600-2.000% of Mn, 0.200-0.600% of Si, 2.000-4.000% of Al, 0.300-1.200% of Ni, 0.001-0.005% of B, P not greater than 0.012%, S not greater than 0.005%, and the balance of Fe and inevitable impurities. The steel plate consists of dual phases of ferrites and martensites, the ferrites are high-temperature delta ferrites, the martensites are lath martensites, the delta ferrites are distributed in the lath martensites in a lamellar mode. The steel plate has excellent mechanical properties, for example, the yield strength in the rolling direction is not less than 1000 MPa, the tensile strength is not less than 1600 MPa, the elongation is not less than 8.0%, and the average value of Charpy V-Notch impact energy at −40° C. is not less than 350J.

公开(公告)号：US20220002849A1

公开(公告)日：2022-01-06

申请号：US17130785

申请日：2020-12-22

Applicant: NORTHEASTERN UNIVERSITY

Inventor： Qibin YE ,  Liye KAN ,  Cheng ZHOU ,  Qinghai WANG ,  Yimin WANG ,  Yong TIAN ,  Zhaodong WANG

IPC: C22C38/46 ,  C22C38/42 ,  C22C38/44 ,  C22C38/02 ,  C22C38/04 ,  C21D8/02 ,  C21D8/00 ,  C21D9/46

Abstract: The present invention discloses a low-yield-ratio ultra-high-strength high-toughness steel for pressure hulls and a preparation method therefor, wherein the chemical components by weight percentage are: 0.05%-0.10% of C, 0.15%-0.35% of Si, 0.60%-1.00% of Mn, 0.10%-0.50% of Cu, 0.10%-1.00% of Mo, 0.40%-0.70% of Cr, 0.05%-0.15% of V, 5.00%-10.00% of Ni, and the balance of Fe and unavoidable impurities. The technical solution of the present invention adopts secondary quenching heat treatment, the first quenching is performed to achieve complete austenitizing, and then the second quenching and tempering are performed to finally obtain complex phase structures such as tempered martensite, critical ferrite and retained austenite, so as to meet the performance index requirements of low yield ratio, ultra-high strength and high toughness, and thereby promoting application in practice.