公开(公告)号：US20220205082A1

公开(公告)日：2022-06-30

申请号：US17564616

申请日：2021-12-29

Applicant: GM GLOBAL TECHNOLOGY OPERATIONS LLC

Inventor： Qi LU ,  Jianfeng WANG

IPC: C23C16/06 ,  C23C16/44 ,  C23C16/02 ,  C22C38/18 ,  C22C38/02

Abstract: A method of manufacturing zinc-coated steel having a reduced susceptibility to liquid metal embrittlement (LME) according to various aspects of the present disclosure includes providing a steel substrate including iron, carbon in amount ranging from about 0.01-0.45 weight percent, chromium in an amount ranging from about 0.5-5 weight percent, and silicon in an amount ranging from about 0.5-2.5 weight percent. The method includes forming an oxide-containing layer on a surface of the steel substrate by annealing the steel substrate in an oxygen-containing atmosphere. The method further coating a zinc layer on the oxide-containing layer by a spray coating process. In certain aspects, the present disclosure also provides a method of forming an assembly having a reduced susceptibility to LME via resistance spot welding. The present disclosure also provides, in various aspects, a zinc-coated steel component including a steel substrate, an oxide-containing layer, and a zinc layer.

公开(公告)号：US20210276065A1

公开(公告)日：2021-09-09

申请号：US17251655

申请日：2018-06-19

Applicant: GM GLOBAL TECHNOLOGY OPERATIONS LLC

Inventor： Jiachen PANG ,  Qi LU ,  Jianfeng WANG

IPC: B21D22/02 ,  C21D1/673 ,  C21D1/19 ,  C21D1/76 ,  C22C38/14 ,  C22C38/12 ,  C22C38/06 ,  C22C38/04

Abstract: A method of forming a shaped steel object is provided. The method includes cutting a blank from an alloy composition including 0.05-0.5 wt. % carbon, 4-12 wt. % manganese, 1-8 wt. % aluminum, 0-0.4 wt. % vanadium, and a remainder balance of iron. The method also includes heating the blank until the blank is austenitized to form a heated blank, transferring the heated blank to a press, forming the heating blank into a predetermined shape to form a stamped object, and decreasing the temperature of the stamped object to a temperature between a martensite start (Ms) temperature of the alloy composition and a martensite final (Mf) temperature of the alloy composition to form a shaped steel object comprising martensite and retained austenite.

公开(公告)号：US20210189531A1

公开(公告)日：2021-06-24

申请号：US17128588

申请日：2020-12-21

Applicant: GM GLOBAL TECHNOLOGY OPERATIONS LLC

Inventor： Qi LU ,  Jianfeng WANG

IPC: C22C38/18 ,  B21D22/02 ,  C21D1/18 ,  C22C38/02 ,  C22C38/04

Abstract: A press-hardened steel component after hot forming including an alloy composition including carbon at a concentration of greater than or about 0.01 wt. % to less than or about 0.2 wt. %, chromium at a concentration of greater than or about 0.5 wt. % to less than or about 6 wt. %, manganese at a concentration of greater than or about 0.5 wt. % to less than or about 4.5 wt. %, silicon at a concentration of greater than or about 0.5 wt. % to less than or about 2.5 wt. %, and a balance of the alloy composition being iron, wherein the press-hardened steel component includes greater than or 90 volume % martensite and bainite, has an ultimate tensile strength of greater than or about 800 megapascals to less than or about 1,200 megapascals and a VDA 238-100 bending angle of greater than or about 60° to less than or about 80°.

公开(公告)号：US20210187906A1

公开(公告)日：2021-06-24

申请号：US17128631

申请日：2020-12-21

Applicant: GM GLOBAL TECHNOLOGY OPERATIONS LLC

Inventor： Qi LU ,  Jianfeng WANG

IPC: B32B15/01 ,  C21D9/46 ,  C21D6/00 ,  B23K20/04 ,  B21D22/02

Abstract: A press-hardened steel assembly after hot stamping/hot forming including a core layer having a tensile strength of ≥about 1,800 megapascals to ≤about 2,200 megapascals and ≥about 90 volume % martensite, the core layer having a first thickness ≥about 40% to ≤about 96% of the thickness of the press-hardened steel assembly; and a first surface layer along a first surface of the core, the first surface layer having a tensile strength of ≥about 800 megapascals to ≤about 1,200 megapascals and ≥about 90 volume % martensite and bainite. The press-hardened steel assembly has a tensile strength of ≥about 1,600 megapascals to ≤about 2,000 megapascals and a VDA 238-100 bending angle of ≥about 50° to ≤about 80°.

公开(公告)号：US20210002746A1

公开(公告)日：2021-01-07

申请号：US16460369

申请日：2019-07-02

Applicant: GM GLOBAL TECHNOLOGY OPERATIONS LLC

Inventor： Qi LU ,  Jianfeng WANG

IPC: C22C38/02 ,  C22C38/04 ,  C22C38/22 ,  C22C38/24 ,  C22C38/26 ,  C22C38/32 ,  C21D1/18

Abstract: A press-hardened steel is provided. The press-hardened steel has an alloy matrix including from about 0.01 wt. % to about 0.35 wt. % carbon, from about 1 wt. % to about 9 wt. % chromium, from about 0.5 wt. % to about 2 wt. % silicon, and a balance of iron. The alloy matrix is greater than or equal to about 95 vol. % martensite. A first layer is disposed directly on the alloy matrix. The first layer is continuous, has a thickness of greater than or equal to about 0.01 μm to less than or equal to about 10 μm, and includes an oxide enriched with chromium and silicon. A second layer is disposed directly on the first layer, and includes an oxide enriched with Fe. Methods of preparing the press-hardened steel are also provided.