Hyun Yun Jun, 57302 Redwing Dr, Bannockburn, IL 60015

2020034, Nov 5, 2020

Jul 16, 2020

16/931001

- Luxembourg, LU
Hyun Jo Jun - East Chicago IN, US
Dongwei Fan - East Chicago IN, US

C21D 9/46
B32B 15/01
C23C 2/02
C23C 2/06
C23C 2/40
C21D 8/02
C21D 1/18
C22C 38/02
C22C 38/38
C22C 38/34
C22C 38/06
C22C 38/58

A method is for producing a high strength coated steel sheet having a yield stress YS>800 MPa, a tensile strength TS>1180 MPa, and improved formability and ductility. The steel contains: 15%≤C≤0.25%, 1.2%≤Si≤1.8%, 2%≤Mn≤2.4%, 0.1%≤Cr≤0.25%, Al≤0.5%, the remainder being Fe and unavoidable impurities. The sheet is annealed at a temperature higher than Ac3 and lower than 1000 C. for a time of more than 30 s, then quenched by cooling it to a quenching temperature QT between 250 C. and 350 C., to obtain a structure consisting of at least 60% of martensite and a sufficient austenite content such that the final structure contains 3% to 15% of residual austenite and 85% to 97% of martensite and bainite without ferrite, then heated to a partitioning temperature PT between 430 C. and 480 C. and maintained at this temperature for a partitioning time Pt between 10 s and 90 s, then hot dip coated and cooled to the room temperature.

2020022, Jul 16, 2020

Mar 23, 2020

16/827696

- Luxembourg, LU
Hyun Jo JUN - EAST CHICAGO IN, US
Rashmi MOHANTY - EAST CHICAGO IN, US
Pavan K. C. VENKATASURYA - EAST CHICAGO IN, US

C21D 9/46
C22C 38/02
C22C 38/04
C21D 8/02
C21D 1/18
C21D 6/00
C22C 38/06
C22C 38/12
C22C 38/14
C23C 2/06
C23C 2/28
C23C 2/40

A method is for producing a high strength coated steel sheet having an improved ductility and an improved formability, and a chemical composition containing: 0.13%≤C≤0.22%, 1.9%≤Si≤2.3%, 2.4%≤Mn≤3%, Al≤0.5%, Ti≤0.05%, Nb≤0.05%, the remainder being Fe and unavoidable impurities. The sheet is annealed at temperature TA higher than Ac3 but less than 1000 C. for a time of more than 30 s, quenched by cooling to a quenching temperature QT between 200 C. and 280 C. in order to obtain a structure consisting of austenite and at least 50% of martensite, the austenite content being such that the final structure can contain between 3% and 15% of residual austenite and between 85% and 97% of the sum of martensite and bainite, without ferrite, heated up to a partitioning temperature PT between 430 C. and 490 C. and maintained at this temperature for a time Pt between 10 s and 100 s, hot dip coated and cooled to the room temperature.

2019025, Aug 22, 2019

Apr 30, 2019

16/398873

- Luxembourg, LU
Hyun Jo Jun - East Chicago IN, US
John A. Rotole - East Chicago IN, US

C21D 9/46
C23C 2/28
B32B 15/01
C22C 38/24
C21D 8/02
C23C 2/40
C23C 2/12
C22C 38/22
C22C 38/08
C22C 38/04
C22C 38/00
C22C 38/38
C22C 38/32
C22C 38/28
C22C 38/26
C22C 38/14
C22C 38/12
C22C 38/06
C22C 38/02
C23C 2/06
C23C 2/02

A method for producing a cold rolled and hot dip coated steel sheet is provided. The method includes casting a steel into a slab, reheating, hot rolling, cooling, coiling, descaling and cold rolling the slab. The cold rolled steel sheet is annealed so a layer of iron oxide forms on the surface with an internal oxidation underneath. The sheet is then heated so the surface is oxidized and the layer of iron oxide is fully reduced to obtain an internally oxidized depth between 200 nm and 100 μm which includes one or more of Si, Mn, Al, Ti containing oxides. The sheet is then hot dip coated and cooled.

2019000, Jan 3, 2019

Dec 21, 2016

16/064545

- Luxembourg, LU
Hyun Jo JUN - East Chicago IN, US

C21D 9/46
C22C 38/06
C22C 38/04
C22C 38/02
C21D 8/02
C21D 6/00
B32B 15/01
C21D 1/18

A method for producing a steel sheet having a microstructure including 71% to 91% martensite and bainite, 9% to 13% retained austenite, and at most 20% ferrite is provided. The method includes providing a cold-rolled steel sheet including, in weight percent: 0.13%≤C≤0.22%, 1.2%≤Si≤2.3%, 0.02%≤Al≤1.0%, with 1.25%≤Si+Al≤2.35%, 2.4%≤Mn≤3%, Ti≤0.05%, Nb≤0.05% and a remainder of Fe and unavoidable impurities, annealing the steel sheet to obtain 80% to 100% austenite and 0% to 20% ferrite, quenching the steel sheet at a cooling rate between 20 C./s and 50 C./s to a quenching temperature between 240 C. and 310 C., heating the steel sheet to a partitioning temperature between 400 C. and 465 C. and maintaining the steel sheet at the partitioning temperature for 50 to 250 seconds, then immediately cooling the sheet to room temperature. Steel sheets are also provided.

2017013, May 18, 2017

Jun 3, 2015

15/316600

- Luxembourg, LU
Hyun Jo Jun - East Chicago IN, US
John A. Rotole - East Chicago IN, US

C21D 9/46
C23C 2/06
C23C 2/02
C23C 2/40
C23C 2/28
C22C 38/38
C22C 38/32
C22C 38/28
C22C 38/26
C22C 38/24
C22C 38/22
C22C 38/02
C22C 38/06
C22C 38/00
C21D 8/02

The invention deals with a cold rolled and hot dip steel sheet, with a tensile strength of at least 980 MPa, with yield strength above or equal to 500 MPa, with total elongation above or equal to 8%, the composition consisting by weight percent: 0.05