JFE TECHNICAL REPORT
JFE TECHNICAL REPORT
No. 10 (Dec. 2007)
Newly-Developed Ultra-High Tensile Strength Steels with Excellent Formability and Weldability†
MATSUOKA Saiji*1
HASEGAWA Kohei*2
TANAKA Yasushi*3
Abstract:
JFE Steel has developed and commercialized ultrahigh tensile strength steel series from TS780 MPa to
1 470 MPa with excellent formability and weldability which reduces weight and increases safety in collision when they are applied to the reinforcement parts around a cabin. Those ultra-high tensile strength steels are developed by applying JFE Steel’s own technology, continuous annealing line water-quenching facilities which greatly contribute to reduce alloy elements in the steel.
Especially, the TS1180 MPa steel which is expected to expand in application, excels in elongation. It is 1.5 times larger than the conventional one which is the same level with 980 MPa, and strech-flangeability has also been achieved as the same level with TS980 MPa. It is remarkable work-hardenability and bake-hardenability make it possible to replace hot-stamping parts.
1. Introduction
In recent years, high strength steel sheets have been increasingly applied to automobile bodies to improve crashworthiness so as to secure the safety of the passengers in the automobile and improve fuel economy by reducing automobile body weight in order to reduce CO2 emissions. Up to 1990, application of TS440–590 MPa grade high strength steel sheets (TS: tensile strength) was studied as a substitute for conventional mild steel sheets.
These steel sheets were improved to overcome problems such as difficulty of press formability, weldability, and corrosion resistance, and have played an important role as front end collision members such as the front side
†
Originally published in JFE GIHO No. 16 (June 2007), p. 16–20
*1
Dr. Eng.,
Senior Researcher General Manager,
Automotive Sheet Products Res. Dept.,
Steel Res. Lab.,
JFE Steel
member and others which
No. 10 (Dec. 2007)
Newly-Developed Ultra-High Tensile Strength Steels with Excellent Formability and Weldability†
MATSUOKA Saiji*1
HASEGAWA Kohei*2
TANAKA Yasushi*3
Abstract:
JFE Steel has developed and commercialized ultrahigh tensile strength steel series from TS780 MPa to
1 470 MPa with excellent formability and weldability which reduces weight and increases safety in collision when they are applied to the reinforcement parts around a cabin. Those ultra-high tensile strength steels are developed by applying JFE Steel’s own technology, continuous annealing line water-quenching facilities which greatly contribute to reduce alloy elements in the steel.
Especially, the TS1180 MPa steel which is expected to expand in application, excels in elongation. It is 1.5 times larger than the conventional one which is the same level with 980 MPa, and strech-flangeability has also been achieved as the same level with TS980 MPa. It is remarkable work-hardenability and bake-hardenability make it possible to replace hot-stamping parts.
1. Introduction
In recent years, high strength steel sheets have been increasingly applied to automobile bodies to improve crashworthiness so as to secure the safety of the passengers in the automobile and improve fuel economy by reducing automobile body weight in order to reduce CO2 emissions. Up to 1990, application of TS440–590 MPa grade high strength steel sheets (TS: tensile strength) was studied as a substitute for conventional mild steel sheets.
These steel sheets were improved to overcome problems such as difficulty of press formability, weldability, and corrosion resistance, and have played an important role as front end collision members such as the front side
†
Originally published in JFE GIHO No. 16 (June 2007), p. 16–20
*1
Dr. Eng.,
Senior Researcher General Manager,
Automotive Sheet Products Res. Dept.,
Steel Res. Lab.,
JFE Steel
member and others which
References: 1) Yoshitake, A.; Iwase, K. Proc.of the 2000 Annual Meeting of JSAE/MMD, WS(2)-4, 2000. products borne in a last decade. NKK Technical Report. 2002, no Giho. 2000, vol. 32, no. 1, p. 1–6. and 1 560 MPa. Bull. of the Jpn. Inst. of Metals. 1993, vol suitable for mechanical-clinching. Materia Jpn. 2003, vol. 42, no cold-rolled high strength steel sheets. CAMP-ISIJ, 2002, vol JFE TECHNICAL REPORT No. 10 (Dec. 2007)