STEEL PLATE HAVING TENSILE STRENGTH OF 1,180MPa AND EXCELLENT IN DELAYED FRACTURE RESISTANCE

• Main Authors: OTSUKA SHINJI, TSUCHIMOTO KAZUAKI, YOSHIMI NAOTO, MASUOKA HIROYUKI, TAIRA SHOICHIRO
• Format: Patent
• Language: English; Japanese
• Published: 05.01.2017
• Subjects: APPARATUS THEREFOR; CHEMICAL SURFACE TREATMENT; CHEMISTRY; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATIONOR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY IONIMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; COATING MATERIAL WITH METALLIC MATERIAL; COATING METALLIC MATERIAL; DIFFUSION TREATMENT OF METALLIC MATERIAL; ELECTROFORMING; ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION INGENERAL; METALLURGY; PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTIONOF COATINGS; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THESURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION

PROBLEM TO BE SOLVED: To provide a steel plate having a tensile strength of 1,180MPa and excellent in delayed fracture resistance, being a steel plate mainly suitable for strength members for automobiles and building materials.SOLUTION: By forming an Fe film containing a vanadium oxide with a prescribed coating weight or an Fe film containing vanadium oxide and molybdenum on the surface of a steel plate having a tensile strength of 1,180 MPa or more, hydrogen intrusion to the inside of the steel plate is suppressed, and excellent delayed fracture resistance can be obtained. Further, by forming an organic resin layer with a prescribed film thickness on the upper layer thereof, excellent corrosion resistance and weldability as well as excellent delayed fracture can be obtained.SELECTED DRAWING: None 【課題】主として自動車、建材用の強度部材に好適な鋼板であって、引張強度１１８０ＭＰａ以上である耐遅れ破壊特性に優れた鋼板を提供する。【解決手段】引張強度が１１８０ＭＰａ以上の鋼板表面に、所定付着量のバナジウム酸化物を含有するＦｅ皮膜若しくは所定付着量のバナジウム酸化物とモリブデンを含有するＦｅ皮膜を形成することにより、鋼板内部への水素侵入が抑制され、優れた耐遅れ破壊性が得られる。また、それらのＦｅ皮膜を電気めっき法で形成するとともに、その上層に所定膜厚の有機樹脂層を形成することにより、優れた耐遅れ破壊性とともに、優れた耐食性および溶接性が得られる。【選択図】なし