Quenched and tempered GL F690 shipbuilding steel plate owned the higher tensile strength within 770-940 Mpa,and the minimum yield point shall be 690 Mpa.Class F690 indicates the low temperature impacting test shall be done under minus 60 centigree.Xinsteel exported 500,000 tons higher strength shipbuilding steel materials all over the world especially southeast asia shipyards each year. When delivery shipbuilding steel plates,heat treatment mark would be appear on our each steel plate as steel mark,such as Normalized would be marked as N,TMCP would be marked as TMCP which is short for Thermo-Mechanical Control Process,QT is for Quenching and tempering.