GB/T16270 standard specifies the grade, size, shape, weight and allowable deviation, technical requirements, test methods, inspection rules, packaging, marking and quality certificates of high quality structural quenched and tempered steel plates.GB/T16270 standard applies to the thickness of not more than 150mm, quenched and tempered (quenched and tempered) state delivery of high strength structural steel plate.GB/T16270 Standard main steel grade:Q500E,Q550D,Q550C,Q550F,Q550E,Q620D and so on.