碳素结构钢系统.pdf

ICS 77.140.45 H 40 National standard of the Peoples Republic of China GB/T 700-2006 Replace GB/T 700-1988 碳素结构钢 Carbon structural steels (ISO 630:1995, Structural steels – Plates, wide flats, bars, sections and profiles, NEQ) Issue date: Nov 1, 2006 Implementation date: Feb 1, 2007 Issued by: General Administration of Quality Supervision, Inspection and Quarantine of the People ’s Republic of China Standardization Administration of the Peoples Republic of China (SAC) Foreword This standard is not equivalent to ISO 630:1995 Structural Steels in the respect of consistency. The main differences between the two standards are as follows: 2 - No grades are specified corresponding to the yield strength levels of 185N/mm and 2 355N/mm ; 2 2 - Grades Q195 and Q215 are specified corresponding to levels 195N/mm and 215N/mm ; - The phosphorus contents of class A steels of Q235 and Q275 are decreased by 0.005%; The thickness of Q235 class B steel is divided into two levels according to the deoxidization method and the carbon content is 0.20% in both levels; - Q235 class B steel of which the thickness is smaller than 25mm may not be subject to test with the consent of the buyer if the supplier can ensure that the impact absorb