Q195 structural steel chemical composition in EnglishNational Standard of the People’s Republic of ChinaGB 700-88 Carbon structural steels extract 5 Technical requirements51 Type and chemical composi

the residual content of As shall not more than 0.20%.5.1.1.5 Steel of grades Q195, Q215A, Q235A and Q255A are suitable for making welded structural parts, such as welded steel bars, welded steel pipes, welded steel brackets, etc. Steel of grades Q235B, Q275 and Q345B are suitable for making all kinds of welded structures, such as welded steel bars, welded steel pipes, welded steel brackets, etc.5.1.2 The carbon content of steel shall be not less than 0.12%.5.1.3 The permissible deviation of chemical composition for batches of steel shall comply with the provisions of GB/T 222.5.2 Smelting method5.2.1 The steel shall be smelted by oxygen converter or electric furnace.5.2.2 The steel shall be killed by aluminum or silicon deoxidization.5.2.3 The steel shall be vacuum degassed if necessary.5.3 Delivery status5.3.1 The steel shall be delivered in hot-rolled or heat-treated condition.5.3.2 The heat treatment of steel shall comply with the provisions of GB/T 6394.5.3.3 The surface quality of steel shall comply with the provisions of GB/T 8923.5.3.4 The shape, size, weight and allowable deviation of steel shall comply with the provisions of GB/T 708.5.4 Mechanical properties5.4.1 The mechanical properties of steel shall comply with the provisions of Table 2.Table 2Type and mechanical properties of steelGradeTensile strength，MPaYield strength，MPaElongation，%Not less thanQ19537519533Q215A37521531Q235A37523526Q255A41025524Q27541027522Q345B49034521 Note: The elongation is measured in 50mm gage length.5.4.2 The bending test shall be carried out according to the provisions of GB/T 232.5.4.3 The impact test shall be carried out according to the provisions of GB/T 229, and the impact toughness value shall comply with the provisions of Table 3.Table 3Impact toughness value of steelGradeImpact toughness value，AkVNot less thanQ19527Q215A27Q235A27Q255A27Q27527Q345B2