1 The requirements for beveling surface

　　According to the different materials, the groove surface should meet the requirements of 1.1 ~ 1.4 respectively.

　　1.1 The requirements for the steel beveling surface

　　A) Such as cracks, layers and impurities shall be not found on the surface of the groove;

　　B) The flame-cut beveling surface of the steel with standard tensile strength lower limit Rm> 540MPa, and the flame-cut beveling surface of Cr-Mo low alloy steel should be polished smoothly by grinding wheel, and magnetic powder or penetration test should be performed on the processed surface.

　　1.2 The requirements for beveling surface of Aluminium

　　A) Generally, mechanical method is used to process the beveling. When the thickness is great, plasma, arc or other cutting methods that will not damage the performance of the aluminum material and not affect the welding quality.

　　B) Such as cracks, layers, impurities, and other defects that affect the welding quality shall be not found on the surface of the beveling.

　　1.3 The requirements for beveling surface of Iron

　　A) Metal pencils should be used for marking on iron materials. Only the parts that can be removed in later processing are allowed to punch holes. Iron-steel composite plate should be marked on the base steel plate;

　　B) Generally, mechanical methods should be used to process the bevel, and flame cutting and plasma cutting are also allowed when the thickness is great. When using thermal cutting to process the groove, sparks should be prevented from splashing on the surface of the iron material, and a mechanical method should be used to remove the contaminated layer after cutting. The iron-steel composite board should be oriented with the steel base downward when cutting with machinery, taking care to prevent delamination;

　　C) Such as cracks, layers, impurities, and other defects that affect the welding quality shall be not found on the surface of the beveling.

　　1.4 The requirements for beveling surface of copper, nickel and nickel alloys

　　A) Generally, mechanical processing or underwater plasma, ultra-high pressure water cutting and other methods should be used to process the beveling. When thermal cutting is used, a mechanical method should be used to remove the contaminated layer after cutting;

　　Such as layer, folding, crack and other defects shall be not found on the surface of the beveling.