英文版dl5031-1994电力建设施工及验收技术规范管道篇

英文版dl5031-1994电力建设施工及验收技术规范管道篇内容摘要：

pipe fittings, pipe accessories and valves General regulations Qualified certificate of manufacturer must be provided for pipes, pipe fittings, pipe accessories and valves, and corresponding indexes should be in concordance with active national or trade technical standards, Specification, material and technical parameter must be checked according to the design requirements prior to the using of any pipe, pipe fitting, pipe accessory and valve. Appearance inspection is required prior to the using of any pipe, pipe fitting, pipe accessory and valve, and the appearance demands are as following: Without any defects such as crack, shrinkage cavity, included slag, adhering sand, folding, missing welding, coldlap and so on。 The surface should be smoothness without any sharp scratches。 Concave depth should not be more than , and the Max. dimension should not be 5% more than the pipe perimeter, and not be more than 40mm, Spectrum reexamining is required and material marks should be made prior to the using of pipes, pipe fittings pipe accessories and valves which made of medium and low alloy steel. Checking of pies Following items must be to determine if they are in ac0dance with active national or trade technical standards prior to the construction of pipes which designing pressure is more than or equal to . Analysis results of chemical position。 Test results of mechanical property (tensile strength, yield strength and ratio of elongation)。 Test results of impact ductility for high pressure alloy steel pipes which wall thickness is more than or equal to 12mm。 Heat treatment condition or metallurgical phase analysis results of alloy steel pipes. Welding seam checking report must be examined prior to the using of seamed pipe which designing pressure is more than MPa. 6 Local defects such as scratches, concave cavities and corrodes on pipe surface should be checked。 pipe wall thickness which had been treated should not be less than the calculation wall thickness of straight pipe, and the checking report must be recorded and submitted. Thickness of no less than 3 cross sections should be measured and checked for medium or low alloy steel pipes which used as high pressure, and the recording is required. Qualified steel pipes should be stored according to their materials and specifications, to avoid corrosion. Checking of pipe fittings Following items must be checked to determine if they are in accordance with active national or trade technical standards prior to the pipe fittings used in the construction of medium or high pressure pipes: Analysis results of chemical position。 Heat treatment condition or metallurgical phase analysis results of alloy steel pipes。 Nondestructive flaw detection results of high pressure pipe fittings. Sealing surface of flange should be smooth and clean without radial groove, and air cavity, crack, burr or other defects that can reduce strength and connecting reliability are forbidden. Flanges with concave/convex surface or concave/convex ring should be snapped naturally, and the height of concave surface should not be less than the depth of notch. Supporting area of connecting bolts on flange end face should be parallel to the junction surface of flange, to insure even force acted on flange end surface when connecting. Dimensions of each part should be checked according to the design drawing and examined to determinate its conformity with flange on device to be connected, to ensure proper connection. Checking of pipe accessories Thread of bolts and nuts should Be undamaged without any defects such as scratches, burrs and etc. and the matching between bolt and nut should be in good condition without loosen or blocking. Each alloy steel bolt, which designing temperature is above 430 oC, and diameter is more than or equal to M30, should be numbered and its hardness should be checked, and unqualified one must not be used. Pad material of flange should be in concordance with the designing requirement. Table A5 in Appendix A can be used to select material in case of no concrete requirement provided. Asbestos rubber pad should be soft and pliant, without any aging or delaminating。 and any defect such as buckle and wrinkle is forbidden on surface. Visual inspection should be made for the surface of metal shim with leveling rule, the good contact is necessary and defects such as crack, burr, rust or coarse processing are not allowed。 and its hardness should be less than the flange39。 s. Radial scratch, loosen and other defects are all not allowed for the cladding metal and winding shim. Assembling dimension and welding type of steel structure of pipe supporting and suspending bracket should be concordance with the regulation of the code . Working surface of sliding bracket should be smooth and move flexibly without any blocking. Spring of pipe supporting and suspending bracket should be checked according to the article and of the code. Checking of valves Following examining is necessary prior to the installation of all types of valves: If padding material is in concordance with the requirement of design, and if padding method is correct or not. Sealing padding material can be selected according to the Table A6 in Appendix A in case of no design requirement provided。 Whether corrosion occurs on the valve stem wherever padding sealing。 If the action of switches are flexible and the indications are all correct。 Obvious manufacturing defect is forbidden on the appearance of casting valve. Tightness checking must be made prior to the installation of valve used as closed circuit element (acting as isolation), to check the tightness of joint surfaces between valve seat and valve core, valve cover and padding chamber. Water pressure, which times more than pressure marked on nameplat。