4.2　Inspection of Pipes

4.2.1　Before the pipe construction with the working pressure no less than 5.88MPa or the working temperature no less than 400℃,the following items shall be confirmed to meet current national or industrial standards according to the quality certificate from the manufacturer.

1　The results of mechanical property test such as tensile strength,yield strength and enlongation.

2　The result of impact toughness test.

3　Metallographic analysis result of alloy-steel pipes.

4.2.2　The local defects on the pipe surface such as scratches,dents and corrosion shall be checked and identified.The unqualified pipe shall not be used after identification.

4.2.3　Thickness inspection of high-pressure pipes for medium and low alloy steel shall be carried out at no less than three crosssection and recorded.

4.2.4　Qualified steel pipes shall be placed separately according to materials and specification and be marked with identifications.They shall be stored properly to prevent rust.