Size，shape and weight of seamless steel pipe for high-pressure chemical fertilizer equipment (GB 6479-2000)
Seamless steel pipes for high-pressure chemical fertilizer equipment mainly refer to those with an outer diameter of 10.3 to 711.2mm and the wall thickness of 0.8 to 64mm, used in petroleum, chemical industry, gas and other high-pressure equipment and pipelines.
In GB 6479-2000, the size, shape, technical requirements, test methods, inspection rules, packaging and marking of seamless steel pipes for high-pressure chemical fertilizer equipment are specified.
Size requirements:
In GB 6479-2000, the outer diameter of seamless steel pipe for high-pressure chemical fertilizer equipment is specified as O.D. 10.3-711.2mm. The actual wall thickness shall not be greater than the nominal wall thickness specified in the standard. The dimensional tolerance of outer diameter and wall thickness of different sizes of steel pipe is different. In the case of a agreed upon, the wall thickness shall not be greater than the limiting value of the corresponding indicated wall thickness of the specified size, or shall not be greater than the wall thickness of the corresponding size as specified in GB 6479-2000.
Shape requirements:
The basic shape of seamless steel pipe for high-pressure chemical fertilizer equipment is circular. In the actual measurement, the roundness of the tube is required to be within the tolerance of 0.50%. The requirement of flattening is 0.25%~0.50%. The end face of the steel pipe shall be flat and perpendicular to the central axis of the steel pipe. At the same time, the maximum departure from the reference plane is 0.20~0.50%.
Weight requirements:
The weight of seamless steel pipe for high pressure chemical fertilizer equipment is calculated according to its density: ρ / kg/m3 = 7850～8000. The measured weight of the steel pipe should be within the allowable tolerance range of +1.50%.
Technical requirements, test methods, inspection rules, packaging and marking for high pressure chemical fertilizer equipment:
In order to ensure the safety performance and operating efficiency of the sealed steel pipe, the following technical requirements are specified in GB 6479-2000: mechanical properties, hydrostatic test stress, flattening test and flaring test. The steel pipe must pass the non-destructive test for the size and surface quality, and no obvious defects such as welding slag, pits, cracks and notches are allowed.
The hydrostatic test of steel pipe should be carried out in accordance with the relevant requirements of the standard, and the pressure should not exceed the order agreement. Flattening and flaring test shall be carried out in accordance with the relevant requirements of the standard.
The following test results should be included in the inspection of seamless steel pipe for high-pressure chemical fertilizer equipment: outer diameter, wall thickness, length, shape, mechanical properties, hydrostatic test and static elastic test, as well as non-destructive test and tensile test results.
The packing and marking of steel pipes shall comply with the requirements of GB 6479-2000. The applicable marking should be consistent with the order agreement and shall not be illegally increased or altered.
Conclusion
In conclusion, GB 6479-2000 is applicable to seamless steel pipe for high-pressure chemical fertilizer equipment, which mainly stipulates the size, shape, technical requirements, test methods, inspection rules, packaging and marking of seamless steel pipes. Under the agreement, the wall thickness of the steel pipe shall not be greater than the limiting value of the corresponding indicated wall thickness of the specified size, or shall not be greater than the wall thickness of the corresponding size as specified in GB 6479-2000. The weight of steel pipe shall be calculated according to its density, and the mechanical and non-destructive test shall be done as required. At the same time, the packing and marking shall be included in the inspection according to the standard.
