The Mechanical Properties of Seamless Steel Pipes for High Pressure Fertilizer Equipment (GB 6479-2000)
The mechanical properties of seamless steel pipes for high-pressure fertilizer equipment (GB 6479-2000) refer to the properties of materials and the performance of various products in the production process. Steel pipe material for high-pressure fertilizer equipment and its chemical composition, mechanical properties and technological requirements are specified by GB 6479-2000. The specified mechanical properties of seamless steel pipes are divided into tensile strength, yield strength, elongation, reduction of area, impact energy and hardness.
First, the tensile properties of seamless steel pipes are described. Tensile properties refer to the ability of the material to withstand the pulling force, expressed in the maximum load in the axial direction of the sample when the sample is stretched to fracture, expressed in N/mm2, and its symbol is sb. The tensile properties of seamless steel pipes for high-pressure fertilizer equipment are mostly not lower than 250MPa. Comparing the tensile properties with the yield strength, the tensile properties indicate the material failure condition when the sample breaks.
The yield strength of seamless steel pipes for high-pressure fertilizer processing refers to the drop of the load when decompression test under constant deformation of the specimen. It expresses in N/mm2, and its symbol is Re. For seamless steel pipes for high-pressure fertilizer equipment, the yield strength is usually not lower than 220MPa. Therefore, the tensile strength and yield strength in the tensile test indicate the materials yield and bearing capacity in the actual use process.
The elongation of seamless steel pipe refers to the increase in length of sample when the sample is stretched to fracture. It symbolizes using δ5, expressed in a%, generally national GB6479-2000 requirements should not be lowδ5. It can reflect the materials ability to withstand external force without damage. The elongation of seamless steel pipe for high-pressure fertilizer equipment is usually not less than 25%.
The reduction of area of seamless steel pipes for high-pressure fertilizer processing refers to the contraction ratio of the cross-sectional area of the specimen when the specimen is stretched to fracture. It is represented by δ2, expressed as a percentage, generally not less than 10%. It can reflect the materials resistance to cracking.
The impact energy of seamless steel pipes for high-pressure fertilizer equipment refers to the energy consumed of the specimen during the impact test, and its symbol is A. It expresses in J/cm2, and its national standard shall not be lower than 27J/cm2. It is related to the toughness of the material and can reflect the materials ability to absorb energy.
The hardness of seamless steel pipe for high-pressure fertilizer processing refers to the surface hardness of sample after Rockwell or Brinell hardness test. It expresses in HRC or HBW, and its national standard shall not be lower than 150HV. The hardness of the material indirectly indicates the mechanical properties of the material.
All in all, the mechanical properties of seamless steel pipes for high-pressure fertilizer processing meet the national GB 6479-2000 standards, which have good performance and high quality, and have passed all necessary tests, demonstrating a good overall performance.
