Different uses of steel in accordance with the actual use and working conditions for the different response to pipe size tolerance, surface quality, chemical composition, mechanical properties, process performance, and other special properties such as, the different technical conditions.
General seamless steel tubes for conveying water, gas, oil pipelines and manufacture of fluid structural components, the response to its mechanical properties such as tensile strength, yield strength and elongation for the sample test. Duct generally work under conditions of pressure, also called pressure test done and flaring, squash, curling and other process performance tests. For large-scale long-distance crude oil, refined oil, natural gas pipelines with a pipe is to increase the carbon equivalent, welding performance, low-temperature toughness, stress corrosion under harsh conditions, corrosion, corrosion fatigue strength and corrosion environment and other requirements. Ordinary boiler tubes used in the manufacture of structural steel pipe and superheated steam boilers boiling water pipes. High-pressure boiler tubes for high pressure or high pressure superheated steam boilers, heat exchangers and pipes for high pressure equipment.
The steel thermal equipment in different conditions of high temperature and pressure of work, should ensure good surface condition, mechanical and technological properties. Generally to test its mechanical properties, flattening, and hydrostatic testing to do, high-pressure boiler tubes also asked to do the test and the grain size of more stringent non-destructive testing. Mechanical seamless steel pipe according to the application requirements to be a higher dimensional accuracy, good mechanical properties and surface condition. Regulatory requirements such as bearing high wear resistance, homogeneous, and strictly within the diameter tolerance. In addition to doing general mechanical performance test items, we need to do low-magnification, fracture, annealing (ball of the organization, mesh light, strip), non-metallic inclusions (oxides, sulfides, dot, etc.), de- indicators of carbon layer and its hardness test. Fertilizer industry often use high pressure seamless steel pressure of 2200 ~ 3200Mpa, working temperature -40 ℃ ~ 400 ℃ and the corrosive environment, transport chemical medium (such as ammonia, methanol, urea, etc.). Fertilizer industry with high-pressure seamless carbon steel pipe should have a strong corrosion resistance, good mechanical properties and surface condition. In addition to doing mechanical properties, flattening, and hydrostatic testing, it should be based on different kinds of steel corrosion test streamlined accordingly, managers and more rigorous degree of non-destructive testing. Petroleum, geological drilling pipe at high pressure, alternating stress, corrosive, harsh environments, it should be a high intensity level, and to wear, torsion and corrosion-resistant properties. According to the different grades of steel should be done tensile strength, yield strength, elongation, impact toughness and hardness tests. Used for oil well casing, tubing and drill pipe, is a detailed breakdown of the grade, category, and for different environmental, geological conditions selected by the user's own additional requirements for high technical requirements, to meet different specific needs. Chemical, petroleum cracking, aviation and other machinery industry with a variety of acid-resistant stainless steel pipe and mechanical properties than do the pressure test, but also specifically for the intergranular corrosion test, flattening, flaring and non-destructive testing and other tests.