Usually, according to the purpose of the steel pipe and working condition is different, dealing with the allowable deviation of the size of the steel pipe, surface quality, chemical composition, mechanical properties, process performance and other special performance and so on different technical conditions were put forward.
Generally seamless steel pipe is used to transport oil, gas, water and other fluid pipeline and manufacture of various structure parts, dealing with its mechanical properties such as tensile strength, yield strength and elongation to do sampling test. Duct usually works under the condition of pressure, also asked to do hydrostatic test and flaring, flattening and crimping process performance test. For large long distance crude oil, refined oil, natural gas pipeline steel pipe is increased the carbon equivalent and welding performance, low temperature impact toughness, severe corrosion condition, the stress corrosion and corrosion fatigue strength and corrosion environment and so on.
Ordinary boiler tube is used in the manufacture of all kinds of structure of boiler superheated steam pipe and boiling water. High pressure boiler tube is used in the high voltage or super high pressure boiler superheated steam pipe, heat exchanger, and is used in the high pressure pipe of the equipment. The thermal technology equipment in steel tube are working in different conditions of high temperature and high pressure, should guarantee the good surface state, mechanical properties and process performance. Is to test its mechanical properties, flattening and water pressure test, high pressure boiler tube also asked to do about the inspection of the grain size and more strictly nondestructive testing.
Machinery with the size of the seamless steel pipe according to the requirements must have higher precision, good mechanical properties and surface condition. Such as bearing tube of high wear resistance, uniform organization and strict inner and outer diameter tolerance. Except for general mechanical performance inspection items, also want to do low power, fracture, annealing organization (spheroidizing, net light, strip), non-metallic inclusions (oxide, sulfide, dotted, etc.), such as decarburization layer and its hardness index test.
Be used in the chemical fertilizer industry in the normal pressure high-pressure seamless steel tube is 2200 ~ 3200 mpa, the working temperature for – 40 ~ 400 ℃ and corrosive environment chemical medium (such as ammonia, methanol, urea, etc.). High-pressure seamless steel tube should have strong corrosion resistance, good mechanical properties and surface state. In addition to do mechanical properties, flattening and water pressure test, should according to different types of steel accordingly reduced corrosion test, grain size and more strictly nondestructive testing.
Be used in oil drilling, geology with steel pipe under high pressure, alternating stress, work under corrosive environment, therefore, should have a high level of strength, and anti-wear, torsional and corrosion resistant properties. According to the different grade of steel should be tested for tensile strength, yield strength, elongation, impact toughness and hardness test. To be used in oil well casing, tubing and drill pipe, more detailed division of the steel grade, class, and is suitable for different environment, geological condition by the users to choose their own higher requirements of additional technical conditions, to meet the specific requirements of the different.
Been used in chemical, petroleum cracking, aviation and other machinery industry of various kinds of stainless heat acid tube in addition to the mechanical properties and water pressure test, but also specifically between works corrosion test, flattening, flaring, NDT test, etc.
Source: Zhejiang Yaang Pipe Industry Co., Limited (www.yaang.com)