Alloy tube can be divided into: low-alloy tube, alloy tube, high alloy pipe, high-strength pipe. Bearing tube, heat-resistant acid-resistant stainless steel tube, precision alloy (Kovar alloy) pipe and high-temperature alloy Steel pipe. Top connection Steel pipe end connections can be divided into: light pipe (threaded pipe end) and threading pipe (pipe end with a thread). Threading tube is divided into: ordinary car wire tube and pipe end upsetting threading. Thickening car wire tube can be divided into: external upset (with external thread), thickening of the inner (with threads) and inside and outside the thicker (with internal and external threads) and other places threading. Threading pipe thread type can also be divided into: ordinary cylindrical or conical thread and special thread to threading pipe. In addition, according to user needs, threading pipe usually equipped with fittings delivery. Plate feature classification Steel plated coating characteristics can be divided into: clarinet (not plated coating) and plated coating tube. Pipe coating galvanized pipe, aluminum pipe, chrome pipes, and infiltration of aluminum tubes as well as of other alloy layer steel pipe. Coated tube outer coating pipe, pipe inner coating, inside and outside the coated tube. Coatings commonly used plastics, epoxy, coal tar epoxy resin and a variety of glass-based anti-corrosion coating material. Galvanized pipe is divided into the KBG pipe, the JDG pipe, threaded carbon steel pipe, etc. By Type A piping tube. Such as: water, gas pipes, steam pipes with seamless pipe, oil pipeline, oil and gas trunk pipe. Agricultural irrigation taps with pipes and sprinkler irrigation with tubes. Thermal equipment tube. Such as boiling water tube boiler, superheated steam locomotive boiler overheating tube, opium pipe, a small breathing tube, arched brick pipe and high temperature and high pressure boiler tubes. Mechanical industrial pipe. Such as aviation structural tube (tube, oval tube, flat oval tubes), automobile axle tube, axle tubes, structural tubes of automobile and tractor, tractor oil cooler pipe, agricultural machinery with a square tube and rectangular pipe, transformers, tubes and bearings tubes. Petroleum geology drilling pipe. Such as: oil drilling pipe, drill pipe (Kelly and hexagonal drill pipe), drill collar, oil pipeline, oil casing and various fittings, geological drilling pipe (core pipe, casing, active drill pipe, drill collar hoop and pin connector). Chemical industry pipe. Such as: petroleum cracking tubes, chemical equipment, heat exchangers and piping tube, stainless acid-resistant pipe, conveying chemical fertilizer with high-pressure pipe and medium Seamless steel pipe. Six other departments with the tube. Such as: the container tube (high-pressure cylinder tube pipe and container), instrumentation tube watch shell pipe, tube needle medical devices. Classified by cross sectional shape Steels of different specifications of steel pipe products are extremely numerous, and their performance requirements and a variety of. All these should be distinguished with the user requirements or conditions of work changes. Typically, steel products according to the cross sectional shape, production methods, pipe material, connection mode, plated coating characteristics and the intended use of the classification. Pipe cross-sectional shape can be divided into: a circular steel and shaped steel tubing. Shaped steel tubing is non-circular annular cross-section of steel pipe. Including: a square tube, rectangular tube, oval tube, flat elliptical tube, semicircle tube, hexagonal tube within the tube hexagon, equilateral hexagonal tube, triangle tube, the Pentagon Plum, octagonal tube, convex shaped tube, the double-convex tube. Double concave tube, multi-concave pipe, oval-shaped tube, flat tube, diamond-shaped tube, star-shaped tube, parallelogram tube, the ribbed tube, drop-shaped tube, finned tube, twisted the different tube-tube B, D, tube and multi-layer tube. The steel pipe according to the shape of longitudinal section is divided into: section steel tubes and variable cross-section steel tube. Steel pipe of variable cross section (or variable cross-section) is the cross sectional shape along the tube length direction, inside and outside diameter and wall thickness of the periodic or aperiodic changes of steel pipes. The main are: the outer cone within a cone-shaped tube, outside the ladder within the ladder pipe, cycle cross-section tubes, bellows, spiral pipe, steel pipe with a heat sink and the double line of the barrel. Edit this paragraph Chemical composition of test (1) GB/T3087-2008 "low and medium pressure boiler seamless steel pipe provided. The chemical composition of test methods according to GB222-84 and GB223 "steel and alloy chemical analysis of the relevant part of the method". (2) GB/T5310-2008 "high-pressure boiler seamless steel Seamless pipe under. The relevant part of the chemical composition of test methods according to GB222-84 steel and alloy chemical analysis method, GB223, steel and alloy chemical analysis method ". (3) imports of the chemical composition of the boiler tube inspection by the relevant standards of the contract. Edit this paragraph Methods of identification of the inferior steel pipe