☻ HG（chemical industry standard）
    Chemical Industry Standard of the People's Republic of China, People's Republic of China Ministry of Chemical Industry released.

☻ ASME（American Society of Mechanical Engineers）
    An organization of engineers dedicated to the preparation of design code requirements, and material and testing standards. Adopts, sometimes with minor changes, specifications prepared by ASTM. The adopted specifications are those approved for use under the ASME Boiler and Pressure Code and are published by ASME Code. The ASME specifications have the letter “S” preceding the “A” or “B”, of the ASTM specifications. The “SA” series are for iron base materials, while the “B” series are fot other materials such as nickel base, copper, etc.

☻ ASTM（American Society for Testing Materials）
    A body of industry professionals involved in writing universally accepted steel material and test specifications and standards. The “A” series of material specifications are for iron base materials, while the “B” series are for other materials such as nickel base, copper, etc.

☻ Stainless steel

☻ Austenitic stainless steel
    These grades of stainless steels (300 Series plus some 200), have chromium (roughly 18% to 30%) and nickel (roughly 6% to 20%)as their major alloying additions. They have excellent ductility and formability at all temperatures, excellent corrosion resistance and good weldability. In the annealed condition they are nonmagnetic. Some have the ability to be hardened by cold rolling as a final step. These grades are usually non-magnetic and are used for applications requiring good general corrosion resistance such as food processing, chemical processing, kitchen utensils, pots and cans, brewery tanks, sinks, wheel covers and hypodermic needles.

☻ Duplex stainless steel
    Stainless steel exhibiting both austenitic and ferritic phase and characteristics.

☻ 焊接管 Welded tube

☻ Gas Tungsten Arc Welding（GTAW）
    An arc welding process that uses an arc between a tungsten electrode (nonconsumable) and the weld pool(base metal of strip). A high quality full fusion weld is achieved. The process can be performed with or without the addition of filler materials. The GTAW process is also commomly referred to as Tungsten Inert Gas(TIG) welding.

☻ Bright Annealing
    A heat treatment process performed in a carefully controlled furnace atmosphere resulting in a clean, smooth, scale free metal surface. During typical annealing, the heated steel combines with oxygen in the air to form an oxide layer on the steel’s surface. In brightness annealing, the steel is heated in a furnace filled with gases, such as hydrogen or nitrogen, or in a vacuum, to prevent oxide scale formation. The material comes out of the bright anneal furnace with the same surfaces as it had when it went into the furnace. The process eliminates the need for the old fashioned acid bath pickling operations.

☻ Oxidation
    An electro-chemical reaction in which oxygen attacks a metal surface to form a metallic oxide, such as rust or the protective layer on stainless steel.

☻ Passivation
    A protective layer of oxides on the surface of a metal, which resists corrosion. This passive oxide layer is the chief reason why stainless steels have such good corrosion resistant properties. It is a natural phenomenon, but can be accelerated by special passivating solutions that can be applied to tubular products by an optional process.

☻ Heat number

☻ Ovality
    A quantitative measurement of how ‘round’ a tube is by comparing width to height. Limits are specified on the appropriate specification of a product.

☻ Intergranular corrosion

☻ Stress corrosion cracking（SCC）
       Catastrophic failure by generally intergranular cracking occurring in stainless steels and other metals. It is caused by combined action of a corrosive environment and stress, often without outward appearance of general corrosion attack.

☻ Deburring
    Removal of a small ridge of metal formed by upset during a machining or cutting operation.

☻ Destructive testing
    Any of the mechanical tests performed on an expendable sample of tubing to check physical properties. These tests include: tensile test, hardness test, bending test, flattening test, flaring test.

☻ Tensile test
    A procedure used to determine the load at which a material will begin to plastically deform(the tensile yield strength) and ultimstely at which it will break (the ultimate tensile strength). Resulting test values are a ratio of applied load(pounds) to cross-sectional area of the test sample(square inchs) and are expressed in units of pounds per square inch(psi) or in metric units of megaPascals(Mpa).

☻ Tensile strength
    A short form of “ultimate tensile strength”. The maximum load per unit area that a material is capable of withstanding before it fails(pulls apart). Units are in psi.

☻ Yield strength

☻ Bending test

☻ Hardness
    Resistance to deformation or indentation. Materials with little resistance are called soft; and those with high resistanceare called hard. Finer grained structures are harder than larger grained structures.

☻ Hydrostatic test
     A nondestructive test procedure that checks for holes, cracks or porosity. Tubing is pressurized internally with water to a high pressure, but does not exceed material yield strength.

☻ Intergranular corrosion test
    A corrosion test for evaluating intergranular corrosion resistance by boiling in refluxed sulfuric acid - copper sulphate solution for 16 hours. GB/T4334.5 or ASTM A262 Practices E.

☻ NDT
    NDT is a test means that damage to the workpiece or raw materials of the state under the premise, to be tested parts of the surface and internal quality check.

☻ Eddy current testing
    A nondestructive testing procedure which is a continuous process performed on the tubular products during fabrication and in final inspection.It is by nature an electrical test that utilizes fluctuations in magnetic field strength to check tubing(against a calibrated standard) for possible defects such as holes, cracks, gouges, etc. on both inside and outside surfaces of the tube. The eddy current test is done in accordance with GB/T7735 or ASTM E426.

☻ Ultrasonic testing