| What is annealing (general)?
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| Annealing is a general term referring to the thermal treatment process involving heating and cooling, usually applied to change mechanical or physical properties, used to produce a desired microstructure.
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| What is normalizing (annealing)?
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| Normalizing is an annealing process in which steel is heated to a temperature that is above the upper transformation range and then cooled in air. The surface of the tube will have black or blue color due to oxidation at elevated temperature. Tubing can be heated above the upper transformation temperature and then cooled in a reducing atmosphere to maintain a bright surface, known as bright annealing.
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| What are the dimensions of tubing?
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| A round tube section has three dimensions, any two of which may be measured. The three dimensions are outside diameter (O.D.), inside diameter (I.D.), and wall thickness (t, w, or W.T.). Nominal as applied to any of these dimensions refers to the theoretical or stated single value of that dimension. The dimensions ordinarily specified by the customer are termed "nominal". Maximum and minimum referring to the greatest and least values of any dimension. Average dimensions are those secured by averaging a series of micrometer readings. (Welded tubing is generally specified by the outside diameter (O.D.) and wall thickness (W.T.).
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| What is bright annealing (annealing)?
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| Bright annealing is an annealing process usually carried out in a controlled atmosphere furnace using a reducing atmosphere to achieve desired mechanical properties with minimum surface oxidation. The tube surface is relatively bright.
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| What is hardness?
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| Hardness is the resistance of metal to plastic deformation. Various surface hardness tests such as Rockwell, may be used . For thin walled tubing, superficial Rockwell testing is generally specified and testing performed on the inside surface of the tubing without correction for sample shape. The hardness of tubing is a result of the steel chemistry, the amount of cold-work performed on the tubing, annealing time and temperature, the degree of quench, and age hardening that occurs following production.
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What is total elongation?
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| Total elongation is the total amount of permanent extension in the vicinity of the fracture in the tensile test to failure; usually expressed as a percentage of the original gauge length.
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| What does the term fatigue refer to?
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Fatigue is the tendency for a metal to break at a point that is considerably below the ultimate tensile strength due to the conditions of repeated cyclic stressing considerably below the ultimate tensile strength.
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What does the term formability refer to?
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Formability is the ease with which a metal can be shaped through plastic deformation. Evaluation of the formability of a metal involves measurement of strength, ductility, and the amount of deformation required to cause fracture.
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| What is carbon steel tubing?
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| Carbon steel tubing is steel tube containing only residual quantities of elements other than carbon and manganese. Typical industrial AISI designated steel grades include 1006, 1008, and 1010. The grade designation indicates the nominal percent carbon, i.e., 1006 nominally has .06% carbon, 1008 nominally has .08% carbon etc. Grades 1006and 1008 are the most common grades specified for low carbon welded seam tubing.
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| What does the heat-affected zone (HAZ) refer to?
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| The heat-affected zone refers to the adjacent portions of the base metal that were not melted during welding, but whose microstructure and mechanical properties were altered by the heat of welding.
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| What is a non-conformance?
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| A non-conformance is defined as any failure to meet a written specification for dimension or surface appearance.
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| What is an inclusion?
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| An inclusion is defined as a physical or mechanical discontinuity occurring within a metal product, usually consisting of nonmetallic foreign material. Inclusions are often capable of transmitting some structural stresses and energy fields, but to a noticeably different degree than from the parent material. The foreign particles are usually compounds, such as oxides, sulfides, silicates or combination of these.
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| What are mechanical properties?
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| Mechanical properties are the properties of a material that reveal its elastic and inelastic behavior when force is applied, thereby indicating its suitability for mechanical applications; for examples tensile strength, yield strength, elongation, hardness, and fatigue limit. Tubing's mechanical properties are typically produced to an ASTM, SAE or customer specified specification.
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| What are physical properties?
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| Physical properties are properties of a material that are relatively insensitive to structure and can be measured without the application of force; for example, density, electrical conductivity, coefficient of thermal expansion, magnetic permeability.
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| What is tensile strength?
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| Tensile strength is the value obtained by dividing the maximum load observed during tensile straining until breakage occurs by the specimen cross-sectional area before straining. Also called "ultimate strength".
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| What is tubing?
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| Tubing is a non-standardized hollow shaped product with a relatively uniform wall thickness, generally round and manufactured to specified requirements or dimensions. Chemical composition, mechanical properties and other physical characteristics may be required for applications in automotive, mechanical, pressure or structural uses. It is generally specified to two dimensions, i.e., outside diameter (O.D.) and wall thickness (W.T.).
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| What is induction welding?
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| Induction welding is a form of electric resistance welding wherein the welding heat is generated on the edges of the strip by resistance to the flow of an electric current in the metal by means of a circumferential coil surrounding the un-welded tubing and excited at high frequency.
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| What is yield strength?
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| Yield strength is the stress at which a material exhibits a specified limiting deviation form proportionality of stress to strain. An offset of 0.2% is used for steel.
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| What is a rotary cut?
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| A rotary cut occurs when a pull-apart machine holds the tube under controlled tension between two clamps during cut off to produce a cut with no inside burr. This eliminates the need for additional deburring on the inside diameter of the tube.
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| What is a dual blade cut?
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| A dual blade cut is achieved when a horizontal blade makes the initial scarfing cut as the vertical blade begins to descend. The vertical blade enters through the scarf and shears the tube clean leaving minimal burr.
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| What is double end chamfering?
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| Double end chamfering refers to an operation that chamfers both inside and outside of the tube diameters, and faces the ends, leaving a smooth, lathe-cut like finish. Standard chamfer angle is 30 degrees, although it can produce any angle to meet the customer specifications.
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| What is double end radius?
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| Double end radius refers to an operation identical to chamfering; however, chamfering is an angled cut and radius is a radius cut. Wall thickness is a factor that must be considered when defining the radius dimension, to ensure a uniform blend on both the inside and outside of the tube.
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| What is wire brush deburr?
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| Wire brush deburr refers to an operation consisting of a hand fed machine, once loaded this high speed process will brush deburr the end of the tubing. There are various setting to adjust the extent of deburring required. MARKIN's wire brush deburr machine is also equipped with a vacuum system to significantly reduce any debris and dust particles generated during the operation.
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