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The defects terms of seamless steel pipe

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The defects terms of seamless steel pipe

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The defects terms of seamless steel pipe / steel
No.	Name	Explain
l	Roundness	Rolled products of circular cross-section, such as round and round steel pipe cross-section diameter ranging from all directions.
2	The shape is not correct	Rolled products of cross-sectional geometry of crooked, uneven.Hexagonal six angles ranging Angle apex angle section steel to reverse.
3	Uneven thickness	Steel plate (or strip) not the same as the thickness of the various parts, some on both sides of thick middle thin edge thin, middle thick, some head-to-tail difference exceeds requirements.
4	Curvature	Rolling in the length or width direction is not straight, curved shape
5	Camber	In the longitudinal direction of the steel plate (or strip) is bent to one side in the horizontal plane.
6	Scoop curvature	The steel sheet (or strip) in length and width directions at the same time, the the undulating wave phenomenon, making it a "scoop-shaped" or "boat".
7	To reverse	The strip rolling along the longitudinal axis of the twisted into a spiral.
8	Off side, off the moment	Square, rectangular cross-section of material ranging the edge ranging sectional diagonal.
9	Pull marks (zoned Road)	Linear groove-shaped, can be seen by the naked eye ditch located in a partial or full length of the steel.
10	Crack	General linear shape, and sometimes Y-shaped, and more consistent with the direction of the pull system, but there are also other directions, general openings for an acute angle.
ll	Heavy leather (scarring)	Surface of the tongue or ichthyosis sheet cocked sheet: a steel body is linked, and equivalent to the surface easy to fall off; another is no link with the body of the steel, but are bonded to the surface is easy to fall off.
12	Fold	The steel surface partially overlapping folding pattern.
13	Rust	Surface rust generated by apricot yellow to dark red, rust, its color, severe corrosion pitting.
14	Hairline	Surface hairline is a very shallow depth, and width of the tiny hair-like fine lines, generally extending along the rolling direction of the formation of fine grain strand.
15	Stratification	The local metal structure in the steel sectional separated severe divided into 2 to 3 layers, between the layers visible inclusions.
16	Bubble	Irregular surface distribution was relatively smooth circular convex hull, large and small, its outer edge. Most is to muster some not muster after pickling smooth shiny surface stratified shear section.
17	The pitting (Ma surface)	Surface showed partial or continuous into a piece of rough surface, the distribution of different shapes, different sizes pits, similar like orange peel, deep pitting Ma spot serious.
18	Oxidation color	Steel plate (or strip) on the surface after annealing showing a pale yellow, dark brown, light blue, dark blue or light gray.
19	Roller printing	Periodic roll printed surface of the strip or sheet, the lighter parts of its imprint, and no significant bump feeling.
20	Loose	Steel not dense sexual performance. Slice after acid erosion, expanded into many caves, according to its distribution can be divided into: general loose, center porosity.
2l	Segregation	Steel, the chemical composition and non-metallic inclusions of the various parts of the uneven distribution of the phenomenon. Its manifestations can be divided into: of dendritic, box-shaped, punctate segregation and anti-segregation.
22	Residual shrinkage	Showed irregular voids or cracks in the of lateral acid leaching the center portion of the test piece. Voids or cracks often remain outside impurities.
23	Nonmetallic inclusions	Lateral acidic specimen to see some non-metallic luster was off-white, beige and dark gray and other colors, Department of steel residual oxide, sulfide, silicate.
24	Metallic inclusions	Seen in a transverse low specimen some metallic luster and the matrix metal is clearly different metal salts.
25	Overfiring	Observe the microstructure after the erosion, often in the matrix metal around the network-like oxide can be seen decarburization tissue, other metals such as copper and its alloys, copper oxide along the grain boundary network-shaped or point-like to the test kind of internal extension.
26	White spots	It is a steel internal rupture. In the longitudinal direction on the fracture surface of the steel parts were round or oval silver white spots, after later horizontal slice polishing and etching, and the performance of the elongated hair crack sometimes radially distributed, and sometimes in parallel to deformation direction or irregular distribution.
27	Coarse grains	Acid leaching test fragment mouth with strong metallic luster.
28	Decarburization	Steel surface decarburization phenomenon known as carbon points points lower than the inner carbon. Whole decarburized layer is to render all of ferrite tissue portion refers to the surface of the steel due to decarburization; portion decarburized refers to the carbon content of the steel is not reduced at the organization after the whole decarburized layer. Seamless steel pipe