1、Imperfection and Defect TerminologyAPI BULLETIN 5T1 ELEVENTH EDITION, OCTOBER 2017Special NotesAPI publications necessarily address problems of a general nature. With respect to particular circumstances, local, state, and federal laws and regulations should be reviewed.Neither API nor any of APIs em
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13、atus of the publication can be ascertained from the API Standards Department, telephone (202) 682-8000. A catalog of API publications and materials is published annually by API, 1220 L Street, NW, Washington, DC 20005.Suggested revisions are invited and should be submitted to the Standards Departmen
14、t, API, 1220 L Street, NW, Washington, DC 20005, standardsapi.org.iiiContentsPage1 Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 References . . . . . . . . . . . . . . . . .
15、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Terms, Definitions, and Associated Example Figures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23.1 Occurrences in Steel Pipe in Locat
16、ions Other than the Weld . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23.2 Occurrences in Electric Resistance Welds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 223.3 Occurrences in Double Submerged Arc Welds (Submerge
17、d Arc WeldsLongitudinal) . . . . . . . . . . . . . 343.4 Occurrences in Threads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41vImperfection and Defect Terminology 1 Scope This document provides terms, definitions
18、, and example figures of imperfections and defects that occur in manufacturing steel tubulars. The words imperfection and defect refer to metallurgical and other features of steel tubular products that may or may not affect the performance of the products. Inspection requirements and acceptance crit
19、eria are not defined in this document and are found instead in the respective product specification. 2 References For undated references, the latest edition of the referenced document (including any amendments) applies. API Specification 5B, Specification for Threading, Gauging, and Thread Inspectio
20、n of Casing, Tubing, and Line Pipe Threads API Specification 5CT, Specification for Casing and Tubing API Recommended Practice 5C1, Recommended Practice for Care and Use of Casing and Tubing API Specification 5DP, Specification for Drill Pipe API Specification 5L, Specification for Line Pipe API Spe
21、cification 5LCP, Specification for Coiled Line Pipe API Recommended Practice 5L1, Recommended Practice for Railroad Transportation of Line Pipe API Recommended Practice 5L2, Recommended Practice for Internal Coating of Line Pipe for Non-corrosive Gas Transmission Services API Recommended Practice 5L
22、3, Drop-weight Tear Tests on Line Pipe API Recommended Practice 5L7, Recommended Practices for Unprimed Internal Fusion Bonded Epoxy Coating of Line Pipe API Recommended Practice 5SI, Recommended Practice for Purchaser Representative Surveillance and/or Inspection at the Supplier API Specification 5
23、ST, Specification for Coiled TubingU.S. Customary and SI Units Kiessling, Roland (with the collaboration of Nils Lange), Non-metallic Inclusions in Steel, Parts IIV, Book 194, Metals Society: London, 1978 Krauss, George, Steels: Processing, Structure, and Performance, Materials Park, OH: ASM Interna
24、tional, 2005, ISBN: 978-0-87170-817-5 Nichols, Robert K., Common HF Welding Defects, East Haven, CT: Thermatool Corp., 1999 2 API BULLETIN 5T1 3 Terms, Definitions, and Associated Example Figures For the purposes of this document, the following terms and definitions apply. Included are photographs (
25、figures) associated with the respective terms and definitions. These are intended to serve as example(s) illustrating the defined terms but not be the only or absolute representationsthey are not considered to be exclusive or exhaustive in nature. 3.1 Occurrences in Steel Pipe in Locations Other tha
26、n the Weld 3.1.1 arc burns Localized points of surface melting caused by arcing between electrode or ground and pipe surface. Figure 1 Figure 2 Figure 3 Figure 4 IMPERFECTION AND DEFECT TERMINOLOGY 3 3.1.2 blister A raised spot on the surface of pipe caused by expansion of gas in a cavity within the
27、 pipe. NOTE Also see lamination (3.1.9). NOTE Cross section with midwall blister. Figure 5 NOTE Top view with midwall blister. Figure 6 3.1.3 crack A stress-induced separation of the metal characterized by a tip and ratio of length to opening displacement that, without any other influence, is insuff
28、icient in extent to cause rupture of the material. NOTE Quench cracks in steel result from stresses produced during the austenite-to-martensite transformation, which is accompanied by an increase in volume. Figure 7 4 API BULLETIN 5T1 Figure 8 Figure 9 Figure 10 IMPERFECTION AND DEFECT TERMINOLOGY 5
29、 3.1.4 dent A local change in surface contour caused by mechanical impact or excessive localized pressure, but not accompanied by loss of metal. Figure 11 Figure 12 3.1.5 eccentricity A condition in which the pipe OD and ID axes are not coincident, which results in wall thickness variation around th
30、e circumference at a given section plane. Figure 13 6 API BULLETIN 5T1 Figure 14 3.1.6 gouge Elongated grooves or cavities caused by mechanical removal of metal. NOTE Pipe ID. Figure 15 NOTE Pipe ID. Figure 16 IMPERFECTION AND DEFECT TERMINOLOGY 7 NOTE Pipe OD. Figure 17 NOTE Pipe OD. Figure 18 NOTE
31、 Pipe OD. Figure 19 NOTE Pipe OD. Figure 20 8 API BULLETIN 5T1 3.1.7 hard spot An area in the pipe with a hardness level higher than that of the surrounding metal that can result from variations in the manufacturing process such as localized rapid cooling. Figure 21 3.1.8 inclusion Foreign material
32、or nonmetallic particles entrapped within the metal during solidification. NOTE See reference Steels: Processing, Structure, and Performance and Non-metallic Inclusions in Steel. Figure 22 IMPERFECTION AND DEFECT TERMINOLOGY 9 3.1.9 lamination An internal metal separation creating layers parallel to
33、 the surface. NOTE Also see blister (3.1.2). Figure 23 Figure 24 Figure 25 10 API BULLETIN 5T1 3.1.10 lap Fold of parent metal that has been rolled or otherwise worked against the surface of rolled metal but has not fused into sound metal. Figure 26 Figure 27 3.1.11 pit A depression resulting from t
34、he removal of foreign material pressed into the surface during manufacture or caused by localized environmental corrosion. NOTE Also see slug (3.1.19). Figure 28 IMPERFECTION AND DEFECT TERMINOLOGY 11 Figure 29 Figure 30 3.1.12 plug scores Internal longitudinal grooves occurring in seamless pipe tha
35、t can be caused by pieces of metal adhering to the high-mill plug. Figure 31 12 API BULLETIN 5T1 Figure 32 Figure 33 3.1.13 ring mark/pattern Hot mill induced variation of ID surface. Figure 34 IMPERFECTION AND DEFECT TERMINOLOGY 13 Figure 35 3.1.14 roll mark Surface imperfections that are caused by
36、 improper roll alignment or roll surface damage and may be periodic or continuous. NOTE Internal surface. Figure 36 NOTE Internal surface. Figure 37 14 API BULLETIN 5T1 NOTE Periodic external surface. Figure 38 NOTE Continuous external surface. Figure 39 3.1.15 scab An imperfection in the form of a
37、shell or veneer that may be attached to the surface by sound metal and can have its origin in a parent metal defect. NOTE Internal surface. Figure 40 NOTE Internal surface. Figure 41 IMPERFECTION AND DEFECT TERMINOLOGY 15 NOTE External surface. Figure 42 3.1.16 scale The oxide present on the surface
38、 of steel products exposed to temperatures during manufacture (rolling) or later processing (heat treating). NOTE When present in excess, it can lead to a flaky or rough surface finish. Figure 43 3.1.17 seam Crevice in rolled metal that has been closed, or nearly closed, by rolling or other work but
39、 has not been fused into sound metal. Figure 44 16 API BULLETIN 5T1 Figure 45 Figure 46 3.1.18 sliver An elongated piece of metal (typically very thin) that has been rolled into the surface of the parent metal to which it is attached (may be attached by only one end). Figure 47 IMPERFECTION AND DEFE
40、CT TERMINOLOGY 17 Figure 48 Figure 49 Figure 50 18 API BULLETIN 5T1 3.1.19 slug A foreign metallic body rolled into the metal surface but usually not fused. NOTE Also see pit (3.1.11). Figure 51 Figure 52 Figure 53 IMPERFECTION AND DEFECT TERMINOLOGY 19 Figure 54 3.1.20 stretch mill indentation Loca
41、lized thinning of the pipe body wall (often located on the inside surface). Figure 55 3.1.21 stretch mill overfill Longitudinal protrusions extending above the OD or ID surface of the tube that are caused by feeding too much stock into the next roll stand. NOTE The incoming diameter or wall thicknes
42、s of the tube is too large or the amount of reduction of the subsequent roll stand is too great. Figure 56 20 API BULLETIN 5T1 Figure 57 3.1.22 tear Surface imperfection caused by damaged tooling during hot rolling processes. Figure 58 Figure 59 IMPERFECTION AND DEFECT TERMINOLOGY 21 Figure 60 3.1.2
43、3 upset underfill A depression on the outside or inside surface of an upset caused by insufficient flow of metal to completely fill out the upset to the desired shape. Figure 61 Figure 62 3.1.24 upset wrinkles Surface irregularity occurring on pipe upsets in the form of transverse forging laps. 22 A
44、PI BULLETIN 5T1 Figure 63 3.2 Occurrences in Electric Resistance Welds 3.2.1 black spot A localized area in the weld line containing an un-extruded oxide. NOTE Black spots are black or dark gray in appearance and may also be known as “entrapment,” “black penetrator,” or “weld-line oxides.” Figure 64
45、 Figure 65 Figure 66 IMPERFECTION AND DEFECT TERMINOLOGY 23 Figure 67 Figure 68 3.2.2 contact marks Intermittent marks adjacent to the weld line resulting from the electrical contact between the electrodes supplying the welding current and the pipe surface. Figure 69 3.2.3 edge damage Improperly pre
46、pared or damaged skelp edges that can lead to imperfections in the weld seam. NOTE 1 Imperfections caused by edge damage may appear as a discontinuity to one side of the bond line (which does not follow flow lines). NOTE 2 See Figures 76 to 78 for etched photos of flow lines. 24 API BULLETIN 5T1 Fig
47、ure 70 3.2.4 edge misalignment Radial offset of strip edges. NOTE May also be referred to as “cave,” “offset plate,” or “offset edges.” NOTE Prior to weld trim. Figure 71 3.2.5 excessive trim A condition in which the depth of the weld trim exceeds the limits of the applicable API standard. Figure 72 3.2.6 hook cracks upturned fiber imperfections
