1、Drop-Weight Tear Tests on Line PipeAPI RECOMMENDED PRACTICE 5L3 FOURTH EDITION, AUGUST 2014Special 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 o
2、f APIs employees, subcontractors, consultants, committees, or other assignees make any warranty or representation, either express or implied, with respect to the accuracy, completeness, or usefulness of the information contained herein, or assume any liability or responsibility for any use, or the r
3、esults of such use, of any information or process disclosed in this publication. Neither API nor any of APIs employees, subcontractors, consultants, or other assignees represent that use of this publication would not infringe upon privately owned rights.API publications may be used by anyone desirin
4、g to do so. Every effort has been made by the Institute to assure the accuracy and reliability of the data contained in them; however, the Institute makes no representation, warranty, or guarantee in connection with this publication and hereby expressly disclaims any liability or responsibility for
5、loss or damage resulting from its use or for the violation of any authorities having jurisdiction with which this publication may conflict.API publications are published to facilitate the broad availability of proven, sound engineering and operating practices. These publications are not intended to
6、obviate the need for applying sound engineering judgment regarding when and where these publications should be utilized. The formulation and publication of API publications is not intended in any way to inhibit anyone from using any other practices.Any manufacturer marking equipment or materials in
7、conformance with the marking requirements of an API standard is solely responsible for complying with all the applicable requirements of that standard. API does not represent, warrant, or guarantee that such products do in fact conform to the applicable API standard.Users of this Recommended Practic
8、e should not rely exclusively on the information contained in this document. Sound business, scientific, engineering, and safety judgment should be used in employing the information contained herein. All rights reserved. No part of this work may be reproduced, translated, stored in a retrieval syste
9、m, or transmitted by any means, electronic, mechanical, photocopying, recording, or otherwise, without prior written permission from the publisher. Contact the Publisher, API Publishing Services, 1220 L Street, NW, Washington, DC 20005.Copyright 2014 American Petroleum InstituteForewordThis standard
10、 is under the jurisdiction of the API Subcommittee on Standardization of Tubular Goods and includes changes approved by letter ballot in 2013.The need for a determination of the fracture toughness of line pipe was considered in 1964 and at the midyear meeting in 1965. Certain ground rules were submi
11、tted at the 1965 meeting for the development of a specification on fracture toughness.As a result of the information obtained through the research efforts of the American Gas Association, methods for conducting drop-weight tear tests for line pipe were developed. The methods of conducting this test
12、and evaluating the results are described in this recommended practice.The verbal forms used to express the provisions in this recommended practice are as follows: the term “shall” denotes a minimum requirement in order to conform to the recommended practice; the term “should” denotes a recommendatio
13、n or that which is advised but not required in order to conform to the recommended practice; the term “may” is used to express permission or a provision that is optional; the term “can” is used to express possibility or capability.Nothing contained in any API publication is to be construed as granti
14、ng any right, by implication or otherwise, for the manufacture, sale, or use of any method, apparatus, or product covered by letters patent. Neither should anything contained in the publication be construed as insuring anyone against liability for infringement of letters patent.This document was pro
15、duced under API standardization procedures that ensure appropriate notification and participation in the developmental process and is designated as an API standard. Questions concerning the interpretation of the content of this publication or comments and questions concerning the procedures under wh
16、ich this publication was developed should be directed in writing to the Director of Standards, American Petroleum Institute, 1220 L Street, NW, Washington, DC 20005. Requests for permission to reproduce or translate all or any part of the material published herein should also be addressed to the dir
17、ector.Generally, API standards are reviewed and revised, reaffirmed, or withdrawn at least every five years. A one-time extension of up to two years may be added to this review cycle. Status of the publication can be ascertained from the API Standards Department, telephone (202) 682-8000. A catalog
18、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 Department, API, 1220 L Street, NW, Washington, DC 20005, standardsapi.org.iiiContentsPage1 Scope . . . . . . . . . . . . .
19、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Normative References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
20、13 Abbreviations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 General Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
21、 . . . . . . . . . . . . . . . 14.1 Apparatus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14.2 Metric Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
22、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Specimens . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25.1 Orientation . . . . . . . . . . . . . . . . . . .
23、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25.2 Notch Geometry. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35.3 Dimensions
24、36 Specimen Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 Specimen Evaluation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
25、 . . . . . . . . . . . . 48Report. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7Annex A (normative) Metric Conversion Factors. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
26、 . . . . . . . . . . . . . . . . . . . . . . . 8Annex B (normative) Measurement of Shear Area. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9Figures1 Drop-Weight Tear Test Specimen and Support Dimensions . . . . . . . . . . . . . . . . . . . . .
27、 . . . . . . . . . . . . . . . . 22 Drop-Weight Tear Test Chevron Notch Details . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 Shear Area Rating of Separations in Controlled-rolled Steel Fracture Surfaces. . . . . . . . . . . . . . . . . . . . . 54
28、 Fracture Surface Included in Shear Area Determination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65 Alternate Shear-cleavage Fracture Appearance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6B.1 Representative DWT
29、T Fracture Surfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10B.2 Chart for Determining Percent Shear for 0.312 in. (7.9 mm) Material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11B.3 Chart for Determining Percent Shear fo
30、r 0.344 in. (8.7 mm) Material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11Tables1 Test Temperature Reduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 Minimum Bath Time Requirements . . . . . . . .
31、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3v1Drop-Weight Tear Tests on Line Pipe1 ScopeThese procedures describe a recommended method for conducting Drop-Weight Tear Tests to measure the fracture appearance or fracture ductility of the pipe
32、as referenced in API Specification 5L, Specification for Line Pipe.2 Normative ReferencesThe following referenced document is indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced documen
33、t (including any amendments) applies. API Specification 5L, Specification for Line Pipe3 AbbreviationsFor the purposes of this document, the following abbreviations apply.D/t diameter-to-thickness ratioDWTT Drop-Weight Tear Testt pipe wall thicknessT neglected regions for shear area evaluationtsDWTT
34、 specimen thickness4 General Information4.1 Apparatus4.1.1 The testing machine may be of any configuration that has sufficient energy to completely break the specimens in one impact.4.1.2 The velocity of the hammer at impact shall be in the range of 16 ft/sec to 30 ft/sec (5 m/sec to 9 m/sec).4.1.3
35、The specimen shall be inserted in the testing machine so that the notch is lined up with the centerline of the hammer tip within 1/16 in. (1.59 mm). The notch should also be centered between the supports of the anvil.4.1.4 The radius of the anvil supports for the specimen should not be larger than 5
36、/8 in. (15.9 mm). Larger radii have been found to contribute to specimen jamming.4.2 Metric UnitsMetric conversions of US customary units are shown in parenthesis in the test, figures, and tables. See Annex A for metric conversion factors.NOTE Drop-Weight Tear Testing pipe with upper shelf Charpy im
37、pact energies greater than 200 J (148 ft-lb) often results in invalid tests, making the test method ineffective.2 API RECOMMENDED PRACTICE 5L35 Specimens5.1 Orientation5.1.1 The specimens shall be removed from pipe such that the length of the specimen is in the circumferential direction of the pipe.
38、5.1.2 The specimens shall be flattened unless the D/t is less than 40. If the D/t is less than 40, then the center 1 in. to 2 in. (25 mm to 51 mm) may be left unflattened. If buckling occurs, the test results are not valid and replacement tests shall be conducted.Flattening has been observed to decr
39、ease the percent shear of the fracture. In the case of a difference between flattened and nonflattened specimen results, or in referee testing, the results from nonflattened specimens shall govern.5.1.3 The specimens may be removed from the pipe wall by sawing, shearing, or flame cutting with or wit
40、hout machining, provided the dimensions of the finished specimen are within the tolerances shown in Figure 1.NOTE If the specimen is flame cut, it is usually difficult to press in the notch unless the heat-affected zone is removed by machining. Figure 1Drop-Weight Tear Test Specimen and Support Dime
41、nsionsThickness (see 5.3)SECTION A-APRESSED NOTCHWidth3.00 in. 1/8in.(76.2 mm 3 mm)Notch depth0.20 in. 0.02 in.(5.1 mm 0.51 mm)Radius0.562 in. 0.0625 in.(14.3 mm 1.59 mm)Radius1 in. 0.250 in.(25.4 mm 6.35 mm)Pressed notch radiusLQ PP Length 12.00 in. 0.75 in. (305 mm 19 mm)Span 10.00 in. 1/16in. (25
42、4 mm 1.6 mm)Notch angle 45 25 in. 1/16in. (127 mm 1.6 mm)HammerAAFull plate thicknessSECTION A-ACHEVRON NOTCHWidth3.00 in. 1/16in.(76.2 mm 1.6 mm)Notch depth0.20 in. 0.02 in.(5.1 mm 0.51 mm)Radius0.562 in. 0.0625 in.(14.3 mm 1.59 mm)Radius1 in. 0.250 in.(25.4 mm 6.35 mm)Length 12.00 in. 0.75 in. (30
43、5 mm 19 mm)Span 10.00 in. 1/16in. (254 mm 1.6 mm)5 in. 1/16in. (127 mm 1.6 mm)HammerAADROP-WEIGHT TEAR TESTS ON LINE PIPE 35.2 Notch GeometryThe pressed notch is the preferred notch. The chevron notch may be considered an alternative to the pressed notch, particularly for higher Charpy V-notch energ
44、y steels where invalid results are more likely to occur with pressed notch.The chevron notch can eliminate excess initiation energy associated with some higher toughness line-pipe steels, which frequently result in invalid specimens as defined in 7.1.a) Pressed Notch.The pressed notch shall be press
45、ed to the depth shown in Figure 1 with a sharp (no radius) tool steel chisel with an included angle of 45 2. Machined notches are prohibited.When many specimens are to be tested, it is helpful to use a jig which will guide the chisel and stop it at the proper depth.b) Chevron Notch.The chevron notch
46、 shall be cut or machined to the 90 nominal configuration shown in Figure 2 with a width not to exceed 0.047 in. (1.2 mm). There is no notch radius requirement (i.e. the notch may be round or have a flat bottom).Figure 2Drop-Weight Tear Test Chevron Notch Details2.8 in.(71 mm)0.2 in.(5.1 mm)0.047 in
47、. (1.2 mm)maximumSECTION A-Ats90NOTE SECTION A-A is the through-notch fracture plane shown in Figure 1.4 API RECOMMENDED PRACTICE 5L35.3 DimensionsSpecimens from pipe with a wall thickness of 0.750 in. (19.0 mm) and less shall be the full-wall thickness of the pipe. Specimens from pipe with wall thi
48、ckness greater than 0.750 in. (19.0 mm) shall be either: (1) the full wall thickness; or (2) reduced in thickness to 0.750 in. (19.0 mm) minimum by machining one or both surfaces. Specimens that are reduced to a thickness less than the pipe wall thickness shall be broken at a temperature that is red
49、uced from the specified test temperature by the amount shown in Table 1.NOTE Heavy wall pipe tested at a reduced temperature shall be marked with the specified temperature. 6 Specimen Testing6.1 The specimens shall be completely immersed in a batch of a suitable liquid at a temperature within 2 F (1 C) of the desired test temperature for the minimum time requirement as given in Table 2. The specimens shall be separated from each other and the bath sides and bottom by at least 1 in. (25 mm) or one wall th
