1、Design Calculations for Pressure-containing EquipmentAPI STANDARD 6XFIRST EDITION, MARCH 2014ERRATA, MAY 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.Nei
2、ther API nor any of 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
3、 any use, or the results 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.Classified areas may vary de
4、pending on the location, conditions, equipment, and substances involved in any given situation. Users of this specification should consult with the appropriate authorities having jurisdiction.Users of this specification should not rely exclusively on the information contained in this specification.
5、Sound business, scientific, engineering, and safety judgment should be used in employing the information contained herein. API is not undertaking to meet the duties of employers, service providers, or suppliers to warn and properly train and equip their employees, and others exposed, concerning heal
6、th and safety risks and precautions, nor undertaking their obligations to comply with authorities having jurisdiction.Information concerning safety and health risks and proper precautions with respect to particular materials and conditions should be obtained from the employer, the service provider o
7、r supplier of that material, or the material safety datasheet.API publications may be used by anyone desiring 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 guara
8、ntee in connection with this publication and hereby expressly disclaims any liability or responsibility for 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 broa
9、d availability of proven, sound engineering and operating practices. These publications are not intended to 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
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11、antee that such products do in fact conform to the applicable API standard.All rights reserved. No part of this work may be reproduced, translated, stored in a retrieval system, or transmitted by any means, electronic, mechanical, photocopying, recording, or otherwise, without prior written permissi
12、on from the publisher. Contact the Publisher, API Publishing Services, 1220 L Street, NW, Washington, DC 20005.Copyright 2014 American Petroleum InstituteForewordNothing contained in any API publication is to be construed as granting any right, by implication or otherwise, for the manufacture, sale,
13、 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.Shall: As used in a standard, “shall” denotes a minimum requirement in order to conform to
14、 the specification.Should: As used in a standard, “should” denotes a recommendation or that which is advised but not required in order to conform to the specification.This document was produced under API standardization procedures that ensure appropriate notification and participation in the develop
15、mental 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 which this publication was developed should be directed in writing to the Director of Standards, American Petroleu
16、m 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 director.Generally, API standards are reviewed and revised, reaffirmed, or withdrawn at least every five years. A o
17、ne-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 of API publications and materials is published annually by API, 1220 L Street, NW, Washington, DC 20005.This sta
18、ndard shall become effective on the date printed on the cover but may be used voluntarily from the date of distribution.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 Terms, Definitions, and Symbols. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.1 Terms and Definitions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
21、. . . . . . . . . . . . . . . . . 13.2 Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 Elastic Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
22、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24.2 Stress Components. . . . . . . . . . . . . .
23、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24.3 Combined Stresses. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34.4 Stress Categories
24、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 Special Stress Considerations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
25、 55.1 Temperature Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55.2 Bearing Stress . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
26、. . . . . . . . . . . . . . . . . . 55.3 Pure Shear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65.4 Progressive Distortion of Nonintegral Connections. . . . . . . . . . . . . . . . . . .
27、. . . . . . . . . . . . . . . . . . . . . . . . . 65.5 Triaxial Stresses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65.6 Stress Linearization. . . . . . . . . . . . . . . . . . . . . . . . . . . .
28、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66 Nonlinear Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66.1 General . . . . . . . . . . . . . . . . . . .
29、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66.2 Limit Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76.3
30、Plastic Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76.4 Shakedown Analysis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
31、. . . . . . . . . . . . . . 77 Reporting Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
32、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8vIntroductionThis standard is intended to document the design methodology from the ASME Boiler and Pressure Vessel Code, Section VIII, Division 2, Appendix 4, which has been used in the oil and gas industry since the 15th Edition
33、of API Specification 6A was published in 1986. API 6A modified the rules of the ASME Code to permit higher stresses than were allowed by ASME. API 6A adopted a design stress intensity of two thirds of the minimum specified yield strength.Shortly after the 15th Edition of API 6A was published, API re
34、leased the First Edition of API Specification 16A, Specification for Drill-through Equipment. API 16A permitted higher stresses than API 6A at hydrostatic test. Where API 6A limited the membrane stress intensity to 83 % of the minimum specified yield strength, API 16A permitted 90 % of yield strengt
35、h. With the 19th Edition of API 6A in 2004, the design stress intensity of high-strength non-standard materials was changed to the lower of two thirds of the yield strength or one half of the tensile strength. API 16A did not make this change.In 2007, ASME totally rewrote Section VIII, Division 2, u
36、sing generally more liberal design requirements and more stringent material requirements. A joint task group from SC 6, SC 16, and SC 17 reviewed the new ASME Code and recommended that, since the earlier design and material requirements have been used successfully for over 25 years, API should conti
37、nue to reference the 2004 ASME Code. This recommendation was accepted by SC 6, SC 16, and SC 17. The methods included in this document are those of the 2004 ASME Code, as modified by an API Design Task Group.vii1 Design Calculations for Pressure-containing Equipment 1 Scope This standard describes a
38、 design analysis methodology and requirements that apply to design verification of certain pressure-containing products and equipment in the oil and gas industry. The methods included in this document apply to designs where normative reference to this standard is made in an API product specification
39、 and to those components for which the methods of this standard are required or permitted. This standard is based on ASME Boiler and Pressure Vessel Code, Section VIII, Division 2, Appendix 4 (2004 edition with 2005 and 2006 addenda) but includes further limits established for oil and gas products a
40、s determined by API standardization committees. It includes closed-form solutions and methods for elastic analysis, elastic-plastic analysis, and guidance on finite element analysis methods. The methodology assumes ductile metallic material behavior and has no provision for material defects. Fatigue
41、 analysis is outside the scope of this document. 2 Normative References No other document is identified as indispensable or required for the application of this standard. 3 Terms, Definitions, and Symbols 3.1 Terms and Definitions For the purpose of this document the following terms and definitions
42、apply. 3.1.1 extreme conditions Conditions due to specified events including seismic loading, wind loading, and wave loading in which loading is additive to the normal loading at operating conditions. See 4.4.2.4. 3.1.2 gross distortion Distortion to the extent that the product no longer functions a
43、s intended. 3.1.3 gross structural discontinuity Change in vessel shape, such as the junction of a cylinder and cone or a cylinder and head. 3.1.4 operating conditions Any combination of internal and external pressures, temperatures, and applied loading to which the product is to be exposed in servi
44、ce, excluding hydrostatic shell testing. 3.1.5 pressure-containing Component whose failure to function as intended results in a release of retained fluid to the atmosphere. 3.1.6 ratcheting Progressive plastic deformation caused by cyclical thermal and/or mechanical stresses. 2 API STANDARD 6X 3.1.7
45、 small-displacement analysis Finite-element analysis wherein the stiffness of the elements is calculated based on their initial undeformed geometry. 3.1.8 stress intensity The equivalent intensity of combined stresses at a point based on the maximum shear theory of failure. The stress intensity is t
46、wice the maximum shear stress. 3.1.9 yield strength The engineering stress at which, by convention, it is considered that plastic elongation of the material has commenced. 3.2 Symbols For the purposes of this document, the following symbols apply. F peak stress k stress intensity k factor, see 4.4.2
47、.4 Pbprimary bending stress PLlocal primary membrane stress Pmgeneral primary membrane stress Q secondary membrane plus bending stress Seequivalent stress based on the von Mises distortion energy theory Sistress intensity, the equivalent stress based on the Tresca maximum shear stress theory Smdesig
48、n stress intensity Snprincipal stress, where n = 1, 2, or 3 Stmaximum allowable general primary membrane stress intensity at test pressure Syminimum specified yield strength x,y,zdirect stress components in the x, y, and z directions shear stress xy yz zx, , shear stress components in the x-y-z coor
49、dinate system 4 Elastic Analysis 4.1 General Elastic analysis is based on the assumption that the material has a linear stress-strain relationship and therefore does not account for yielding or plastic behavior. 4.2 Stress Components For elastic analysis, stress components shall be calculated, combined, and compared to limits for each category of stress based on multiples of the design stress intensity, Sm, for the material in use and for the category of stress. DESIGN CALCULATIONS FOR PRESSURE-CONTAINING EQUIPMENT 3 The design stress intensity shall be two thirds of the minimum
