API PUBL 938-A-1996 Experimental Study of Causes and Repair of Cracking of 1 1 4Cr- 1 2Mo Steel Equipment《1 1 4Cr- 1 2Mo钢设施开裂的起因和修复的实验研究》.pdf
《API PUBL 938-A-1996 Experimental Study of Causes and Repair of Cracking of 1 1 4Cr- 1 2Mo Steel Equipment《1 1 4Cr- 1 2Mo钢设施开裂的起因和修复的实验研究》.pdf》由会员分享,可在线阅读,更多相关《API PUBL 938-A-1996 Experimental Study of Causes and Repair of Cracking of 1 1 4Cr- 1 2Mo Steel Equipment《1 1 4Cr- 1 2Mo钢设施开裂的起因和修复的实验研究》.pdf(222页珍藏版)》请在麦多课文档分享上搜索。
1、An Experimental Study of Causes and Repair of Cracking of 11/4Cr-1/2Mo Steel EquipmentAPI PUBLICATION 938-A MAY 1996API PUBL*938 96 m 0732290 0560345 973 = SPECIAL NOTES (1) API publications necessarily address problems of a general nature. With respect to particular circumstances, local, state, and
2、 federal laws and regula- tions should be reviewed. (2) API is not undertaking to meet the duties of employers, manufacturers, or suppliers to warn and properly train and equip their employees, and others exposed, concerning health and safety risks and precautions, nor undertaking their obligations
3、under local, state, or federal laws. (3) Information concerning safety and health risks and proper precautions with respect to particular materials and conditions should be obtained from the employer, the manufacturer or supplier of that material, or the material safety data sheet. (4) Nothing conta
4、ined in any API publication is to be construed as granting 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
5、for infringement of letters patent. (5) Generally, API standards are reviewed and revised, reaffirmed, or with- drawn at least every five years. Sometimes a one-time extension of up to two years will be added to this review cycle. This publication will no longer be in effect five years after its pub
6、lication date as an operative API standard or, where an extension has been granted, upon republication. Status of the publication can be ascertained from the API Authoring Department telephone (202) 682-8000. A catalog of API publications and materials is published annually and updated quarterly by
7、API, 1220 L Street, N.W., Washington, D.C. 20005. Copyright 1996 Welding Research Council Inc./American Petroleum Institute API PUBLJ3B 96 0732290 0560346 BOT FINAL REPORTTO THE AMERICAN PETROLEUM INSTITUTE OF RESEARCH UNDER THE GUIDANCE OF THE TASK GROUP ON MATERIALS AND CORROSION RESEARCH OF THE C
8、OMMIlTEE ON CORROSION AND MATERIALS AN EXPERIMENTAL STUDY OF CAUSES AND REPAIR OF CRACKING OF 1 l/qCr=%Mo STEEL EQUIPMENT MAY 1996 Contractor: The Materials Properties Council, Inc. Investigator: M. Prager Subcontractor: Department of Materials Science University of Tennessee Investigators: C. D. Lu
9、ndin, P. Liu, C. Y. P. Qiao, G. Zhou and K. K. Khan API PUBL*738 76 = 0732270 O560347 74b FOREWORD The origin of this project was an in-depth study for API of numerous reported incidents of cracking of equipment of lCr-%Mo and l%Cr-/zMo-Si steels, The report to MI is an explanation of the problem an
10、d the basis for further work to help prevent and repair such cracking. Metallurgical reports, fabrication records and service histories were reviewed. Worldwide research on the subject by steelmakers and studies of these alloys and similar materials in related applications were considered. In many c
11、ases, the cracking was major and cracks propagated in service. Emphasis in the report was placed on the causes of crack initiation during fabrication or of their appearance after only a short time in service. It was concluded that major contributions to the cracking were from poor design, fabricatio
12、n and operating practices which should be corrected using reasonable precautions and well known technology. Such action would pre- vent future vessels from entering service with preexisting cracks or initiating cracks in service. However, there was strong evidence that some of the plates and forging
13、s used for vessel construction were more prone to cracking than others or have disturbingly low toughness. This study was intended to recommend ways to eliminate detrimental fabrication practices and materials. Fabrication and repair operations must be upgraded because subsurface cracks which cannot
14、 be readily detected may occur and then emerge in service. Repairs have been troublesome. Specifically, the study was developed to address the materials, fabrication and repair issues of greatest concern. Under API and MPC Task Groups, Chaired by J. McLaughlin. The objec- tives of the Phase II Study
15、 were established as follows: 1) Develop an understanding of the fabrication/welding factors that affect cracking of Cr-Mo equipment, including the effects of PWHT and pre- heat temperature. 2) Develop an understanding of the inherent material properties that affect cracking of Cr-Mo equipment. This
16、 was to include the effects of impuri- ties in the steel and initial condition of the steel (i.e., annealed vs. normalized and tempered). 3) Define a controlled deposition (temper bead) procedure for repair and initial fabrication that will produce a fine grain, more damage tolerant, microstructure
17、in the weld heat affected zone (HAZ). 4) Determine the effect of using lower carbon, lower strength fillers for repair welds. Experience suggests that depending on conditions, the use of a low carbon filler can either improve or impair the performance of a repaired weld. Appreciation is expressed to
18、 API for support. Portions of the work were cost shared by MPC, PVRC and WRC. This work resulted in important new physical simulation, weldability and notched bar test methods. Fresh insight was gained into the heat affected zone metallurgy of this important class of materials. Dr. M. Prager Executi
19、ve Director, Materials Properties Council, Inc. 11 API PUBL*938 96 0732290 0560348 682 CONTENTS Executive Summary 1 For Applications of 11/ evaluate controlled deposition repair tech- niques; determine the suitability of low carbon filler materials; and understand the role of fabrication and welding
20、 practices on susceptibility to cracking. The program succeeded in all objectives. It was found that fabrication, repair- and service-related cracking often have the same roots and are responsive to the same remedial action. Problems arise where there is low heat affected zone ductility. The followi
21、ng conclusions and recommendations are therefore pro- vided. For Applications of 11/4Cr-1/2Mo Steel at 825F and Higher (a) It is strongly recommended that Class 1 (60/35 ksi tensile, yield strength) materials be specified in Final report to API on Prevention and Repair ofcracking zn Chrome Moly Equi
22、pment, MPC, September, 1990. preference to Class 2 (75/45 ksi tensile, yield strength), accelerated cooled materials. (b) High PWHT temperatures were found to be necessary to improve heat affected zone ductility. PWHT requirements are related to welding variables and material composition. Fabricatio
23、n guidelines are provided herein with specific PWHT recommenda- tions depending on composition, desired strength and welding variables. (c) High PWHT temperatures may be used with- out undesirably impairing creep strength and charpy impact values provided carbon content is not too high. (d) Certain
24、materials display a high sensitivity to cracking. Materials Composition Factors (MPC-5, MPC-7) have been identified and can be used to screen the materials. All of the elements included in the factors may not normally be included in the specification requirements and thus the range of elements contr
- 1.请仔细阅读文档,确保文档完整性,对于不预览、不比对内容而直接下载带来的问题本站不予受理。
- 2.下载的文档,不会出现我们的网址水印。
- 3、该文档所得收入(下载+内容+预览)归上传者、原创作者;如果您是本文档原作者,请点此认领!既往收益都归您。
下载文档到电脑,查找使用更方便
10000 积分 0人已下载
下载 | 加入VIP,交流精品资源 |
- 配套讲稿:
如PPT文件的首页显示word图标,表示该PPT已包含配套word讲稿。双击word图标可打开word文档。
- 特殊限制:
部分文档作品中含有的国旗、国徽等图片,仅作为作品整体效果示例展示,禁止商用。设计者仅对作品中独创性部分享有著作权。
- 关 键 词:
- APIPUBL938A1996EXPERIMENTALSTUDYOFCAUSESANDREPAIROFCRACKINGOF114CR12MOSTEELEQUIPMENT114CR12MO 设施 开裂 起因

链接地址:http://www.mydoc123.com/p-399903.html