ASTM E1921-2008a Standard Test Method for Determination of Reference Temperature To for Ferritic Steels in the Transition Range.pdf
《ASTM E1921-2008a Standard Test Method for Determination of Reference Temperature To for Ferritic Steels in the Transition Range.pdf》由会员分享,可在线阅读,更多相关《ASTM E1921-2008a Standard Test Method for Determination of Reference Temperature To for Ferritic Steels in the Transition Range.pdf(22页珍藏版)》请在麦多课文档分享上搜索。
1、Designation: E 1921 08aStandard Test Method forDetermination of Reference Temperature, To, for FerriticSteels in the Transition Range1This standard is issued under the fixed designation E 1921; the number immediately following the designation indicates the year oforiginal adoption or, in the case of
2、 revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of a referencetemperature, To, which characterizes th
3、e fracture toughness offerritic steels that experience onset of cleavage cracking atelastic, or elastic-plastic KJcinstabilities, or both. The specifictypes of ferritic steels (3.2.1) covered are those with yieldstrengths ranging from 275 to 825 MPa (40 to 120 ksi) andweld metals, after stress-relie
4、f annealing, that have 10 % orless strength mismatch relative to that of the base metal.1.2 The specimens covered are fatigue precracked single-edge notched bend bars, SE(B), and standard or disk-shapedcompact tension specimens, C(T) or DC(T). A range ofspecimen sizes with proportional dimensions is
5、 recommended.The dimension on which the proportionality is based isspecimen thickness.1.3 Median KJcvalues tend to vary with the specimen typeat a given test temperature, presumably due to constraintdifferences among the allowable test specimens in 1.2. Thedegree of KJcvariability among specimen typ
6、es is analyticallypredicted to be a function of the material flow properties (1)2and decreases with increasing strain hardening capacity for agiven yield strength material. This KJcdependency ultimatelyleads to discrepancies in calculated Tovalues as a function ofspecimen type for the same material.
7、 Tovalues obtained fromC(T) specimens are expected to be higher than Tovaluesobtained from SE(B) specimens. Best estimate comparisons ofseveral materials indicate that the average difference betweenC(T) and SE(B)-derived Tovalues is approximately 10C (2).C(T) and SE(B) Todifferences up to 15C have a
8、lso beenrecorded (3). However, comparisons of individual, smalldatasets may not necessarily reveal this average trend. Datasetswhich contain both C(T) and SE(B) specimens may generateToresults which fall between the Tovalues calculated usingsolely C(T) or SE(B) specimens. It is therefore stronglyrec
9、ommended that the specimen type be reported along withthe derived Tovalue in all reporting, analysis, and discussion ofresults. This recommended reporting is in addition to therequirements in 11.1.1.1.4 Requirements are set on specimen size and the numberof replicate tests that are needed to establi
10、sh acceptablecharacterization of KJcdata populations.1.5 The statistical effects of specimen size on KJcin thetransition range are treated using weakest-link theory (4)applied to a three-parameter Weibull distribution of fracturetoughness values. A limit on KJcvalues, relative to thespecimen size, i
11、s specified to ensure high constraint conditionsalong the crack front at fracture. For some materials, particu-larly those with low strain hardening, this limit may not besufficient to ensure that a single-parameter (KJc) adequatelydescribes the crack-front deformation state (5).1.6 Statistical meth
12、ods are employed to predict the transi-tion toughness curve and specified tolerance bounds for 1Tspecimens of the material tested. The standard deviation of thedata distribution is a function of Weibull slope and median KJc.The procedure for applying this information to the establish-ment of transit
13、ion temperature shift determinations and theestablishment of tolerance limits is prescribed.1.7 The fracture toughness evaluation of nonuniform mate-rial is not amenable to the statistical analysis methods em-ployed in this standard. Materials must have macroscopicallyuniform tensile and toughness p
14、roperties. For example, multi-pass weldments can create heat-affected and brittle zones withlocalized properties that are quite different from either the bulkmaterial or weld. Thick section steel also often exhibits somevariation in properties near the surfaces. Metallography andinitial screening ma
15、y be necessary to verify the applicability ofthese and similarly graded materials. Paticular notice should begiven to the 2% and 98% tolerance bounds on KJcpresented in9.3. Data falling outside these bounds may indicate nonuniformmaterial properties.1This test method is under the jurisdiction of AST
16、M Committee E08 on Fatigueand Fracture and is the direct responsibility of E08.07 on Fracture Mechanics.Current edition approved May 15, 2008. Published June 2008. Originallyapproved in 1997. Last previous edition approved in 2008 as E 1921 08.2The boldface numbers in parentheses refer to the list o
17、f references at the end ofthis standard.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.1.8 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of
18、this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:3E4 Practices for Force Verification of Testing MachinesE8M Test Methods for Tension Testing of Metallic Mate-rials Me
19、tric4E23 Test Methods for Notched Bar Impact Testing ofMetallic MaterialsE74 Practice of Calibration of Force-Measuring Instru-ments for Verifying the Force Indication of Testing Ma-chinesE 208 Test Method for Conducting Drop-Weight Test toDetermine Nil-Ductility Transition Temperature of FerriticSt
20、eelsE 399 Test Method for Linear-Elastic Plane-Strain FractureToughness KIcof Metallic MaterialsE 436 Test Method for Drop-Weight Tear Tests of FerriticSteelsE 561 Test Method for K-R Curve DeterminationE 812 Test Method for Crack Strength of Slow-Bend Pre-cracked Charpy Specimens of High-Strength M
21、etallicMaterials4E 1820 Test Method for Measurement of Fracture Tough-nessE 1823 Terminology Relating to Fatigue and Fracture Test-ing3. Terminology3.1 Terminology given in Terminology E 1823 is applicableto this test method.3.2 Definitions:3.2.1 ferritic steelsare typically carbon, low-alloy, andhi
22、gher alloy grades. Typical microstructures are bainite, tem-pered bainite, tempered martensite, and ferrite and pearlite.Allferritic steels have body centered cubic crystal structures thatdisplay ductile-to-cleavage transition temperature fracturetoughness characteristics. See also Test Methods E 23
23、, E 208and E 436.NOTE 1This definition is not intended to imply that all of the manypossible types of ferritic steels have been verified as being amenable toanalysis by this test method.3.2.2 stress-intensity factor, KFL3/2the magnitude ofthe mathematically ideal crack-tip stress field coefficient (
24、stressfield singularity) for a particular mode of crack-tip regiondeformation in a homogeneous body.3.2.3 DiscussionIn this test method, Mode I is assumed.See Terminology E 1823 for further discussion.3.2.4 J-integral, JFL1a mathematical expression; aline or surface integral that encloses the crack
- 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。
本资源只提供5页预览,全部文档请下载后查看!喜欢就下载吧,查找使用更方便
5000 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:
- ASTME19212008ASTANDARDTESTMETHODFORDETERMINATIONOFREFERENCETEMPERATURETOFORFERRITICSTEELSINTHETRANSITIONRANGEPDF

链接地址:http://www.mydoc123.com/p-529799.html