Hydraulic fluid power — Fatigue pressure testing of metal pressure-containing envelopes — Part 2: Rating methods

ISO/TR 10771-2:2008 specifies a test method for fatigue rating of the pressure-containing envelopes of components used in hydraulic fluid power systems, as tested under steady internal cyclic pressure loads in accordance with ISO 10771-1.

Transmissions hydrauliques — Essais de fatigue des enveloppes métalliques sous pression — Partie 2: Méthodes de classement

General Information

Status
Published
Publication Date
23-Nov-2008
Current Stage
9093 - International Standard confirmed
Start Date
17-Jun-2011
Completion Date
26-Mar-2019
Ref Project

Buy Standard

Technical report
ISO/TR 10771-2:2008 - Hydraulic fluid power -- Fatigue pressure testing of metal pressure-containing envelopes
English language
40 pages
sale 15% off
Preview
sale 15% off
Preview

Standards Content (sample)

TECHNICAL ISO/TR
REPORT 10771-2
First edition
2008-12-01
Hydraulic fluid power — Fatigue pressure
testing of metal pressure-containing
envelopes —
Part 2:
Rating methods
Transmissions hydrauliques — Essais de fatigue des enveloppes
métalliques sous pression —
Partie 2: Méthodes de classement
Reference number
ISO/TR 10771-2:2008(E)
ISO 2008
---------------------- Page: 1 ----------------------
ISO/TR 10771-2:2008(E)
PDF disclaimer

This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but

shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In

downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat

accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.

Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation

parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In

the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.

COPYRIGHT PROTECTED DOCUMENT
© ISO 2008

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,

electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or

ISO's member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2008 – All rights reserved
---------------------- Page: 2 ----------------------
ISO/TR 10771-2:2008(E)
Contents Page

Foreword............................................................................................................................................................ iv

Introduction ........................................................................................................................................................ v

1 Scope ..................................................................................................................................................... 1

2 Normative references ........................................................................................................................... 1

3 Terms and definitions........................................................................................................................... 2

4 Selection of material factors................................................................................................................ 2

5 Determination of cyclic test pressure................................................................................................. 2

6 Conduct of fatigue test......................................................................................................................... 3

7 Rating by similarity............................................................................................................................... 4

8 Rating declaration................................................................................................................................. 4

9 Identification statement (reference to this part of ISO 10771) ......................................................... 4

Annex A (informative) Material factor database.............................................................................................. 5

A.1 Values of coefficient of variation, k , for commonly used metals ................................................... 5

A.2 Procedures used to establish values of coefficient of variation, k , for the metals listed in

Table A.1 ................................................................................................................................................ 5

Annex B (normative) Calculation of variability factor K .............................................................................. 13

B.1 General................................................................................................................................................. 13

B.2 Method ................................................................................................................................................. 13

Annex C (informative) Proposal for an acceleration factor.......................................................................... 15

C.1 General................................................................................................................................................. 15

C.2 Extrapolating data to 10 cycles ....................................................................................................... 15

C.3 Examples ............................................................................................................................................. 19

[9]

Annex D (informative) Basis of fatigue pressure rating .......................................................................... 21

D.1 Basis of pressure rating..................................................................................................................... 21

D.2 Statistical analysis theory.................................................................................................................. 22

D.3 Fatigue distribution data.................................................................................................................... 28

D.4 Data calculation example................................................................................................................... 33

D.5 Raw data points for sample problem................................................................................................ 39

Bibliography ..................................................................................................................................................... 40

© ISO 2008 – All rights reserved iii
---------------------- Page: 3 ----------------------
ISO/TR 10771-2:2008(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies

(ISO member bodies). The work of preparing International Standards is normally carried out through ISO

technical committees. Each member body interested in a subject for which a technical committee has been

established has the right to be represented on that committee. International organizations, governmental and

non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the

International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.

International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.

The main task of technical committees is to prepare International Standards. Draft International Standards

adopted by the technical committees are circulated to the member bodies for voting. Publication as an

International Standard requires approval by at least 75 % of the member bodies casting a vote.

In exceptional circumstances, when a technical committee has collected data of a different kind from that

which is normally published as an International Standard (“state of the art”, for example), it may decide by a

simple majority vote of its participating members to publish a Technical Report. A Technical Report is entirely

informative in nature and does not have to be reviewed until the data it provides are considered to be no

longer valid or useful.

Attention is drawn to the possibility that some of the elements of this document may be the subject of patent

rights. ISO shall not be held responsible for identifying any or all such patent rights.

ISO/TR 10771-2 was prepared by Technical Committee ISO/TC 131, Fluid power systems, Subcommittee

SC 8, Product testing.

ISO/TR 10771 consists of the following parts, under the general title Hydraulic fluid power — Fatigue pressure

testing of metal pressure-containing envelopes:
⎯ Part 1: Test method
⎯ Part 2: Rating methods
iv © ISO 2008 – All rights reserved
---------------------- Page: 4 ----------------------
ISO/TR 10771-2:2008(E)
Introduction

In hydraulic fluid power systems, power is transmitted and controlled under pressure within a closed circuit. It

is important for the manufacturer and user of hydraulic components to have information on their global

reliability because of the importance of the fatigue failure mode and the relationship with their functional safety

and service life. This part of ISO 10771 provides a method for fatigue-testing in order to verify the rating of a

pressure-containing envelope.

During operation, components in a system can be subjected to loads that arise from:

⎯ internal pressure;
⎯ external forces;
⎯ inertia and gravitational effects;
⎯ impact or shock;
⎯ temperature changes or gradients.

The nature of these loads can vary from a single static application to continuously varying amplitudes,

repetitive loadings and even shocks. It is important to know how well a component can withstand these loads,

but this part of ISO 10771 addresses only the loads due to internal pressure.

There are several International Standards already in existence for pressure rating of individual components

(e.g. for determining maximum allowable rated pressure) and this part of ISO 10771 is not intended to replace

them. Instead, a method of fatigue verification is provided.

This part of ISO 10771 describes a universal verification test to give credibility to the many in-house and other

methods of determining the pressure rating of the components. Credibility is based upon the fundamental

nature of metal fatigue with its statistical treatment and a mathematical theory of statistical verification.

Nevertheless, it is necessary to have design knowledge of the component and its representative specimens to

maximize accuracy of the verification method. The use of this test method can reduce the risk of fatigue failure

for a hydraulic component regardless of sample size.

In order to rate components in accordance with this part of ISO 10771, it is necessary to propose a rating for

the component, select test specimens and select a test pressure. A fatigue test is then conducted in

accordance with ISO 10771-1. If the test is successful, the proposed rating is verified for the family of

components represented by the sample.

This part of ISO 10771 is based on ANSI/(NFPA) T 2.6.1, a standard which was developed and has been

used in the United States for over 25 years and has been adopted for use in Japan as JSME S006-1985. If

sufficient experience is gained in other parts of the world, and additional data on materials are obtained, this

part of ISO 10771 might be re-drafted as an International Standard in the future.

It should be noted that the test factors in Annex A are based on material data obtained from sources

originating in the USA. One of the objectives in issuing this part of ISO 10771 is to obtain material data from

other countries. The test factors are based only on the material properties and not on any tolerances of the

elements in the pressure-containing envelope.

Annex C describes a possible method for accelerating testing. The example shows how material property data

can be used to determine an acceleration factor and shows that they have to be carefully chosen. Another

objective of this part of ISO 10771 is to seek additional data as described in Annex C. Contributors are asked

to submit any available data to the secretary of ISO TC 131/SC 8.
© ISO 2008 – All rights reserved v
---------------------- Page: 5 ----------------------
TECHNICAL REPORT ISO/TR 10771-2:2008(E)
Hydraulic fluid power — Fatigue pressure testing of metal
pressure-containing envelopes —
Part 2:
Rating methods
1 Scope

This part of ISO 10771 specifies a test method for fatigue rating of the pressure-containing envelopes of

components used in hydraulic fluid power systems, as tested under steady internal cyclic pressure loads in

accordance with ISO 10771-1.

This part of ISO 10771 is only applicable to components whose failure mode is the fatigue of any element in

the pressure-containing envelope, and that:
⎯ are manufactured from metals;

⎯ are operated at temperatures that exclude creep and low-temperature embrittlement;

⎯ are only subjected to pressure-induced stresses;

⎯ are not subjected to loss of strength due to corrosion or other chemical action;

⎯ can include gaskets, seals and other non-metallic components; however, these are not considered part of

the pressure-containing envelope being tested (see note 3 of 5.5 of ISO 10771-1:2002).

This part of ISO 10771 does not apply to piping as defined in ISO 4413 (i.e. connectors, hose, tubing, pipe).

NOTE See ISO 19879, ISO 6803 and ISO 6605 for methods of fatigue testing of tube connectors, hoses and hose

assemblies.

This part of ISO 10771 establishes a general rating method that can be applied to many hydraulic fluid power

components. In addition, EN 14359 has been developed for accumulators.
2 Normative references

The following referenced documents are indispensable for the application of this document. For dated

references, only the edition cited applies. For undated references, the latest edition of the referenced

document (including any amendments) applies.
ISO 5598, Fluid power systems and components — Vocabulary

ISO 10771-1:2002, Hydraulic fluid power — Fatigue pressure testing of metal pressure-containing

envelopes — Part 1: Test method
© ISO 2008 – All rights reserved 1
---------------------- Page: 6 ----------------------
ISO/TR 10771-2:2008(E)
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 5598, ISO 10771-1 and the

following apply.
3.1
rated fatigue pressure

maximum pressure that a component pressure-containing envelope, selected at random, has been verified to

sustain for the rated cycle life without failure, with a known probability
3.2
assurance level

probability that the fatigue strength of a randomly selected test specimen exceeds its rated fatigue pressure

3.3
verification level

probability that the fatigue strength of a randomly selected test specimen is not less than its cyclic test

pressure
3.4
coefficient of variation

standard deviation of the fatigue strength distribution of a material at a given fatigue life, divided by its mean

[1]
NOTE Adapted from ISO 3534-1:2006 .
3.5
variability factor
ratio of cyclic test pressure to rated fatigue pressure
3.6
element

part of a component; for example, tie rods on a cylinder, end caps on a valve, bolts on a pump housing

4 Selection of material factors

4.1 Select a coefficient of variation, k , for each type of material in the pressure-containing envelope. The k

o o

factor should be obtained from fatigue tests on coupons for the particular temper of material used in the

pressure-containing envelope. The fatigue test method used to obtain this data should be in accordance with

a recognized national or International Standard.

4.2 As an alternative to testing the specific material, coefficients described in Annex A can be used for the

k factor.
5 Determination of cyclic test pressure

5.1 Select an assurance level for the fatigue pressure rating. A nominal value is 90 %.

5.2 Select a verification level for the fatigue pressure rating. A nominal value is 90 %.

NOTE See Annex D for a tutorial that describes these terms.

5.3 Select a number of component specimens to be tested, then determine the number of element

specimens that will be tested in the components.

NOTE The verification is independent of sample size because the test pressure compensates for different quantities.

2 © ISO 2008 – All rights reserved
---------------------- Page: 7 ----------------------
ISO/TR 10771-2:2008(E)

5.4 Determine the variability factor, K , for each element in the component using Table 1 and the procedure

described in the example given in Annex B. Use the largest K factor so obtained, for the calculations

described in the example.

5.5 Propose a rated fatigue pressure for the pressure-containing envelope of the component.

5.6 Calculate the cyclic test pressure, P , using Equation (1):
PK=×P (1)
CT V RF
where
K is the variability factor;
P is the rated fatigue pressure of the component pressure-containing envelope.
Table 1 — Variability factor, K (at a verification level of 90 %)
Assurance No. of Material coefficient of variation, k
level specimens
0 0,02 0,04 0,06 0,08 0,10 0,12 0,14 0,16 0,18 0,20 0,22 0,24 0,26 0,28 0,30
1 1,001,09 1,20 1,321,461,631,832,082,382,773,29 — — — — —
2 1,001,08 1,16 1,261,381,521,681,882,132,452,87 — — — — —
99,9 %
3 1,00 1,07 1,15 1,23 1,34 1,46 1,61 1,78 2,01 2,29 2,66 3,18 — — — —
4 1,00 1,06 1,13 1,22 1,31 1,42 1,56 1,72 1,93 2,19 2,54 3,02 — — — —
5 1,00 1,06 1,13 1,20 1,29 1,40 1,53 1,68 1,87 2,12 2,44 2,89 — — — —
1 1,00 1,08 1,16 1,25 1,35 1,47 1,60 1,75 1,92 2,12 2,35 2,63 2,96 — — —
2 1,00 1,06 1,12 1,20 1,28 1,37 1,47 1,58 1,72 1,87 2,05 2,26 2,52 2,85 — —
99 %
3 1,00 1,05 1,11 1,17 1,24 1,32 1,40 1,50 1,62 1,75 1,90 2,09 2,31 2,59 2,94 —

4 1,00 1,05 1,10 1,15 1,21 1,28 1,36 1,45 1,55 1,67 1,81 1,98 2,18 2,43 2,74 3,16

5 1,00 1,04 1,09 1,14 1,20 1,26 1,33 1,41 1,51 1,62 1,75 1,90 2,08 2,31 2,60 2,98

1 1,00 1,05 1,11 1,17 1,23 1,29 1,36 1,44 1,52 1,60 1,69 1,79 1,89 2,00 2,12 2,25

2 1,00 1,04 1,07 1,11 1,16 1,20 1,25 1,30 1,35 1,41 1,47 1,54 1,61 1,69 1,77 1,86

90 % 3 1,00 1,03 1,06 1,09 1,12 1,16 1,19 1,23 1,28 1,32 1,37 1,42 1,48 1,54 1,60 1,67

4 1,00 1,02 1,05 1,07 1,10 1,13 1,16 1,19 1,23 1,26 1,30 1,34 1,39 1,44 1,49 1,55

5 1,00 1,02 1,04 1,06 1,08 1,11 1,13 1,16 1,19 1,22 1,25 1,29 1,33 1,37 1,41 1,46

Test twice the number of specimens if a 99 % verification level is chosen.

Use an interpolation of k values between those tabulated here, or calculate K from Equation (D.14) in Annex D.

o V
6 Conduct of fatigue test
5 7

6.1 Determine the number of cycles, between 1 × 10 and 1 × 10 , for which the component will be rated.

6.2 Subject the test specimens to a fatigue pressure test in accordance with ISO 10771-1 for the number of

cycles determined in 6.1, using the P calculated from Equation (1).
© ISO 2008 – All rights reserved 3
---------------------- Page: 8 ----------------------
ISO/TR 10771-2:2008(E)

6.3 The fatigue pressure test is successful if all of the element specimens selected in 5.3 do not fail as

described in ISO 10771-1:2002, Clause 8.
7 Rating by similarity

It is permitted to extend a verified P to other components of similar shape if it can be shown that differences

between those components and the components tested do not result in any reduction of their fatigue strength

capabilities. Examples of this are components that have smaller ports or different axial lengths but are

otherwise identical in geometry to the component tested.
8 Rating declaration

The P proposed in 5.5 will be verified if the requirements of 6.3 are met. A code should be applied to the

component to declare its rating as:

P = P (in megapascals)/assurance level/verification level/K in the test/number of test cycles

RF RF V

EXAMPLE The rated fatigue pressure (12,5 MPa) of a component’s pressure-containing envelope that was tested at

an assurance level of 99 %, a verification level of 90 %, a K of 1,36 for 2 × 10 cycles, would be declared as:

P = 12,5 MPa/ 99 %/ 90 %/ 1,36/ 2 × 10 cycles
9 Identification statement (reference to this part of ISO 10771)

Use the following statement in test reports, catalogues and sales literature when complying with this part of

ISO 10771:

“Method for fatigue pressure rating conforms to ISO TR 10771-2:2008, Hydraulic fluid power — Fatigue

pressure testing of metal pressure-containing envelopes — Part 2: Rating methods”.

4 © ISO 2008 – All rights reserved
---------------------- Page: 9 ----------------------
ISO/TR 10771-2:2008(E)
Annex A
(informative)
Material factor database
A.1 Values of coefficient of variation, k , for commonly used metals
Table A.1 tabulates data calculated from the sources listed in the bibliography.
Table A.1 — Values of coefficient of variation, k , for commonly used metals
Metal
Alloy, low 0,14
Carbon, plain 0,08
Steel
Nickel 0,10
Stainless 0,09
Tool 0,10
Iron 0,14
Aluminium (except unalloyed) 0,13
Unalloyed aluminium 0,23
Cobalt 0,13
Nonferrous Copper 0,09
Magnesium 0,17
0,27
Monel
Titanium 0,12

A.2 Procedures used to establish values of coefficient of variation, k , for the metals

listed in Table A.1

A.2.1 Values of k were calculated from fatigue test data on test coupons that were published in the

references cited in the bibliography. The types of data taken from these references were one of the following:

a) Means, µ, and standard deviations, σ, of normal distributions;
b) parameters of Weibull distributions;

c) raw data points on S-N curves. From these data, individual coefficients of variation, k , were calculated at

10 cycles for:
1) normal distributions; k equals the standard deviation divided by the mean;

1) This is an example of a suitable product available commercially. This information is given for the convenience of users

of this document and does not constitute an endorsement by ISO of this product.
© ISO 2008 – All rights reserved 5
---------------------- Page: 10 ----------------------
ISO/TR 10771-2:2008(E)

2) Weibull distributions; k were calculated from a formula given in Reference [12]. The formula includes

a gamma function, the value of which was selected as a constant at 0,89 because its variations were

generally less than ± 2 % in the range of interest (a few data points went to a difference of ± 4 %);

3) S-N curves; the references had either included limit bands (assumed to be two sigma from the mean)

or actual standard deviation points. These were then used to calculate k in the same manner as a

normal distribution.

A.2.2 The resulting k values (shown as individual values in Table A.2 to Table A.13) include a mix of

notched and unnotched specimens, several different tempers, plus different methods of testing (e.g. axial,

rotating beam). However, only those tested at room temperature were used. No attempt was made to

segregate these data. It is reasoned that the components to be tested will have a variety of tempers and

notches, so an application of these published data to components can only be justified if the data are treated

statistically at a conservative value.

A.2.3 Therefore, the values given in Table A.1 were derived by assuming that all k data for a particular

metal group are part of a normal distribution, and a value that is greater than 90 % of this distribution was

selected. This ensures that the selection is substantially conservative. However, this part of ISO 10771 allows

the use of a more accurate k value, which is representative of the specific alloy and temper of the elements

being tested, if sufficient testing is performed to obtain those data, as described in 4.1. This approach will

likely yield a value that would be more advantageous for a particular application, but less than the

conservative values presented in Table A.1.

A.2.4 Table A.2 to Table A.13 describe all of the k calculations made from the data obtained from

Reference [10], Reference [11], and Reference [13] to Reference [17]. Most of the data are based on the

strength distribution at 10 cycles, but some data are at the endurance limit and these are identified in each

table, if applicable.
Table A.2 — Summary of k calculations for iron
k values
Type Reference Number of distributions
[11] 1 0,0220
Armco
a a a a
0,0402; 0,042 ; 0,044 ; 0,0652; 0,126 ; 0,146 ;
Pearlitic (grey) [15];[17] 8
0,137
a a a a
Ferritic (malleable) [15];[17] 7 0,055 ; 0,0596; 0,0649; 0,065 ; 0,075 ; 0,109
a a a a a a
0,029 ; 0,040 ; 0,049 ; 0,065 ; 0,086 ; 0,094 ;
Nodular [15] 10
a a a a
0,095 ; 0,098 ; 0,173 ; 0,185
Fe; 5,5 % Mo; 2,5 %
[13] 2 0,0286; 0,0477
Cr; 0,5 % C
(k ) 90 % = 0,1335; (µ = 0,0771; σ = 0,0440)
Summary of all data
[13];[15];[11];[17] 28
above Conclusion: k value selected = 0,14
Data from reference [15] are at endurance limit.
6 © ISO 2008 – All rights reserved
---------------------- Page: 11 ----------------------
ISO/TR 10771-2:2008(E)
Table A.3 — Summary of k calculations for aluminium
k values
Alloy Reference Number of distributions
1) 0,0720
[13] 1
Duraluminum
356 [15] 2 0,038; 0,042
355 [14] 1 0,0766
1100 [14] 2 0,1742; 0,2377
0,017; 0,0400; 0,0527; 0,0534; 0,0541; 0,0556;
2014 [14];[15] 13 0,0702; 0,0732; 0,1152; 0,1164; 0,1215; 0,1386;
0,1400
0,026; 0,0498; 0,0542; 0,0561; 0,0613; 0,0708;
2024 [14];[15] 14 0,0717; 0,0765; 0,0825; 0,0974; 0,1039; 0,1190;
0,1404; 0,1840
2025 [14] 3 0,0347; 0,0549; 0,0947
2026 [14] 2 0,0507; 0,0834
2219 [14] 2 0,0701; 0,0705
5052 [14] 2 0,0845; 0,0914
5056 [14] 1 0,0947
5086 [14] 1 0,0640
5154 [14] 1 0,0662
5456 [14];[15] 2 0,012; 0,0708
6061 [14];[15] 4 0,018; 0,027; 0,0478; 0,087
7039 [14] 1 0,1405
0,040; 0,0505; 0,059; 0,0615; 0,0689; 0,0906;
7075 [14];[15] 8
0,1686; 0,2157
a a
0,0413 ; 0,0593
7076 [10] 2
7079 [14] 3 0,0560; 0,0942; 0,1486
7178 [14] 2 0,0484; 0,0881
R303 [14] 1 0,0434
0,0934; 0,1302
5 Mg Al [14] 2
7,5 Zn 2,5 Mg Al [14] 1 0,0570
Summary of all (k ) 90 % = 0,1390; µ = 0,0811; σ = 0,0452
[13];[14];[15];[10] 71
data above
(k ) 90 % = 0,1288; µ = 0,0775; σ = 0,0400
Conclusion: select k = 0,13 for alloyed
Remove the o
69
aluminium;
1100 data
select k = 0,23 for unalloyed
aluminium
Data from reference [10] are at endurance limit.
© ISO 2008 – All rights reserved 7
---------------------- Page: 12 ----------------------
ISO/TR 10771-2:2008(E)
Table A.4 — Summary of k calculations for low alloy steels

(containing silicon at less than 1 % and 1 or more of the following: nickel - less than 4 %;

chrome - less than 2 %; molybdenum - less than 0,5 %)
Number of
Alloy Reference k values
distributions
2340 [13] 6 0,0190; 0,0296; 0,0311; 0,0374; 0,0622 0,0696
3140 [13] 4 0,0145; 0,0283; 0,0435; 0,0919
4140 [13] 2 0,0650; 0,1102
4330 [10] 6 0,0313; 0,0372; 0,0498; 0,0644; 0,1063; 0,1129
0,0525; 0,0819; 0,1023; 0,1037; 0,1219; 0,1285;
4340 [13] 14 0,1301; 0,1335; 0,1428; 0,1438; 0,1476; 0,1484;
0,1600; 0,2035
4340 [11] 4 0,0253; 0,0301; 0,0321; 0,0627
0,0497; 0,0509; 0,0607; 0,0608; 0,0640; 0,0795;
4340 [10] 10
0,0822; 0,0833; 0,0880; 0,0966
0,0759; 0,0837; 0,0878; 0,0895; 0,1025; 0,1055;
4350 [10] 8
0,1209; 0,1213
AMS 5727 [13] 3 0,0341; 0,0385; 0,1002
(k ) 90 % = 0,1348; µ = 0,0812; σ = 0,0418
Summary of all data
[13];[11];[10] 57
above
Conclusion: k value selected = 0,14
Data from reference [10] are at endurance limit.
Table A.5 — Summary of k calculations for cobalt
Metal and alloy Reference Number of distributions k values
Stellite 31 [14] 3 0,0771; 0,1202; 0,1472
S-816 (AMS5765) [13];[14] 4 0,0448; 0,0456; 0,0730; 0,0777
S-816 (AMS5534) [13] 1 0,0646
(k ) 90 % = 0,1269; µ = 0,0813; σ = 0,0355
Summary of all data
[13];[14] 8
above
Conclusion: k value selected = 0,13
8 © ISO 2008 – All rights reserved
---------------------- Page: 13 ----------------------
ISO/TR 10771-2:2008(E)
Table A.6 — Summary of k calculations for copper
Number of
Metal and alloy Reference k values
distributions
100 % Cu [14] 2 0,0522; 0,0804
70/30 Brass [14] 2 0,0153; 0,0735
Cu-7,3 AI BRNZ [14] 2 0,0496; 0,1037
AI Ni BRNZ [10] 1
0,0938
Beryllium [10] 1
0,0740
0,0153; 0,0173; 0,0181; 0,0185; 0,0200; 0,0211;
Copper casting alloys [16] 8
0,0234; 0,0514
(k ) 90 % = 0,0853; µ = 0,0455; σ = 0,0311
Summary of all data
[14];[16];[10] 16
above
Conclusion: k value selected = 0,09
Data from reference [10] are at endurance limit.
Table A.7 — Summary of k calculations for magnesium
Metal and alloy Reference Number of distributions k values
AZ31A [14] 1 0,0331
AZ31B [14] 1 0,0714
AZ61A [14] 3 0,0854; 0,1705; 0,1735
AZ80A-F [14] 1 0,0457
AZ81 [14] 2 0,0458; 0,0761
ZK60A [14] 1 0,1053
2,5 Al Mg [14] 3 0,1152; 0,1444; 0,1702
(k ) 90 % = 0,1694; µ = 0,1031; σ = 0,0517
Summary of all o
[14] 12
data above
Conclusion: k value selected = 0,17
Table A.8 — Summary of k calculations for plain carbon steel
k values
Group and alloy Reference Number of distributions
1045 [13] 3 0,0273; 0,0581; 0,0682
1050 [11] 1 0,0171
(k ) 90 % = 0,0739; µ = 0,0427; σ = 0,0244
Summary of all
[13];[11] 4
data above
Conclusion: k value selected = 0,08
© ISO 2008 – All rights reserved 9
---------------------- Page: 14 ----------------------
ISO/TR 10771-2:2008(E)
Table A.9 — Summary of k calculations for stainless steel
k values
Metal and alloy Reference Number of distributions
321 [13] 3 0,0439; 0,0606; 0,0755
A-286 [13] 2 0,0958; 0,1303
347 [13] 4 0,0302; 0,0491; 0,0802; 0,1162
0,0163; 0,0180; 0,0230; 0,0313; 0,0313; 0,0315;
[13] 14 0,0325; 0,0367; 0,0381; 0,0407; 0,0427; 0,0544;
Multimet N-155
0,0547; 0,0574
PH 15-7 [13] 2 0,0676; 0,0936
17-7 PH [13] 4 0,0135; 0,0145; 0,0168; 0,0505;
...

Questions, Comments and Discussion

Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.