# JIS-Z-2273-1978-R2005-ENG.pdf

UDC 620.178.3:669.017 7 J I S Z*Z273 78 W 4933b08 0075459 8 JIS . 4 % a e I i JAPANESE I NDUSTRIAL STANDARD General Rules for Fatigue Testing of Metals Translated and Published by Japanese Standards Association Printed in Japan J I S Z*2273 78 4933608 00754b0 4 , Translation without guarantee standard in Japanese is to be evidence i n the event of aqy doubt arising, the original --`,`,`,,,,,``,`,,,,,`,``,`,,`-`-`,,`,,`,`,,`--- UDC 620.178.3 :669. O 17 J I S Z*2273 78 4933b08 0075463 b W a JAPANESE INDUSTRIAL STANDARD J I S General Rules for Fatigue Testing of Metals Z 2273-1978 1. .Scope This Japanese Industrial Standard specifies the general rules for fatigue testing of metals by the use of standard test pieces in the atmospheric air at room temperature, covering fatigue life under the number of stress cycles not less than lo4 times. 2, Definitions 2.1 Terms Concerning Stress and Number of Stress Cycles 2.1.1 Nominal Stress Stress calculated elastically without taking into con- The normal stress sideration the stress concentration due to notches or others. is expressed by U and the shearing stress by T . Applicable Standard: J E 3 Z 8401-Rules for Rounding Off of Numerical Values --`,`,`,,,,,``,`,,,,,`,``,`,,`-`-`,,`,,`,`,,`--- 2 J I S Z*2273 78 4933608 00754b2 8 W Z 2273-1978 2.1.2 Varying Stress Stress the magnitude of which changes with time (Fig. 1). 2.1.3 Repeated Stress Stress varying simply and periodically between the constant maximum and minimum values (Fig, 2). Fig. 1. Varying Stress Rig. 2. Repeated Stress + - Time - Time 2.1.4 Maximum Stress urnox, Tmax The highest algebraic value of repeated stress (Fig. 2). 2.1.5 Minimum Stress umins rmln The lowest algebraic value of repeated In the case of tensile and compressive stresses, the maximum and minimum stresses take, considering sign, positive sign for tensile stress and negative sign for compressive stress. In the case of shearing stress, if one direction takes positive sign, so the opposite direction negative sign, stress (Fig. 2). Remark: 2.1.6 Mean Stress um, rm One-half of the algebraic sum of the maximum and minimum stresses of the repeated stresses (Fig. 2). 2.1.7 Stress Amplitude ou, ru One-half of the algebraic difference between the maximum and minimum stresses of the repeated stresses (Fig. 2). 2.1.8 Range of Stress UR, r~ The algebraic difference between the maximum and minimum stresses of the repeated stresses (Fig. 2). 2.1.9 Stress Amplitude-Mean Stress Ratio A The stress amplitude to the mean stress. U Ta U m A = L or A=- T m 2.1.10 Minimum-Maximum Stress Ratio R The a minimum stress to the maximum stress. algebraic ratio of the gebraic ratio of the --`,`,`,,,,,``,`,,,,,`,``,`,,`-`-`,,`,,`,`,,`--- J I S Z*Z273 78 4933b08 0075463 T 3 Z 2273-1978 2.1.11 Symmetrical Reversed Stress Stress alternating repeatedly between two values opposite in sign but equal in magnitude (where uin=O or ra=O,Fig, 3). 2.1.12 Asymmetrical Reversed Stress Stress alternating repeatedly between the positive maximum value and the negative minimum value, the abso- lute values of which are different (where O ~ ~ or rmra, Fig. 6). Fig. 5. Completely Fluctuating Fig. 6. Partially Fluctuating 2.1.15 Number of Stress Cycles n The number of stress during the fatigue test. - Time cycles applied 2.1.16 Endurance N The number of stress cycles to fatigue failure. 2.1.17 Cycle Ratio 72/N The ratio of the applied stress cycles, 72 to cycles to failure, N. --`,`,`,,,,,``,`,,,,,`,``,`,,`-`-`,,`,,`,`,,`--- 4 JI S Z*Z273 78 9 4933b08 00754b4 I M I Z 2273-1978 2.1.18 Shape Coefficient a The quotient obtained by dividing the elastically calculated maximum stress concerning a stress concentrated part by the nominal stress of the same part, when a load is applied on a notched test piece. 2.2 Terms Concerning the Fatigue Strength 2.2.1 S-N Curve (Stress-number of stress cycles curve) The curve drawn by plotting the stress as ordinate and the number of stress cycles to failure (including the number of stress cycles where the test is completed without failure) as abscissa. 2.2.2 Fatigue Limit The upper limit value of the stress up to which the test piece can endure an infinite number of stress cycles. shall be made as shown in 2.2.3 to 2.2.10 according to the type of test. The expression Remark: The above term means an ideal case without dispersion of test values. Usually, the test values obtained in the vicinity of the fatigue limit show dispersion, so that the fatigue limit shall be obtained statistically. 2.2.3 Reversed Tension and Compression Fatigue Limit u# The fatigue To be limit when the reversed tensile and compressive stresses are applied. expressed by the stress amplitude. 2.2.4 Fluctuating Tension Fatigue Limit GU The fatigue limit when the fluctuating tensile stress is applied To be expressed by twice the stress am- pi itude . 2.2.5 Fluctuating Compression Fatigue Limit u-U The fatigue limit when the fluctuating compressive stress is applied. stress amplitude. To be expressed by twice the 2.2.6 Rotating Bending Fatigue Limit U W ~ The fatigue limit when the rotating bending stress is applied. To be expressed by the stress amplitude. 2.2.7 Reversed Plane Bending Fatigue Limit @WP The fatigue limit when the reversed plane bending stress in applied. amplitude. To be expressed by the stress 2.2.8 Fluctuating Plane Bending Fatigue Limit UUP The fatigue limit when the fluctuating plane bending stress is applied. stress amplitude. To be expressed by twice the 2.2.9 Reversed Twisting Fatigue Limit Tio The fatigue limit when the reversed twisting stress is applied. To be expressed by the stress amplitude. 2.2.10 Fluctuating Twisting Fatigue Limit TU The fatigue limit when the fluctuating twisting stress is applied. amplitude. To be expressed by twice the stress 2.2.11 Fatigue Limit Diagram The diagram showing the status of change in the fatigue limit due to the influence of the mean stress or the stress ratio. 2.2.12 Fatigue Limit Ratio The quotient obtained by dividing the fatigue limit by the tensile strength. 2.2.13 Endurance Limit The upper limit value of the stress up to which the test pieces can endure the designated number of stress cycles. endurance limit, the specifications of 2 . 2 . 3 to 2.2.12 apply as appropriate. In this case, the number of stress cycles shall be shown in parentheses at the end. For the 2.2.14 Fatigue Strength A general nomination for the fatigue limit and the endurance limit, 2.2.15 Fatigue Strength of a Notched Test Rece The fatigue strength of a notched test piece expressed by the nominal stress. a 2.2.16 Notch Coefficient (Fatigue Strength Reduction Factor) , ß The quotient obtained by dividing the fatigue strength of the plain polished test piece by the fatigue strength of a notched test piece. 2.2.17 Notch Sensitivity Coefficient i7 A coefficient to express the degree of coincidence of the notch coefficient based on the shape, dimensions, and the material quality of a notched test piece with the shape coefficient (the sensitivity against the notch). 3. Test Pieces 3 . 1 The test pieces shall, as a rule; be of circular cross section or of 0 plate type. 3.2 In preparing test pieces by machining through cutting or grinding, pre- cautions should be taken to ensure that the process does not cause on the test piece tearings and appreciable work strains, and also that the test pieces are not heated. The machined test pieces shall be polished by means of abrasive papers or cloths of successively finer grain size and finally of finer than No. 320 in order to eliminate streaks caused by cutting or grinding. 3.3 The edges of plate type test pieces should preferably be rounded adequately. 3.4 Test pieces shall be handled with sufficient care so that they will not be rusted or damaged after being finished. , J I S Z*Z273 78 m Yî33b08 00754bb 5 m 6 Z 2273-1978 3.5 The sectional dimensions of a test piece shall be measured with an ac- curacy at least better than 0.5 %. 2 mm, it shall be measured with the accuracy of 0.01 mm. However, if the dimension is not more than 3.6 The diameter of a test piece with circular section shall be measured in two directions at right angles to each other and the arithmetic mean value shall be taken as the diameter of the section. 3.7 When a test piece having circular section has a parallel portion, and when the parallel portion is applied with uniform stress, the diameter shall, as a rule, be measured at several places of the parallel portion in accordance with the specification in 3.6 and the smallest value shall be taken as the diameter of the test piece. 3.8 To the measurement of the width and thickness of a plate type test piece, the specifications of 3.6 and 3.7 apply, as appropriate. 4. Testing Machine The testing machine shall be capable of applying quickly the required load to the test piece, and the applied load shall be stable. The testing machine shall be equipped with a device by means of which it is possible to obtain the number of stress cycles to failure of the test piece. Also, the testing machine shall be equipped with a mechanism to prevent restarting so that the machine will not automatically restart after stoppage due to interruption of service or other reasons. 5. Test Methods 5.1 The test piece shall be mounted in the machine without eccentricity and However, care should be taken so firmly so as not to loosen during the test. as to ensure that its mounting does not impose on the test portion of the test piece appreciable stresses and the test piece is not damaged by tools or the like at the time of mounting. 5.2 When commencing the test, the specified load shall be applied quickly without shock. 5.3 possible. the adjustment does not exceed the range between the specified maximum and minimum stresses. During the test, the load shall be so adjusted as to be as stable as At this time, care should be taken to ensure that the stress during 5.4 Where the test is to be conducted at several stress stages in order to obtain the S-N curve, it is desirable that the stress stages of equal interval be selected in such a manner that the ratio of adjacent stresses falls between 1.05 and 1.5 at the inclined portion of the S-N curve, and between 1.02 and 1.05 in the vicinity of the fatigue limit. several stress stages in the vicinity of the endurance limit in order to obtain the endurance limit in accordance with the method described in 6.11.2, it is desirable that stress stages of equal interval be selected in such a manner that the ratio of the adjacent stresses falls between 1.02 and 1.05. Further, where the test is conducted over J I S Z*K2273 78 9 4933bOB 0075467 7 W 7 Z 2273-1978 5.5 speed. It is desirable that a series of tests be conducted at a constant repetition 5.6 The tests shall, as a rule, be conducted without intermission from begin- ning to the end for one test piece. be kept regarding the number of stress cycles until the suspension and the period of time of suspension. Where the test is suspended, records shall 5.7 Unless otherwise specified, the test may be terminated if the test piece remains unbroken up to the number of stress cycles of 107. 5.8 The test pieces which have not been broken through the test shall not be employed again. 6. Test Results 6.1 For the nominal stress, the value calculated concerning a section at a which the maximum stress is generated shall be employed. 6.2 Whenever there is a fear of doubt as to the stress, the method of calculation shall be shown clearly. 6.3 The unit of stress shall be kgf/mm2 or N/mm2, and the value of stress shall, as a rule, be rounded off to three significant figures in accordance with SIS 2 8401. 6.4 The number of stress cycles shall be, as a rule, counted from the time when the load applied to the test piece has reached the specified test load. 6.5 Fatigue life or endurance shall, as a rule, take the number of stress cycles to failure. 6.6 in the case of other than 6.5, the method of determining the number of stress cycles to failure shall be added to the report of the test results. 6.7 The number of stress cycles in the test results shall be stated as mul- tiples of 10“ , for example, 2.34 x 106, and the value shall be rounded off to three significant figures. 6.8 The S-N curve shall be drawn by plotting the values of stress amplitude, range of stress, or the maximum stress, as ordinate and the number of stress cycles as abscissa. the scale of ordinate, a logarithmic scale or linear scale. The scale of abscissa shall be a logarithmic scale, and 6.9 A rightward arrow mark shall be placed at the point denoting the test results for the unbroken test piece in the S-ìv curve diagram (Fig. 7). --`,`,`,,,,,``,`,,,,,`,``,`,,`-`-`,,`,,`,`,,`--- a . J I S Z*Z273 78 4933608 00754b8 9 Z 2273-1978 Fig. 7. An Example of S-N Curve - Number of stress cycles N Remark: In this standard, the units and numerical values in { accordance with the International System of Units (Si) and are given for reference, }are in where 1 N/mm2 = 1 MPa. 6.10 The number of stress cycles in the case of obtaining the endurance limit shall, as a rule, be designated to either one of the following numbers: 104, 2 104, 5 2 107. 104, 105, 2 x 105, 5 x 105, 106, 2 106, 5 x 106, 107, 6.11 The determination of the endurance limit shall be made in accordance with either one of the following two methods: (1) The Method to Determine the Endurance Limit by the S-N Curve The S-N curve shall be drawn at an approximately central area of the points denoting the test results, and the stress corresponding to the designated number of stress cycles shall be obtained on the S-N curve to determine the endurance limit. drawn by extrapolation. with a symbol A attached as for instance #(A 105) = 28.0 kgf/mm2 (274.6 N/mm2 }. on the test result report. The Method to Determine the Endurance Limit without the S-N Curve The endurance limit shall be determined as the stress obtained through one of the following matters, on the basis of the results obtained from testing not less than two test pieces for each of stress stages which have been so established that the number of stress cycles to failure falls in the vicinity of the designated number of stress cycles (refer However, the S-N curve shall not be Thus obtained endurance limit shall be indicated Also, the used S-N curve shall be indicated clearly (2) to 5.4). (a) The highest stress of the stress stages when not less than half of the test pieces at each stress stage has remained unbroken at the des- ignated number of stress cycles. Provided that the number of the test pieces which have remained unbroken at the designated number of stress cycles shall assume a majority at the lower stress stages thereto. 9 Z 2273-1978 J I S Z*Z273 78 4933608 0075469 O (b) In the case where the test pieces at the stress stage at which the endurance limit has been obtained in the above (a) have not broken at all at the designated number of stress cycles, the mean stress of the st