STATE STANDARD OF THE UNION OF SSR

METALS

METHODS OF TENSION TEST

GOST 1497-84

(ISO 6892-84, ST SEV 471-88)

IPC STANDARDS PUBLISHING HOUSE

Moscow

STATE STANDARD OF THE UNION OF SSR

METALSMethods of tension test

GOST1497-84

(ISO 6892-84,ST SEV 471-88)

Date of introduction 01.01.86

This standard establishes the methods of static tensile tests of ferrous and non-ferrous metals and articles from them of nominal diameter or minimum size in cross-section 3,0 mm and more for the determination of characteristics of mechanical properties at temperature (20+15

-10) ºC: limit of proportionality; modulus of elasticity; physical yield point; conventional yield point; temporal resistance; relative uniform extension; relative extension after rupture; relative narrowing of cross-section after rupture. The standard is not applied to the tests of wire and tubes. The standard corresponds to ST SEV 471-88 and ISO 6892-84 by the essence of methods, by conducting tests and processing the results of testing of metals and articles from them of the minimum size in cross-section 3,0 mm and more. The terms, used in this standard, and explanations to them are given in appendix 1.

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(Changed edition, Changes No. 2, 3).

1. METHODS OF SAMPLING

1.1. Metal blocks are cut out on machine-tools, shears, dies by using oxygen and anode-me-chanical cutting and other means, providing allowances for the metal zone with changed properties when heated and work-hardened. The places of cutting out metal blocks for samples, their number, direction of longitudinal axis of samples in regard to the metal block, values of allowances when cutting out shall be indicated in the normative-technical documentation for the rules of sampling, selection of metal blocks and samples or for the metal production. 1.2. The samples are recommended to be produced on machine-tools. When producing the samples the measures are taken (cooling, respective modes of working), which exclude the opportunity of changing metal properties when heated or work-hardened, occurring as a result of mechanical operation. The cutting depth at the last pass shall not exceed 0,3 mm. 1.2. Flat samples shall keep surface rolling layers, if there are no other instructions in the norma-tive-technical documentation for the rules of sampling, selection of metal blocks and samples or for the metal production. For fl at samples the bending defl ection over length 200 mm shall not exceed 10% of the sample thickness, but not more than 4 mm. In the presence of instructions in the normative-technical documen-tation on the metal production leveling or other type of straightening of metal blocks and samples is allowed. 1.4. The burrs on faces of fl at samples should be removed mechanically without damaging the sample surface. It is allowed to subject edges in the working part of samples to grinding and fettling on the grinding wheel or by the grinding sandpaper. 1.5. When there are no other instructions in the normative-technical documentation for the metal production the value of roughness parameters of the worked surfaces of Ra samples should be not more than 1,25 μm – for the surface of the working part of the cylindrical sample and Rz not more than 20 μm – for side surfaces in the working part of the fl at sample. The requirements to surface roughness of cast samples and fi nished articles should correspond to the requirements of surface roughness of cast samples and fi nished articles, tested without mechanical working. (Changed edition, Change No. 3). 1.6. When there are instructions in the normative-technical documentation for the rules of sam-pling, selection of metal blocks and samples or for the metal production it is allowed to test the special item, cast samples and fi nished articles without preliminary working by taking into account tolerances for sizes, provided for tested articles. 1.7. The tests are carried out on two samples, unless other quantity is not provided in the norma-tive-technical documentation for the metal production. 1.8. For tensile testing proportional cylindrical or fl at samples are used of diameter or thickness in the working part 3,0 mm and more with the initial effective length l0=5,65 or l0=11,3 . The use of short samples is more preferable. Cast samples and samples from fragile materials are allowed to be manufactured with the initial effective length l0=2,82 . When there are instructions in the normative-technical documentation for the metal products it is allowed to use also other types of samples, including also non-proportional ones, for which the initial effective length l0 is fi xed irrespective of the initial cross-section area of the sample F0.

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(Changed edition, Change No. 2). 1.9. Types and sizes of proportional cylindrical and fl at samples are given in appendices 2 and 3. The type and sizes of the sample shall be indicated in the normative and technical documentation for the rules of sampling, selection of metal blocks and samples or for the metal production. When testing it is allowed to use samples of other sizes. For fl at samples the ratio between width and thickness in the working part of the sample should not exceed 8:1. 1.10. The shape and sizes of heads and transition parts of cylindrical and fl at samples are deter-mined by way of fastening samples in gripping devices of the testing machine. The way of fastening shall prevent from creeping of samples in gripping devices, contortion of bearing surfaces, deformation of heads and rupture of samples in places of transition from the working part to heads and in the heads. 1.11.Extreme deviations by sizes of the working part of cylindrical and fl at samples are given in appendices 2 and 3. For cast machined cylindrical samples the extreme deviations by the diameter are doubled. The extreme deviations by thickness of fl at samples with non-machined surfaces shall corre-spond to extreme deviations by thickness, fi xed for the metal production. The extreme deviations by thickness of fl at samples with machined surfaces are 0,1 mm. 1.12. The sample working length shall be: from l0+0,5d0 to l0+2d0 for cylindrical samples, from l0+1,5 to l0+2,5 for fl at samples. When there are differences in the estimation of the metal quality the working length of samples shall be: l0+2d0 for cylindrical samples, l0+2 for fl at samples. N o t e: When using strain gages it is allowed to use samples with other working lengths l, whose value is more than indicated. (Changed edition, Change No. 2). 1.13.The samples are marked beyond the sample working length.

2. EQUIPMENT

2.1. The tearing and universal testing machines shall correspond to the requirements of GOST 28840. 2.2. The slide gage shall correspond to the requirements of GOST 166. Micrometers shall correspond to the requirements of GOST 6507. It is allowed to use also other measuring means, which provide the measurement with the error, not exceeding the error, indicated in it. 3.1. 2.3. Strain gages shall correspond to the requirements of GOST 18957. When determining the limit of proportionality and conventional limits of yield with tolerances for the value of plastic or full deformation when loaded or residual deformation when unloaded to 0,1% the relative scale factor of the strain gage shall not exceed 0,005% of the initial effective length by the strain gage le; when determining the conventional limit of yield with tolerance for the value of defor-mation from 0,1 to 1%, the relative scale factor of the strain gage shall not exceed 0,05% of the initial effective length by the strain gage le. (Changed edition, Change No. 2). 2.4. Metal rulers shall correspond to the requirements of GOST 427.

+_

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3. PREPARATION FOR TESTING

3.1. In order to determine the initial cross-section area F0 necessary geometrical sizes of samples are measured with the error not more than 0,5%. (Changed edition, Change No. 2). 3.2. The measurement of sample sizes before testing is carried out in not less than three places – in the middle part and on boundaries of the working length. As the initial cross-section area of the sample in its working part F0 the least of received values is taken on the basis of carried out measurements with rounding according to Table 1.

Table 1mm2

+_

Cross-section area of sample F0 RoundingUp to 10,00 inclusive Up to 0,01In exc. 10,00 » 20,00 » » 0,05» 20,0 » 100,0 » » 0,1» 100,0 » 200,0 » » 0,5» 200 » 1

When there are instructions in the normative-technical documentation for the metal production it is allowed to determine the initial cross-section area of samples F0 by nominal sizes (without measuring the sample before testing) provided, the extreme deviations correspond by sizes and shape to the given ones in Table 1a. 3.1; 3.2. (Changed edition, Change No. 2). The value of the initial effective length l0 is rounded to a larger value: for samples with l0=5,65 - to the nearest number, multiple of 5, if the difference between the calculated and fi xed values l0 doesn’t exceed 10%; for samples with l0=11,3 – until the nearest number, multiple of 10. The initial effective value of l0 of error up to 1% is restricted on the working length of the sample by centre marks, hairlines or other marks and is measured with a slide gage or other measuring means with the measurement error up to 0,1 mm. In order to recalculate the relative extension after the rupture δ by carrying the rupture place to the middle and in order to determine the relative uniform extension δp along the whole working length of the sample it is recommended to make marks in every 5 or 10 mm.

Table 1amm

Sample type Sample sizes (diameter, thickness, width)

Extreme deviation of size

Limit difference of the largest and least diam-eter, largest and least width by the working

partCylindrical machined From 3 to 6

In exc. 6 » 10» 10 » 20» 20 » 30

±0,06±0,075±0.09±0,105

0,030,030,040,05

Flat machined from four sides

From 3 to 6In exc. 6 » 10

» 10 » 20» 20 » 30

±0,06±0,075±0.09±0,105

0,030,030,040,05

Flat machined from two sides

From 3 to 6In exc. 6 » 10

» 10 » 20» 20 » 30

----

0,180,220,270,33

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Marking is carried out with the help of ruling machines or manually by using a metallic ruler. On samples from low-plastic metals marking is carried out by ways, excluding the damage of the working part surface of the sample (knurling of dividing grids or cross strokes, by photographic way, dye, pencil). It is allowed to mark the transition parts of a sample by punching or by the other way.

N o t e s: 1. If for determining the relative extension after the rupture δ the strain gage is used, then the initial effective length by the strain gage le shall be equal to the initial sample length l0. 2. If on the testing machine the determination of the relative extension after rupture δ is carried out automatically, then marking for the restriction of the initial effective sample length l0 is not obligatory.

(Changed edition, Change No. 2). The initial cross-section area F0 for samples of complex shape is determined by design formulae or by weight. The way of determination of the initial cross-section area F0 for such samples shall be stipulated in the normative-technical documentation for the metal production.

4. CONDUCTING TESTS AND RESULTS PROCESSING

4.1. The limit of proportionality σpc is determined: with the help of the strain gage (design method); graphically by the initial part if the diagram, recorded from the electric dynamometer and defor-mation meter. The strain gage or deformation meter is mounted on the sample after applying to it the initial force P0, which corresponds to strain, equal to 5-10% of the assumed limit of proportionality σpc. 4.1.1. When determining the limit of proportionality σpc by the design method after mounting the strain gage the sample loading is made by equal steps till the force, corresponding to the strain, equal to 70-80% of the assumed limit of proportionality σpc. The step number of force shall be not less than 4. The release time on each step is 5-7 s. The further loading is carried out by small steps. When the extension increment for a small step of loading exceeds the average value of extension increment (with the same force step), the further load-ing is stopped. The average value of extension increment is determined for a small step of loading. The found value is increased in accordance with the accepted tolerance. The force Ppc, corresponding to the calculated value of the extension increment, is determined. It is allowed to use the method of linear interpolation for the more accurate defi nition of the value Ppc. 4.1.2. The determination of the limit of proportionality σpc graphically is carried out by the ini-tial part of the tensile stress-strain diagram, recorded from electric dynamometer and deformation meter. The extension is determined on the section, equal to the deformation meter base. The scale in axis of extension shall be not less then 100:1 with the deformation meter base 50 mm and more and not less than 200:1 with the meter base less than 50 mm; in force axis 1 mm of the diagram it shall correspond to not more than 10 N/mm2 (1,0 kgs/mm2). From point of origin (drawing 1) a straight line is drawn, which coincides with the initial linear section of the tensile stress-strain diagram. Then on the arbitrary level the straight line AB is drawn, which is parallel to the abscissa axis, and on this straight line the section kn is put, equal to the half of the section mk. Through the point n and the point of origin the straight line On is drawn and parallel to it the tangent CD to the tensile stress-strain diagram is drawn. The point of contact determines the desired force Ppc. 4.1.3. The limit of proportionality (σpc), N/mm2 (kgs/mm2) is calculated by the formula

The example of determination of the limit of proportionality σpc by the design method is given in appendix 4.

σpc=Ppc

F0

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Drawing 1

forc

e P

extension, ∆t

Ppc

4.1-4.1.3. (Changed edition, Change No. 2). 4.2-4.2.4. (Excluded, Change No. 2). 4.3. Modulus of elasticity E is determined: with the help of the strain gage (design method); graphically by the initial part of the tensile stress-strain diagram, recorded from electric dyna-mometer and deformation meter. The strain gage or deformation meter is mounted onto the sample after applying to it the initial force P0, corresponding to the strain, equal to 10-15% of the assumed limit of proportionality σpc. 4.3.1. After mounting the strain gage the sample loading is made by equal steps till the force, cor-responding to the strain, equal to 70-80% of the assumed limit of proportionality σpc. The value of the loading step shall be 5-10% of the assumed limit of proportionality σpc. By the test results the average value of the sample extension increment ∆lcp, mm, per loading step ∆P, N (kgs) is determined. 4.3.2. When determining the modulus of elasticity graphically the sample is loaded till the force, corresponding to the strain, equal to 70-80% of the assumed limit of proportionality σpc. The scale in axis of extension shall be not less then 100:1 with the deformation meter basis 50 mm and more and not less than 200:1 with the meter base less than 50 mm; in force axis 1 mm of the diagram it shall cor-respond to not more than 10 N/mm2 (1,0 kgs/mm2). 4.3.3. The modulus of elasticity (E), N/mm2 (kgs/mm2) is calculated by the formula

E=∆P • l0

∆lcp • F0

The example of determination of the modulus of elasticity E by the design method is given in appendix 6.

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The limits of yield physical σт, upper σтв and lower σтн are determined by the tensile stress-strain diagram, received on the testing machine provided the diagram scale in the axis of force will be such, that 1 mm corresponds to the strain not more than 10 N/mm2. With check and delivery trials it is allowed to determine the physical limit of yield σт by the explicit stop of the arrow or the digital indicator of the dynamometering device of the testing machine. When there are differences in the estimation of quality of the metal production the physical limit of yield σт is determined by the tensile stress-strain diagram. The examples of determination of forces, corresponding to the limit of yield σт, σтв and σтн for the most typical types of tensile stress-strain diagrams, are given in appendix 7. When determining the upper limit of yield σтв the speed of loading shall be fi xed within the lim-its, given in Table 1b, unless there are other indications in the normative-technical documentation for the metal production.

T a b l e 1b

Modulus of elasticity E, N/mm2 Loading speed, N/(mm2 s)Minimal maximal

E≤1,5 x 105 (for non-ferrous metals)

1 10

E>1,5 x 105 (for ferrous metals) 3 30

The loading speed shall be fi xed in the elasticity fi eld and maintained, if possible, constant until the upper limit of yield σтв is reached. When determining the physical σт and lower σтн limits of yield the speed of the relative defor-mation of the working part of the sample at the stage of yield shall be within the limits from 0,00025 to 0,0025 s-1, if in the normative and technical documentation for the metal products there are no other indications. The speed of the relative deformation shall be supported, if possible, constant. If the speed of the relative deformation at the stage of yield cannot be provided by the direct regulation of the testing machine, than testing should be carried out by setting the loading speed in the elasticity fi eld. The loading speed before achieving the stage of yield shall be within the limits, specifi ed in Table 1b. In addition, the machine control shall not be changed until the end of the yield stage. 4.5. The conventional limit of yield with tolerance for the value of plastic deformation with load-ing σ0,2 (or with other fi xed tolerance) is determined by the diagram, received on the testing machine or with the help of special devices. When there are differences in the estimation of quality of the metal production the conventional limit of yield is determined by the tensile stress-strain diagram, received by using the strain gage. N o t e. The conventional limit of yield with tolerance for the value of plastic deformation with loading σ0,2 (or with other fi xed tolerance) can be determined without potting the tensile stress-strain diagram with the help of special devices (microprocessor, etc.) 4.5.1. For determining the conventional limit of yield σ0,2 (or with other conventional tolerance) by the tensile stress-strain diagram the value of plastic deformation is calculated by taking into account the fi xed tolerance, on the basis of length of the working part of sample l or initial effective length by the strain gage le. The found value is increased in proportion to the diagram scale, and the section of the received length OE is put in the axis of extension from the point O (drawing 3). From point E a straight line is drawn parallel to OA. The point intersection of the straight line with the diagram corresponds to the force of the conventional limit of yield with the fi xed tolerance by the value of plastic deformation. The diagram scale in the axis of extension shall be not less than 50:1. When there are no testing ma-chines with diagrams of specifi ed scale and opportunity to receive them with the help of special devices it is allowed to use, except for cases of differences in the estimation of quality of the metal production, diagrams with the scale in the axis of extension not less than 10:1 when using samples with the working length not less than 50 mm.

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4.5.2. If the straight section of the tensile stress-strain diagram is expressed indistinctly, then the following way of determination of the conventional limit of yield σ0,2 (or with other fi xed tolerance) is recommended – drawing 3a. After the expected conventional limit of yield is exceeded, the force onto the sample is decreased till the value, being approximately 10% of the achieved one. Further the new sample loading is made until the value of the applied force exceeds the original one.

To determine the force the straight line is drawn on the diagram along the hysteresis loop. Further a line is drawn parallel to it, the distance from whose beginning to point O of the diagram, laid in the axis of extension, corresponds to tolerance for the value of plastic deformation. The force value, corresponding to the point of intersection of this line with the tensile stress-strain diagram, corresponds to the force of the conventional limit of yield with the fi xed tolerance for the value of plastic deformation.

Drawing. 3

Drawing. 3a

forc

e P

extension, ∆t

extension

forc

e

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4.5.3. When determining the conventional limit of yield σ0,2 (or with other fi xed tolerance) the loading speed shall correspond to the speed specifi ed in Table 1b, if in the normative-technical documen-tation for the metal products there are no other instructions. 4.5.4. The conventional limit of yield (σ0,2), N/mm2 (kgs/mm2) is calculated by the formula

The conventional limit of yield σ0,2 (or with other fi xed tolerance) is determined only with the absence of yield area, if there are no other instructions in the normative and technical documentation for the metal products. 4.6. When there are instruction in the normative and technical documentation for the metal prod-ucts the conventional limit of yield is carried out with tolerance for the value of full deformation σn and the conventional limit of yield σp, determined by the method of consecutive loading and unloading of the sample. The conventional limit of yield with tolerance for the value of full deformation σn is determined by the tensile stress-strain diagram (drawing 3b). To determine the specifi ed limit of yield the straight line is drawn on the tensile stress-strain diagram parallel to the axis of ordinates (axis of forces) and being located from it at distance, equal to the tolerance for the value of full deformation by taking into account the diagram scale. The point of in-tersection with the tensile stress-strain diagram corresponds to the force at the conditional limit of yield σn. The value σn is calculated by dividing the value of the received force by the initial cross-section area of the sample F0.

N o t e. This characteristic can be determined also without plotting the tensile stress-strain diagram with the help of special devices (microprocessors, etc.).When determining the conditional limit of yield σn the loading speed shall correspond to the requirements of it. 4.5.3. 4.6.2. To determine the conditional limit of yield σp, determined by the method of consecutive loading and unloading. The strain gage is mounted on the sample after its mounting into gripping devices of the testing machine and applying to it the initial strain σ0, being not more than 10% of the expected conventional limit of yield σp. Then the sample is loaded till the strain σ = 2σ0 and after restraint within 10-12 s is unloaded till the initial strain σ0. Beginning from the force, being 70-80% of the expected con-ventional limit of yield σp, the sample is loaded in series by the increasing force with the measurement the residual extension each time after unloading till the initial value σ0. The test is stopped when the residual extension exceeds the set value. As the force, corresponding to the conventional limit of yield σp that force is taken, at which the extension achieves the set value. If it is necessary to make more precise the numerical value of the determined characteristic it is allowed to use the linear interpolation. 4.3-4.6.2. (Changed edition, Change No. 2). 4.6.3. (Excluded, Change No. 2). 4.7. For determination of the temporal resistance the sample σn is subject to extension under the action of the smoothly increasing force till rupture. The largest force, preceding the sample rupture, is taken as force Pmax, corresponding to temporal resistance. 4.7.1. When determining the temporal resistance σv the straining speed shall be not more than 0,5 of the initial effective sample length l0, expressed in mm/min.

σ0,2=P0,2

F0

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forc

e

extension

Drawing. 3b

4.7.2. The temporal resistance (σв), N/mm2 (kgs/mm2) is calculated by the formula

4.7-4.7.2. (Changed edition, Change No. 2). 4.8. The determination of the relative uniform extension is carried out on samples with the initial effective length l0 not less than l0=11,3 .The relative uniform extension δp is determined on the larg-est part of the ruptured sample on the design section A’B’ (drawing 4), being located at distance not less than 2d0 or 2b0 from the rupture place. The fi nite length of the design section lkp shall be not less than 2d or 1,5b0. The initial length of the design section lnp is determined by the number of marks in the design section and by the initial distance between them. It is allowed to determine the relative uniform extension δp by the tensile stress-strain diagram with the scale in the axis of extension not less than 10:1 as corresponding the maximal force Rmax. 4.8.1. The relative uniform extension (δp), %, is calculated by the formula:

σB=Pmax

F0

δp =(lkp – lnp) • 100

F0

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Drawing 4

4.8; 4.8.1. (Changed edition, Change No. 3). 4.9. To determine the fi nite effective sample lk the ruptured parts of the sample are densely laid together so that their axes could form a straight line. The measurement of the fi nite effective length of the sample lk is carried out by the slide gauge at the value of vernier reading 0,1 mm. 4.9.1. The determination of the fi nite effective length of the sample is carried out by measuring the distance between marks, restricting the effective length. 4.9.2. If the distance from the rupture place till the nearest mark, restricting the effective length of the sample is 1/3 or less than the initial effective length l0, and the determined value of relative exten-sion after rupture doesn’t satisfy the requirements of the normative and technical documentation for the metal production, then it is allowed to determine the relative extension after the rupture δ with carrying the rupture place to the middle. The recalculation is carried out on centre marks or hairlines, made beforehand along the working part of the sample, for example, in 5 or 10 mm (drawing 5).

Drawing 5.Example. On the initial effective length of the sample l0 N number of intervals are laid. After the rupture we’ll denote the extreme hairline A on the short part of the ruptured sample. On the long part of the section we’ll denote the hairline Б, the distance from which to the rupture place is close by value to the distance from the rupture place to the hairline A. The distance from A to Б is n intervals. If the difference (N-n) is the even number, then from the hairline Б to the hairline В is N - n 2taken as intervals and the fi nite effective length of the sample is determined by the formula lk = AБ + 2БВ.

If the difference (N-n) is the odd number, then from the hairline Б to the hairline В’ is N – n – 1 N – n + 1taken as 2 intervals and to the point B’’ is taken as 2 (in sum БВ’+БВ’’=N-n). In this case the fi nite effective length of the sample lk is calculated by the formula lk = АБ + БВ’ + БВ’’.

(N-n) even number

(N-n) odd number

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4.9.3. When there are instructions in the normative-technical documentation when determining the relative extension after the rupture for low-plastic metals (δ≤5%) the following is determined:

a) absolute extension lk-l0. Before testing near one of the ends of the working sample length a barely perceptible mark is put. With the help of the meter on the sample an arc is drawn with radius, equal to the initial effective sample length l0 and with the center in the put mark. After rupture both sample halves are densely put together and pressed to each other under the action of the axial force. The second arc of the same radius is drawn from the same centre. The distance between the arcs, equal to the absolute extension of the sample (drawing 6), is mea-sured with the help of the measuring microscope or other measurement means;

Drawing 6 b) the fi nite effective length lk on the tensile stress-strain diagram at the diagram scale on the axis of deformation (extension) not less than 50:1; c) the fi nite effective sample length lk by the distance between the sample heads or marks, put on transition parts of the sample, by using the calculation formulae. (Changed edition, Change No. 2, 3). 4.10. The relative extension of the sample after the rupture (δ) is calculated in percent by the formula

4.10.1. In the test protocol it should be indicated, on what effective length the relative extension after the rupture δ is determined. For example, when testing samples with the initial effective length l0=5,65 and l0=11,3 the relative extension after the rupture is determined δ5, δ10 respectively. 4.11. For determination of the relative narrowing ψ of the cylindrical sample after rupture the minimal diameter dk is measured in two mutually perpendicular directions. The measurement of the minimal diameter dk is carried out by the slide gage with vernier reading till 0,1 mm. By simple average from the received values the cross-section area of the sample is calculated after the rupture Fk. 4.11.1. The relative narrowing after the rupture (ψ) is calculated by the formula

δ=(lx – l0) • 100

l0

ψ=(F0 – Fk) • 100

F0

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The rounding of calculated results of tests is made in accordance with Table 2.

T a b l e 2

Characteristics of mechanical properties Interval of characteris-tics values Rounding

Limit of proportionality, N/mm2 (kgs/mm2)Limit of elasticity, N/mm2 (kgs/mm2)Limit of yield physical, N/mm2 (kgs/mm2)Limit of yield conventional, N/mm2 (kgs/mm2)Temporal resistance, N/mm2 (kgs/mm2)

Up to 100 (to 10,0)In exc.. 100 to 500(in exc.. 10 to 50)

In exc. 500 (in exc. 50)

Up to 1,0 (to 0,1)Up to 5,0 (to 0,5)

Up to 10 (to 1)

Modulus of elasticity, N/mm2 (kgs/mm2) 1,00-2,50x105(1,00-2,50x104)

Up to 0,01x105(up to 0,01x104)

Relative uniform extension, %Relative extension after rupture, %Relative narrowing of cross-section area after rup-ture, %

Up to 10,0In exc. 10,0 to 25,0

In exc. 25,0

Up to 0,1Up to 0,5Up to 1,0

(Changed edition, Change No. 2). 4.13. The results of tests are not taken into account: at sample rupture on centre marks (hairlines), if in addition any characteristic of mechanical properties doesn’t meet the established requirements of the normative and technical documentation for the metal production; at sample rupture in gripping devices of the testing machine or beyond the effective sample length (when determining the relative uniform extension δр and the relative extension at rupture δ); at sample rupture on defects of the metallurgical production and receiving in addition unsatisfac-tory test results. When there are no other instructions in the normative-technical documentation for the metal production the tests instead of the neglected ones, are repeated on the same sample number. 4.14. The test results are recorded in the protocol, whose form is given in appendix 1.

APPENDIX IInformation

Term ExplanationWorking length of sample l

Initial effective length of sample l0 Finite effective length of sample lk Initial diameter of sample d0 Sample diameter after rupture dk Initial thickness of the sample a0 Sample thickness after rupture ak Initial width of sample bo Width of sample after rupture bk

A part of the sample with the constant cross-section area between its heads or sections for gripping A section of working length of the sample between the put marks before testing, on which the extension is determined Length of the design part after the sample rupture

Diameter of the working part of the cylindrical sample before testing Minimal diameter of the working part of the cylindrical sample after rupture Thickness of the working part of the fl at sample before testing Minimal thickness of the working part of the fl at sample after testing Width of the working part of the fl at sample before testing Minimal width of the working part of the fl at sample after testing

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Term Explanation Initial cross-section area of sam-ple Fo Cross-section area of sample after rupture Fk Axial stretching force P Strain σ

Absolute extension of sample ∆l Limit of proportionality σпц

Modulus of elasticity E

Physical limit of yield (upper limit of yield) σт Upper limit of yield σтв

Temporal resistance (ultimate strength) σв Relative uniform extension δp

Relative extension after the rup-ture δ Relative narrowing after rupture Ψ Conventional limit of yield with tolerance for the value of plastic de-formation when loading σ0.2 Conventional limit of yield with tolerance for the value of full σп de-formation

Conventional limit of yield with tolerance for the value of residual deformation when unloading σp

Initial effective length by strain gage lc

Deformation speed Loading speed Initial length of effective section lнр Finite length of effective section lкр

Cross-section area of the working part of the sample before testing

Minimal cross-section area of the working part of the sample after testing

Force, acting onto the sample, at this moment of testing Strain, determined by the ration of the axial stretching force P to the initial cross-section area of the working part of sample F0 Increment of the initial effective length of the sample at any moment of testing Strain, at which the deviation from the linear dependence between the force and extension achieves such value, that the slope ratio, formed by the tangent to the curve “force-extension” in point Pпц with the axis of forces increases by 50% of its value on the elastic (linear) part Ratio of strain increment to the respective extension increment within the elastic deformation The least strain, at which the sample is deformed without signifi cant stretching force Strain, corresponding to the fi rst force peak, registered before the beginning of yield of the working part of the sample Strain, corresponding to the largest force Pmax, preceding to the sample rupture

Ratio of increment of section length in the working part of the sample after rupture, on which the relative uniform extension is determined, to the length before testing, expressed in percent Ratio of increment of effective sample length (lk-l0) after rupture to the initial ef-fective length l0, expressed in percent Ratio of difference F0 and minimal Fk cross-section area of the sample after the rupture to the initial cross-section area of the sample F0, expressed in percent Strain, at which the plastic deformation of the sample achieves 0,2% of the work-ing length of the sample l or the initial effective length by strain gage lc

Strain, at which the full deformation of the sample achieves the set value, ex-pressed in percents of the working length of the sample l or the initial effective length by strain gage lc The tolerance value (from 0,05 to 1%) is indicated in denotation, for example σп0,5) Strain, at which after unloading the sample preserves the set residual deforma-tion, expressed in percent of the working length of the sample l or the initial effective length by strain gage lc The tolerance value (from 0,005 to 1%) is indicated in denotation, for example σp0,1) Length of the working part of the sample, equal to the strain gage basis Value of changing the distance between the fi xed sample points to the unit time (GOST 14766) Value of changing the force (or strain) to the unit time Section on the initial effective length of the sample l0, on which the relative uni-form extension δ is determined Section on the fi nite effective length of the sample lк, on which the relative uniform extension δp is determined

N o t e. When there are instructions in the normative-technical documentation for the metal production it is allowed to determine the limit of proportionality and the conventional limit of yield with tolerance for the value of plastic deformation when loaded with other tolerances: limit of proportionality – 10 and 25% limit of yield – from 0,005 to 1%. The tolerance value is indicated in the denotation (for example σпц 10, σ0,3). At tolerances from 0,005 to 0,05% for the values of plastic deformation when loaded, the full deformation when loaded, residual deformation when unloaded instead of the term conventional “limit of yield” it is allowed to use the term “limit of elasticity” with the indexation, established for the respective conventional limit of yield.

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(Changed edition, Change No. 2,3).APPENDIX 2

RecommendedPROPORTIONAL CYLINDRICAL SAMPLES

Type I

Drawing 1Table 1

Sizes, mm

Sample number d0 l0 = 5d0 l0 = 10d0 L D D1 r h1 h2 h3

1234

25201510

1251007550

250200150100

l0 + (0,5…2)

d0

45362820

28241813

(0,10…0,15)d

25201510

12,510,07,55,0

25201510

(Changed edition, Change No. 3).

Type II

Drawing 2

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Table 2Sizes, mm

Sample number d0 l0 = 5d0 l0 = 10d0 L D D1 r r1 h1 h2

12345678

252015108654

125100755040302520

25020015010080605040

l0 + (0,5…2)

d0

4536282016131211

2824181311877

(0,10…0,15)d

1,01,01,01,0

5,05,04,04,03,03,02,52,5

252015108655

12,510,07,55,04,04,04,04,0

(Changed edition, Change No. 1, 3).

Type III

Drawing 3Table 3

Sizes, mm

Sample number d0 l0 = 5d0 l0 = 10d0 L D h1 r

123456789

2520151086543

12510075504030252015

2502001501008060504030

l0 + (0,5…2) d0

4534281613121197

3025201010101087

55332

1,51,51,51,5

Type IV

Drawing 4

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Table 4Sizes, mm

Sample number d0 l0 = 5d0 l0 = 10d0 L D h1 r

123456789

2520151086543

12510075504030252015

2502001501008060504030

l0 + (0,5…2) d0

M36M30M24M16M14M12M9M8M7

40302515151210108

12,510,07,55,04,03,03,03,02,0

Type V

Drawing 5Table 5

Sizes, mm

Sample number d0 l0 = 5d0 l0 = 10d0 L D D1 h1 h2

11234567

25201510865

1251007550403025

250200150100806050

l0 + (0,5…2) d0

45362820161311

302418121087

25201510865

25201510865

Type VI

Drawing 6

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Table 6Sizes, mm

Sample number d0 l0 = 5d0 l0 = 10d0 L D h1 h2

123456

2520151086

12510075504030

2502001501008060

l0 + (0,5…2) d0

35302215129

Not regu-lated

2520151086

Type VII

Drawing 7Table 7

Sizes, mm

Sample number d0 l0 = 5d0 l0 = 10d0 L D r h1

1234

151086

75504030

1501008060

l0 + (0,5…2) d0

2015129

25252525

50403025

(Changed edition, Change No. 3).

Table 8Extreme deviation by sizes of cylindrical samples

mm

Diameter of the sample working part Extreme deviations

Allowable difference of the largest and least diameter on the

length of the sample working part

Up to 10,00 inclIn exc. 10,00 to 20,00 incl.

In exc. 20,00

±0,10±0,20±0,25

0,030,040,05

N o t e. Sizes of heads and transition parts of samples are recommended ones.

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Changed edition, Change No. 1).

APPENDIX 3Recommended

PROPORTIONAL FLAT SAMPLES

Type I

Flat samples with heads

Drawing 1

Type II

Flat samples without heads

Drawing 2

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Table 1mm

Sample number a0 b0 l0 = 5,65 l0 = 11,3 l B h1 L

1234567891011121314151617181920212223

252423222120191817161514131211109876543

3030303030303030303030303030303030302020202020

15515515014514014013513012512512011511010510510090857065605045

31031030029028027027026025025024023022021021020018017014013012010090

L0 + (1,5…2,5)

4040404040404040404040404040404040404040404030

100100909080808080808070707060606050505050505040

l+2x(h1+h2)

Notes: 1. For samples, whose thickness is between the values, given in Table 1, it is necessary to take the smaller effective length, if when compared with the nearest less thickness (see Table 1) the difference will be less than 0,5 mm, and the larger length, if the difference is 0,5 mm and more. 2. The radius coupling of the working part with the head is taken as equal to 25-40 mm depending on the cutter radius, used when manufacturing samples, in addition h2 accepts the value approximately 15-20 mm respectively. 3. It is allowed to divide samples into groups with equal working length so, that the difference of the maximal and minimal different lengths could not exceed 25 mm. The lmaximal working length of this group is taken as the total working length.

Table 2

Extreme deviations by sizes of fl at samplesmm

N o t e. Sizes of heads and transition parts of samples are recommended ones.

Width of the sample working part Extreme deviations

Allowable difference of the larg-est and least width on the length

of the sample working part10,00 15,0020,00.30,00

±0,20±0,20±0,50±0,50

0,050,100,150,20

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(Changed edition, Change No. 1).

APPENDIX 4Information

EXAMPLE OF DETERMINATION OF THE LIMIT OF PROPOERTIONALITY σпц

The tolerance for the increase of tangent of angle, formed by the tangent to the deformation curve with the axis of forces – 50% of its value on the linear section. The tested material is construction steel. Sample sizes: initial diameter d0 = 10 mm, initial cross-section area F0 = 78,5 mm2. The initial effective length (strain gage basis) l0 = 100 mm, scaling factor of strain gage is 0,002 mm. The expected limit of proportionality σпц = 690 N/mm2 (70 kgs/mm2). The initial force is taken as P0 = 3900 N (400 kgs). The force P in N (kgs), meeting 75% of the force of expected limit of proportionality, is 39600 N (4040 kgs). We take P equal to 39000 N (4000 kgs). The loading step is fi xed to be equal to 8800 N (900 kgs). Further loading is carried out by steps ∆P = 1500 N (1500 kgs), what corresponds to the strain increment ∆σ= 19,5 N/ mm2 (2,0 kgs/mm2) till the perceptible deviation from the law of proportionality by taking the readings of the strain gage. The test results are written into the table. The mean value of extension increment ∆lп by a small step of force ∆P = 1500 N (150 kgs) is:

(150 – 0) x 150 ∆lп = 5350 – 400 = 4,5 scale factor.

Force P, N (kgs) Reading on strain gage scale Difference of reading on scale gage

3900 (400)12700 (1300)21600 (2200)30400 (3100)39200 (4000)40700 (4150)42200 (4300)43700 (4450)45100 (4600)46600 (4750)48100 (4900)49500 (5050)51000 (5200)52500 (5350)54000 (5550)55400 (5650)

0,027,054,582,0109,0113,3118,0122,5127,5131,5136,0141,0145,0149,5156,0164,0

0,027,027,527,527,04,54,54,55,04,04,55,04,04,56,58,0

The found value of the extension increment by a small force step on the linear section according to the fi xed tolerance is increased by 50%. The desired extension by a force step P = 1500 N (150 kgs) is:4,5 x 1,5 = 6,8 scale factor. As the force, meeting σпц, we take the force P = 54000 N (5500 kgs).

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The limit of proportionality is: 54000σпц = 78,5 = 690 N/mm2 (70,5 kgs/mm2).

The found force Pпц can be defi ned more exact by using the linear interpolation method: (55400 – 54000)(6,8 – 6,5) Pпц = 54000 + 8 – 6,5 = 54300 N (5530 kgs).

The limit of proportionality σпц , meeting the calculated force, is equal to: 54300 σпц = 78,5 = 690 N/mm2 (70,5 kgs/mm2).Appendix 4. (Changed edition, Change No. 2).Appendix 5. (Excluded, Change No. 2).

APPENDIX 6Information

EXAMPLE OF DETERMINATIOB OF MODULUS OF ELASTICITY E

The tested material is construction steel. Sample sizes: initial diameter d0 = 10,0 mm, initial cross-section area F0 = 78,5 mm2. The initial effective length (strain gage basis) l0 = 100 mm, scaling factor of strain gage is 0,002 mm. The assumed limit of proportionality σпц = 686 N/mm2 (70 kgs/mm2). The initial force is taken as P0 = 5400 N (550 kgs). The force P, corresponding to 70% of the assumed limit of proportionality, is 37695 N (3847 kgs). We take P equal to 37800 N (3850 kgs). The loading is carried out by steps ∆P = 5400 N (550 kgs), what corresponds to the strain increment ∆σ= 69 N/ mm2 (7,0 kgs/mm2) till the force P, corresponding to 70% of the expected limit of proportionality σпц with readings of the strain gage. The results are written into the table.

Determine the mean value of extension increment of the sample ∆lcp by the force step ∆P = 5400 N (550 kgs):

(105-0)x5400x0,002∆lcp = (37800-5400) = 0.035 mm.

The modulus of elasticity E, N/ mm2 (kgs/mm2) is equal to: 5400x100E = 0,035x78,5 = 1,96x105 N/ mm2 (1.96x104 kgs/mm2)

Force P, N (kgs) Reading on strain gage scale Difference of reading on scale gage

5400 (550)10800 (1100)16200 (1650)21600 (2200)27000 (2750)324000 (3300)37800 (3850)

017,535,053,070,588,3105,0

17,518,017,517,517,517,0

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(Changed edition, Change No. 2).

APPENDIX 7Information

SAMPLES OF DETERMINATION OF FORCES Рт, Ртн, Ртв IN DEPENDENCE OF THE TYPE OF TESILE STRESS-STRAIN DIAGRAM

1- initial transition effect

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Appendix 7. (Changed edition, Change No. 2). Appendices 8,9. (Excluded, Change No. 2).

APPENDIX 10Information

PROTOCOL No.of tests for strain of cylindrical samples _____________________on the machine ______________

PROTOCOL No.

of tests for rupture of fl at samples _________________ on the machine __________________

(Changed edition, Change No. 2).

INFORMATION DATA1. DEVELOPED AND INTRODUCED by the Ministry of Ferrous Metallurgy of the USSR DEVELOPERS V.I. Matorin, B.M. Ovsyannikov, V.D. Khromov, N.A. Birun, A.V. Minashin, E.D. Petrenko, V.I. Chebotarev, M.F. Zhembus, V.G. Geshelin, A.V. Bogacheva

2. APPROVED AND PUT INTO OPERATION by the Resolution of the State Committee of the USSR according to standards dtd. 16.07.84 No. 2515

3. INSTEAD OF GOST 1497-73

4. The standard corresponds fully to ST SEV 471-88 and ISO 6892-84 by the essence of methods, by conducting tests and processing the results of testing of metals and articles from them of the least size in cross-section 3,0 mm and more.

5. REFERENCE NORMATIVE-TECHNICAL DOCUMENTS

6. The restriction of the period of validity is removed by the decision of the Interstate Council for Standardization, Metrology and Certifi cation (IUS 11-12-94)REEDITION (February 1997) with Changes No. 1, 2, 3, approved in August 1987, October 1989, May 1990 (IUS 12-87, 2-90, 8-90)

Mark Smelt number

Marking Initial diameter d0, mm

Diame-ter after rupture, dk mm

Initial effective length, l0 mm

Finite effective length, lk mm

Maxi-mal

force Pmax, N (kgs)

Force at the

limit of propor-tionality Pпц, N (kgs)

Tem-poral resis-

tance σв, N/mm2 (kgs/mm2)

Limit of yield σп, σ0,2N/mm2 (kgs/mm2)

Limit of propor-tional-ity σпц, N/mm2 (kgs/mm2)

Modu-lus of

elastic-ity E,

N/mm2 (kgs/mm2)

Relative uniform exten-sion δp, %

Relative exten-sion δ, %

Relative nar-

rowing Ψ, %

Note

Mark S m e l t number

Marking I n i t i a l width and thickness of sample a0, b0 mm

I n i t i a l cross-sec-tion area F0, mm2

C r o s s -s e c t i o n area after r u p t u r e Fk, mm2

Initial ef-f e c t i v e length, l0 mm

Finite ef-f e c t i v e length, lk mm

Maximal force Pmax, N (kgs)

Force at the limit of yield Pт, P0,2 N (kgs)

Force at the limit of pro-portional-ity Pпц, N (kgs)

Temporal resistance σв, N/mm2 (kgs/mm2)

Limit of yield σп, σ0,2N/mm2 (kgs/mm2)

Limit of pro-portionality σпц, N/mm2 (kgs/mm2)

Re la t ive extension δ, %

NTD denotation, to which the reference is given Number of item, appendixGOST 166-89GOST 427-75GOST 6507-90GOST 14766-69GOST 18957-73GOST 28840-90

2.22.42.2

Appendix 12.32.1

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