GOST 30003-93

• gost-30003-93.pdf (240.21 KiB)
  ГОСТ 30003-93

GOST 30003−93 Metals. The bend test by coiling of sheets and strips thickness less than 2.5 mm

GOST 30003−93

Group B09

INTERSTATE STANDARD

METALS

The bend test by coiling of sheets and strips thickness less than 2.5 mm

Metals. Cylindrical bending test of sheets and strips less than 2,5 mm thick

OKS 77.160
AXTU 1909
______________
* According to the official website of Rosstandart
OKS 77.040.10. — Note the manufacturer’s database.

Date of introduction 1997−01−01

Preface

1 DEVELOPED by the Technical Committee for standardization TC 150 «Powder metallurgy"

INTRODUCED by Gosstandart of Russia

2 Adopted by the Interstate Council for standardization, Metrology and certification (Protocol No. 3−93 dated February 17, 1993)

The adoption voted:

3 Decree of the Russian Federation Committee on standardization, Metrology and certification dated June 19, 1996 N 385 inter-state standard GOST 30003−93 introduced directly as state standard of the Russian Federation from January 1, 1997

4 INTRODUCED FOR THE FIRST TIME

1 PURPOSE AND SCOPE

This standard specifies a method for determining deformation and strength under bending, twisted, flat specimens made of ferrous and non-ferrous metals and products with thickness less than 2.5 mm at a temperature of (20) °C.

Allowed application of the method for testing non-metallic materials under the same conditions.

The method consists in the coiling of the specimen without slip on the lateral surface of a straight cylinder, the base of which is a logarithmic spiral, and the calculation of strain and stress in the sample arising under the action of the applied load.

2 NORMATIVE REFERENCES

The present standard features references to the following standards:

GOST 427−75 Rulers measuring metal. Specifications

GOST 10905−86 Plate calibration and marking. Specifications

GOST 25347−82 Basic norms of interchangeability. ESDP. Tolerances and recommended planting

GOST 28840−90 Machine for testing materials in tension, compression and bending. General technical requirements

3 SAMPLING METHOD

3.1 Method of sampling and preparation of samples for testing — according to the normative documentation on the specific products with add-ons referred to in 3.1.1−4.1.3.

3.1.1 Samples should be flat and rectangular, with a length of not less than 280 mm. Deviation from flatness (warpage) in the cross section should be not more than 0.1 of the thickness of the sample.

3.1.2 Width of the samples should be not more than 60 mm thickness of less than 1 mm.

When the thickness of the samples from 1.0 to 2.5 mm width samples , mm should be determined from the ratio

,

where  — thickness of specimen, mm;

60 — six times the resistance moment of the cross section of bending, mm.

Maximum deviations along the width of the sample from the nominal should not be more than class 11 according to GOST 25347.

To assess the characteristics of structural strength allowed the production of samples with a width equal to the width of the product, but not more than 90 mm.

3.1.3 the Test at least three samples, unless a different number is specified in the normative documentation on the product.

4 EQUIPMENT

Universal testing machine according to GOST 28840.

A device for testing a circuit is shown in figure 1, consisting of forward cylinder 1 with the axis of rotation 2, in which base is made of a logarithmic spiral 3, which is described by the equation:

,

where is the polar radius of the spiral, mm.

 — polar helix angle, radians.

Figure 1 Fixture for the test

Figure 1

The polar radius of the spiral should be from 116,0 to 13.2 mm, which corresponds to a change of the polar angle of the helix from 11,7238 to 6,3704 radian (365,0 to 671,7°) and provides a deformation of the outer fibers of the specimens under test is not more than 10%.

The conformity of the contour of the helical surface of the cylinder the contour of a logarithmic spiral determined by combining the projection of the spiral cylinder surface with a pattern of a logarithmic spiral (a pattern), limiting the field of tolerance of the contour of the helical surface of the cylinder to not more than class 8 according to GOST 25347, drawn to scale of not less than 5:1.

The contour of the helical surface of the cylinder must be within the tolerances of the corresponding polar radii of the template.

Movable object table 4 on four ball bearings mounted on a hemispherical guide rail 5that is connected through thrust 6, yoke 7 and the sleeve 8 with the shank upper crosshead of the testing machine. The axis of rotation 2 is connected via a thrust9, yoke 10 and the bushing 11 with the shank of the lower beam of the test machine. Thrust 9 and the guide 5 are connected to each other movably by means of rolling bearings with the forks 12, is fixed on the guide 5.

A sample of 13 across the width fixed at one end on the slide table 4 by means of a clamp 14, and the other end on the spiral surface 3 in the place where =116 mm (corresponds to the radius of curvature of the cylinder 125 mm), by means of a clamp 15.

On the axis of the cylinder is attached to the balancer 16. Balancing of the cylinder is static.

5 PREPARING FOR THE TEST

5.1 Prior to test, the samples are subjected to visual inspection without using of magnifying means.

On the surface of the samples shall be free of protuberances, dents, cracks, burrs, delaminations, foreign inclusions and mechanical damage.

5.2 Thickness and width measured in middle part of the sample with an accuracy of at least 0.01 and 0.1 mm, respectively.

5.3 Fixture mounted on the testing machine so that the surface of the sample fixed on the object table, was tangent to the spiral cylinder surface in the place where =116 mm (figure 1).

In the case of determining the maximum elastic deformation of the bottom across the width of the sample at risk is applied along the slice of the subject table.

Set the limit switch stops the testing machine at the beginning and end positions of the active traverse of the machine. The distance between stops has to be 87mm.

6 TESTING

6.1 Sample clips of the subject in the middle of the table. The distance measured from the lateral edges of the specimen to the lateral surfaces of the subject of the table should not differ more than 1 mm.

The scale of the testing machine lead to the zero position.

6.2 Include the drive of the test machine. The cylinder 1, moving down rods 9, rotates around the axis 2 and is wound without slip on the spiral surface 3 sample 13. When the critical radius of curvature is the destruction of the sample. About the destruction of the sample or the appearance of a crack is judged by an abrupt decrease in load during the test. In the absence of destruction of the testing machine off the limit switch.

6.3 After the test, records the highest maximum load up to 0.5 of the smallest division of measurement the indicator mechanism and the length of the deformed area of the sample, accurate to 0.5 mm.

The deformed portion of the sample is considered distance from a place of attaching it to the spiral cylinder surface (=116 mm) to break the specimen on its longitudinal axis, measured with a ruler according to GOST 427, applied along the axis of the object stage. In the absence of destruction of sample =250 mm.

6.4 Samples coated with line 3, after testing, put the side edge of the flat plate according to GOST 10905 and using the scale ruler according to GOST 427 measure the length of the straight portion up to 1 mm (figure 2).

Figure 2 Measurement of the length of the straight segment L (y)

Figure 2

6.5 Materials and products, samples of which are destroyed by less than 25.0 mm, the test according to the present method are not subject.

7 PROCESSING OF RESULTS

7.1 Maximum elastic deformation, %, is calculated by the formula

, (1)

where  — thickness of specimen, mm;

125 is the maximum radius of curvature of the helical surface of the cylinder, mm;

 — the length of the straight portion of the specimen, mm.

7.2 the maximum deformation of the sample in % is calculated by the formula

, (2)

where  — thickness of specimen, mm;

 — length of the deformed section of the specimen, mm.

7.3 Flexural Strength , MPa, calculated by the formula

, (3)

where  — the maximum ultimate load, N;

262 — given the starting polar radius of the cylinder, mm;

0,85 — angle coefficient of the current polar radius of the cylinder;

 — length of the deformed section of the specimen, mm;

 — sample width, mm;

 — sample thickness, mm.

7.4 Voltage of undistorted specimen , MPa, the corresponding maximum deformation of the outer fibres is calculated by the formula

, (4)

where 49,5 — given arm length application maximum limit of load on the sample, mm;

 — maximum limit load, N;

 — sample width, mm;

 — sample thickness, mm.

7.5 For the values of the characteristics defined in 7.1, 7.2, 7.3, 7.4, be the arithmetic mean of the results of testing at least three specimens, rounded to the first decimal place.

7.6 Controlled quality indicators must be specified in regulatory documents for specific materials and products.

7.7 test Results recorded in a Protocol containing:

is the name or brand of material;

— the dimensions of the samples;

— maximum limit the test load and length of the deformed area of the samples;

— deformation and Flexural strength of each sample;

— the arithmetic average of the test results;

— the designation of this standard;

— the date of the test.


_______________________________________________________________________________________
UDC 669.01.001.4:006.354 OKS 77.160 B09 AXTU 1909

Key words: metals, bend testing, specimen
_______________________________________________________________________________________



The electronic text of the document
prepared by JSC «Code» and checked by:
the official publication of the
M.: IPK Publishing house of standards, 1996