Aluminum rods according to GOST 21488-97

pressed rods round, square and hexagonal cross-sections aluminum and aluminum alloys made by GOST 21488-97. Below is an overview of the main provisions of GOST 21488-97. The numbering of the sections does not coincide with the numbering of the sections in the standard. For professional use only standard should refer to its full and updated text.

1 Klassifiktsiya and designations of aluminum rods according to GOST 21488-97

1.1 Aluminum rods are divided into:
1) in sectional shape:
– round (KR);
– square (KB);
– hex (SHG);
2) for manufacturing accuracy:
– normal accuracy (no designation);
– increased accuracy (P);
– high accuracy (V);
3) according to the state of the material:
– without heat treatment (hot-pressed) (no designation);
– soft (annealed) (M);
– hardened and naturally aged (T);
– hardened and artificially aged (T1);
4) by type of strength:
– normal strength (no designation);
– high strength (PP).

1.2 Aluminum rods manufactured random length to diameter, including inscribed:-
– to 80 mm - from 1,0 to 6,0 m;
– over 80 to 110 mm – from 1,0 to 5,0 m;
– over 110 mm - from 0,5 to 4,0 m.

1.3 Diameter round aluminum rods to 15 mm inclusive in a state without heat treatment or in a soft (annealed) state made in coils of unmeasured length.

2 The cross-section of aluminum rods according to GOST 21488-97

2.1 Round aluminum rods

Diameter round bars made from 8 to 400 mm.
In the manufacture of round bars, the following is monitored:
– bar diameter;
– maximum deviations from the nominal diameter;
– the theoretical mass 1 m bar.

Ovality of round bars should not display their sizes for the tolerances on diameter.

2.2 Square aluminum rods

The square bars made from the diameter of the inscribed circle 8 to 200 mm.

In the manufacture of square bars, the following is controlled:
– diameter of the inscribed circle of the bar;
– maximum deviations in the diameter of the inscribed circle of the bar;
– the theoretical mass 1 m bar;
– the radii of curvature of the longitudinal edges of bars.

2.3 Hexagonal aluminum rods

Hexagonal rods are manufactured with a diameter of the inscribed circle of 8 to 200 mm.

In the manufacture of square bars, the following is controlled:
– diameter of the inscribed circle of the bar;
– maximum deviations in the diameter of the inscribed circle of the bar;
– the theoretical mass 1 m bar;
– the radii of curvature of the longitudinal edges of bars.

2.4 Rods made of aluminum alloys AMg3, AMg5 and AMg6

Tolerances on diameter, including inscribed diameter square and hexagonal rods, c 1,5 times more, than rods of other alloys, and the radii of curvature - in 2 times more.

3 Tolerances form square and hexagonal aluminum rods GOST 21488-97

3.1 Parallelism of the opposite sides of the rods
bars opposite sides must be parallel.
3.2. angle of twist
Controlling the angle of twisting around the longitudinal axis is made to 1 m any portion of rod.
The angle of twisting of the bars in the soft (annealed) state is not controlled.
3.3 Normal and high precision rods:
– nominal diameter of the inscribed circle to 25 mm - not controlled;
– nominal diameter of the inscribed circle more 25 mm should not exceed 5 degrees;
3.4 High precision rods:
– nominal diameter of the inscribed circle to 30 mm - no more than 1,5 mm; на 5 meters - no more 2,5 mm;
– nominal diameter of the inscribed circle over 30 mm 80 mm - no more than 2,0 mm; на 5 meters - no more 4,0 mm;
– nominal diameter of the inscribed circle over 80 mm 120 mm - no more than 2,5 mm; на 5 meters - no more 5,0 mm;
– nominal diameter of the inscribed circle over 120 mm 200 mm - no more than 1,5 mm; на 5 meters - no more 6,0 mm.

4 Control curvature aluminum rods GOST 21488-97

4.1 The curvature of the rods is normalized to 1 m length, bars for improved accuracy and on 300 mm length.
4.2 The curvature of rods in a soft (annealed) state and rods in coils is not standardized.
4.3 The curvature of the rods normal and high accuracy 1 m of length should not exceed for rods with a diameter:
to 100 mm - 3 mm;
– over 100 to 120 mm - 6 mm;
– over 120 to 150 mm - 9 mm;
– over 150 to 200 mm - 12 mm;
– over 200 to 300 mm - 15 mm;
– over 300 to 400 mm - 20 mm.
4.4 The curvature of the rods normal and high accuracy 1 m of length should not exceed for rods with a diameter:
to 80 mm - 2 mm (on 300 mm - 1 mm);
over 80 to 120 mm - 3 mm (on 300 mm - 1,5 mm);
over 120 to 200 mm - 4 mm (on 300 mm - 2 mm);
over 200 to 350 mm - 8 mm (on 300 mm - 5 mm);

5 Stamps aluminum and aluminum alloys for aluminum rods GOST 21488-97

Aluminum rods are made from:
1) aluminum grades AD0, AD1 and AD GOST 4784-97;
2) aluminum alloys in accordance with GOST 4784-97:
– AMC, AMcS;
– AMg2, AMg3, AMg5, АМг6;
– AD31, AD33, AD35, АВ;
– D1, D16, AK4, AK4-1, AK6, AK8;
– B95, 1915, 1925;
3) aluminum alloys in accordance with GOST 1131-76: ВД1, V95-2, AKM;
4) by agreement - from aluminum grades in accordance with GOST 11069.

6 Aluminum rods normal strength according to GOST 21488-97

6.1 Standing and aluminum alloys rods normal strength
Bars of normal strength are made from the following grades of aluminum and aluminum alloys, depending on the state of the material:
1) without heat treatment - from all grades of aluminum and aluminum alloys, specified in section 5;
2) soft (annealed) - from aluminum alloys AMg3, AMg5, Amg6, 1915, 1925, AKM;
3) hardened and naturally aged - from aluminum alloys AD31, AD33, AD35, AB, D1, D16, 1915, 1925, VD1, AKM;
4) hardened and artificially aged - AD31, AD33, AD35, AB, AK4, AK4-1, AK6, AK8, B95, V95-2.
6.2 Mechanical properties of bars of normal strength (examples)
6.2.1 Stamps aluminum AD0, AD1, FROM:
– condition - without heat treatment;
– diameter rods - from 8 to 300 mm;
– tensile strength - at least 60 MPa;
– yield stress 0,2 - not controlled;
– Elongation - at least 25 %.
6.2.2 Aluminum alloy AD31
1) Condition - without heat treatment:
– diameter rods - from 8 to 300 mm;
– tensile strength - at least 90 MPa;
– yield stress 0,2 - not less than 60 MPa;
– Elongation - at least 15 %.
2) Condition - hardened and naturally aged:
– diameter rods - from 8 to 100 mm;
– tensile strength - at least 135 MPa;
– yield stress 0,2 - not less than 70 MPa;
– Elongation - at least 13 %.
3) Condition - hardened and artificially aged:
– diameter rods - from 8 to 100 mm;
– tensile strength - at least 195 MPa;
– yield stress 0,2 - not less than 145 MPa;
– Elongation - at least 8 %.
6.2.3 Aluminum alloy AD33
1) Condition - without heat treatment:
– diameter rods - from 8 to 300 mm;
2) Condition - hardened and naturally aged:
– diameter rods - from 8 to 100 mm;
– tensile strength - at least 175 MPa;
– yield stress 0,2 - not less than 110 MPa;
– Elongation - at least 15 %.
3) Condition - hardened and artificially aged:
– diameter rods - over 8 to 100 mm:
– tensile strength - at least 265 MPa;
– yield stress 0,2 - not less than 225 MPa;
– Elongation - at least 10 %.
6.2.4 Aluminum alloy D16
1) Condition - without heat treatment:
a) the diameter of the rods - from 8 to 300 mm;
– tensile strength - at least 245 MPa;
– yield stress 0,2 - not less than 120 MPa;
– Elongation - at least 12 %.
2) Condition - hardened and naturally aged:
a) the diameter of the rods - from 8 to 22 mm:
– tensile strength - at least 390 MPa;
– yield stress 0,2 - not less than 275 MPa;
– Elongation - at least 10 %.
b) the diameter of the rods - over 22 to 100 mm:
– tensile strength - at least 420 MPa;
– yield stress 0,2 - not less than 296 MPa;
– Elongation - at least 10 %.

7 Aluminum rods increased strength according to GOST 21488-97

7.1 Standing aluminum alloys and high-strength rods
High-strength rods are made from the following grades of aluminum and aluminum alloys, depending on the state of the material:

1) without heat treatment - from aluminum alloys AB, D1, D16, AK6, AK8, B95;
2) hardened and naturally aged - from aluminum alloys D1, D16;
4) hardened and artificially aged - AB, AK6, B95.
7.2 Mechanical properties of high strength bars (example)
7.2.1 Aluminum alloy D16
1) Condition - without heat treatment:
a) the diameter of the rods - from 8 to 300 mm;
– tensile strength - at least 245 MPa.
– yield stress 0,2 - not less than 120 MPa;
– Elongation - at least 12 %.
2) Condition - hardened and naturally aged:
a) the diameter of the rods - from 8 to 22 mm:
– tensile strength - at least 390 MPa;
– yield stress 0,2 - not less than 275 MPa;
– Elongation - at least 10 %.
b) the diameter of the rods - over 22 to 100 mm:
– tensile strength - at least 420 MPa;
– yield stress 0,2 - not less than 296 MPa;
– Elongation - at least 10 %.

8 The requirements for surface quality of aluminum rods GOST 21488-97

8.1 The surface of the rods should have no cracks, bundles, non-metallic inclusions, spots of corrosion origin and traces of ammonium nitrate.
8.2 On the surface of the rods, the following are allowed:
– captivity, Nick, dents, scratch, isolated bubbles, various kinds of press-fit, if the depth of their occurrence does not bring the bar beyond the minus tolerances;
– discoloration, dark and light spots and stripes.

9 Requirements to the microstructure and macrostructure of aluminum rods according to GOST 21488-97

9.1 The microstructure of aluminum rods should have no cracks, microporosity, bundles and sink marks.
9.2 For all aluminum alloys, except alloys AMg5 and AMg6, macrostructure rods should not have inclusions intermetallics.
9.3 On the macrostructure of aluminum rods, the following are allowed:
– nonmetallic inclusions in the form of dots size is not more 0,5 mm or a length of not more strokes 3 mm, if their number does not exceed:
2 PCS. - for bars with diameter up to 50 mm;
3 PCS. - for bars diameter over 50 to 300 mm;
5 PCS. - for bars diameter over 300 mm;
– intermetallics on bars of aluminum alloy size AMg5 0,5 mm in an amount of not more than 5 PCS, and on the bars of aluminum alloy AMg6 - no larger than 0,1 mm in the form of single scattered points;
9.4. Microstructure of bars, who have been hardened, must not have any trace of burnout.

10 Coarse rim on the macrostructure of aluminum rods according to GOST 21488-97

10.1 On the macrostructure of aluminum bars normal strength Coarse allowed the rim part or the entire perimeter, which is not limited to the value.
10.2 On the macrostructure of aluminum bars increased strength may have limited Coarse rim, located partially or along the whole perimeter, if its depth does not exceed:
– 3 mm - for bars of aluminum alloy D1, D16 and B95;
– 5 mm - bars of aluminum alloy AB, AK6 and AK8.