AIRCRAFT PLATES FROM ALUMINUM ALLOYS
(Instead of OST 90124−74)
This standard applies to plates made of aluminum alloys of grades D16ch, 1163, V95pch and V95och used in aviation.
Examples of symbols:
and). Plate made of aluminum alloy grade D16ch with technological cladding (B), in a hardened and naturally aged state (T), 20 mm thick, 1200 mm wide, 3000 mm long, normal accuracy manufactured in thickness, supplied according to TU1−92−161−90 …
Plate D16ch.B.T. 20х1200х3000 TU1−92−161−90
b). The same with normal plating (A), increased accuracy of manufacturing in thickness (P):
Plate D16ch.A.T. 20Pх1200х3000 TU1−92−161−90
1.1. Plates are made according to the assortment provided by GOST 17232 with a thickness of 11 to 80 mm, with a width of up to 2000 mm, inclusive.
2. Technical requirements
2.1. Plates are subdivided:
by manufacturing method:
- — unclad — marked with an alloy grade without additional signs;
- — clad with normal plating — A (D16chA, 1163A, V95pchaA);
- — clad with technological plating — B (D16chB, 1163B, V95pchB);
- by manufacturing accuracy by thickness:
- — normal accuracy — no additional designation;
- — increased accuracy — P;
by material condition:
- — without heat treatment — without additional designation (D16ch, 1163, V95pch);
- — hardened and naturally aged — T (D16chT, 1163T);
- — hardened and artificially aged — T1 (D16chT1, 1163T1, B95pchT1);
- — hardened and artificially aged in a softening mode — T2 (V95pchT2, V95ochT2);
- — hardened and artificially aged in a softening mode (T3) — V95pchT3, V95ochT3.
2.2. The thickness of the cladding layer on each side of the slab should be:
a) for normal cladding in the range of 2.0−4.0%;
b) for technological cladding no more than 1.5%.
2.3. The chemical composition of plates of aluminum alloy grade D16ch, 1163 must comply with the requirements of OST 90048, and from aluminum alloy of grade V95pch, V95och must comply with the requirements of OST1 90026.
2.4. The hydrogen content in the metal should not exceed 0.4 cm 3 per 100 g of metal.
2.5. The mechanical properties of samples cut from the middle layers of the plate across the rolling direction must comply with the requirements of the table.
|Alloy grade||Condition of test specimens||Plate thickness, mm||Tensile properties, not less|
|Ultimate tensile strength, σ 6||Yield strength, σ 0.2||Elongation, σ%|
|MPa (kgf / mm 2)|
|Hardened and naturally aged (T)||
|Hardened and artificially aged (T1)||11−25||450 (46.0)||400 (41.0)||5.0|
|B95pch||Hardened and artificially aged (T1)||
1. Mechanical properties of specimens cut from plates of alloys of grades V95pch, V95och, V95pchA, heat-treated according to regimes T2 and T3 are established in accordance with OST1 90125.
2. Testing of the mechanical properties of samples in the quenched and artificially aged state for alloys of grades D13ch, 1163 is carried out at the request of the consumer, as specified in the order.
2.6. Indicators of the mechanical properties of the slabs in the fractional direction, for all thicknesses, as well as in the direction, for all thicknesses, as well as in the direction perpendicular to the plane of the slab for a thickness of 40 mm or more, must be determined and entered into the slab.
2.7. Plates are subjected to tension straightening in a freshly hardened state with a residual deformation of 1.5−3.0%.
2.7.1. At the request of the consumer, for alloys of grades V95pch and V95och, the residual deformation when straightening the plates by tension should be set within 2−3%.
2.8. Plates made of alloys of grades V95pch, V95och, V95pchA and V95ochA in hardened and artificially aged according to softening modes T2 and T3 are subjected to the determination of corrosion resistance in accordance with OST 90125.
2.9. The microstructure of quenched slabs should not have burnout.
3. Acceptance rules and test methods
3.1. Each melt is controlled for hydrogen content in accordance with GOST 21132.1.
3.2. Mechanical properties are monitored for 100% of the slabs in three mutually perpendicular directions.
The test of the mechanical properties of the slabs in height is carried out only on slabs with a thickness of 40 mm or more.
3.2.1. It is allowed to test mechanical properties on samples taken from the original plate before cutting it into measuring plates.
3.3. The control of mechanical properties is carried out in accordance with GOST 1497 on short samples, with ℓ 0 = 5d 0. The relative elongation is determined at the design length ℓ 0 = 4d 0 .
3.4. The thickness of the cladding layer of the slabs is guaranteed by the supplier. Arbitration control is carried out in accordance with OST1 90047.
3.5. After quenching, each plate is subjected to ultrasonic testing according to the MK 129−40−90 method on an automated installation or MK 52−40−81 by a manual contact method.
Echo signals from defects are recorded, which in amplitude are equal to or exceed the echo signals from the control reflector with a diameter of 2.0 mm.
For plates made of V95pch alloy of all thicknesses, plates made of alloy D16ch, with a thickness of less than 35 mm, no more than 20 defects are allowed per 1 m 2 of surface, including no more than 5 defects equivalent to a control reflector with a diameter of 4.0 to 5.0 mm.
For plates made of alloy D16ch, with a thickness of 35 mm and more, no more than 10 defects are allowed per 1 m2 of surface, including no more than 2 defects equivalent to a control reflector with a diameter of 4.0 to 5.0 mm.
The distance between the registered defects must be at least 25 mm.
The total number of defects in each square meter, measured over the entire width of the slab made of alloy grade L63, starting from one of the ends of the slab at the discretion of the supplier, no more than 5, including defects equivalent to a reflector with a diameter of 3.2 to 4.0 mm more than 1 «.
3.6. The actual value of the permanent deformation of each slab is recorded in the quality document (at the request of the consumer).
3.7. Determination of the permanent deformation after straightening by stretching is carried out in the middle part of the slab along the length, by applying two notches with a length of 5−10 mm on a base of 1000 mm before straightening.
Test risks for checking permanent deformation are highlighted with paint.
3.8. To control the plates for the absence of burnout, one plate is taken from each heat treatment charge.
If there are plates of different heats in the thermal cage, then the microstructure control is carried out on one sample from each melt.
3.9. In the presence of a burnout, the entire heat treatment cage is rejected.
3.10. The microstructure of the plates for the absence of burnout is checked by metallographic method according to MK 266−31−83.
3.11. All other requirements for slabs must comply with GOST 17232.
State and industry related standards
with the requirement of TU1−92−161−90
GOST 1497−84 Metals. Tensile test methods.
GOST 17232−79 Plates from aluminum and aluminum alloys. Technical requirements.
GOST 21132.1−81 Aluminum and aluminum alloys. Methods for the determination of hydrogen in solid metal.
OST1 90026−80 Wrought aluminum alloys of high purity. Stamps.
OST1 90047−72 Determination of thickness and quality of cladding on semi-finished products from aluminum alloys.
OST1 90048−77 Wrought aluminum alloys. Stamps.
OST1 90125−83 Semi-finished products from wrought aluminum alloys. Mechanical and corrosive properties of semi-finished products aged according to softening aging conditions.
MK 52−40−81 Ultrasonic testing of large-sized forgings, stampings, plates, extruded profiles from aluminum alloys and parts made from them.
MK 129−40−90 Ultrasonic testing of rolled plates, flat ingots and extruded sections.
MK 266−31−83 Metallographic method for determining burnout in semi-finished products from wrought aluminum alloys.