Specification for aluminum alloy rod and bar for aerospace
1 Scope
1.1 Subject content
This specification specifies the requirements, quality assurance requirements and delivery preparation of aluminum alloy round rods, square rods and regular hexagonal rods (referred to as hexagonal rods) for aerospace.
1.2 Application scope
This specification is applicable to aluminum alloy extruded round rods, square rods and hexagonal rods used in aerospace departments.
1.3 Classification
The alloy designation, supply status and specifications of the rod and bar are shown in Table 1.
Table 1
Alloy designation Supply state Ordinary rod, mm High-strength rod, mm
Round rod diameter Inscribed circle diameter of square rod and hexagonal rod Round rod diameter Inscribed circle diameter of square rod and hexagonal rod
LF2, LF3, LF5, LF6, LF11, LF21 R, M 5~350 5~200 - -
LY11, LY12 R 5~350 5~200 20~150 20~100
CZ 5~150 5~120 20~150 20~100
LY2, LY16 R, CS 5~150 5~120 - -
LD7, LD8 R 5~350 5~120 - -
CS 5~150 5~120 - -
LD2, LD5, LD10, LC4, LC9 R 5~350 5~200 20~150 20~100
CS 5~150 5~120 20~150 20~100
2 Normative references
GB 228-87 Metallic materials - Tensile testing
GB 3190-82 Wrought aluminium and aluminium alloy - Chemical composition
GB 3199-82 Wrought aluminium and aluminium alloy products - Packing marking transporting and storing
GB 3246-82 Inspection method for structure of wrought aluminium and aluminium alloy products - Inspection method for microstructure
GB 3247-82 Aluminum and aluminum alloys - Inspection method of macrostructure for wrought products
GB 6395-86 Metallic materials - Stress-rupture test in tension
GB 6987.1~21-86 Methods for chemical analysis of aluminium and aluminium alloys
GB 6987.22~23-87 Methods for chemical analysis of aluminium and aluminium alloys
GJB 1694-93 Heat treatment specification for aluminium alloys
3 Requirements
3.1 Chemical composition
The chemical composition of the rod and bar shall meet the requirements of GB 3190.
3.2 Mechanical properties
3.2.1 The longitudinal mechanical property at ambient temperature of ordinary rod and bar shall meet those specified in Table 2.
Table 2
Alloy designation Supply state Sample state Diameter range, mm Tensile strength
σb
MPa Specified non-proportion elongation stress, σP0.2
MPa Elongation
δ5
%
Not less than
LF2 R, M R, M 5~250 ≤225 - 10
LF3 R, M R, M 5~250 176 78 13
LF5
LF11 R, M R, M 5~150 265 118 15
>150~250 230 90 10
LF6 R, M R, M 5~150 315 157 15
>150~250 180 120 10
LF21 R, M R, M 5~150 ≤167 - 20
>150~250 ≤167 - 15
LY2 R, CS CS 5~150 430 275 10
LY16 R, CS CS 5~150 350 235 8
LY11 R, CZ CZ 5~150 375 215 12
R CZ >150~250 340 200 8
LY12 R, CZ CZ 5~22 390 255 12
R, CZ CZ >22~150 420 275 10
R CZ >150~250 380 260 6
LD2 R, CS CS 5~150 295 - 12
R CS >150~250 280 - 8
LD5 R, CS CS 5~150 350 - 12
R CS >150~250 350 - 8
LD7
LD8 R, CS CS 5~150 355 - 8
R CS >150~250 345 - 6
LD10 R, CS CS 5~22 440 - 10
R, CS CS >22~150 450 - 10
R CS >150~250 380 - 8
LC4
LC9 R, CS CS 5~22 490 370 7
>22~150 530 400 6
R CS >150~250 500 400 4
Note: If the diameter exceeds the range specified in Table 2, the longitudinal mechanical property at ambient temperature of rod and bar shall be negotiated between the ordering party and the manufacturer.
3.2.2 The longitudinal mechanical property at ambient temperature of high-strength rod and bar shall meet those specified in Table 3.
Table 3
Alloy designation Supply state Sample state Diameter range, mm Tensile strength
σb
MPa Specified non-proportion elongation stress, σP0.2
MPa Elongation
δ5
%
Not less than
LY11 R, CZ CZ 20~150 390 245 8
LY12 R, CZ CZ 20~150 440 305 8
LD2 R, CS CS 20~150 305 - 8
LD5 R, CS CS 20~150 380 - 10
LD10 R, CS CS 20~150 460 - 8
LC4
LC9 R CS 20~100 550 450 6
R CS >100~150 530 430 6
CS CS 20~150 550 450 6
3.2.3 The longitudinal properties of LY2 and LY16 alloy rods and bars shall meet those specified in Table 4 when the high temperature durability is indicated in the contract.
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Table 4
Alloy designation Temperature
℃ Stress
MPa Holding time
h
LY2 270±3 64 100
78 50
LY16 300±3 69 100
Note: If LY2 alloy rods and bars are unqualified under the condition of 78Mpa for 50h, the final judgment shall be based on the test results under the condition of 64Mpa for 100h.
3.3 Dimensions and shapes
3.3.1 The permissible deviation of rod and bar diameter (or inscribed circle diameter) shall meet those specified in Table 5.
Table 5 In: mm
Round rod diameter Inscribed circle diameter of square rod or hexagonal rod Permissible diameter deviation
Grade A Grade B Grade C Grade D
5~6 5~6 -0.30 -0.48 - -
>6~10 >6~10 -0.36 -0.58 - -
>10~18 >10~18 -0.43 -0.70 -1.10 -1.30
>18~29 >18~29 -0.52 -0.84 -1.30 -1.50
>29~50 >29~50 -0.62 -1.00 -1.60 -2.00
>50~84 >50~84 -0.74 -1.20 -1.90 -2.50
>84~120 >84~120 - -1.40 -2.20 -3.20
>120~180 >120~180 - - -2.50 -3.80
>180~250 >180~200 - - -2.90 -4.50
>250~300 - - - -3.30 -5.50
>300~350 - - - - -7.20
Note: If positive and negative deviations are required, they shall be indicated in the contract, and the deviation value shall be half of the corresponding value in the above table.
3.3.2 Uniform bending degree of rod and bar: for the rod and bar with diameter not more than 10mm, uniform bending that can be eliminated by light pressing is allowed. The rod and bar with a diameter greater than 10mm shall meet those specified in Table 6.
Table 6 In: mm
The diameter or inscribed circle diameter Ordinary grade High precision grade Ultra-high precision grade
Length per meter ≤ Total length L, m, ≤ Length per meter ≤ Total length L, m, ≤ Length per meter ≤ Total length L, m, ≤
>10~120 3.0 3.0×L 2.0 2.0×L 1.2 1.2×L
>120~200 5.0 5.0×L 2.8 2.8×L 2.0 2.0×L
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Note: If the diameter exceeds the range specified in Table 6, the bending degree of rod and bar shall be negotiated between the ordering party and the manufacturer.
3.3.3 The twisting degree of square rod and hexagonal rod shall meet those specified in Table 7.
Table 7
Inscribed circle diameter, mm Allowable twisting degree per meter, ≤
5~14 60°
>14~30 45°
>30~75 30°
>75~120 20°
Note: If the inscribed circle diameter exceeds the range specified in Table 7, the twisting degree of rod and bar shall be negotiated between the ordering party and the manufacturer.
3.3.4 Both ends of the rod and bar shall be cut flush, and the cutting angle of its end face is not allowed to exceed 5°.
3.3.5 For the rod and bar with cut length or multiple length, its maximum cut length is 5,800mm, and the permissible length deviation is +20mm. For the rod and bar with multiple length, a sawing allowance of 5mm shall be reserved for each saw bite. For the rod and bar with random length, the supply length is 1,000 ~ 5,800mm when the diameter is less than 50mm, and 500 ~ 5,800mm when the diameter is greater than 50mm
3.4 Macrostructure
3.4.1 Cracks, shrinkage tails, air holes and bright grains are not allowed on the macro test piece of the rod and bar.
3.4.2 The spot- or needle-like non-metallic inclusions and compound segregation defects on the macro test piece of the rod and bar shall meet the following requirements: for LF6 alloy, the length of each point defect is not more than 0.1mm; for LF11 alloy, when the length of each point defect is less than 0.4mm, it is allowed; when the length of each point is between 0.4 and 0.5mm, it is not allowed to exceed 5 points; when the length of each point is greater than 0.5mm, it is not allowed; and for other alloys, point defect is not allowed.
3.4.3 The layer depth on the macro test piece of the rod and bar shall not exceed half of the negative deviation of the rod and bar diameter, but the minimum diameter or inscribed circle diameter of the rod and bar shall be ensured. For the rod and bar used for die forging, if there is no lamination requirements, the requirements for rod and bar with diameter less than 120mm may be indicated in the contract; for the rod and bar with diameter not less than 120mm, the requirements shall be negotiated by the ordering party and the manufacturer.
3.4.4 Oxide coating on the macro test piece of the rod and bar shall meet those specified in Table 8.
Table 8
Defect name Inspected area Provided the defect length of each point is within the following ranges, mm
≤0.3 >0.3~2.0 >2.0
Oxide coating Whole section Allowed ≤4 points Not allowed
3.4.5 The depth of coarse grain ring on the macro test piece of the rod and bar shall meet those specified in Table 9. For rod and bars required by ordinary coarse grain ring, if the depth of coarse grain ring exceeds that specified in Table 9, samples may be taken in the coarse grain region for mechanical property test, and the coarse grain region is allowed when the mechanical properties are qualified.
