Copper-Aluminium Bars (CUAL)

Material Cu-ETP / EN-AW 1050
Article number
UWVS 2992
Product group
0001
Material
200
Hardness
XXXX
Thickness
XXXXX
Width
Material conditions R200 soft
Technical data
Properties Copper Aluminium CUAL
Tensile strength ((MN/m2) 217 130-170 60
Elasticity modulus ((MN/m2) 95*103 85*103 69*103
Density at 20°C(kg/m3) 8.89*103 3.63*103 2.70*103
Max. electrical resistance at 20°C (Ωm) 1.724*10-8 2.65*10-8 2.826*10-8
Minimum conductivity at 20°C (1/Ωm) 58*106 37.7*106 35.4*106
Temperature coefficient of electrical resistance at 20°C: (1/°C) 3.93*10-3 4.01*10-3 4.03*10-3
Linear thermal expansion coefficient at 20-100°C: (1/°C) 17*10-6 21.9*10-6 23*10-6
Melting point (°C) 1083 658 658
Spec. heat: (J/kg*°C) 393.5 711.7 921.1
Thermal conductivity: (W/m*°C) 3.85*106 2.38*106 1.80*106
Structure

The CUAL (CU-coated AL busbar) consists of an E-AL (85 % vol.) core with a pressed-on coating made of CU (15 % vol.).

2992_querschnitt

Dimensions 3 mm x 10 mm to 15 mm x 120 mm
Tolerances

Length

Area Tolerance (mm)
w≤10 ±0.08

Width (w)

Area (mm) Tolerance (mm)
w≤10 ±0.08
10<w≤18 ±0.1
18<w≤30 ±0.15
30<w≤50 ±0.2
50<w≤80 ±0.25
80<w≤120 ±0.3

Thickness (t)

Area (mm) Tolerance (mm)
w≤10; 3<t≤6 0.07
w≤10; 6<t≤10 0.08
10<w≤30; 3<t≤6 0.07
10<w≤30; 6<t≤10 0.09
10<w≤30; 10<t≤16 0.1
30<w≤50; 3<t≤6 0.09
30<w≤50; 6<t≤10 0.1
30<w≤50; 10<t≤16 0.12
50<w≤80; 3<t≤6 0.11
50<w≤80; 6<t≤10 0.12
50<w≤80; 10<t≤16 0.15
80<w≤120; 3<t≤6 0.12
80<w≤120; 6<t≤10 0.15
80<w≤120; 10<t≤16 0.18
Bending

CUAL bars may be slightly bent. Important: Do not bend over sharp edges; only perform drilling and punching after bending; avoid sudden deformation pressure.

Recommended radius of the forming tool

Thickness (t) Width (w) ≤90° 90°-120° >120°
t≤3 10 – 25 1 t 1 t 1 t
3<t≤5 16 – 60 1 t 2 t 4 t
5<t≤6,3 12 – 50
50 – 120
1 t
2 t
2 t
3 t
4 t
6,3<t≤10 10 – 120 2 t 3 t 4 t
10<t≤15 40 – 120 2 t 3 t 4 t

All data relates to bending over the flat side.

Drilling

Recommendation for drilling

  • Cutting speed: 50 m/min
  • Drilling / cutting angle: 135°-140°
  • Twist angle (helix): 45°
  • Lubricating / cooling fluid: turpentine substitute
Punching The punching tool is constructed just like for flat copper bars. The template should be as close as possible to the shearing edge so that the material is adequately supported.
Screwing

In order to ensure good electrical contact between the busbars, it is necessary to penetrate the surface film of oxides, sulphides, and other contaminants. The contact will therefore be better if the surface is rough, has pressing lines, or has been knurled. Copper oxide has a considerably lower electrical resistance than aluminium oxide and a negative temperature resistance coefficient. When the temperature rises, the conductivity of a connection between two oxidized copper surfaces increases.

Since CUAL has a copper plating, it has the same outstanding contact properties as copper, and so CUAL bars can be used in the same way as copper bars. The contact between the surfaces is initially limited to the tip of each surface, which are therefore subjected to a significantly higher pressure than the average pressure of the connection. Deformations therefore occur during the binding process. In a completed connection, the actual contact area is significantly smaller than that of the total surface area of the connection. The effective contact area is normally limited to the surface near the bolts. Sufficient overlapping will therefore be required for this purpose as well as for the “streamlining effect,” in order to enable a distortion of the electrical flux lines through the overlapping joint. The contact area should be flat, clean, and uniformly roughened. Exaggeratedly flat surfaces are not necessary for the connection, since the connection is clean and fixed. A slight improvement can be achieved here: a reoxidation of the surface can be prevented after cleaning by treating the surface with petroleum jelly. If the surfaces are pressed together to be connected without the Vaseline being removed, the excess Vaseline is pressed out and contributes to the sealing of the connection and to the protection against harmful effects. For a given contact pressure, a copper surface has a contact resistance that is 20-50 times lower than that of aluminium. The connection resistance falls rapidly with an increase in pressure, but the improvement over a contact pressure of around 20 N/mm2 is minimal. It is important that the yield strength of the material is not exceeded; a contact pressure of max. 20 N/mm2 is therefore recommended. The DIN 43673 recommends screw connections with a contact pressure between 7 and 20 N/mm². The creep behaviour of CUAL lies between that of copper and aluminium. The screws can be made of a wide variety of steel grades, brass, or bronze. Due to their higher availability, steel screws are recommended. These should be higher strength (8.8 or higher) and be sufficiently protected (i.e., galvanized). The contact pressure should be spread out across oversized washers. Spring washers are preferable for obtaining a constant pressing force during the various thermal stresses. They ensure the different expansions between the screws and the bar and compensate for any potential relaxations of the metal. CUAL can be tin- and silver-plated.

Torque for the tightening of the screws and dimensions of the washers

2992_unterlegschreibe_normal

Screw dimensions Torque (Nm) DIN 43673 Flat washer DIN 7349
in buildings outdoors D (mm) d (mm) S (mm)    
M5 2.5 3 15 5.3 2    
M6 4,5 5.5 17 6.4 3    
M8 10 15 21 8.4 4    
M10 20 30 25 10.5 4    
M12 40 60 30 13 6    

2992_unterlegschreibe_federnd

Screw dimensions Torque (Nm) DIN 43673 Spring washer DIN 6796
in buildings outdoors D (mm) d (mm) S (mm) h (mm) P (kN)
M5 2.5 3 11 5.3 1.2 1.45 5.5
M6 4.5 5.5 14 6.4 1.5 1.85 8.6
M8 10 15 18 8.4 2 2.42 14.9
M10 20 30 23 10.5 3 3 22.1
M12 40 60 29 13 3.5 3.69 34.1

Arrangement of the screws (DIN 43673)

Rod width (mm) 12-50 25-60
Form 1 2
Drill pattern 2992_schrauben-bild1 2992_schrauben-bild2
Bore dimensions Nominal width: b d e1   d e1 e2
12 5.5 6  
15 6.6 7.5  
20 9 10  
25 11 12.5   11 12.5 30
30 11 15   11 15 30
40 13.5 20   13.5 20 40
50 13.5 25   13.5 20 40
60   13.5 20 40
80  
100  
120  
Rod width (mm) 60 80-120
Form 3 4
Drill pattern 2992_schrauben-bild3 2992_schrauben-bild4
Bore dimensions Nominal width: b e1 e2 e3 e1 e2 e3
12
15
20
25
30
40
50
60 17 26 26
80 20 40 40
100 20 40 50
120 20 40 60

Permissible deviations for the centre-to-centre distances of the holes: ±0.3 mm

Cutting

CUAL can be cut using the same method as aluminium. Therefore, cutting with every second saw tooth produces good results. (Deburring is not necessary.)

Recommendations for cutting

  • Cutting speed: 50-90 m/sec
  • Lubricating/cooling fluid: turpentine substitute

Geometrical details of the saw teeth

2992_saegezaehne

The data in this technical product information is based on our current knowledge and experience. Due to the abundance of possible influences during its application, it does not release the processor nor the user from performing their own tests and trials. A legally binding guarantee of certain properties or of suitability for a specific purpose cannot be derived from our information. Depending on the individual case, we recommend consulting with us. Any property rights and existing laws must be observed by the recipient of our products under their own responsibility.