Joining method
Schematic diagram of joint
SPR
FDS
RES
FSPR
Joint of two-layer
Material
interval of joint
TL 4225/C611
22 mm
20 mm
20 mm
>16.5 mm
Strength
Al alloy
δmin
Strength is not required, elongation has certain requirements, generally should be >8%
Not require
150 MPa
<600 MPa
δmax
320 MPa
Steel
δmin
Not require
<780 MPa
>270 MPa
<1800 MPa
δmax
<1600 MPa
<1800 MPa
Thickness
Steel
tmin
Cold-formed sheets are generally not required
<1.5 mm (780 MPa)
0.8 mm
t1 < 2 mm (1800 MPa)
tmax
1.7 mm (1600 MPa)
3 mm
Al alloy
tmin
>0.8 mm
Do not do special requirements, meet the total thickness requirements
1 mm
< (t1 + t2)/3
tmax
Abide by t1 + t3 + t3 < 6.5 mm
4 mm
Total
6.5 mm
<7 mm (Based on the length of the rivet)
<6 mm
<5.3mm
Flange
Steel
tmin
E > 7.5 mm, C > 15 mm
E > 10 mm, C > 20 mm
E > 7 mm, C > 14 mm
E > 8 mm, C > 16.8
tmax
Al alloy
tmin
E > 12.5 mm, C > 20 mm
E > 10 mm, C > 20 mm
E > 7 mm, C > 14 mm
E > 15 mm, C > 30 mm
tmax
Preformed hole
Steel
tmin
Not require
<1.0 mm (340 MPa)
no
Not require
tmax
Al alloy
tmin
Not require
Don’t need prehole, according to product requirements
Not require
tmax
Joint of three-layer
Material
interval of joint
TL 4225/CR5/C611
22 mm
20 mm
60 - 70 mm
>16.5 mm
Strength
Al alloy
δmin
Strength is not required, elongation has certain requirements, generally should be >8%
Not require
>150 MPa
<600 MPa
δmax
<320 MPa
Steel
δmin
Not require
<780 MPa
>270 MPa
<1800 MPa
δmax
<780 MPa
<1800 MPa
Thickness
Steel
tmin
<1.7 mm (1600 MPa)
<1.5 mm (780 MPa)
0.8 mm
t1 < 2 mm (1800 MPa)
tmax
3 mm
Al alloy
tmin
>0.8 mm (底层)
Do not do special requirements, meet the total thickness requirements
1 mm
< (t1 + t2 + t3)/3
tmax
Abide by t1+ t2+ t3 < 6.5 mm
4 mm
Total
6.5 mm
<7 mm
<9 mm
Flange
Steel
tmin
E > 7.5 mm, C > 15 mm
E>10mm, C>20mm
E > 7 mm, C > 14 mm
E > 8 mm, C > 16.8
tmax
Al alloy
tmin
E > 12.5 mm, C > 20 mm
E > 15 mm, C > 25 mm
E > 7 mm, C > 14 mm
E > 10 mm, C25
tmax
Preformed hole 
Steel
tmin
Not require
Hole requirements: the first layer of plate is diameter +2 - 3 mm; Middle layer top layer +2 mm
Depending on the thickness, the first layer is required, diameter +2 - 3 mm
Not require
tmax
Al alloy
tmin
Not require
Not require
tmax