Punch forming

Welding material

To reduce the stress concentration at the joint and the welding seam, it is advised to use welding material with strength no higher than the recommended value, provided that the mechanical properties of the joint can satisfy the requirements of the structural part.

See the following table for welding materials that can be used for Baosteel’s hot-rolled high strength automotive steel:


Typical designation Welding wire designation Welding wire type Suppliers of welding wire Welding wire diameter
GB/TB AWS
B750L HS80
BHG-4
GMn3Ni1CrMo		 ER76-G
ER76-G
-		 ER110S-G
-
ER100S-G		 Shanghai Baoxuan
Harbin Welding Institute
SAF
(OERLIKON)		 Φ1.2~1.6
B700L
B650L BHG-3 ER69-G -
B600L BH503 ER50-6 ER70S-6

Typical welding parameters recommended:(Ф1.2mm welding wire,8mm thick steel plate for example)


Welding method Shielding gas Gas flow rate Length of welding wire Groove
MAG 80%Ar+20%CO2 15 L/min 12mm V shape60ο
Welding current
(A)		 Welding voltage
(V)		 Welding speed
(mm/min)		 Welding heat input
(KJ/mm)
200~280 22~28 350~400 0.8~1.4

Mechanical properties of the welding joint

Typical designation
Steel Grade
（Thickness）
Welding wire
Wire		 Pass
Pass		 热输入Q
Heat input
(KJ/mm)		 拉伸试验（Tensile test）
Tensile strength
Rm（MPa）		 Breaking point
Position
B750L (8mm) HS80 2 layers 3 passes 0.8 835 Heat affected zone
(HAZ)
B750L (8mm) BHG-4 2 layers 3 passes 0.8 835 Heat affected zone
(HAZ)
B750L (8mm) GMn3Ni1CrMo 2 layers 3 passes 0.8 820 Heat affected zone
(HAZ)
B700L (8mm) BHG-4 2 layers 3 passes 0.8 785 Base metal (BM)
B650L (8mm) BHG-3 2 layers 3 passes 0.8 735 Base metal(BM)

B550CL is the steel used for automobile wheel rims, the welding process parameters of which are as follows:


Step Number of cycles（0.02s） Current density（KA/mm2） Pressure（KN）
1 Preheating 4 80-100 53
2 Welding 4 100-200 53
3 Tempering 2 60-80 37
4 Holding 2 0 27