gas metal arc welding of advanced high- strength steels...er cusi-a 173 111 weld 18,182 527 91.2...

GDIS2017

Gas Metal Arc Welding of Advanced High-

Strength Steels

Min Kuo, PhD

ArcelorMittal

#GDIS | #SteelMatters 3

A/SP Team Members

• Min Kuo, ArcelorMittal

• Tom Natale, AK Steel Corporation

• Stephen Tate, AK Steel

Corporation

• Hassan Ghassemi, ArcelorMittal

• Elliot Biro, ArcelorMittal

• Amanda Scherzer,

FiatChryslerAmerica US LLC

• Doug Howe, Ford Motor Company

• Mike Palko, Ford Motor Company

• Richard Carlson, General Motors

• Weiping Sun, Nucor Corporation

• Chonghua (Cindy) Jiang, AET Integration

Inc.

• Justin Hunt, AET Integration Inc.

• Donald F. Maatz, Jr. R&E Engineering

Services

• Daniel L. Galiher, Tower International

• Vaidyanath B. Rajan, Lincoln Electric

• Richard Paul, Auto/Steel Partnership


Study Objective

• The objective of this project is to evaluate

the effects of gas metal arc welding (GMAW)

and gas metal arc brazing (GMAB) on AHSS

and UHSS and to identify the impact of

welding on joint strength and

microhardness.


Test Methods

• Tests include X-ray inspection, micro

hardness, quasi-static shear tension, and

metallurgical cross-sections. Selected thin

gauge steels were joined using both GMAW

and GMAB.


Test Methods

• X-ray inspections were conducted on all zinc coated materials,

referencing ISO 17636-2 and ISO 5817.

• Cross-sections were taken from the welded and brazed plates. The

microhardness indent spacing was 0.2 mm.

• Quasi-static shear tension testing was conducted to obtain nominal

stress-displacement curves. Nominal stress was calculated as the load

divided by the coupon cross-sectional area. Actual weld or braze

geometry was not considered in the nominal stress value. Tests were

conducted at 5.0 mm/min.


Test Materials

• Steel grades obtained from the A/SP Sample Bank include the

following:

• 0.67 mm BH210 HDGI

• 0.65 mm BH240 HDGI

• 0.69 mm DP490 HDGA

• 2.00 mm DP780 HDGI

• 2.53 mm CP780 HDGI

• 2.70 mm 780SF Uncoated

• 1.95 mm DP980 HDGA

• 1.38 mm DP1180 Uncoated

• 1.40 mm DP1180 EG

• 1.40 mm MS1700 Uncoated


Project Approach - Test Matrix

Material Received MaterialThickness

(mm)Coating GMAB GMAW

X-ray

Inspection

Quasi-static

Shear TensionMetallurgical Microhardness

x BH210 0.67 HDGI x 3 3 3 0

x BH240 0.65 HDGI x 3 3 3 0

x DP490 0.69 Galvanneal x 3 3 3 0

x BH210 0.67 HDGI 70 ksi 3 3 3 1

x BH240 0.65 HDGI 70 ksi 3 3 3 1

x DP490 0.69 Galvanneal 70 ksi 3 3 3 1

x DP980 1.95 Galvanneal 70 ksi 3 3 3 1

x MS1700 1.40 Uncoated 70 ksi 0 3 3 1

x DP1180 1.38 Uncoated 70 ksi 0 3 3 1

x DP1180 1.40 EG 70 ksi 3 3 3 1

x CP780 2.53 HDGI 80 ksi 3 3 3 1

x DP780 2.00 HDGI 80 ksi 3 3 3 1

x 780SF 2.70 Uncoated 80 ksi 0 3 3 1

x CP780 2.53 HDGI 100 ksi 3 3 3 1

x DP780 2.00 HDGI 100 ksi 3 3 3 1

x 780SF 2.70 Uncoated 100 ksi 0 3 3 1


Specimen Configuration Steel sheets were

sheared to 6” x 12”

and welded in a lap

joint configuration

along the 12”

length. Test

specimens were

waterjet cut from

the center of the

welded plates, in

order to avoid the

weld start and stop

locations.

Specimen length

was parallel to the

sheet rolling

direction.


Welding Position and Set-up

Welded and brazed joints were

produced using an OTC DP400

power supply with an OTC Almega

AX-V6 robot. Both DC constant

voltage (GMAW) and DC pulsed

(GMAW-P) processes were used,

depending on the material

thickness and coating. All welds

were made in the 1F position.


Weld Fillers

• Lincoln SuperArc L56 (ER70S-6), Lincoln SuperArc

LA-90 (ER80S-D2), and

• Lincoln SuperArc AK-10 (ER100S-G) steel filler

were used with 90% argon 10%CO2 shielding gas

for GMAW joints.

• Luvata LuvaWeld S1 (CuSi-A) silicon bronze filler

was used with 100% argon shielding gas for GMAB

joints.


Welding Parameter

Zinc coated steels were welded with lower travel speed than uncoated

steels in order to reduce porosity. For thin zinc coated steels, it was found

that the L2 leg length needed to be greater than the targeted 2.5t. Low

current and the fastest feasible travel speeds were attempted in order to

minimize heat input for all materials.


Welding Parameter Summary

MaterialThickness

(mm)Coating Filler Wire Mode

Current

(A)

Voltage

(V)

Travel Speed

(in/min)

ER70S-6 DC Pulse 110 21 20

ER80S-D2 DC Pulse 110 20 20

ER100S-G DC Pulse 110 20 20

ER70S-6 DC Pulse 105 21 20



ER70S-6 DC Pulse 180 22 50



ER70S-6 DC 68 14 25

ERCuSi-A DC Pulse 68 15.4 30

ER70S-6 DC 68 14 25

ERCuSi-A DC 125 11.2 30

ER70S-6 DC 70 15.5 25

ERCuSi-A DC Pulse 70 18 30

DP980 1.95 Galvanneal ER70S-6 DC Pulse 105 21 20

DP1180 1.40 EG ER70S-6 DC Pulse 85 18.5 20

MS1700 1.40 uncoated ER70S-6 DC Pulse 110 15.5 50

DP1180 1.38 uncoated ER70S-6 DC Pulse 105 15 50

780SF

BH210 HDGI0.67

uncoated2.70

CP780

DP780 HDGI2.00

HDGI2.53

BH240 0.65 HDGI

DP490 0.69 Galvanneal


Test Results

High quality joints were achieved with all materials.

With appropriate parameters and sheet gaps

targeted at 0.1 mm, zinc coated materials were able

to be joined with minimal porosity. Coated materials

exhibited moderate degrees of spatter. This is likely

caused by the low current and voltage levels required

to produce small weld sizes.


X-ray Results

Example X-ray Images Without Porosity (Left) and With Porosity (Right)

Minor porosity was observed in the weld or braze metal of zinc

coated materials. The highest area percent porosity was 1.98%,

as determined from X-ray images.


GMAB Test Results (BH210 and DP490)

0

100

200

300

400

500

600

700

800

0 5 10 15 20 25 30 35 40

No

min

al S

tre

ss (

MP

a)

Displacement (mm)

70ksi BH210-ST-2

70ksi BH210-ST-3

70ksi BH210-ST-4

0

100

200

300

400

500

600

700

800

0 5 10 15 20 25 30 35 40

No

min

al S

tre

ss (

MP

a)

Displacement (mm)

GMAB-BH210-ST-2

GMAB-BH210-ST-3

GMAB-BH210-ST-4

ER

70

S-6

Wir

e

ER

Cu

Si-

A W

ire


DP780GI Test Results (ER70, 80, 100) E

R7

0S

-6

ER

80

SD

-2

ER

10

0S

-G


Metallurgical Results

MaterialThickness

(mm)Coating Filler

Leg Length

L1 (mm)

Leg Length

L2 (mm)

Penetration

(mm)

Throat

(mm)

Convexity

(mm)

Toe Angle

(degrees)

ER70S-6 1.05 2.64 1.06 0.71 0.48 143.02

ERCuSi-A 1.22 3.71 0.16 0.74 0.57 147.30

ER70S-6 1.13 2.54 0.74 0.64 0.63 136.24

ERCuSi-A 1.52 3.49 0.27 0.66 0.98 155.63

ER70S-6 0.97 2.99 1.00 0.71 0.55 149.51

ERCuSi-A 1.38 4.25 0.12 0.74 0.78 150.56

ER70S-6 2.60 4.39 0.81 2.07 0.41 160.16

ER80S-D2 2.23 4.34 0.62 1.83 0.37 164.09

ER100S-G 2.15 4.61 0.91 1.81 0.66 152.08

ER70S-6 2.60 4.39 0.81 2.07 0.41 166.89

ER80S-D2 2.56 4.00 0.74 1.85 0.29 158.16

ER100S-G 2.56 4.45 0.91 2.08 0.38 151.02

ER70S-6 2.57 3.70 0.74 1.92 0.60 151.67

ER80S-D2 2.60 3.65 0.55 1.93 0.51 147.44

ER100S-G 2.54 3.79 0.63 1.99 0.72 155.98

DP980 1.95 HDGA ER70S-6 2.36 4.57 0.90 1.75 0.53 151.16

DP1180 1.38 uncoated ER70S-6 1.38 3.14 0.42 1.18 0.25 162.54

DP1180 1.40 EG ER70S-6 1.49 3.99 0.76 1.32 0.46 166.50

MS1700 1.40 uncoated ER70S-6 1.55 2.96 0.30 1.21 0.43 149.17

780SF 2.70 uncoated

DP490 HDGA0.69

0.65 HDGIBH240

CP780 2.53 HDGI

BH210 0.67 HDGI

DP780 2.00 HDGI


Project Results

MaterialThickness

(mm)Coating Filler Metal

Base Metal

Microhardness

(HV500g)

Minimum

Microhardness

(HV500g)

Minimum

Microhardness

Location

Average Joint

Peak Load

(N)

Average Joint

Strength

(MPa) *

Joint

Efficiency

(%) **

Percent

Porosity

(X-ray)

Fracture Location

ER70S-6 284 211 HAZ 85,680 683 77.6 0.70 weld metal

ER80S-D2 276 239 HAZ 80,519 637 73.0 0.44 weld metal

ER100S-G 279 239 HAZ 97,530 771 88.4 0.32 near fusion line

ER70S-6 232 199 HAZ 73,387 735 91.0 0.10 weld metal

ER80S-D2 229 190 HAZ 71,895 720 89.2 0.37 weld metal

ER100S-G 237 199 HAZ 75,986 760 94.2 0.10 HAZ

ER70S-6 269 233 HAZ 90,060 648 85.0 - near fusion line

ER80S-D2 267 222 HAZ 90,647 664 85.6 - HAZ

ER100S-G 261 228 HAZ 88,305 647 83.4 - HAZ

ER70S-6 119 111 base metal 11,952 357 100.4 0.12 HAZ

ER CuSi-A 129 122 base metal 12,039 359 101.2 0.15 base metal


ER CuSi-A 128 110 base metal 12,089 372 104.9 0.11 base metal


ER CuSi-A 173 111 weld 18,182 527 91.2 1.51 weld metal

DP980 1.95 Galvanneal ER70S-6 299 232 HAZ 76,086 780 74.8 1.73 weld metal

DP1180 1.40 EG ER70S-6 370 218 weld 48,751 696 55.2 0.97 weld metal

MS1700 1.40 uncoated ER70S-6 545 205 HAZ 51,060 714 41.2 - HAZ

DP1180 1.38 uncoated ER70S-6 378 264 HAZ 55,225 788 61.3 - weld metal

BH210 0.67 HDGI

uncoated

HDGI

HDGICP780

DP780

780SF 2.70

2.00

2.53

BH240 0.65 HDGI

DP490 0.69 Galvanneal


Project Results

• Quality welded and brazed joints were achieved with all test materials

• The current practice consisting of mechanical, metallographic, X-ray, and

microhardness testing quantifies joint characteristics and could be used as a GMAW

and GMAB qualification procedure

• Zinc coated steels were able to be welded with average area percent porosity less than

2% using appropriate welding schedules and the test conditions used in this study

• Sheet gaps targeted at 0.1 mm were shown to minimize porosity

• Fractures occurred in the base metal, HAZ, weld metal, or near the weld fusion line,

depending on material grade and thickness

• Joint efficiency ranged from 41% (MS1700 Uncoated GMAW) to 105% (BH240 HDGI

GMAB)

• Nominal joint strength ranged from 357 MPa (BH210 HDGI GMAW) to 788 MPa

(DP1180 uncoated GMAW).


Project Results

• Of the 780 MPa tensile strength materials tested, ER100S-G filler increased nominal

joint strength for both CP780 HDGI and DP780 HDGI compared to ER70S-6 filler

• Fracture location did not necessarily correspond to the areas with the lowest

microhardness

• Fracture location may be dependent on the stress concentration at the weld root,

microhardness distribution and microstructure difference (metallurgical notch)

• For BH210 HDGI and BH240 HDGI, fracture occurred in the heat-affected zone close to

the weld for steel filler and in the base metal away from the joint for silicon bronze filler

• DP490 HDGA joints welded with steel filler fractured outside of the weld metal and

provided close to 100% joint efficiency

• For DP490 HDGA brazed with silicon bronze filler, fractures occurred in the softer braze

metal, with average joint efficiency approximately 91%

• Joint efficiency generally decreased as steel strength increased


For More Information

Richard Paul

Auto/Steel Partnership

248.875.7336

[email protected]

Min Kuo, PhD

ArcelorMittal

248.358.9245

[email protected]

gas metal arc welding of advanced high- strength steels...er cusi-a 173 111 weld 18,182 527 91.2...

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