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Effects of heat input ratio of laser–arc hybrid weldingon welding distortion and residual stressYou-Chul Kima, Mikihito Hirohatab, Masaki Murakamic & Koutarou Inosed

a Joining and Welding Research Institute, Osaka University, Japanb Graduate School of Engineering, Nagoya University, Japanc Graduate School of Engineering, Osaka University, Japand IHI Corporation, JapanPublished online: 12 Aug 2014.

To cite this article: You-Chul Kim, Mikihito Hirohata, Masaki Murakami & Koutarou Inose (2014): Effects of heatinput ratio of laser–arc hybrid welding on welding distortion and residual stress, Welding International, DOI:10.1080/09507116.2014.921039

To link to this article: http://dx.doi.org/10.1080/09507116.2014.921039

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Effects of heat input ratio of laser–arc hybrid welding on weldingdistortion and residual stress

You-Chul Kima, Mikihito Hirohatab, Masaki Murakamic and Koutarou Inosed

aJoining and Welding Research Institute, Osaka University, Japan; bGraduate School of Engineering, Nagoya University, Japan;cGraduate School of Engineering, Osaka University, Japan; dIHI Corporation, Japan

(Received 19 April 2012; final version received 25 January 2013)

For predicting welding distortion and residual stress generated by laser–arc hybrid welding, a series of experiments andanalyses were carried out. A bead-on-plate welding was performed on SM490 steel by using a fibre laser and CO2 arcwelding by changing their heat input ratio. The experiment was simulated by thermal elastic–plastic analysis with theproposed simulation model considering the penetration shape by laser and arc separately. By using this model, theexperimental results could be simulated with high accuracy. Therefore, the validity and generality of the numericalsimulation model could be verified. The tendency and magnitude of angular distortion varied with the heat input ratio oflaser and arc. The results indicated the possibility of the ideal heat input ratio of laser and arc for controlling angulardistortion generated by hybrid welding. On the other hand, it was confirmed that the heat input ratio of laser and arc did notaffect residual stress generated by hybrid welding.

Keywords: laser–arc hybrid welding; welding distortion; control of welding distortion; residual stress; heat input ratio

1. Introduction

Research and development were carried out with the aim

of increasing the fatigue strength of high-strength steel

(HT780, HT980) and to ensure welded joints of high

quality. There was an active investigation of laser welding,

principally the laser beam [1,2].

Comparison of laser welding and previous arc welding

shows differences in heat input and welding speed. For

these reasons, laser welding is used for general structural

steel resulting in a significant inhibition of welding

distortion and residual stress [3]. It has been noted, on the

other hand, that although laser welding achieves high-

quality joints, the root gap requires extremely rigorous

management. Currently, the use of laser–arc hybrid

welding is regarded as a promising technique in terms of

improvements in workability due to its greater root gap

tolerance [4,5].

With laser–arc hybrid welding, two heat sources –

laser and arc – are used together.

In this article, laser–arc hybrid welding tests [6] were

performed on standard structural SM490, and the

experiment was simulated by thermal elastic–plastic

analysis. A heat input model was also constructed for the

prediction of the distortion and residual stress caused by

laser–arc hybrid welding and its validity shown. The

validated heat input model was used in the experimental

simulations in which the heat input ratio between the heat

inputs of arc and laser was varied for comparison. The

general validity of the heat input model thus constructed

was verified by this. The effects of differences in this

heat input ratio on welding distortion and residual stress

were considered during one-pass laser–arc hybrid butt

welding.

2. Experiment

2.1 Experimental methods and materials

The shape and dimensions of the test specimens are shown

in Figure 1.

In order to obtain with high accuracy the welding

distortion and residual stress caused by butt welding, it is

necessary to fabricate test specimens in which no

irregularity etc. is caused by tack welding. The present

authors have previously proposed a test specimen for use

in high-precision prediction of out-of-plane distortion in

arc welding [7] and have improved this for use in laser–

arc hybrid welding, a 0.1-mm-wide I groove being made in

the centre of such specimens by electrical discharge

machining.

The chemical composition and mechanical properties

of the specimen steel (SM490, sheet thickness 7mm) are

shown in Table 1.

Hybrid welding was carried out by joint use of fibre

laser and CO2 arc laser, with the arc used first. The welding

wire used was commercially available 490MPa wire.

Here, the laser–arc hybrid welding simulation model

described below, that is a heat input model which

individually handles the two heat sources used in the

hybrid welding, was constructed and validated, and an

attempt was made to verify its general validity. For this,

the experimental specimens were made for three sets of

welding conditions, with different heat input ratios

between laser and arc [6].

The welding conditions are shown in Table 2.

The specimen with a heat input ratio between laser and

arc of approximately 5:5 was taken as the basic specimen,

one with a ratio of approximately 7:3 as the laser emphasis

q 2014 Taylor & Francis

†Presented at the Spring National Conference 2012.

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(LE) specimen and of approximately 3:7 was taken as the

arc emphasis (AE) specimen. The basic specimen was

used to verify the construction and validity of the heat

input model, and the LE and AE specimens to verify the

general validity of the constructed heat input model.

Cross-sectional macrographs were obtained after the

completion of welding and the penetration shape

confirmed and an experimental simulation grid, based on

this, was prepared by thermal elastic–plastic analysis [8].

Thermocouples were attached at four locations

(y ¼ 15, 30, 50, 80mm) at the centre (x ¼ 10mm) of the

weld line direction on the specimen surface (z ¼ 7mm)

and the temperature history was measured. Due to the

hybrid welder, it was not possible to measure the

temperature near the weld line (y , 15mm).

After welding was completed, the weld out-of-plane

distortion was measured, twin axis strain gauges (gauge

length: 1mm) were attached at 11 locations (y ¼ 0, ^ 12,

^ 30, ^ 50, ^ 80, ^ 130mm) near the centre of the

specimen (x ¼ 20mm) along two axes on the specimen

surface (z ¼ 0, 7), and the residual stress was found by the

stress relaxation method. In the stress relaxation method,

slitting was performed with a target side length of 13–

15mm, and the relaxation strain accompanying slitting

was measured.

2.2 Experimental results

2.2.1 Cross-sectional macrographs

Figure 2 shows cross-sectional macrographs (at

x ¼ 10mm).

It could be confirmed that in all the specimens, there

was complete penetration welding after 1 pass. The weld

bead differed in shape according to the heat input ratio

between laser and arc. In the basic specimen (Figure 2(a)),

in which the laser–arc heat input ratio was 5:5, the sizes of

the reinforcements above and below the sheet were

approximately equivalent. By contrast, in the LE specimen

(Figure 2(b)), in which the laser–arc heat input ratio is 7:3,

the reinforcement produced by the laser below was large

and that produced by the arc above is barely visible. By

contrast, in the AE specimen (Figure 2(c)), in which the

laser–arc heat input ratio is 3:7, the reinforcement

produced by the laser below is reduced and the

reinforcement produced by the arc above is extremely

Figure 1. Test specimen.

Table 1. Chemical compositions and mechanical properties.

Chemicalcompositions(mass %)

Mechanicalproperties

C Si Mn P S

Yieldstress(MPa)

Tensilestrength(MPa)

0.17 0.40 1.41 0.015 0.004 436 535

Table 2. Welding conditions.

Specimen

Energy(kW)

Speed(m/min)

Heat input (J/mm)

Laser Arc QL: laser QA: arc QT: total

Basic 4.8 4.4 1.0 290 265 555LE 6.8 2.8 410 290 700AE 2.9 6.7 173 403 576

(c) A.E. specimenL.E. specimenBasic specimen

(a) (b) (c)

Figure 2. Macrographs (x ¼ 10mm).

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large. It is clear from these that the bead shape is greatly

affected by the heat input ratio.

2.2.2 Weld out-of-plane distortion

Welding out-of-plane distortion is shown in Figure 3.

The direction and size of angular distortion (Figure 3

(a)) is dependent on the degree of contraction of the upper

and lower surfaces of the sheet in respect of the thickness

centre of the sheet, that is the quantity of the weld metal.

The angular distortion of the basic specimen (j) is V-

shaped and the absolute value is approximately 0.28mm.

By contrast, the angular distortion of the LE specimen (e)

is inverted V-shaped and the absolute value is approxi-

mately 0.52mm. The angular distortion of the AE

specimen (A) is V-shaped and the absolute value is

approximately 1.9mm, the greatest angular distortion of

the three samples. On the other hand, the absolute value of

the longitudinal bending distortion of all of the samples

(Figure 3(b)) is very small.

2.2.3 Residual stress

The welding residual stress found by the stress relaxation

method is shown in Figure 4.

The sheets were thin and the welding residual stresses

found at the upper and lower surfaces were approximately

equal. Because of this, the average value for welding

residual stresses at the upper and lower surfaces is given.

For the residual stress of the weld metal part (y ¼ 0mm), a

strain gauge was attached after reinforcement removal.

Considering Figure 4(a), in the case of the stress

component along the weld line sx, the distribution of the

residual stress created in the three specimens is

approximately the same, but the absolute values for the

weld metal parts differed slightly creating a tensile stress

of 330–390MPa. To balance this tensile stress, a

compressive stress of 30–40MPa is created in the base

metal.

Considering Figure 4(b), in the case of the stress

component perpendicular to the weld line sy, as for sx, the

distribution of the residual stress created in the three

specimens is approximately the same, the absolute values

for the weld metal parts being somewhat different and

tensile stress of 60–110MPa created.

When the total heat inputs are approximately the same,

no differences in the distribution of the residual stresses

produced are evident even if the laser–arc heat input ratios

are different, but the absolute values for the weld metal are

somewhat different.

Figure 3. Welding out-of-plane distortion.

Figure 4. Welding residual stress.

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3. The construction of hybrid welding simulation

models and their validity and generality

A numerical simulation model was constructed for laser–

arc hybrid welding and its validity and generality were

verified. Analysis models for Basic, LE andAE are referred

to below as the basic model, the LE model and AE model.

3.1 The construction of a heat input simulation modeland its validation

A heat input model was constructed for the basic specimen

and its validity was shown.

A heat input model prepared on the basis of a cross-

sectional macro is shown in Figure 5.

An eight-node isoparametric grid element was used for

the thermal plastic–elastic analysis. Here, in consideration

of symmetry, a half model was used. The element was

divided with reference to the penetration shape (weld metal

part) obtained from the cross-sectional macro (Figure 2(a)).

For thermal conduction analysis, the element of the

penetration shape made by the laser corresponding to the

heat input by the laser (qL (J/mm3)) and the element of the

penetration shape made by the arc corresponding to the

quantity of the heat input by the arc (qA (J/mm3)) were

projected. As shown in Table 2, the heat input quantities

for the unit QL and QA to the specimen per unit length of

welding (J/mm) in the specimens by the laser and the arc

were found by dividing qL and qA (J/mm3) by the surface

area of the penetration. It is not easy to determine these

clearly for the region where the laser and arc overlap

(outlined in red in Figure 5; see http://dx.doi.org/10.1080/

09507116.2014.921039 for colour version of figures).

Because of this, the shape of the region on the upper

surface where it is mainly the arc and the shape of the

region on the lower surface where it is mainly the laser is

extrapolated by the lines and the area where these overlap

were taken as the regions where the heat sources overlap.

For the physical constants and the temperature

dependence of the mechanical properties of the materials

used for the analysis, please see [8].

3.1.1 Temperature history

Using the heat input model, a temperature history was

found by repeating the non-steady heat conduction

analysis so that the temperature history obtained

experimentally could be reproduced accurately. This is

shown in Figure 6. The thermal efficiency of the laser and

arc used in the analysis is h ¼ 0.7.

The experimental results are shown by the symbols,

and the analysis results are shown by solid lines which

reproduce the experimental results with great accuracy.

3.1.2 Welding distortion

The experiments were simulated by thermal plastic–

elastic analysis, using the temperature histories obtained

by non-steady heat conduction analysis.

The results of the analysis of angular distortion and

longitudinal bending distortion are shown in Figure 7. The

experimental results (as symbols) are shown in the figure.

In the case of angular distortion (Figure 7(a)), the

analysis results accurately reproduce the experimental

Figure 6. Temperature histories (basic model).

Figure 5. Model for thermal elastic–plastic analysis (basic model).

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results. The analysis results for longitudinal bending

distortion (Figure 7(b)) also reproduce the experimental

results with great accuracy.

3.1.3 Residual stress

The residual stress obtained by analysis is shown in

Figure 8. The previous experimental results (as symbols)

are shown in the figure. As with the experimental results,

the analytical results for residual stress are the average

values of the upper and lower surfaces.

The stress component along the weld line: sx (Figure 8

(a)) is discussed first.

The analysis results for the weld metal (y ¼ 0mm) are

approximately 1.4-fold the experimental results but when

the mean stress in the element corresponding to the test

specimen (15 £ 15mm2) used in the strain relaxation

measurement was found, the analysis results were

approximately 1.1-fold the experimental results. In the

case of the base metal (y % 30, y ^ 30mm), the analysis

results matched the experimental results with great

accuracy.

In the case of the component perpendicular to the weld

line: sy (Figure 8(b)), the analysis results accurately

matched the experimental results.

The heat input model constructed for this study

showed validity when used for laser–arc hybrid welding.

Its generality is verified in the next section.

3.2 Verification of the generality of the hybrid heatinput model

A heat input model, as constructed in Section 3.1 for use

with the basic specimen, was prepared by the same

procedures, and the experiments with the LE and AE

specimens were simulated. The generality of the heat input

model constructed for laser–arc hybrid welding was

verified.

Figure 9 shows the heat input model prepared on the

basis of the cross-sectional macrographs of LE and AE

specimens (Figure 2(b),(c)).

3.2.1 Temperature histories

The temperature histories obtained by non-steady heat

conduction analysis are shown in Figure 10.

As in the case of the basic model (Figure 6), the

analysis results for the LE model (Figure 10(a)) and AE

model (Figure 10(b)) reproduce the experimental results

(symbols) with great accuracy.

Figure 7. Welding out-of-plane distortion obtained by analysis of basic model.

Figure 8. Welding residual stress obtained by analysis of basic model.

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3.2.2 Welding distortion

Thermal elastic–plastic stress analysis was performed

using the temperature histories obtained by non-steady

heat conduction analysis.

The analysis results and experimental results (sym-

bols) for angular distortion and longitudinal bending

distortion are shown in Figure 11.

In the case of angular distortion (Figure 11(a)), the

analysis results reproduce the experimental results with

great accuracy. In the case of longitudinal bending

distortion (Figure 11(b)), on the other hand, although the

analysis results for the LE model reproduce the

experimental results with great accuracy, the analysis

results for the AE model are slightly greater than the

Figure 9. Models for thermal elastic–plastic analysis (LE and AE models).

Figure 10. Temperature histories (LE and AE models).

Figure 11. Welding out-of-plane distortion obtained by analyses of LE and AE models.

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experimental results. However, the absolute values are

extremely small.

3.2.3 Residual stress

The residual stress obtained by analysis and the

experimental results are shown in Figure 12. The residual

stress is the average of the upper and lower surfaces.

As in the basic model (Figure 8), the analysis results

for the component along the weld line: sx (Figure 12(a))

and the component perpendicular to the weld line: sy

(Figure 12(b)) in both the LE and AE models could

reproduce the experimental results with great accuracy.

As described above, the heat input model constructed

using the basis model was applied to the LE model and AE

model, and the experiment was simulated by thermal

elastic–plastic analysis. The temperature history welding

distortion and residual stress thus obtained reproduced the

experimental results with great accuracy and the generality

of the heat input model was verified.

4. Effect of the hybrid welding heat input ratio on

welding distortion and residual stress

It is clear from the results of the experiments and analysis

that the welding distortion caused by hybrid welding,

especially angular distortion, is changed greatly by the

heat input ratio between the laser and arc. Here, the effect

of the laser–arc heat input ratio on welding distortion and

residual stress is taken into consideration.

4.1 Effect of heat input ratio on welding distortion

It is known that, during arc welding, V-shaped angular

distortion occurs due to the temperature gradient in the

sheet thickness direction and for the size, can be adjusted

by the heat input parameter (Q/t 2), which is the heat input

per unit of weld length (Q) divided by the square of the

sheet thickness (t) [9]. Figure 13 shows adjustment of

angular distortion in laser–arc hybrid welding by this heat

input parameter (Q/t 2).

Laser/arc hybrid welding in which two heat sources are

used together has characteristics that are greatly different

from those when a single heat source is used. Because of

this, the size of the angular distortion produced seems not

to be adjustable by the above parameter. It seems to be

necessary to take the differences between the heat inputs

from the individual heat sources into account to adjust the

tendency and size of the angular distortion caused by

hybrid welding.

In the case of penetration due to hybrid welding, the

subject of this study, penetration at the upper surface due

to the arc is shallow but extensive, whereas penetration at

the lower surface due to the laser is deep but narrow.

Because of this, it was considered likely that the laser–arc

heat input ratio QL/QAwould be a simple index to express

the difference between the heat inputs at the upper and

lower surfaces.

The relationship between the laser–arc heat input ratio

QL/QA and angular distortion is shown in Figure 14.

A clear correlation can be observed between the laser–

arc heat input ratio: QL/QA and angular distortion. This

Figure 12. Welding residual stress obtained by analyses of LE and AE models.

Figure 13. Relationship between heat input parameter andangular distortion.

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indicates the possibility of performing ideal welding, with

no angular distortion, by controlling the individual heat

inputs.

4.2 Effects of heat input ratio on residual stress

When laser–arc hybrid welding is carried out, the weld

metal part on the arc side is different from that on the laser

side due to the heat input ratio (Figure 2). This means that

the degrees of contraction are also different due to the heat

input ratio. The weld line stress component, on the other

hand, is produced due to the contraction in the weld line

direction being inhibited [10]. The differences in the

absolute values of weld line stress components sx of the

weld metal parts of the three models are due to this.

In one-pass laser–arc hybrid butt welding, the

distribution of the resultant weld residual stress is largely

unaffected by the heat input ratio when the total heat

inputs are approximately the same, but the sizes are

somewhat affected and the absolute values for the weld

metal are somewhat different.

5. Conclusions

Experiments were first performed for the prediction of

distortion and residual stress produced by laser–arc hybrid

welding. Next, the construction of a hybrid welding heat

input model was attempted, based on the experimental

results for the basic model and the validity of the heat input

model thus constructed was shown. Next, the heat input

model thus constructed was applied to the LE and AE

models and the generality of the heat input model verified.

The effects of the heat input ratio of the laser and the arc on

welding distortion and residual stress were considered.

The principal findings were as follows.

As a result of hybrid welding tests with a fibre laser and

CO2 arc welding (arc first) conducted on 7-mm-thick

SM490 steel sheet:

(1) The tendency and size of angular distortion were

changed variously by the laser–arc heat input

ratio. When the arc heat input dominated, the

angular distortion was a V-shape and the absolute

value was approximately 2mm. When, on the

other hand, the laser heat input dominated, the

angular distortion was an inverse V-shape and the

absolute value was approximately 0.5mm. When

the two heat sources are approximately the same,

the angular distortion was approximately 0.2mm,

which is very small. The longitudinal bend

distortion was very small, whatever the laser–arc

heat input ratio.

(2) Although there was no evident difference in the

distribution of the residual stress produced when

the total heat inputs were approximately the same,

even when the laser–arc heat input ratios differed,

the absolute values for the weld metal part were

slightly different. The weld line stress component

was such that a tensile stress of 330–390MPa

occurred in the weld metal part and compressive

stress of 30–40MPa occurred in the base metal.

The stress component perpendicular to the weld

direction was such that tensile stress of 60–

110MPa occurs in the weld metal.

A heat input model was constructed for laser–arc

hybrid welding, in which two heat sources are used

together, and its validity and generality were verified. The

results of this were:

(3) A heat input model was constructed for the basic

specimen, and using this the experiment was

simulated by thermal elastic–plastic analysis. The

temperature histories, welding distortion and

residual stress found experimentally were com-

pared with the analysis results, and the validity of

the constructed heat input model was shown.

(4) The heat input model constructed for the basic

model was applied to LE model and AE model

and the generality of the constructed heat input

model was shown.

The effect of the laser–arc heat input ratio during

hybrid welding on angular distortion and residual stress

were considered and the results were:

(5) It was found that, during laser–arc hybrid butt

welding, the laser–arc heat input ratio had a major

effect on the angular distortion produced. This

indicates the possibility of performing ideal

welding, with no angular distortion, by controlling

the heat input ratio.

(6) When the total heat inputs are nearly the same, the

distribution of the weld residual stress produced is

unaffected by the heat input ratio, but the size is

slightly affected and the absolute values for the

weld metal parts are slightly different.

References

1. Hirohata M, Inose K, Kim Y-C. Fatigue characteristics ofjoints of high strength steel welded by laser beam. Prepr NatlMeet JWS. 2009;84:198–199 (in Japanese).

Figure 14. Relationship between heat input ratio and angulardistortion.

Y.-C. Kim et al.8

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2. Hirohata M, Yanamoto K, Inose K, Kim Y-C. Propagation of

fatigue crack in laser beam welded joints of high strength

steel. Prepr Natl Meet JWS. 2009;85:162–163 (in Japanese).

3. Inose K, Lee J-Y, Nakanishi Y, Kim Y-C. Characteristics of

welding distortion and residual stress generated by fillet

welding with laser beam and verification of generality of its

high accurate prediction. Q J Japan Weld Soc. 2008;26

(1):61–66 (in Japanese).

4 Kim Y-C, Hirohata M, Mutyaba G, Inose K. Fatigue

characteristics of HT780 welded joints by Laser–arc hybrid

welding. PreprNatlMeet JWS. 2011;89:212–213 (in Japanese).

5. Kim Y-C, Hirohata M, Yamamoto K, Inose K. Welding

distortion and residual stress generated by laser–arc hybrid

welding for high strength steel. Q J Japan Weld Soc. 2011;29

(3):234–240 (in Japanese).

6. Inose K, Abe D, Matsumoto N, Ohwaki K. Effect of laser–arc hybrid welding condition for welded joint properties.Prepr Natl Meet JWS. 2011;88:108 (in Japanese).

7. Kim Y-C, Lee J-Y, Sawada M, Inose K. Verification ofvalidity and generality of dominant factors in high accurateprediction of welding distortion. Q J Japan Weld Soc.2007;25(3):450–454 (in Japanese).

8. Kim Y-C, Lee J-Y, Inose K. High accurate prediction ofwelding distortion generated by fillet welding. Q J JapanWeld Soc. 2005;23(3):431–435 (in Japanese).

9. Satoh K, Terasaki T. Effect of welding conditions onwelding deformations in welded structural materials. J JapanWeld Soc. 1976;45(4):54–60 (in Japanese).

10. Kim Y-C. Distortion and residual stress caused by weldingand joining. Weld Eng Summ School Mater.2004;2004:37–50 (in Japanese).

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