Underwater local dry cavity laser welding of 304 stainless steel

Guo, Ning; Fu, Yunlong; Xing, Xiao Ming; Liu, Yangkun; Zhao, Sixiang; Feng, Jicai

doi:10.1016/j.jmatprotec.2018.05.025

Cited by 41 publications

(13 citation statements)

References 19 publications

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“…Damaged areas can be located under the water surface, which determines the necessity of repairs in water conditions. There are three methods of underwater welding [20][21][22][23]:…”

Section: Introductionmentioning

confidence: 99%

Underwater In Situ Local Heat Treatment by Additional Stitches for Improving the Weldability of Steel

Tomków

Janeczek

2020

Applied Sciences

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In this paper the influence of in situ local heat treatment performed by additional stitches on the weldability of high-strength low-alloy (HSLA) S355J2C+N steel was tested. The investigated steel is characterized by high susceptibility to cold cracking. It is necessary to find a method to improve the quality of welded joints. The local heat treatment was applied as an effect of bead-on plate welding made on the face of a Tekken test joint. The specimens were made by the use of covered electrodes in the water environment. For testing weldability, Tekken test specimens were made. Then, the different number of the pad welds with different overlapping were laid on the face of the tested welds. Non-destructive (NDT) visual and penetrant tests were undertaken. During the NDT, imperfections like shape mistakes and spatters were found. Then, metallographic macro- and microscopic testing were performed. The macroscopic observations proved that water environment can generate imperfections like cracking and pores. However, for specimens with additional stitches the number of imperfections decreased. Microscopic tests proved that the proposed technique affected the structure of the heat-affected zone (HAZ). The specimens without the application of additional stitches are characterized by brittle bainitic and martensitic structure. Specimens, in which the additional stitches were applied, contain tempered martensite, fine ferrite and fine pearlite in their HAZ. It was also observed that the number of cracks decreased for in situ local heat-treatment specimens. The final step was Vickers HV10 hardness measurement. These measurements confirmed previous results. The heat from additional stitches affected the steel by significantly decreasing the hardness by 80–100 HV10. The results of experiments showed that the heat from pad welds provided microstructural changes in heat-affected zones and a decrease in the susceptibility to cold cracking, which results in improvement in the weldability of HSLA steel in wet welding conditions.

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“…Damaged areas can be located under the water surface, which determines the necessity of repairs in water conditions. There are three methods of underwater welding [20][21][22][23]:…”

Section: Introductionmentioning

confidence: 99%

Underwater In Situ Local Heat Treatment by Additional Stitches for Improving the Weldability of Steel

Tomków

Janeczek

2020

Applied Sciences

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“…Pessoa et al indicated the porosity formed owing to water vapor, molecular hydrogen, or carbon monoxide during UWW [11]. In comparison to underwater arc welding (UAW), ULBW has some significant advantages, for instance, more convenience, precise heat input, and a completely automatic welding process [12]. Shannon et al investigated the direct ULBW, the result indicated that the Nd:YAG laser was unfeasible, while the CO 2 laser was suitable for direct ULBW [13].…”

Section: Introductionmentioning

confidence: 99%

“…Zhang et al studied the influence of shielding conditions and optical signals on the quality of weld metals during ULBW, respectively [17,18]. Guo et al indicated that the high-quality welded joints of ULBW were obtained under appropriate welding parameters by using a double-layer gas curtain nozzle [12].…”

Section: Introductionmentioning

confidence: 99%

Microstructure and Mechanical Properties of Underwater Laser Welding of Titanium Alloy

et al. 2019

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Underwater laser beam welding (ULBW) with filler wire was applied to Ti-6Al-4V alloy. Process parameters including the back shielding gas flow rate (BSGFR) (the amount of protective gas flowing over the back of the workpiece per unit time), focal position, and laser power were investigated to obtain a high-quality butt joint. The results showed that the increase of BSGFR could obtain the slighter oxidation level and refiner crystal grain in the welded metals. Whereas the back shielding gas at a flow rate of 35 L/min resulting in pores in the welded metals. With the increasing of the heat input, the welded metals went through three stages, i.e., not full penetration, crystal grain refinement, and coarseness. Crystal grain refinement could improve the mechanical properties, however, not full penetration and pores led to the decline in mechanical properties. Under optimal process parameters, the microstructure in the fusion zones of the underwater and in-air weld metals was acicular martensite. The near the fusion zone of the underwater and in-air weld metals consisted of the α + α′ phase, but almost without the α′ phase in the near base metal zone. The tensile strength and impact toughness of the underwater welded joints were 852.81 MPa and 39.07 J/cm2, respectively, which approached to those of the in-air welded joints (861.32 MPa and 38.99 J/cm2).

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“…The investigations showed that the method could be used for cladding layers on the surface of AISI 304 steel. The same material was chosen for investigations by Guo et al [30]. The authors proposed underwater local cavity laser welding.…”

Section: Introductionmentioning

confidence: 99%

Underwater Local Cavity Welding of S460N Steel

et al. 2020

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In this paper, a comparison of the mechanical properties of high-strength low-alloy S460N steel welded joints is presented. The welded joints were made by the gas metal arc welding (GMAW) process in the air environment and water, by the local cavity welding method. Welded joints were tested following the EN ISO 15614-1:2017 standard. After welding, the non-destructive—visual, penetrant, radiographic, and ultrasonic (phased array) tests were performed. In the next step, the destructive tests, as static tensile-, bending-, impact- metallographic (macroscopic and microscopic) tests, and Vickers HV10 measurements were made. The influence of weld porosity on the mechanical properties of the tested joints was also assessed. The performed tests showed that the tensile strength of the joints manufactured in water (567 MPa) could be similar to the air welded joint (570 MPa). The standard deviations from the measurements were—47 MPa in water and 33 MPa in the air. However, it was also stated that in the case of a complex state of stress, for example, bending, torsional and tensile stresses, the welding imperfections (e.g., pores) significantly decrease the properties of the welded joint. In areas characterized by porosity the tensile strength decreased to 503 MPa. Significant differences were observed for bending tests. During the bending of the underwater welded joint, a smaller bending angle broke the specimen than was the case during the air welded joint bending. Also, the toughness and hardness of joints obtained in both environments were different. The minimum toughness for specimens welded in water was 49 J (in the area characterized by high porosity) and in the air it was 125 J (with a standard deviation of 23 J). The hardness in the heat-affected zone (HAZ) for the underwater joint in the non-tempered area was above 400 HV10 (with a standard deviation of 37 HV10) and for the air joint below 300 HV10 (with a standard deviation of 17 HV10). The performed investigations showed the behavior of S460N steel, which is characterized by a high value of carbon equivalent (CeIIW) 0.464%, during local cavity welding.

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Underwater local dry cavity laser welding of 304 stainless steel

Cited by 41 publications

References 19 publications

Underwater In Situ Local Heat Treatment by Additional Stitches for Improving the Weldability of Steel

Underwater In Situ Local Heat Treatment by Additional Stitches for Improving the Weldability of Steel

Microstructure and Mechanical Properties of Underwater Laser Welding of Titanium Alloy

Underwater Local Cavity Welding of S460N Steel

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