Characteristics of Welds of High Strength Steel Sheets with Ultra-fine Grained Microstructure Welded by Resistance Spot Heating Method.

Otani, Tadayuki; Sasabe, Ken; Shiga, Chiaki; Nagashima, Nobuo

doi:10.2207/qjjws.20.114

Cited by 3 publications

(4 citation statements)

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“…( 4)-( 6) is that R m nugget and HV nugget are measurable but hardly predictable in the planning stage. Some models are developed for their prediction (e.g., [16][17][18][19][20][21]), mostly based on the chemical composition of the base material, but their usage is limited to selected steel groups. Kuo and Chiang [22] investigated steel grades in 400 MPa < R m < 1000 MPa strength range, and for interfacial fracture they proposed a correlation; where STS is proportional with the weld nugget size, the hardness ratio between nugget and base material ( Hard.…”

Section: S D Hvmentioning

confidence: 99%

Global Approach on the Shear and Cross Tension Strength of Resistance Spot Welded Thin Steel Sheets

Májlinger,

Katula,

Varbai

2023

Period. Polytech. Mech. Eng.

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Several correlations from the professional literature describing the shear and cross tension strength (STS and CTS) of resistance spot welded (RSWed) thin steel sheets were investigated. Some of them need chemical composition or weld nuggets strength hardness as input parameters, making them hardly applicable in the planning stage of the joints. Using STS and CTS data collected from over 250 papers, selected correlations were tested, whether they are applicable to predict the STS and CTS of the RSWed joints at the planning stage to help designers plan their static-loaded welds strength. Most correlations had limitations in the applicable base materials' tensile strength range. Therefore, new equations for STS and CTS are proposed, which can be used to plan in the 300–18900 MPa base metals tensile strength range for similar and dissimilar RSWed joints of thin steel sheets.

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Section: S D Hvmentioning

confidence: 99%

Global Approach on the Shear and Cross Tension Strength of Resistance Spot Welded Thin Steel Sheets

Májlinger,

Katula,

Varbai

2023

Period. Polytech. Mech. Eng.

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“…This means that the grain coarsening in hyper-interfacial bonding is depressed compared with other fusion welding processes. According to previous reports, [5][6][7] the grain coarsening and softening in HAZ of fusion welded and spot welded joints are almost inevitable as a result of the high weld heat input. From these results, it is suggested that the hyperinterfacial bonding technique developed in the present study is one of the most advanced bonding techniques for UFG steels, able to depress grain growth in the joint sufficiently and to suppress thermal damage (softening) of base metal with fine-grained structure.…”

Section: Microstructural Characteristics Of Hyper-interfacial Bondingmentioning

confidence: 99%

“…On the other hand, the applicability of some welding techniques to UFG steel joining has been investigated. [3][4][5][6][7] The weldability of UFG steel for conventional arc welding and laser welding is generally excellent. However, the material properties of the heat affected zone (HAZ) in UFG steel weldments are poorer than the base metal as a result of grain coarsening and softening by weld heat input.…”

Section: Introductionmentioning

confidence: 99%

“…Some researchers have tried to control the softening in HAZ by ultra-narrow gap welding, 5 CO 2 laser welding 6 and resistance spot welding. 7 However, the softening in HAZ cannot be prevented completely. From this background, a new conceptual bonding technique which does not harm the properties of the HAZ and weld metal must be established for joining UFG steels.…”

Section: Introductionmentioning

confidence: 99%

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Development of hyper-interfacial bonding technique for ultra-fine grained steels and microstructural analysis of bonded joints

Saida¹,

Jeong²,

Nishimoto³

2004

Science and Technology of Welding and Joining

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A new conceptual bonding technique, 'hyper-interfacial bonding' has been proposed as the most effective bonding technique for ultra-fine grained steels. The hyper-interfacial bonding process was characterised by instantaneous surface-melted pressure bonding which involved a series of steps, namely surface heating by high frequency induction, rapid removal of a heating coil and simultaneously pressing specimens together with an oil pressure system. All sequences were typically completed within 1 s under a vacuum/gas atmosphere. Ultra-fine grained high strength steels with an average grain size of 1 . 0-1 . 5 mm were used for bonding. The surface of the specimen could be rapidly heated up and melted within about 0 . 2 s. No voids existed on the bond interface and primary ferritic phase was formed at the bond interface. A bainitic structure and martensite-austenite constituents were confirmed in the heat affected zone (HAZ), while the base metal indicated a fine ferrite-pearlite texture. The hardened area was limited to the higher temperature region in the HAZ (the maximum hardness was 320-400 HV) and softening did not occur in the HAZ. Prior austenitic grains were coarsened in the vicinity of the bond interface, however, grain growth in the bond layer could be depressed below about 11-16 mm. It could be concluded that the hyper-interfacial bonding technique is a feasible joining method for ultra finegrained steels.STWJ/456

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Characteristics of the heat-affected zone in ultra-fine grained steel during ultra-narrow gap GMA welding. Softening zone and microstructures of the heat-affected zone in ultra-fine grained steel

Ito¹,

Hiraoka²,

Shiga³

2005

Welding International

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Characteristics of Welds of High Strength Steel Sheets with Ultra-fine Grained Microstructure Welded by Resistance Spot Heating Method.

Cited by 3 publications

References 1 publication

Global Approach on the Shear and Cross Tension Strength of Resistance Spot Welded Thin Steel Sheets

Global Approach on the Shear and Cross Tension Strength of Resistance Spot Welded Thin Steel Sheets

Development of hyper-interfacial bonding technique for ultra-fine grained steels and microstructural analysis of bonded joints

Characteristics of the heat-affected zone in ultra-fine grained steel during ultra-narrow gap GMA welding. Softening zone and microstructures of the heat-affected zone in ultra-fine grained steel

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