Microstructure Evolution and Toughness Variation of Simulation HAZ with Large Heat Input Welding for E40 Ship Plate Steel

The Gleeble3500 combined with SEM, TEM and other experimental methods are employed in this paper to investigate the effects of zirconium content on impact toughness of heat affected zone (HAZ) of hull structure steel plate during the large heat input welding. The results showed when 0.01% zirconium were added in the steel, the impact energy reached 224 J at-60°C experienced 150 kJ/cm welding heat input. But the large-size rectangular inclusions are found in CGHAZ when 0.02% zirconium were added in the steel, the impact energy fell to 38 J at-60°C experienced 150 kJ/cm welding heat input, the large-size inclusions, especially rectangular inclusion, were the main cause for the sharp decline of low temperature toughness after welding.

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On Fracture Toughness at Heat Affected Zones for Large Heat Input Welding of Electric Arc Furnace Steels including Much Tramp Elements and Nitrogen

QUARTERLY JOURNAL OF THE JAPAN WELDING SOCIETY ◽

10.2207/qjjws.26.137 ◽

2008 ◽

Vol 26 (2) ◽

pp. 137-144

Author(s):

Toshiomi ITATANI ◽

Tadao NAKAGOMI

Keyword(s):

Fracture Toughness ◽

Heat Input ◽

Electric Arc Furnace ◽

Electric Arc ◽

Arc Furnace ◽

Large Heat

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Effect of Nb Content on the Impact Toughness of Coarse-Grained Heat-Affected Zone of Pipeline Steels under Large Heat Input

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1078.3 ◽

2014 ◽

Vol 1078 ◽

pp. 3-7

Author(s):

Feng Zhou ◽

Zhou Gao ◽

Kai Ming Wu

Keyword(s):

Heat Affected Zone ◽

Heat Input ◽

Optical Microscope ◽

Coarse Grained ◽

Electron Backscattered Diffraction ◽

Pipeline Steels ◽

Nb Content ◽

Large Heat ◽

Austenite Grains ◽

The Impact

The effect of large heat inputs (200 kJ/cm) on the microstructures and toughness of heat-affected zone of Nb microalloyed X70 pipeline steels were simulated utilizing Gleeble-3800. The microstructures were observed by optical microscope, scanning electron microscope and electron backscattered diffraction technique. Results showed that when the large heat input welding was applied, big austenite grains and coarse microstructures were formed in the coarse-grained heat-affected zone, and thus the toughness of the coarse-grained heat-affected zone was seriously reduced. With the increase of Nb content, the toughness of the CGHAZ did not change remarkably under the large heat input welding.

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Microstructure and Properties of Grade 700MPa Pressure Vessel Steel with Large Heat Input Welding

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.182-183.1537 ◽

2012 ◽

Vol 182-183 ◽

pp. 1537-1540

Author(s):

Qing Feng Ding ◽

Tian Sheng Wang ◽

Wen Yan Liu ◽

Xian Jun Wang ◽

Wen Bin Liu ◽

...

Keyword(s):

Impact Energy ◽

Heat Input ◽

High Heat ◽

Pressure Vessel Steel ◽

Vessel Steel ◽

Microstructure And Properties ◽

Technical Requirements ◽

High Heat Input ◽

Large Heat ◽

Haz Toughness

The microstructure and properties of grade 700MPa steel with large heat input welding and its heat affected zone (HAZ) were investigated by use of the metallography, scanning electron microscopy, mechanical testing and welding thermal simulation. The results showed that the mechanical properties of the steel meet the technical requirements, namely the yield strength ReL≥570 MPa, the tensile strength 685MPa≤Rm≤830MPa, the elongation A≥17%, the -20°C impact energy KV2≥54J and the -20°C impact energy of HAZ≥47J. The steel also had good match between strength, toughness and anti-high heat input welding, the microstructure was tempered sorbite with small dispersed composite inclusions, which promoted the formation of acicular ferrite and were beneficial to the improvement of HAZ toughness.

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