scholarly journals Influence of Al Content on the Inclusion-Microstructure Relationship in the Heat-Affected Zone of a Steel Plate with Mg Deoxidation after High-Heat-Input Welding

Metals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 1027 ◽  
Author(s):  
Longyun Xu ◽  
Jian Yang ◽  
Ruizhi Wang
Keyword(s):  
Heat Affected Zone ◽  
Heat Input ◽  
Steel Plate ◽  
High Heat ◽  
Al Content ◽  
High Heat Input ◽  
Al Addition ◽  
Inclusions In Steel ◽  
Haz Toughness ◽  
Better Than

The effects of Al content on inclusions, microstructures, and heat-affected zone (HAZ) toughness in a steel plate with Mg deoxidation have been investigated by using simulated high-heat-input welding and an automated feature system. The studies indicated that the main kind of oxysulfide complex inclusions in two steels without and with Al addition were both MgO-MnS. The number densities and mean sizes of inclusions were 96.65 mm−2 and 3.47 μm, 95.03 mm−2 and 2.03 μm, respectively. The morphologies of MgO-MnS complex inclusions in steel were changed obviously with the addition of Al. When containing 0.001 wt.% Al, they consisted of a central single MgO particle and outside, the MnS phase. When containing 0.020 wt.% Al, they comprised several small MgO particles entrapped by the MnS phase. Because the former could nucleate intragranular acicular ferrites (IAFs) and the latter was non-nucleant, the main intragranular microstructures in HAZs were ductile IAFs and brittle ferrite side plates (FSPs), respectively. Therefore, HAZ toughness of the steel plate without Al addition after high-heat-input welding of 400 kJ/cm was significantly better than that of the steel plate with Al addition.

Effect of Mg Content on the Microstructure and Toughness of Heat-Affected Zone of Steel Plate after High Heat Input Welding

2016 ◽  
Vol 47 (7) ◽  
pp. 3354-3364 ◽  
Author(s):  
Long-Yun Xu ◽  
Jian Yang ◽  
Rui-Zhi Wang ◽  
Yu-Nan Wang ◽  
Wan-Lin Wang
Keyword(s):  
Heat Affected Zone ◽  
Heat Input ◽  
Steel Plate ◽  
High Heat ◽  
High Heat Input ◽  
Mg Content

scholarly journals Mechanism of Improving Heat-Affected Zone Toughness of Steel Plate with Mg Deoxidation after High-Heat-Input Welding

Metals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 162 ◽  
Author(s):  
Longyun Xu ◽  
Jian Yang ◽  
Joohyun Park ◽  
Hideki Ono
Keyword(s):  
Heat Input ◽  
Steel Plate ◽  
High Heat ◽  
Steel Plates ◽  
In Situ Observation ◽  
Austenite Grain ◽  
Micron Size ◽  
High Heat Input ◽  
Mg Content ◽  
Haz Toughness

In the present study, the mechanism of improving HAZ toughness of steel plate with Mg deoxidation after the simulated welding with the heat input of 400 kJ/cm was investigated through in situ observation, characterization with SEM-EDS and TEM-EDS, and thermodynamic calculation. It was found that intragranular acicular ferrite (IAF) and polygonal ferrite (PF) contributed to the improvements of HAZ toughness in steels with Mg deoxidation. With the increase of Mg content in steel, the oxide in micron size inclusion was firstly changed to MgO-Ti2O3, then to MgO with the further increase of Mg content in steel. The formation of nanoscale TiN particles was promoted more obviously with the higher Mg content in the steel. The growth rates of austenite grains at the high-temperature stage (1400~1250 °C) during the HAZ thermal cycle of steels with conventional Al deoxidation and Mg deoxidation containing 0.0027 and 0.0099 wt% Mg were 10.55, 0.89, 0.01 μm/s, respectively. It was indicated that nanoscale TiN particles formed in steel with Mg deoxidation were effective to inhibit the growth of austenite grain. The excellent HAZ toughness of steel plates after welding with a heat input of 400 kJ/cm could be obtained by control of the Mg content in steel to selectively promote the formation of IAF or retard the growth of austenite grain.

Improvement of HAZ Toughness of Steel Plate for High Heat Input Welding by Inclusion Control with Mg Deoxidation

2015 ◽  
Vol 86 (6) ◽  
pp. 619-625 ◽  
Author(s):  
Jian Yang ◽  
Longyun Xu ◽  
Kai Zhu ◽  
Ruizhi Wang ◽  
Lejun Zhou ◽  
...  
Keyword(s):  
Heat Input ◽  
Steel Plate ◽  
High Heat ◽  
High Heat Input ◽  
Inclusion Control ◽  
Haz Toughness

scholarly journals Improvement of Heat-Affected Zone Toughness of Steel Plates for High Heat Input Welding by Inclusion Control with Ca Deoxidation

Metals ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 946 ◽  
Author(s):  
Ruizhi Wang ◽  
Jian Yang ◽  
Longyun Xu
Keyword(s):  
Heat Affected Zone ◽  
Heat Input ◽  
High Heat ◽  
Steel Plates ◽  
Number Density ◽  
High Heat Input ◽  
Intragranular Acicular Ferrite ◽  
Average Size ◽  
Inclusion Control ◽  
Haz Toughness

The characteristics of inclusions and microstructure in heat-affected zones (HAZs) of steel plates with Ca deoxidation after high heat input welding of 400 kJ·cm−1 were investigated through simulated welding experiments and inclusions automatic analyzer systems. Typical inclusions in HAZs of steels containing 11 ppm and 27 ppm Ca were recognized as complex inclusions with the size in the range of 1~3 μm. They consisted of central Al2O3 and peripheral CaS + MnS with TiN distributing at the edge (Al2O3 + CaS + MnS + TiN). With increasing Ca content in steel, the average size of inclusions decreased from 2.23 to 1.46 μm, and the number density increased steadily from 33.7 to 45.0 mm−2. Al2O3 + CaS + MnS + TiN complex inclusions were potent to induce the formation of intragranular acicular ferrite (IAF). Therefore, the HAZ toughness of steel plates after high heat input welding was improved significantly by utilizing oxide metallurgy technology with Ca deoxidation.

scholarly journals Grain Refinement of Heat Affected Zone in High Heat Input Welding by Liquid Phase Pinning of Oxy-Sulfide

2015 ◽  
Vol 55 (9) ◽  
pp. 2018-2026 ◽  
Author(s):  
Takako Yamashita ◽  
Junji Shimamura ◽  
Kenji Oi ◽  
Masayasu Nagoshi ◽  
Katsunari Oikawa ◽  
...  
Keyword(s):  
Liquid Phase ◽  
Grain Refinement ◽  
Heat Affected Zone ◽  
Heat Input ◽  
High Heat ◽  
High Heat Input

High Heat Input Welding of 12Cr-6Ni-2.5Mo Supermartensitic Stainless Steel

2003 ◽  
Author(s):  
Ragnhild Aune ◽  
Hans Fostervoll ◽  
Odd Magne Akselsen
Keyword(s):  
Weld Metal ◽  
Stainless Steels ◽  
Heat Affected Zone ◽  
Heat Input ◽  
High Heat ◽  
Maximum Heat ◽  
Final Microstructure ◽  
Girth Welding ◽  
High Heat Input ◽  
Longitudinal Seam

In conventional welding of 13% Cr supermartensitic stainless steels, the normal microstructure that forms on cooling is martensite. Although high heat input tends to give a certain coarsening of the final microstructure, the eventual accompanying loss in toughness is not known. The present study was initiated to examine the effect of heat input on weld metal and heat affected zone mechanical properties of a 12Cr-6Ni-2.5Mo grade. The results obtained showed that the notch toughness is low (25 J) and independent of heat input for the weld metal, while it is reduced with increasing heat input for fusion line and the heat affected zone locations. Subsequent post weld heat treatment gave a substantial increase in toughness for all notch locations. Based on these results, indications are that a specified maximum heat input is not applicable in welding of supermartensitic stainless steels, allowing more production efficient techniques to be used, both in longitudinal seam and girth welding.

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