The microstructure evolution and microhardness of Fe–Mn–Al–C steel heat-affected zone (HAZ) were investigated systematically using the weld thermal simulation technique. The results illustrated that the microstructure in HAZ with different peak temperatures (600, 800, 1000 and 1300°C) and heat inputs (10, 20 and 30 kJ cm–1) mainly consisted of ferrite and austenite. When the peak temperature was 1300°C, there are many high-angle grain boundaries which may inhibit crack propagation. With the increase in heat input, κappa carbide precipitation increased, the grain size became finer and microhardness increased. The microhardness was 438 HV when the peak temperature was 1300°C at 30 kJ cm–1.
Highlights
The welding of high carbon, high aluminium and low-density steel was simulated.
The HAZ was composed of austenite and a small amount of high-temperature δ-ferrite.
The proportion of high- and low-angle grain boundaries has a great influence on the mechanical properties.
The welding heat input was 30 kJ cm–1, the grain size of the HAZ decreased and microhardness was the largest.
HowellRAVan AkenDC.A literature review of age hardening Fe-Mn-Al-C alloys[J]. Iron Steel Tech. 2009;6:193–212.
2.
KimHSuhDWKimNJ.Fe–Al–Mn–C lightweight structural alloys: a review on the microstructures and mechanical properties[J]. Sci Tech Adv Mater. 2013;14:1–11.
3.
FrommeyerGBrüxU.Microstructures and mechanical properties of high-strength Fe-Mn-Al-C light-weight TRIPLEX steels. Steel Res Int.2006;77:627–633.
4.
KalashnikovISAcselradOPereiraLCChemical composition optimization for austenitic steels of the Fe-Mn-Al-C system. J Mater Eng Perform. 2000;9:597–602.
5.
SutouYKamiyaNUminoRHigh-strength Fe–20Mn–Al–C-based alloys with low density. ISIJ Int. 2010;50:893–899.
6.
RaabeDSpringerHGutierrez-UrrutiaIAlloy design, combinatorial synthesis, and microstructure–property relations for low-density Fe-Mn-Al-C austenitic steels. JOM. 2014;66:1845–1856.
7.
WangZLuWZhaoHFormation mechanism of κ-carbides and deformation behavior in Si-alloyed FeMnAlC lightweight steels. Acta Mater. 2020;198:258–270.
8.
RaabeDSunBDa Silva AKCurrent challenges and opportunities in microstructure-related properties of advanced high-strength steels. Metall Mater Trans. 2020;51:5517–5586.
9.
MapelliCBarellaSGruttadauriaAΓ decomposition in Fe–Mn–Al–C lightweight steels. J Mater Res Technol. 2020;9:4604–4616.
10.
WooSDKimNJ.Low-density steels. Scripta Mater. 2013;68:337–338.
11.
ShomeMGupta OPMohantyON.Effect of simulated thermal cycles on the microstructure of the heat-affected zone in HSLA-80 and HSLA-100 steel plates. Metall Mater Trans. 2004;35:985–996.
12.
Chen JHKikutaYArakiTMicro-fracture behaviour induced by M-A constituent (island martensite) in simulated welding heat affected zone of HT80 high strength low alloyed steel. Acta Metall. 1984;32:1779–1788.
13.
EasterlingK.Introduction to the physical metallurgy of welding[M].Elsevier; 2013.
14.
KouS.Welding metallurg. New York: John Wiley; 2003.
15.
YooJKimBParkYMicrostructural evolution and solidification cracking susceptibility of Fe–18Mn–0.6C–xAl steel welds. J Mater Sci. 2015;50:279–286.
16.
TjongSZhuSHoNSolidification microstructure and creep rupture behaviour of electron beam welded austenitic Fe-28M-6Al-1C alloy. Mater SciTechnol.1997;13:251–256.
17.
KuJSHoNJTjongSC.Properties of electron-beam-welded and laser-welded austenitic Fe-28Mn-5Al-1C alloy. J Mater Sci.1993;28:2808–2814.
18.
KimBJeongSParkS-JLocal brittle cracking in the heat-affected zone of lightweight steels. Mater Chem Phys.2019;238:121904.
19.
MoonJParkS-J.An investigation on the microstructure evolution and tensile property in the weld heat-affected zone of austenitic FeMnAlC lightweight steels. J Weld Join. 2017;35:9–15.
20.
SunQDi HSWang XNEffect of heat input on microstructure and properties of dissimilar laser welded joints between TWIP and TRIP steels. Metall Res Technol. 2019;116:616.
21.
JeongSKimBMoonJInfluence of κ-carbide precipitation on the microstructure and mechanical properties in the weld heat-affected zone in various FeMnAlC alloys. Mater Sci Eng A.2018;726:223–230.
22.
JeongSParkGKimBPrecipitation behavior and its effect on mechanical properties in weld heat-affected zone in age hardened FeMnAlC lightweight steels. Mater Sci Eng A.2019;742:61–68.
23.
JeongSParkGKimB.Heat-Affected Zone Characteristics with Post-Weld Heat Treatments in Austenitic Fe–Mn–Al–C Lightweight Steels[J]. Met Mater Int. 2022: 1–10.
24.
Coronado-Alba CEMejíaICabrera JM.Metallographic, structural, and mechanical characterization of weld nuggets in Fe–Mn–Al–C Low-density steels microalloyed with Ti/B and Ce/La by gas tungsten arc welding process. Steel Res Int. 2021;92:2100229.
25.
RykalinRR.Energy source for welding. Weld World. 1974;12:227–248.
26.
AfkhamiSJavaheriVAmraeiMThermomechanical simulation of the heat-affected zones in welded ultra-high strength steels: microstructure and mechanical properties. Mater Des. 2022;213:110336.
27.
Ashby MFEasterling KE.A first report on diagrams for grain growth in welds. Acta Metall. 1982;30:1969–1978.
28.
QianMLippoldJC.The effect of annealing twin-generated special grain boundaries on HAZ liquation cracking of nickel-base superalloys. Acta Mater. 2003;51:3351–3361.
29.
YangJDongHXiaYPrecipitation behavior of carbides and cryogenic toughness in heat-affected zone of high-Mn twinning-induced plasticity steel welded joint. J Manuf Process. 2021;68:716–727.
30.
TakakiSKawasakiKKimuraY.Mechanical properties of ultra fine grained steels. J Mater Process Tech. 2001;117:359–363.
31.
ZhangYXiaoJLiuWEffect of welding peak temperature on microstructure and impact toughness of heat-affected zone of Q690 high strength bridge steel. Materials (Basel). 2021;14:2981.
32.
HuangHGanDKao PW.Effect of alloying additions on the κ phase precipitation in austenitic Fe-Mn-Al-C alloys. Scr Metall Mater. 1994;30:499–504.
33.
RaabeDSpringerHGutiérrez-UrrutiaIAlloy design, combinatorial synthesis, and microstructure–property relations for low-density Fe-Mn-Al-C austenitic steels. JOM. 2014;66:1845–1856.
34.
SpringerHRaabeD.Rapid alloy prototyping: compositional and thermo-mechanical high throughput bulk combinatorial design of structural materials based on the example of 30Mn–1.2C–xAl triplex steels. Acta Mater. 2012;60:4950–4959.
35.
Chen HYJuang JYWu CCNano-carbide strengthened as-welded joint for precipitation-hardened austenitic Fe–Mn–Al–C lightweight alloys. J Mater Res Technol. 2021;14:269–276.
36.
LeeSJeongJLee YK.Precipitation and dissolution behavior of κ-carbide during continuous heating in Fe-9.3Mn-5.6Al-0.16C lightweight steel. J Alloys Compd. 2015;648:149–153.
37.
Bartlett LNVan Aken DCMedvedevaJAn atom probe study of kappa carbide precipitation and the effect of silicon addition. Metall Mater Trans A. 2014;45:2421–2435.
38.
Wan XLChengLWu KM.Growth behavior of ferrite allotriomorphs nucleated on grain boundary faces in a low carbon steel. Met Mater Int.2010;16:865–870.
39.
RadhakrishnaABaligidad RGSarmaDS.Effect of carbon on structure and properties of FeAl based intermetallic alloy. Scr Mater. 2001;45:1077–1082.
40.
Yao MJWelschEPongeDStrengthening and strain hardening mechanisms in a precipitation-hardened high-Mn lightweight steel. Acta Mater. 2017;140:258–273.
41.
Kim CWKwon SILee BHAtomistic study of nano-sized κ-carbide formation and its interaction with dislocations in a cast Si added FeMnAlC lightweight steel. Mater Sci Eng A.2016;673:108–113.
42.
Wu ZQDingHLi HYMicrostructural evolution and strain hardening behavior during plastic deformation of Fe–12Mn–8Al–0.8C steel. Mater Sci Eng A.2013;584:150–155.
43.
LeeJParkSKimHSimulation of κ-carbide precipitation kinetics in aged low-density Fe–Mn–Al–C steels and its effects on strengthening. Met Mater Int.2018;24:702–710.
44.
YangXDiXLiuXEffects of heat input on microstructure and fracture toughness of simulated coarse-grained heat affected zone for HSLA steels. Mater Charact.2019;155:109818.
