The fine microstructure of martensite–austenite (M–A) constituents in simulated coarse grained heat affected zone (HAZ) of high strength low alloy steel with varying aluminium content (0·038 and 0·070 wt-%) at 100 kJ cm−1 heat input welding was investigated. The result shows that M–A constituents with 0·038%Al consisted of lath martensite and retained austenite. The retained austenite was distributed along the martensite lath. Whereas, the M–A constituents with 0·070%Al consisted of lath martensite and retained austenite, as well as a small amount of twinned martensite. The amount of retained austenite in M–A constituents with 0·070%Al was becoming higher slightly than that with 0·038%Al. Accordingly, the volume fraction of M–A constituents was reduced with 0·070%Al. Appropriate aluminium addition could decrease not only the area fraction but also the size of M–A constituents, which are beneficial for improving the toughness of HAZ.
BayraktarE and KaplanD: ‘Mechanical and metallurgical investigation of martensite-austenite constituents in simulated welding conditions’, J. Mater. Process. Technol., 2004, 153–154, 87–92.
2.
XuW, WesterbaanD, NayakSS, ChenDL, GoodwinF and ZhouY: ‘Tensile and fatigue properties of fiber laser welded high strength low alloy and DP980 dual-phase steel joints’, Mater. Des., 2013, 43, 373–383.
3.
MatsudaF, LiZ, BernasovskyP, IshiharaK and OkadaH: ‘An investigation on the behaviour of the M-A constituent in simulated HAZ of HSLA steels’, Weld World, 1991, 29, (9–10), 307–313.
4.
AkselsenOM, SolbergJK and GrongØ: ‘Effects of martensite-austenite (M-A) islands on intercritical heat-affected zone toughness of low carbon miroalloyed steels’, Scand. J. Met., 1988, 17, 194–200.
5.
AkselsenOM, GrongØ and SolbergJK: ‘Structure-property relationships in intercritical heat affected zone of low carbon microalloyed steels’, Mater. Sci. Technol., 1987, 3, 649–655.
6.
LiXD, MaXP, SubramaanianSV, ShangCJ and MisraRDK: ‘Influence of prior austenite grain size on martensite-austenite constituent and toughness in the heat affected zone of 700 MPa high strength linepipe steel’, Mater. Sci. Eng. A, 2014, 616, 141–147.
7.
DavisCL and KingJE: ‘Cleavage initiation in the intercritically reheated coarse grained heat affected zone’, Metall. Mater. Trans. A, 1994, 25A, 563–573.
8.
LanLY, QiuCL, SongHY and ZhaoDW: ‘Correlation of martensite-austenite and cleavage crack initiation in welding heat affected zone of low carbon baintic steel’, Mater. Lett., 2014, 125, 86–88.
9.
LiC, WangY and ChenY: ‘Influence of peak temperature during in-service welding of API X70 pipeline steels on microstructure and fracture energy of the reheated coarse grain heat-affected zones’, J. Mater. Sci., 2011, 46, 6424–6431.
10.
MoeinifarS, KokabiAH and Madaah HosseiniHR: ‘Influence of peak temperature during simulation and real thermal cycles on microstructure and fracture properties of the reheated zones’, Mater. Des., 2010, 31, 2948–1955.
11.
LiY, CrowtherDN, GreenMJW, MitchellPS, BakerTN: ‘The effect of vanadium and niobium on the properties and microstructure of the intercritically reheated coarse grained heat affected zone in low carbon microalloyed steels’, ISIJ Int., 2001, 41, 46–55.
12.
MatsudaF, IkeuchiK, FukadaY, HoriiY, OkadaH, ShiwakuT, ShigaC and SuzukiS: ‘Review of mechanical and metallurgical investigations of M-A constituent in welded joint in Japan’, Trans. JWRI, 1995, 24, (1), 1–24.
13.
YouY, ShangCJ, NieWJ and SubramanianS: ‘Investigation on the microstructure and toughness of coarse grained heat affected zone in X-100 multi-phase pipeline steel with high Nb content’, Mater. Sci. Eng. A, 2012, A558, 692–701.
14.
BonnevieE, FerriereG, IkhlefA, KaplanD and OrainJM: ‘Morphological aspects of martensite-austenite constituents in intercritical and coarse grain heat affected zones of structural steels’, Mater. Sci. Eng. A, 2004, A385, 352–358.
15.
MeinaA, FourlarisbG, CrowthercD and EvansPJ: ‘The influence of aluminum on the ferrite formation and microstructural development in hot rolled dual-phase steel’, Mater. Charact., 2012, 64, 69–78.
16.
Kiani-RashidAR: ‘Effect of aluminum on stability of retained austenite in bainitic malleable cast iron’, Met. Sci. Heat. Treat., 2011, 53, 322–325.
17.
HellerT and NussA: ‘Effect of alloying elements on microstructure and mechanical properties of hot rolled multiphase steels’, Ironmaking Steelmaking, 2005, 32, 303–308.
LeslieWC and RauchGC: ‘Precipitation of carbides in low-carbon Fe-Al-C alloys’, Metal. Trans. A, 1978, 9A, 343–349.
20.
FukadaY and KomizoY: ‘Effect of Al content on critical CTOD propertied in heat affected zone of C-Mn microalloyed steel’, Q. J. JWS, 1992, 10, (3), 93–99.
21.
LanLY, QiuCL and ZhaoDW: ‘Analysis of martensite–austenite constituent and its effect on toughness in submerged arc welded joint of low carbon bainitic steel’, J. Mater. Sci., 2012, 47, 4732–4742.
22.
ChangLC and BhadeshiaHKDH: ‘Carbon concentration of retained austenite in isothermally transformed 300M steel’, Mater. Sci. Eng. A, 1994, A184, 17–19.
23.
YuL, WangHH, WangXL. HuangG, HouTP and WuKM: ‘The improvement in impact toughness of simulated heat-affected zone by addition of aluminum’, Mater. Sci. Technol., 2014, July 15 [Epub ahead of print].
