Yajiang LI
,
Zengda ZOU
,
Dezhen LIU
,
Huiqiang WU
,
Juan WANG
材料科学技术（英）
Cracking morphology in the fusion zone of HQ130 high strength steel was researched by "the y-silt test" and "three point bend test", ultrasonic test and microscope. HQ130+QJ63 high strength steel was welded by Ar+CO2 gas shielded arc welding under the condition of no-preheat. Experimental results indicated that welding crack produced in the partially melted zone of the weld root of HQ130 steel side and propagated parallel to the fusion zone. The cracking developed alternatively between the weld and the partially melted zone, and is not strictly to rupture at W/F boundary surface. Controlling weld heat input (E) about 16 kJ/cm could make the cracking rate to be lowest and satisfy the performance requirement of welded joint zone.
关键词:
High strength steel
,
null
,
null
Yajiang LI
,
Bing ZHOU
,
Tao FENG
,
Jiangwei REN
材料科学技术（英）
Microstructure performance in the welding zone of T91 heat-resistant steel under the condition of TIG welding was researched by means of metallography, X-ray diffraction and scanning electron microscope (SEM).Experimental results indicated that microstructure of T91 weld metal was austenite + a little amount of d ferrite when using TGS-9cb filler wire.Substructure inside the austenite grain was crypto-crystal lath martensite, on which some Cr23C6 blocky carbides were distributed. The maximum hardness (HRC44) in the welding zone is near the fusion zone. There existed no obvious softening zone in the heat-affected zone (HAZ). For T91 steel tube of F63 mm×5 mm, when increasing welding heat input (E) from 4.8 kJ/cm to 12.5 kJ/cm, fracture morphology in the fusion zone and the HAZ changed from dimple fracture into quasi-cleavage fracture (QC). Controlling the welding heat input of about 9.8 kJ/cm is suitable in the welding of T91 heat-resistant steel.
关键词:
T91 heat-resistant steel
,
null
,
null
Yajiang LI
,
Zengda ZOU
,
Bing ZHOU
材料科学技术（英）
Microstructure and alloy element distribution in the welded joint between austenitic stainless steel (1Cr18Ni9Ti) and pearlitic heat-resistant steel (1Cr5Mo) were researched by means of light microscopy, scanning electron microscopy (SEM) and electron probe microanalysis (EPMA). Microstructure, divisions of the fusion zone and elemental diffusion distributions in the welded joints were investigated. Furthermore, solidification microstructure and S-ferrite distribution in the weld metal of these steels are also discussed.
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