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2273660 
Journal Article 
MICROSTRUCTURES AND PROPERTIES OF 0Cr32N17Mo4N DUPLEX STAINLESS STEEL AFTER VARIOUS FORMING PROCESSES 
He Hong; Li Jingyuan; Qin Liyan; Wang Yide; Fang Fei 
2014 
Yes 
Jinshu Xuebao
ISSN: 0412-1961 
50 
1 
1-10 
WOS:000329953000001 
Duplex stainless steels consist of a two phase microstructure involving alpha-ferrite and gamma-austenite. These alloys have a remarkable combination of mechanical properties together with good corrosion resistance under critical working conditions and are suitable for marine and petro-chemical applications. However, the poor hot workability of these materials makes the industrial processing of flat products particularly critical. Many investigations focus on the mechanisms and behaviors of hot deformation on these materials. Several factors are frequently reported give rise to hot cracking: phase proportions, size and morphology of both phases, softening mechanisms in constituting phases, microstructural evolution during hot work, and strain partitioning between alpha and gamma. On the contrary, few studies have been carried on cold rolling performance. Hot cracking should be avoid during forming process of duplex stainless steel, the more effective way of manufacturing in such materials is also needs research. In this work, the formability of 0Cr32Ni7Mo4N duplex stainless steel was studied in the hot rolling and directly cold rolling processes. The deformation mechanism of alpha and gamma phase at room temperature, the microstructure evolution after hot rolling, cold rolling and solution treatment were investigated. Mechanical properties and corrosion resistance of two kinds of cold-rolled sheets were tested. The metallography and corrosion morphology were observed by OM and SEM. The results show that cracks emerged along the edge of hot-rolled plate even it was reheated three times, and it has good cold rolling formability after cutting edge of the plate. On the other hand the as-cast billet solution-treated at 1100 degrees C has good cold rolling performance. Deformation mechanism of alpha phase at room temperature is that multi-slip system form dislocation cell structure, while single slip model and mechanical twins appear in gamma phase. As the temperature of heat-treatment raised, microstructure became more homogeneous and the amount of precipitate particles decreased. The experimental results show that the tensile strength of cold-rolled sheet after heat-treatment reaches 1082.9 MPa and the elongation is 29.3%. Critical pitting potential of the specimen in 3.5%NaCl liquor is 1060 mV; weight loss after intergranular corrosion in 65%HNO3 solution is 0.05 g/(m(2).h). 
stainless steel; forming process; solution treatment; microstructure; corrosion resistance