Effects of tungsten on precipitation behaviour of intermetallic compounds in the HAZ of duplex stainless steel: Study of weldability of high-tungsten duplex stainless steel (2nd Report)

Modelling of Sigma Phase Dissolution by Solution Treatment in Super Duplex Stainless Steel

“…The critical condition of the sigma phase dissolution corresponds to the case with the right side of that equation equal to 0. Therefore, the solution treatment time t d for finishing to dissolve the sigma phase with the initial radius of r 0m into the matrix, is described as the following, r D t m d 0 2 2 = ω ................................ (6) From Eq. ( 6)…”

“…In later years, super duplex stainless steels, improved the corrosion resistance by increasing the amount of chromium, molybdenum, tungsten and nitrogen, have been developed. [1][2][3][4][5][6][7][8][9][10] However, the increase in the amount of these elements promotes the harmful intermetallic such as sigma phase. Therefore the prevention of this phase formation is an important subject in the welding, fabrication, and manufacturing process for practical use.…”

Modelling of Nitride Precipitation during Isothermal Heating after Rapidly Cooled from High Temperature in Duplex Stainless Steel

“…[1][2][3][4] The high performance in terms of mechanical property and corrosion resistance is obtained by the proper solution treatment without formation of harmful precipitates such as sigma phase or nitride during the manufacturing process in the duplex stainless steel. [5][6][7][8][9] However, in the welded portion it is indispensable to be heated at the high temperature where the phase transformation is remarkable, therefore the fraction of austenite phase can be changed to lower in heat affected zone (HAZ) by weld thermal cycles. The HAZ consisting of the small fraction of austenite phase can deteriorate in the mechanical performance and corrosion resistance due to that changing in microstructure.…”

The Role of Tungsten on the Phase Transformation Kinetics and its Correlation with the Localized Corrosion Resistance of 25Cr Super Duplex Stainless Steels

“…Effects of tungsten in solid solution.-There are several studies on the effects of W on the localized corrosion resistance of austenitic, 21,23,[26][27][28] ferritic, 29,30 amorphous, 22 duplex, 21,[31][32][33][34] super duplex 19,[35][36][37][38][39][40][41][42][43][44] and hyper duplex 45 stainless steels. Although most of these investigations concluded that W improves the corrosion resistance of stainless steels, the mechanisms are still uncertain.…”