[MW:11936] Definition of duplex stainless steel?

ref:  ASM Handbook, Volume 1

Duplex stainless steels

have a mixed structure of bcc ferrite and fcc austenite. The exact amount of each phase is a function of composition and heat treatment . Most alloys are designed to contain about equal amounts of each phase in the annealed condition. The principal alloying elements are chromium and nickel, but nitrogen, molybdenum, copper, silicon, and tungsten may be added to control structural balance and to impart certain corrosion-resistance characteristics.

The corrosion resistance of duplex stainless steels is like that of austenitic stainless steels with similar alloying contents. However, duplex stainless steels possess higher tensile and yield strengths and improved resistance to stress-corrosion cracking than their austenitic counterparts. The toughness of duplex stainless steels is between that of austenitic and ferritic stainless steels

Dual-phase steels

have a microstructure with 80 to 90% polygonal ferrite and 10 to 20% martensite islands dispersed throughout the ferrite matrix. These steels have a low yield strength and continuous yielding behavior; therefore they form just like low-strength steel, but they can also provide high strength in the finished component because of their rapid work-hardening rate.

Generally HLSA stells are categorised as dual phase steels

 

On Tue, Jul 26, 2011 at 1:41 PM, limesh M <limesh78@gmail.com> wrote:

Dear Sir,

My query was purely based on literature.If you don't mind could you please clarify my doubt regarding actual definition of duplex steel?


Ist Paper Says






II Paper says






Regards,

Limesh

On Mon, Jul 25, 2011 at 2:21 PM, limesh M <limesh78@gmail.com> wrote:

Dear All,

What is the actual meaning of duplex steel.Is it a steel with austenitic-ferritic phase or a steel with any COMBINATION OF PHASE?


Regards,

Limesh

--
To post to this group, send email to materials-welding@googlegroups.com
To unsubscribe from this group, send email to materials-welding+unsubscribe@googlegroups.com
For more options, visit this group's bolg at http://materials-welding.blogspot.com/
The views expressed/exchnaged in this group are members personel views and meant for educational purposes only, Users must take their own decisions w.r.t. applicable code/standard/contract documents.