High Surface Quality Nb-bearing Ferritic Stainless Steels for Elevators

Transcription

1 CBMM High Surface Quality Nb-bearing Ferritic Stainless Steels for Elevators Yang Weihao Shanghai Mitsubishi Elevator Company, China CHARLES HATCHETT SEMINAR

2 High Surface Quality Nb-bearing Ferritic Stainless Steel for Elevators

3 SMEC for Shanghai Tower

4 Shanghai Tower 632m (2,070 ft)

5 World Record World s Fastest Elevators m / s presenting by SMEC

6 Marketing & Sales Record of SMEC (units) (year) Sales in 2014

7 China s Elevator Market & Relationship with SS

8 China s Elevator Market Largest Elevator market (of both production & sales) in the world 70% of all the globe production of Elevators 65% of all the globe sales of Elevators Average gross need for Stainless Steel = 220,000 Tons / Year 457, , , , Annual Output 375,

9 Why Clients like Stainless Steel Finish 1/3 of our clients choose SS Beautiful Easy to colorize & etching Easy to form any kind of shape Easy to clean and handle with No need to worry about rusting

10 Where may Stainless Steel be Car ceiling Car transom panel Car wall Car operation panel 20,000 Tons SMEC used for 2014 Car handrail Car door Car kick plate Landing Door Landing operation panel

11 443 Nb-bearing FSS

12 Price Finding a substitute for 304 High Austenitic Grade 304 Extra-Low Interstitial Ferritic Grades 443 Conventional Ferritic Grade 430 Price Fluctuation Lower price & Much less fluctuation of price than 304 High

13 Formability Advantage of extra-low interstitial ferritic grades Good Austenitic Grade 304 Extra-Low Interstitial Ferritic Grades 443 Conventional Ferritic Grade 430 Corrosion Resistance Good Equivalent corrosion resistance to 304 with Improved formability over 430

14 Basic features of B443NT Chemical composition of B443NT Grade C Si Mn P S Cr Ni N Ti Nb B443NT ~ ~ ~ ~ ~ Mechanical properties of B443NT Grade Grade Rp0.2 (MPa) Rm (MPa) A(%) Hv B443NT Physical properties of B443NT ρ (g/cm³) R (10-6 Ω*cm) magnetic c 25 (J/kg* ) λ 100 (W/m* ) α 20~100 (10-6 / ) E (Gpa) B443NT Y N

15 Potential Corrosion Resistance of B443NT Pitting Potential Standard:Method of pitting potential measurement for stainless steels Code: GB/T / JIS G Higher number = Better corrosion resistance The pitting potential of B443NT is 370mV, higher than 304(300mV).

16 Corrosion Resistance of B443NT Salt Spray Tests Standard:Corrosion tests in artificial atmospheres Salt spray tests Code: GB/T / ISO 9227:2006, IDT B443NT 304 After 1000h salt spray test, the surface of the samples for both B443NT and 304 remain unchanged, no sign of corrosion.

17 Corrosion Resistance of B443NT Cyclic Corrosion Test Standard: Corrosion test method for automotive materials Code: JASO M / ISO 14993:2001, IDT B443NT After 30 cycles, 240h CCT test, the corrosion phenomenon for B443NT is slightly better than 304, and much better than 439 & 430.

18 Machining Properties of B443NT Laser Cutting Punching Cutting Stud Welding Spot Welding Folding The Machining properties of B443NT is almost as same as 304, only slight adjustment is made to our product line. (90 degree edgefold)

19 Surface Quality of B443NT 304 (HL) Blue film for B443NT B443NT (HL) White film for 304 The surface quality of B443NT is so good, people can hardly tell the difference between B443NT & 304.

20 Ambition of B443NT released Type of Lift Types of Lifts Can save us 4,200,000 US$ next year by using the Nb-bearing FSS

21 Developing of B443Nb

22 High Quality Surface Need for Grade 443 More types of Surface treatment is needed for Grade 443 Near 10% of the SS Surface treatment is Mirror Finish B443NT is not suitable for mirror polish B443Nb for Mirror Surface

23 Advantages of Nb-bearing extra-low interstitial ferritic grade over its Ti stabilized counterpart Higher purity with less oxide inclusions with almost no occurrence of nozzle clogging Much lower chances of roll sticking, leading to better surface quality of hot-rolled coil Precipitate size in Nb-stabilized steel are much smaller than Ti-stabilized High surface quality, suitable for 8K mirror finish

24 Features of B443Nb Extra-low C and N, Nb-stabilized alone Excellent corrosion resistance Good bending properties High surface quality, suitable for 8K mirror finish Chemical composition of B443Nb Grade C N Cr Nb -- Cu Ni B443Nb Mechanical properties of B443Nb Grade Rp0.2 Rm n r A50mm B443Nb

25 Corrosion Resistance of B443Nb Pitting potential of B443Nb is slightly higher than that of 304; B443Nb shows equal corrosion resistance after 18 cycles of CCT test Grade Pitting potential (mv) Result of B443Nb after 18 cycles of cyclic corrosion test B443Nb B443Nb-BA 304-BA 430-BA -3 log <I>/mA # # 443N-800# B443Nb-800# # # Ewe/v

26 Appearance of edgefold of B443Nb Less degree of orange peel than B443NT Smaller grain size due to the effect of grain refining of Nb B443NT B443Nb B443NT B443Nb

27 What s NEXT? Deep Lab Research on the role of Nb in B443Nb Machining Properties TEST for B443Nb Trial manufacture of elevator car by Mirror Surface B443Nb Etching Treatment Research for B443Nb Colorizing Treatment Research for B443Nb Bright future for Nb - bearing FSS

28 Thank you!