254 SMO®

Karakteristik umum

Ultra 254 SMO® is a 6% molybdenum and nitrogen-alloyed austenitic stainless steel with extremely high resistance to both uniform and localized corrosion. This product was developed especially for oil and gas offshore platforms and the pulp and paper industry.

Aplikasi khas

Aplikasi yang membutuhkan ketahanan terhadap air laut terklorinasi
Pembersihan gas buang
Maritime exhaust gas cleaning (EGC)
Peralatan pemutihan di industri pulp dan kertas
Flensa dan katup

254 SMO® Chemical composition

The typical chemical composition for this grade is given in the table below, together with composition limits given for the product according to different standards. The required standard will be fully met as specified on the order.

The chemical composition is given as % by mass.

Standar	Nilai	C	M N	Cr	Ni	Mo	adalah Baja Struktural Kekuatan Tinggi Paduan Rendah Standar GB Cina	Lainnya

Khas	254 SMO®	0.01		20.0	18.0	6.1	0.20	Cu:0.7
ASME II A SA-240	AS S31254	0.020	Huruf pertama dari pinyin Cina dari karakter	19.50-20.50	17.50-18.50	6.00-6.50	0.18-0.25	Cu:0.50-1.00
Selama seseorang tidak memenuhi persyaratan	AS S31254	0.020	Huruf pertama dari pinyin Cina dari karakter	19.5-20.5	17.5-18.5	6.0-6.5	0.18-0.25	Cu:0.50-1.00
EN 10028-7	1.4547	0.020	Huruf pertama dari pinyin Cina dari karakter	19.5-20.5	17.5-18.5	6.0-7.0	0.18-0.25	Cu:0.50-1.00
EN 10088-2	1.4547	0.020	1.0	19.5-20.5	17.5-18.5	6.0-7.0	0.18-0.25	Cu:0.5-1.0
EN 10088-3	1.4547	0.020	Huruf pertama dari pinyin Cina dari karakter	19.5-20.5	17.5-18.5	6.0-7.0	0.18-0.25	Cu:0.50-1.00
EN 10088-4	1.4547	0.020	1.0	19.5-20.5	17.5-18.5	6.0-7.0	0.18-0.25	Cu:0.5-1.0
IS 6911	ISS 312	0.020	Huruf pertama dari pinyin Cina dari karakter	19.5-20.5	17.5-18.5	6.0-6.5	0.18-0.25	Cu:0.50-1.00

Standar	Nilai	C	M N	Cr	Ni	Mo	adalah Baja Struktural Kekuatan Tinggi Paduan Rendah Standar GB Cina	Lainnya

254 SMO® Mechanical properties

The addition of nitrogen to Ultra 254 SMO® gives higher proof strength and tensile strength. Despite the greater strength, the possibilities for cold as well as hot forming are very good.

Mechanical properties at room temperature are shown in the table below.

Standar	Nilai	R_p0.2	R_p1.0	R_M	Pemanjangan	Kekuatan dampak	Rockwell	HB
		MPa	MPa	MPa	%	J
Product type: Cold rolled coil and sheet
Typical (thickness 1 mm)		375	415	735	60
ASME II A SA-240	AS S31254	≥ 310		≥ 655				≤ 223
Selama seseorang tidak memenuhi persyaratan	AS S31254	≥ 310		≥ 655			96HRB	≤ 223
EN 10028-7	1.4547	≥ 320	≥ 350	650-850	≥ 35
EN 10088-2	1.4547	≥ 320	≥ 350	650-850	≥ 35
EN 10088-4	1.4547	≥ 320	≥ 350	650-850	≥ 35
IS 6911	ISS 312	≥ 310		≥ 690			96HRB	≤ 223
Product type: Hot rolled coil and sheet
Typical (thickness 4 mm)
ASME II A SA-240	AS S31254	≥ 310		≥ 655				≤ 223
Selama seseorang tidak memenuhi persyaratan	AS S31254	≥ 310		≥ 655				≤ 223
EN 10028-7	1.4547	≥ 320	≥ 350	650-850	≥ 35
EN 10088-2	1.4547	≥ 320	≥ 350	650-850	≥ 35
EN 10088-4	1.4547	≥ 320	≥ 350	650-850	≥ 35
IS 6911	ISS 312	≥ 310		≥ 690			96HRB	≤ 223
Product type: Hot rolled quarto plate
Typical (thickness 15 mm)		320	350	680	50			160
ASME II A SA-240	AS S31254	≥ 310		≥ 655			96HRB	≤ 223
Selama seseorang tidak memenuhi persyaratan	AS S31254	≥ 310		≥ 655			96HRB	≤ 223
EN 10028-7	1.4547	≥ 300	≥ 340	650-850	≥ 40
EN 10088-2	1.4547	≥ 300	≥ 340	650-850	≥ 40
EN 10088-4	1.4547	≥ 300	≥ 340	650-850	≥ 40
IS 6911	ISS 312	≥ 310		≥ 655			96HRB	≤ 223
Product type: Wire rod
Khas		340	380	680	50

Standar	Nilai	R_p0.2	R_p1.0	R_M	Pemanjangan	Kekuatan dampak	Rockwell	HB	HV
		MPa	MPa	MPa	%	J

¹⁾Elongation according to EN standard: A₈₀ for thickness below 3 mm. A for thickness = 3 mm. Elongation according to ASTM standard A_2” atau A₅₀.
Tahan korosi

Korosi seragam

The high content of alloying elements gives Ultra 254 SMO® exceptionally good resistance to uniform corrosion. It can withstand a wide range of acids due to the high alloying content of chromium and molybdenum. For guidance on material selection in a large number of environments, consult the tables and isocorrosion diagrams in the Buku Pegangan Korosi Outokumpu.

Korosi lubang dan celah

Resistance to pitting and crevice corrosion is determined mainly by the chromium, molybdenum, and nitrogen content. Ultra 254 SMO® has high amounts of these elements and is suitable for demanding environments like chlorinated sea water.

Retak korosi tegangan

Resistance to stress corrosion cracking increases with increased content of nickel and molybdenum in particular. This means that Ultra 254 SMO® has very good resistance to stress corrosion cracking.

Ketahanan korosi lubang		Ketahanan korosi celah
PRA	CPT	CCT
43	87±3	35

Ketahanan korosi lubang		Ketahanan korosi celah
PRA	CPT	CCT

PRE Pitting Resistant Equivalent calculated using the formula: PRE = %Cr + 3.3 x %Mo + 16 x %NCPT Corrosion Pitting Temperature as measured in the Avesta Cell (ASTM G 150), in a 1M NaCl solution (35,000 ppm or mg/l chloride ions).CCT Critical Crevice Corrosion Temperature is the critical crevice corrosion temperature which is obtained by laboratory tests according to ASTM G 48 Method F

Properti fisik

The typical values of some physical properties are given in the table below.

Kepadatan	Modulus elastisitas	Thermal exp. at 100 °C	Konduktivitas termal	Kapasitas termal	hambatan listrik	Dapat dimagnetisasi
kg/dm³	IPK	10^-6/°C	W/m°C	J/kg°C	m
8.0	195	16,5	14	500	0.85	Tidak*

Kepadatan	Modulus elastisitas	Thermal exp. at 100 °C	Konduktivitas termal	Kapasitas termal	hambatan listrik	Dapat dimagnetisasi
kg/dm³	IPK	10^-6/°C	W/m°C	J/kg°C	m

*) Austenitic Besi tahan karat grades may be magnetizable to a certain degree after cold deformation, e.g. in temper rolled condition.
Pembuatan

Ultra 254 SMO® cold hardens considerably faster than conventional austenitic grades. This, together with the initial high strength, makes it necessary to apply high forming forces. The springback for Ultra 254 SMO® is also greater than for conventional austenitic steels. In complicated cold forming operations, intermediate annealing of the material may sometimes be necessary, especially if the workpiece is welded.

permesinan

The work hardening behavior together with the toughness means that highly alloyed grades are often perceived as problematic from a machining perspective, e.g. operations such as turning, milling, and drilling. This applies to an even greater extent to most highly alloyed steels, especially those that have a high nitrogen content. However, with the right choice of tools, tool settings, and cutting speeds, these materials can be sucessfully machined. Machining guidelines for Ultra 254 SMO® can be found here :Machining guidelines Ultra 254 SMO®

Pengelasan

Ultra 254 SMO® is well suited for welding, and the methods used for welding conventional austenitic steels can be used. However, due to its stable austenitic structure, it is somewhat more sensitive to hot cracking in connection with welding, and generally welding should be performed using a low heat input. On delivery, sheet, plate, and other processed products have a homogeneous austenitic structure with an even distribution of alloying elements in the material. Solidification after partial remelting, e.g. by welding, causes redistribution of elements such as molybdenum, chromium, and nickel. These variations, segregation, remain in the cast structure of the weld and can impair the material’s corrosion resistance in certain environments.

More detailed information concerning welding procedures can be obtained from the Outokumpu Welding Handbook, available from our sales offices.

254 SMO® Standards & persetujuan

The most commonly used international product standards are given in the table below.

Standar	Penamaan

ASME SA-240M Code Sect. II. Part A	UNS S31254 / 254
ASTM A240 / A240M	UNS S31254 / 254
EN 10028-7 (PED 2014/68/EU)	1.4547
EN 10088-2	1.4547
EN 10088-3	1.4547
EN 10088-4	1.4547
IS 6911, AMENDMENT NO. 3	ISS 312