254 SMO®Rustfritt stål (UNS31254)

What is 254 SMO®?

254 SMO® is a stainless steel was initially created to utilize in seawater and other aggressive chloride-bearing situations. This grade includes a very high end austenitic stainless steel; mainly comprised within 17.5% til 18.5% nikkel, 19.5% og 20.5% krom, 6% til 6.5% molybdenum and .18% til .22% nitrogen.These particular levels of Cr, I, Mo, and N in this “super austenitic” chemical makeup allow 31254 to join impact toughness resistance to corrosion cracking, with pitting and crevice corrosion resistance.The result is strength of almost double that of 300 series stainless steels.

UNS S31254 is treated as a “6% Moly” grade because of the molybdenum content; the 6% Moly family has the ability to withstand high temperatures and keep up strength under volatile conditions. This grade has surpassed its unique expectation and covered into many different industries demonstrating helpfulness owing to its high level of molybdenum amount other elements, which allows 31254 to be utilized effectively as a part of different applications such as flue gas desulfurization and chemical environments.

 254 SMO® Products Form

• Round, Square, Hexagon ,Flat Bars & Wires
• Sømløs / Welded Pipes
• Sømløs / Welded Tubes
• Hot & Cold Rolled Plates & Sheets
• Forged Bars
• Forged Flanges
• Butt-Weld Pipe Fittings
• Socket-Weld/Forged Pipe Fittings
• Machined Components
• Ferrule Compression Fittings
• Welding Consumables
• Common Manufacturi

Applications for 254 SMO®

1) Ocean: marine structures in the sea environment, seawater desalination, marine aquaculture, seawater heat exchange, etc.;

2) Environmental Protection: flue gas desulfurization device for thermal power generation, wastewater treatment, etc.;

3) Energy: atomic power generation, comprehensive utilization of coal, and ocean wave power generation.;

4) Petrokjemisk industri: refining, chemical equipment;

5) Food: salt making, soy sauce brewing, etc.;

6) High concentration chloride ion environment: paper industry, various bleaching devices;

7) Others.

Equivalents of 254 SMO®

STANDARD	OSS	WERKSTOFF NR.	Afnor	I	HAN	SIS	GOST
SMO 254	S31254	1.4547	Z1 CNDU 20.18.06Az	X1CrNiMoCuN20-18-7	-	2378	-

Komposisjon ranges for 254 SMO®

%	C	Cr	Mn	Mo	N	I	P	Og	S
254 SMO	0.02 maks	min: 19.5 maks:20.0	1.00 maks	min: 6.0 maks: 6.5	min: 0.18 maks: 0.20	min: 17.5 maks: 18.0	0.03 maks	0.80 maks	1.01 maks

Mekaniske egenskaper

Properties	Metric	Imperial
Strekkstyrke	680 MPa	98600 psi
Yield strength	300 MPa	43500 psi
Elastisitetsmodul	195 GPa	28300 ksi
Shear modulus	75 GPa	10900 ksi
Poisson’s ratio	0.30	0.30
Elongation at break	50 %	50 %
Hardhet, Brinell	210	210

Fysiske egenskaper

	Units	Temperatur i °C
Tetthet	8.0 g/cm³	Rom
Spesifikk varme	0.12 Kcal/kg.C	22°
Smelteområde	1320 – 1390 °C	–
Elastisitetsmodul	195 KN/mm²	20°
Elektrisk resistivitet	85 µΩ.cm	Rom
Utvidelseskoeffisient	16.0 µm/m °C	20 – 100°
Termisk ledningsevne	14.0 W/m °K	20 °

Korrosjonsbestandighet

• Excellent resistance to pitting and crevice corrosion due to its high chromium, molybden, and nitrogen content
• Has a very low carbon content, which means there is very little risk of carbide precipitation during heating
• Possesses very good resistance in water containing chlorides, therefore, it is suitable for use in seawater as it can be exposed to it for prolonged periods without suffering from crevice corrosion

Varmebehandling

Stainless steel grade 254 SMO™ does not respond to heat treatment. Hardening is possible only through cold reduction.

Gløding

2100-2200 F (1149-1204 C), followed by a water quench.

Herding

This alloy does not harden by heat treating. High properties might just be acquired through cold reduction

Varmt arbeid

While cold forming is recommended wherever feasible, forging, upsetting and other operations can be performed at 1800-2100 F. Temperatures above this range will cause scaling and a reduction in the workability of the material. Post-process annealing is required to re-attain maximum corrosion resistant properties.

Cold Working

Most common cold work methods are successful with this alloy. It should be understood however that the material will be more difficult to work than other austenitic stainless steels due its high work hardening rate. The resulting hardening will, imidlertid, produce increases in strength and toughness which may be of value in the finished product.

Forging

This is a highly alloyed material and the recommended forging temperature range is 2370/1920ºF (1300/1050ºC), followed by a solution anneal at 2100ºF (1150ºC) minimum temperature.

Bearbeidbarhet

Stainless steel grade 254 SMO™ is quite tough to machine due to the extremely high work hardening rate and lack of sulfur content; however using sharp tools,

overpowered machine tools, positive feeds, good amount of lubrication, and slow speeds tend to provide good machining results.

Weldability

The chemical analysis of 254 SMO grade is such that both ferrite and austenite are formed on cooling from welding, giving resistance to hot cracking. A postweld anneal is recommended, as is consultation with the product manufacturer regarding welding parameters.

Key Benefits of 254 SMO Stainless Steel

254 SMO Stainless Steel offers unrivaled benefits, thanks to its unique composition. Its high levels of chromium and molybdenum provide remarkable resistance to both pitting and crevice corrosion. This capability is especially crucial in environments with aggressive chemicals.

Another advantage is its superior strength compared to traditional stainless steels like 316. This strength allows it to maintain integrity under high pressure and temperature. As a result, it remains a reliable choice for demanding industrial applications.

The alloy also boasts excellent formability and weldability due to its high nickel content. This property enables easy fabrication, making it suitable for various manufacturing processes. It also complies with many global standards, ensuring versatility.

Notable benefits include:

• Resistance to stress corrosion cracking
• High tensile strength and impact toughness
• Long-term durability with low maintenance

254 SMO Stainless Steel vs 316 Rustfritt stål

When comparing 254 SMO stainless steel to 316, there are distinct differences. 254 SMO boasts higher corrosion resistance, which makes it ideal for harsh environments like seawater. Its superior performance in such conditions provides a long-lasting solution.

In terms of strength, 254 SMO outperforms 316 rustfritt stål. The added molybdenum and nickel content contributes significantly to this enhanced strength. These elements are essential for maintaining material integrity under extreme temperatures and pressures.

Key differences include:

• Higher molybdenum content in 254 SMO
• Better corrosion resistance in chloride-rich environments
• Greater strength and toughness

Konklusjon

Avslutningsvis, 254 SMO Stainless Steel offers exceptional benefits for challenging environments. Its superior strength and corrosion resistance surpass alternatives like 316 rustfritt stål. Despite higher costs, its long-term durability and performance make it an excellent investment.

Whether in seawater environments or the chemical industry, 254 SMO delivers reliable results. Its versatility and robust properties ensure it meets diverse industrial needs, promising lasting returns on investment.