Super Duplex UNS 32760 Stainless Steel

What is 32760 stainless steel?

Super Duplex UNS 32760 has excellent corrosion resistance to a wide variety of media, with outstanding resistance to pitting and crevice corrosion in seawater and other chloride containing environments, with Critical Pitting Temperature exceeding 50°C.

Providing higher strength than both austenitic and 22% Cr Duples Stainless Steels 32760 is suited to a variety of applications in industries such as Chemical Processing, Oil & Gas, and Marine environments.

Super Duplex UNS 32760 is listed in NACE MR 01 75 for sour service and having gained ASME Approval for Pressure Vessel applications.

32760 stainless steel Products Form

• Round, Sqaure, Hexagon & Flat Bars
• Seamless / Welded Pipes
• Seamless / Welded Tubes
• Hot & Cold Rolled Plates & Sheets
• Forged Bars
• Buttweld Pipe Fittings
• Forged Fittings
• Ferrule Compression Fittings
• Forged Flanges
• Valves & Gauges

Applications for 32760 stainless steel

1) Neutral chloride environment;

2) Oil refining industry;

3) Pipeline used for chemical industry;

4) Oil and gas industry;

5) Pulp and paper industry;

6) Fertilizer industry, urea industry, phosphate fertilizer industry;

7) Seawater environment, energy and environmental protection industry;

8) Light industry and food industry, food and pharmaceutical industry equipment;

9) High strength structural parts;

10) Hood desulfurization, infiltration desalination equipment, sulfuric acid plant;

11) Submarine pipelines, marine engineering fasteners, etc.;

12) Others.

Equivalents of grade 32760

UNS	S32760
WERKSTOFF NR.	1.4501
EN	X2CrNiMoCuWN25.7.4
SS	10088-3
AFNOR	Z3CND25.06Az
JIS	NAS75N

Composition ranges for 32760 grade of stainless steel

Grade		Ni	C	Cr	Mn	Si	P	CU	Fe	Mo	W
32760	Min.	6	0.2	24	–	–	–	0.5	Balance	3	–
	Max.	8	1	26	1	0.030	0.010	1	–	4	0.03

Mechanical Properties

0.2% Proof Stress (N/mm2 ) [ksi] minimum	550 [79.8]
Ultimate Tensile Strength (N/mm2) [ksi] minimum	750 [108.8]]
Elongation (%) minimum	25
Hardness (HBN)	270max
Reduction of Cross Section Area (%) minimum	45
Charpy V-notch Impact at ambient Temp (J) [ft.lb]	80min [59min]
Charpy V-notch Impact at -46°C (J) [ft.lb]	45av, 35min [33av, 25.8min]

Physical Properties

Density	7.81 Kg/cm
Magnetic Permeability (20°C)	33
Young’s Modulus	199 kN/mm2
Specific Electrical Resistance, 20°C	0.8 µ?.m
Coefficient of thermal expansion, 20-300°C	11.1 x 10-6 m/m/?C
Specific Heat, 20°C	475 J/kg.K
Thermal conductivity, 20°C	14.2 W/m.K

Corrosion Resistance

This grade is commonly used in chloride stress cracking environments which require considerable resistance. Resistance to sulphide cracking is provided along with sour-gas cracking environments. It can effectively resist corrosion in seawater. The grade has exceptional pitting and crevice corrosion resistance, due to its chemical composition and has a critical pitting temperature of about 50°C. It retains its strength along with corrosion resistance in wide range of environments like organic and un-organic acids, strong alkalis, non-oxidizing acids, etc.

Heat Treatment

Annealing is done on the grade to remove internal stresses and restore its grain structure and ductility. It is done after the forming processes to restore its mechanical properties. Annealing is done around 1100-1150°C, followed by appropriate soaking through the sections.

• Time at temperature should be managed according to the sections.
• Sufficient time needs to be provided for the centre sections to reach the heat treatment temperature. Followed by water quenching

Welding

Welding procedures are similar to those applied for conventional duplex stainless steel grades. Electric arc welding

processes is suitable for UNS S32760 super duplex stainless steel, though oxyacetylene welding is not

recommended due to the possibility of carbon pick up in the weld area. We recommend you contact your welding

consumables supplier who should provide you full assistance and information of welding UNS S32760 super

duplex.