Duplex Steel Flanges

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Duplex Steel Flanges Manufacturer, Supplier & Stockist

Duplex Steel Flanges

Kalpaturu Piping Solutions is a well-known manufacturer, supplier and exporter of Duplex Steel S31803 & S32205 Flanges in India. We also offer a full-scale variety of flanges, such as slip-on, socket weld, blind, lapped, screwed, weld neck and reducing flanges, to suit a wide variety of industrial needs. Our ANSI B16.5 Duplex Blind Flanges have superior toughness and ductility over the standard ferritic stainless steels in that they are suitable for the highly demanding applications.

We have various sizes, thicknesses, shapes and specifications of our ASME SA182 Duplex Steel Flanges in order to suit the individual requirements of the clients. The flanges have found extensive application in the chemical, oil and gas, fertiliser and heavy engineering industries. Duplex stainless steel flanges, especially S31803 and S32205, are characterised by high stress corrosion cracking (SCC) capabilities, which are passed on through their ferritic stainless steel characteristics.

The chromium, molybdenum, and nitrogen content of duplex steel is better than the austenitic grades in terms of resistance to chloride pitting and crevice corrosion, and the reduced nickel and molybdenum content makes duplex steel cost-effective in terms of corrosion resistance without significantly reducing corrosion-protecting durability.

Being a reputable manufacturer, supplier, and stockist, Kalpaturu Piping Solutions provides these ASTM A182 duplex steel flanges with very competitive prices guaranteed by quality assurance and timely delivery, and hence is a good solution to the industrial piping needs.

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Table of content

Specification of Duplex Steel Flanges

Parameter Details
Size 1/8″ NB to 24″ NB
Standards ANSI Flanges, ASME Flanges, BS Flanges, DIN Flanges, EN Flanges
Designations ANSI B16.5, BS 1560, BS 10, IS 6392, B2.1 NPT, API, DIN, JIS, MSS SP-44
Grades ASTM A182 / ASME SA182 F51, F52, F53, F54, F55, F57, F59, F60, F61, UNS S31803, UNS S32205
Pressure Class 150 LBS, 300 LBS, 600 LBS, 900 LBS, 1500 LBS, 2500 LBS
Flange Face Types Flat Face (FF), Raised Face (RF), Ring Type Joint (RTJ)

Duplex Steel Flanges Equivalent Grades

Standard Werkstoff Nr. UNS
Duplex 2205 1.4462 S31803 / S32205

Chemical Composition of Duplex Steel Pipe Flanges (%)

Grade C Mn Si P S Cr Mo Ni N Fe
S31803 0.030 max 2.00 max 1.00 max 0.030 max 0.020 max 22.0 – 23.0 3.0 – 3.5 4.50 – 6.50 0.14 – 0.20 63.72 min
S32205 0.030 max 2.00 max 1.00 max 0.030 max 0.020 max 21.0 – 23.0 2.50 – 3.50 4.50 – 6.50 0.08 – 0.20 63.54 min

Mechanical Properties of ASTM A182 Duplex Steel Plate Flanges

Grade Density (g/cm³) Density (lb/in³) Melting Point (°C) Melting Point (°F)
S31803 / S32205 7.805 0.285 1420 – 1465 2588 – 2669

Class 300 SDSS / Duplex Steel Flanges – Dimensional Chart

Most Genuine Duplex Flanges Manufacturer in India as per International Standards
Class NPS Weld Neck Flange Slip-On Flange Blind Flange Loose Flange NPT Flange Socket Weld (SW) Flange
300# ½ 2 2 2 2 2 3
300# ¾ 3 3 3 3 3 3
300# 1 4 3 4 3 3 3
300# 1¼ 5 4.5 6 4.5 4.5 4
300# 1½ 7 6.5 7 6.5 6.5 6
300# 2 9 7 8 7 7 7
300# 2½ 12 10 12 10 10 10
300# 3 18 13 16 14.5 14 13
300# 3½ 20 17 21 17 17 17
300# 4 26.5 23.5 28 24 24 22
300# 5 36 29 37 28 31 28
300# 6 45 39 50 39 39 39
300# 8 69 58 81 58 58 58
300# 10 100 81 124 91 81 81
300# 12 142 115 185 140 115 115
300# 14 206 165 250 190 165 165
300# 16 250 210 315 234 220 190
300# 18 320 253 414 305 280 250
300# 20 400 315 515 375 325 315
300# 22 465 370 640 435 370 370
300# 24 580 490 800 550 490 475

Duplex Stainless Steel Flanges – Size Conversion Chart

NPS DN
1/2 15
3/4 20
1 25
1¼ 32
1½ 40
2 50
2½ 65
3 80
4 100

Gasket Sizes of Duplex Stainless Steel Flanges

NPS Gasket ID 900 LBS OD 600 LBS OD 400 LBS OD 300 LBS OD 150 LBS OD
1/2 0.084 2.050 2.0125 2.0125 2.0125 1.0875
3/4 1.006 2.075 2.0625 2.0625 2.0625 2.025
1 1.031 3.0125 2.0875 2.0875 2.0875 2.0625
1¼ 1.066 3.050 3.025 3.025 3.025 3.000
1½ 1.091 3.0875 3.075 3.075 3.075 3.0375
2 2.038 5.0625 4.0375 4.0375 4.0375 4.0125
2½ 2.088 6.050 5.0125 5.0125 5.0125 4.0875
3 3.050 6.0625 5.0875 5.0875 5.0875 5.0375
4 4.050 8.0125 7.0625 7.000 7.0125 6.0875
5 5.056 9.075 9.050 8.0375 8.050 7.075
6 6.062 11.0375 10.050 9.075 9.0875 8.075
8 8.062 14.0125 12.0625 12.000 12.0125 11.000
10 10.075 17.0125 15.075 14.0125 14.025 13.0375
12 12.075 19.0625 18.000 16.050 16.0625 16.0125

Duplex SS Flange Pressure Rating Chart

Temperature (°F) 2500 LBS 1500 LBS 900 LBS 600 LBS 400 LBS 300 LBS 150 LBS
-20 to 100 6000 3600 2160 1440 960 720 275
200 5000 3000 1800 1200 800 600 230
300 4500 2700 1620 1080 720 540 205
400 4140 2485 1490 995 660 495 190
500 3880 2330 1395 930 620 465 170
600 3640 2185 1310 875 580 435 140
650 3580 2150 1290 860 575 430 125
700 3540 2125 1275 850 565 425 110
750 3460 2075 1245 830 555 415 95
800 3360 2015 1210 805 540 405 80
850 3300 1980 1190 790 530 395 65
900 3240 1945 1165 780 520 390 50
950 3180 1910 1145 765 510 380 35
1000 2675 1605 965 640 430 320 20
1050 2570 1545 925 615 410 310 20
1100 2145 1285 770 515 345 255 20
1150 1655 995 595 400 265 200 20
1200 1285 770 465 310 205 155 20
1250 945 565 340 225 150 115 20
1300 715 430 255 170 115 85 20
1350 515 310 185 125 80 60 20
1400 400 240 145 95 65 50 20
1450 285 170 105 70 45 35 15
1500 230 135 80 55 35 25 10

Applications & Uses of Duplex Steel Flanges

  • Oil and gas
  • Chemical processing
  • Marine engineering
  • Power generation
  • Heat exchangers
  • Desalination
  • Pressure vessels

FAQs About Duplex Steel Flanges

A duplex flange is a piping component manufactured from duplex stainless steel, typically grades UNS S31803 or S32205. It combines the properties of austenitic and ferritic stainless steels, offering high strength, excellent corrosion resistance, and good toughness. Duplex flanges are commonly used to connect pipes, valves, and equipment in high-pressure and corrosive environments.

Duplex stainless steel is widely used in industries that require high strength and superior corrosion resistance. Common applications include oil and gas pipelines, chemical processing plants, offshore platforms, desalination units, heat exchangers, and marine systems, especially where resistance to chloride stress corrosion cracking is essential.

Duplex steel offers several advantages, including higher mechanical strength, excellent resistance to pitting, crevice corrosion, and stress corrosion cracking, and improved durability in harsh environments. It also provides better cost efficiency due to lower nickel content compared to austenitic stainless steels, while maintaining long service life.

The three main types of duplex stainless steel are Lean Duplex, Standard Duplex (such as Duplex 2205), and Super Duplex. Lean duplex provides moderate corrosion resistance with cost efficiency, standard duplex offers balanced strength and corrosion resistance, and super duplex delivers enhanced performance for extreme pressure and highly corrosive applications

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