Material grades for corrosion- and heat-resistant applications

Standard ferritic grade — magnetic, with moderate corrosion resistance, used where an austenitic grade is not required.

Cr

16–18

The classic 18/10 chromium-nickel austenitic and the most widely used stainless steel — good general corrosion resistance, excellent formability and weldability, non-magnetic in the solution-annealed condition.

Cr

17–19.5

Ni

8–10.5

Extra-low-carbon 304 with slightly higher chromium and nickel than 1.4307; weld-stable against intergranular corrosion.

Cr

18–20

Ni

10–12

Low-carbon variant of 304 and the general-purpose austenitic for most applications — good corrosion resistance, easy forming and welding, with low carbon securing resistance to intergranular corrosion as delivered.

Cr

17.5–19.5

Ni

8–10.5

High-silicon austenitic developed for highly concentrated nitric acid (above 95%) and concentrated sulphuric acid (from 98.5%).

Cr

16.5–18.5

Ni

14–16

Mo

≤0.2

Lean duplex (2304) with a balanced austenite/ferrite structure — roughly double the proof strength of 316L with good stress-corrosion-cracking resistance, used wherever 1.4404 is used.

Cr

22–24

Ni

3.5–5.5

Mo

0.1–0.6

Molybdenum-bearing austenitic with markedly better resistance to chlorides and non-oxidising acids than 304.

Cr

16.5–18.5

Ni

10–13

Mo

2–2.5

Low-carbon 316. The molybdenum content handles chlorides while low carbon secures resistance to intergranular corrosion in the welded condition.

Cr

16.5–18.5

Ni

10–13

Mo

2–2.5

316 variant with higher molybdenum (2.5–3.0%) for improved pitting resistance; corrosion-resistant as delivered.

Cr

16.5–18.5

Ni

10.5–13

Mo

2.5–3

317L — higher molybdenum and nickel than 316L for stronger resistance to chlorides and acids; weld-stable.

Cr

17.5–19.5

Ni

13–16

Mo

3–4

Nitrogen-alloyed high-molybdenum austenitic (317LMN) with elevated strength and excellent resistance to chlorides and mixed acids.

Cr

16.5–18.5

Ni

12.5–14.5

Mo

4–5

Tungsten-bearing super-duplex with high strength and excellent resistance to pitting and chloride stress-corrosion cracking.

Cr

24–26

Ni

6–8

Mo

3–4

Copper-bearing super-duplex (255) combining high strength with strong resistance to pitting and stress-corrosion cracking in chloride and acid service.

Cr

24–26

Ni

5.5–7.5

Mo

2.7–4

Low-chromium, titanium-stabilised utility ferritic for less demanding corrosion duty.

Cr

10.5–12.5

Ni

0.5–1.5

6%-molybdenum super-austenitic with very high resistance to pitting and crevice corrosion in chloride media.

Cr

19–21

Ni

24–26

Mo

6–7

High-alloy super-austenitic with elevated nickel, molybdenum and copper for resistance to sulphuric and phosphoric acid and seawater; low carbon secures weld corrosion resistance.

Cr

19–21

Ni

24–26

Mo

4–5

Titanium-stabilised austenitic. The titanium locks up carbon so intergranular corrosion is controlled even after welding, and adds elevated-temperature strength.

Cr

17–19

Ni

9–12

Niobium-stabilised austenitic (347). The niobium addition secures resistance to intergranular corrosion in the welded condition.

Cr

17–19

Ni

9–12

High-nickel/chromium/copper super-austenitic resistant to sulphuric acid and insensitive to stress-corrosion cracking; low carbon secures weld resistance.

Cr

26–28

Ni

30–32

Mo

3–4

Titanium-stabilised 316. Combines the chloride resistance of 316 with stabilisation against intergranular corrosion in the welded state.

Cr

16.5–18.5

Ni

10.5–13.5

Mo

2–2.5

Aluminium-alloyed ferritic heat-resistant steel, particularly resistant to sulphur-bearing gases at elevated temperature under reducing conditions.

Cr

6–8

Titanium-stabilised ferritic heat-resistant steel, used mainly in automotive exhaust and heat-recovery components.

Cr

10.5–12.5

Aluminium-silicon ferritic heat-resistant steel resistant to sulphur-bearing gases, including pickling-plant duty.

Cr

12–14

Aluminium-silicon ferritic heat-resistant steel with good resistance to sulphur-bearing gases to about 1000 °C.

Cr

17–19

High-chromium nitrogen-bearing ferritic heat-resistant steel for sulphur-bearing gases at high temperature.

Cr

24–29

High-chromium titanium-stabilised, nickel-free ferritic heat-resistant steel with good resistance to sulphurous atmospheres. Continuous use in the 400–700 °C range is not recommended.

Cr

24–27

High-chromium aluminium-silicon ferritic heat-resistant steel, especially resistant to sulphur-bearing gases under reducing conditions, to about 1150 °C.

Cr

23–26

Ferritic-austenitic heat-resistant steel with better resistance to oxidising and especially reducing sulphur-bearing gases than the austenitic Cr-Ni heat-resistant grades.

Cr

24–27

Ni

3.5–5.5

High-temperature austenitic with nitrogen and rare-earth additions for raised strength, oxidation and corrosion resistance at 850–1100 °C.

Cr

20–22

Ni

10–12

Heat-resistant austenitic Cr-Ni steel with good scaling resistance and high hot strength, for duty needing both oxidation resistance and mechanical load capacity.

Cr

24–26

Ni

19–22

Heat-resistant austenitic Cr-Ni grade with good scaling resistance and high hot strength.

Cr

24–26

Ni

19–22

High-nickel silicon-bearing austenitic (Alloy DS) with very high hot strength and good resistance to oxidation and carburisation in alternating atmospheres.

Cr

17–19

Ni

34.5–41

High-temperature iron-nickel-chromium alloy (Alloy 800) for high-temperature plant, with good creep strength and oxidation resistance.

Cr

19–23

Ni

30–34

High-chromium cerium-bearing austenitic (AC 66) with outstanding high-temperature corrosion resistance; low Si and Al limit internal oxidation, strong in carburising and sulphur-bearing atmospheres.

Cr

26–28

Ni

31–33

Titanium-stabilised austenitic for elevated temperature (321H) with good scaling resistance and hot strength.

Cr

17–19

Ni

9–12

High-temperature austenitic (253 MA family) with nitrogen and rare earths for strength and oxidation resistance at 850–1100 °C; casting/forging variant of 1.4835.

Cr

20–22

Ni

10–12

Controlled-carbon 316 for elevated-temperature service (316H) with improved creep strength for pressure parts.

Cr

16–18

Ni

12–14

Mo

2–2.5

Controlled-carbon 304 for elevated-temperature service (304H) with improved creep strength for pressure parts.

Cr

17–19

Ni

10–12

Controlled-chemistry, high-temperature grade of Alloy 800 (800H) with enhanced creep-rupture strength for high-temperature plant.

Cr

19–22

Ni

30–32.5

Commercially pure nickel with excellent resistance to alkaline media and good mechanical properties over a wide temperature range; resistant under reducing conditions (e.g. hydrochloric, hydrofluoric acid).

Ni

≥99.2

Low-carbon commercially pure nickel, used mainly in the chemical industry, especially for caustic soda, chlorine and hydrogen chloride.

Ni

≥99

Nickel-copper alloy (Monel-type) with broad chemical resistance, notably seawater-resistant and good under reducing conditions.

Nickel-molybdenum alloy with very high resistance to reducing media such as hydrochloric and sulphuric acid over wide concentration and temperature ranges, and good resistance to intergranular corrosion.

Cr

0.3–3

Ni

≥65

Mo

26–32

Nickel-chromium-molybdenum-tungsten alloy with excellent resistance to oxidising, reducing and mixed acids.

Cr

20–22.5

Mo

12.5–14.5

Nickel-molybdenum-chromium alloy with excellent resistance to crevice corrosion, pitting and stress-corrosion cracking, and to reducing mineral acids and chloride-contaminated media.

Cr

11–18

Mo

14–17

Corrosion-resistant, high-temperature nickel alloy with good weldability and resistance to grain-boundary corrosion in the welded state.

Cr

21–23.5

Mo

6–8

High-temperature, chemically resistant nickel-chromium alloy for the most demanding oxidising and reducing service, including resistance to moist chlorine gas.

Cr

24–26

Highly corrosion-resistant alloy, very resistant in chloride-bearing media to sulphuric, phosphoric and nitric acid.

Cr

19–21

Ni

32–38

Mo

2–3

Non-age-hardening nickel-chromium alloy for service to about 1050 °C in air; the balanced Ni-Cr content gives resistance under both reducing and oxidising conditions, with very good behaviour in nitriding and carburising atmospheres.

Cr

14–17

Aluminium-bearing nickel-chromium alloy with outstanding oxidation resistance to about 1150 °C in air and good mechanical properties at elevated temperature.

Cr

21–25

Ni

58–63

Niobium-stabilised nickel-chromium-molybdenum alloy with outstanding resistance to a broad range of corrosive media combined with high-temperature strength.

Cr

20–23

Ni

≥58

Mo

8–10

Titanium-stabilised nickel-iron-chromium-molybdenum alloy for chemical and offshore service, resistant to sulphuric and phosphoric acid and to chloride stress-corrosion cracking.

Cr

19.5–23.5

Ni

38–46

Mo

2.5–3.5

Silicon- and cerium-bearing nickel-chromium alloy for high-temperature service in extremely corrosive media such as oil-ash corrosion, combustion gases and sulphur dioxide.

Cr

26–29

Ni

≥45