TP038 The Influence of Specific Alloying Elements in Control of Pitting of 25% Cr Duplex Steels

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- Copper
  - Hiduron 130
    
    Hiduron 130
    
    Hiduron® 130 is a high-strength cupronickel supplied in the hot worked condition. Precipitation strengthening means that no further heat treatment is necessary to make it one of the highest strength copper alloys commercially available. Being a cupronickel, it has excellent resistance to corrosion by seawater and in marine and industrial atmospheres and it is highly resistant to crevice corrosion.
  - Hiduron 191
    
    Hiduron 191
    
    Hiduron® 191 is a medium-strength precipitation hardened cupronickel alloy supplied in the hot worked condition. It contains about 14.5% nickel and 4.5% manganese strengthened by additions of aluminium and iron. It was developed to provide both the corrosion resistance and anti-fouling characteristics of conventional cupronickels but with superior tensile and toughness properties compared to aluminium bronzes.
  - Hidurel 5
    
    Hidurel 5
    
    Hidurel® 5 is a precipitation-hardening copper-nickel-silicon alloy possessing high electrical and thermal conductivity with very good notch ductility and high mechanical strength. Despite its high strength, the alloy is resistant to hydrogen embrittlement. Resistance to corrosion under marine and industrial conditions is excellent and the alloy has good anti-frictional and bearing properties.
- Stainless Steels
  - Stainless Steel Hollow Bars
  - Sanmac 316L (Hollow Bar)
    
    Sanmac 316L (Hollow Bar)
    
    Sanmac® 316L is an improved-machinability austenitic stainless steel bar. The addition of Mo provides the product with much improved corrosion resistance compared with Alloy 304, particularly with respect to pitting and crevice corrosion in chloride environments.
  - Alloy 316L
    
    Alloy 316L
    
    Alloy 316L is an austenitic stainless steel supplied in the hot worked and annealed condition. The addition of Mo provides the product with much improved corrosion resistance compared with Alloy 304, particularly with respect to pitting and crevice corrosion in chloride environments.
  - Alloy 254
    
    Alloy 254
    
    Alloy 254, is a high alloy austenitic stainless steel supplied in the hot worked and annealed condition. Significant additions of Mo, Ni and Cu gives this alloy a good resistance to pitting and crevice corrosion, especially in environments containing halide ions e.g. chloride, bromide and fluoride solutions.
  - Fermonic 50 – Annealed
    
    Fermonic 50 – Annealed
    
    Fermonic® 50 – Annealed (also known as Nitronic® 50 – a trademark owned by AK Steel Corporation) is a nitrogen-strengthened austenitic stainless steel supplied in the annealed condition. It provides almost double the yield strength of common austenitic stainless steel grades such as Alloy 304 and Alloy 316L, offering the potential to reduce section size and therefore weight and cost.
  - Fermonic 50 – High Strength / Extra High Strength
    
    Fermonic 50 – High Strength / Extra High Strength
    
    Fermonic® 50 – HS/EHS (also known as Nitronic® 50 – a trademark owned by AK Steel Corporation) is a nitrogen-strengthened austenitic stainless steel that can be supplied in the cold worked or warm worked condition. This product maintains excellent ductility and toughness at both elevated and cryogenic temperatures.
  - Fermonic 60
    
    Fermonic 60
    
    Fermonic® 60 is a fully austenitic alloy supplied in the hot worked and annealed condition. Additions of Silicon and Manganese provide superior wear, galling and fretting resistance
- Duplex Stainless Steels
  - Sanmac 2205 (Hollow Bar)
    
    Sanmac 2205 (Hollow Bar)
    
    Sanmac® 2205 is a 22% Cr duplex stainless steel with improved machinability as standard. As a duplex stainless steel, it combines the desirable aspect of properties of both austenitic and ferritic grades. The high chromium, molybdenum and nitrogen contents results in a Pitting Resistance Equivalent number (PREN) of 33-34, providing pitting and crevice corrosion resistance superior to Alloy 316L in almost all corrosive media.
  - Sanmac 2205
    
    Sanmac 2205
    
    Sanmac 2205 is a machinability-improved version of the duplex (austenitic-ferritic) stainless steel Sandvik SAF 2205.
    The new generation of Sanmac stainless steels present even better opportunities to reduce tool wear and increase cutting speeds, giving productivity improvements and therefore significant cost reductions per produced item.
    In Sanmac materials, machinability has been improved without jeopardizing properties such as corrosion resistance and mechanical strength. The non-metallic inclusions in Sanmac steels are of great significance to the improved machinability. In addition to sulfides, Sanmac steels contain oxide inclusions that improve chip breaking and reduce tool wear.
    
    (Sanmac is a registered trademark of Sandvik Intellectual Property AB)
  - Alloy 2205
    
    Alloy 2205
    
    Alloy 2205 is a 22% Cr duplex stainless steel, supplied in the solution annealed condition. As a duplex stainless steel, it combines the desirable aspect of properties of both austenitic and ferritic grades. The high chromium, molybdenum and nitrogen contents results in a Pitting Resistance Equivalent number (PREN) of 33-34.
- Super Duplex
  - Ferralium 255 – SD50
    
    Ferralium 255 – SD50
    
    Ferralium® 255 – SD50 (super duplex 255) is a stainless steel which is supplied in the hot worked and annealed condition. It achieves higher strengths than most other stainless steels and alternative corrosion resistant alloys, offering the potential to reduce section size and therefore weight and cost.
  - Ferralium 255 (Plate)
    
    Ferralium 255 (Plate)
    
    Ferralium® 255 is a super duplex stainless steel supplied in the hot worked, annealed and pickled condition. It achieves higher strengths than other alternative corrosion resistant alloys, offering the potential to reduce section size and therefore weight and cost.
  - Ferralium 255 (Pipe & Tube)
    
    Ferralium 255 (Pipe & Tube)
    
    Ferralium® 255 is a super duplex stainless steel supplied in the cold finished and annealed condition. It offers excellent corrosion resistance in a wide variety of corrosive chemicals including sulphuric, nitric and phosphoric acid, seawater and other chloride containing environments.
  - SAF2507
    
    SAF2507
    
    Sandvik SAF2507 is a super duplex stainless steel for service in highly corrosive conditions, similar to Alloy 32750. As a super duplex stainless steel, the SAF2507 combines the desirable aspects of both austenitic and ferritic grades. The higher chromium, molybdenum and nitrogen contents result in a Pitting Resistance Equivalent number (PREN) of >41, providing pitting and crevice corrosion resistance superior to austenitic and duplex stainless steels in almost all corrosive media, and a Critical Pitting Temperature exceeding 50°C.
    
    (Sandvik SAF2507 is a registered trademark of Sandvik Intellectual Property AB)
  - Alloy 32750
    
    Alloy 32750
    
    Alloy 32750 is a super duplex stainless steel supplied in the solution annealed condition. As a super duplex stainless steel, it combines the desirable aspects of both austenitic and ferritic grades. The higher chromium, molybdenum and nitrogen contents result in a Pitting Resistance Equivalent number (PREN) of >40.
  - Alloy 32750 (Plate)
    
    Alloy 32750 (Plate)
    
    Alloy 32750 is a super duplex stainless steel supplied in the hot worked and solution annealed condition. As a super duplex stainless steel, it combines the desirable aspects of both austenitic and ferritic grades. The higher chromium, molybdenum and nitrogen contents result in a Pitting Resistance Equivalent number (PREN) of >40.
  - Alloy 32760
    
    Alloy 32760
    
    Alloy 32760 is a super duplex stainless steel supplied in the hot worked and solution annealed condition. As a super duplex stainless steel, it combines the desirable aspects of both austenitic and ferritic grades. The higher chromium, molybdenum and nitrogen contents result in a Pitting Resistance Equivalent number (PREN) of >40.
  - Alloy 32760 (Plate)
    
    Alloy 32760 (Plate)
    
    Alloy 32760 is a super duplex stainless steel supplied in the hot worked and solution annealed condition. As a super duplex stainless steel, it combines the desirable aspects of both austenitic and ferritic grades. The higher chromium, molybdenum and nitrogen contents result in a Pitting Resistance Equivalent number (PREN) of >40.
  - Ferralium 255 – SD50 HS110
    
    Ferralium 255 – SD50 HS110
    
    Ferralium® 255 – SD50 HS110 is a higher strength super duplex stainless steel supplied in the strain hardened condition (Condition S). By precise further processing, it achieves significantly raised yield and tensile strengths whilst still retaining good levels of impact strength.
  - Ferralium 255 – 3AF Aged Grade
    
    Ferralium 255 – 3AF Aged Grade
    
    Ferralium® 255 – 3AF is a super duplex stainless steel supplied in the hot worked, annealed and aged condition. By subjecting the product to an additional ageing process, it is possible to further increase the tensile strength of the product whilst retaining its high levels of ductility.
  - Ferralium 255 – FG46 Fastener Grade
    
    Ferralium 255 – FG46 Fastener Grade
    
    Ferralium® 255 – FG46 is a super duplex stainless steel supplied in the strain hardened condition (Condition S). It is optimised for fastener applications, matching the mechanical properties of the B7 grade alloy carbon steel which is most commonly used for high-pressure bolting applications.
  - Ferralium 255 – 3SF for Forgings
    
    Ferralium 255 – 3SF for Forgings
    
    Ferralium® 255 – 3SF is a super duplex stainless steel supplied as forgings.
  - Ferralium 255 – 3SC for Castings
    
    Ferralium 255 – 3SC for Castings
    
    Ferralium® 255 – 3SC is a super duplex stainless steel supplied in cast form.
  - Ferralium 255 Welding Wire
    
    Ferralium 255 Welding Wire
    
    Ferralium® 255 weld wire is produced to complement our leading super duplex stainless steel. Careful formulation of the weld wire composition ensures the optimum combination of weld strength and corrosion resistance, achieved by over-alloying the wire with Nickel to maintain the correct (austenite / ferrite) phase balance.
- Nickel
  - Alloy 400
    
    Alloy 400
    
    Alloy 400 is a nickel-copper (Monel® is Special Metals Corporation’s trademark for a family of Nickel-Copper alloys) single-phase alloy most commonly supplied in hot worked and annealed condition. In its standard annealed condition it is easy to form and fabricate with no requirements for additional heat treatments to re-balance the alloy.
  - Alloy K500
    
    Alloy K500
    
    Alloy K500 is a precipitation-hardenable nickel-copper alloy which is also known as Monel K500 (Monel® is Special Metals Corporation’s trademark for a family of Nickel-Copper alloys). Although Langley Alloys supply Alloy K500 in all conditions, we predominantly supply material in the hot worked and precipitation treated condition, which offers the optimum combination of high strength and ductility across the size range.
  - Alloy 625
    
    Alloy 625
    
    Alloy 625 is a nickel-chromium-molybdenum-niobium alloy (NiCr22Mo9Nb), supplied in the hot worked and annealed condition. It achieves high-strength levels from the solid solution effects of Molybdenum and Niobium (Colombium) from room temperature up to 800°C.
  - Alloy 718
    
    Alloy 718
    
    Alloy 718 is a high-strength, corrosion-resistant nickel chromium alloy supplied in the hot worked, solution annealed and age hardened condition. The addition of Nb, Ti, Al and Ni form a series of precipitates during the controlled solution annealing and ageing process steps, resulting in a significant increase in strength and hardness.
  - Alloy 725
    
    Alloy 725
    
    Alloy 725 is a nickel-chromium alloy with significant additions of molybdenum, niobium and titanium, supplied in the hot worked, annealed and age-hardened condition. It is age-hardened to achieve extremely high strength, approximately twice that of alloy 625 in the annealed condition.
  - Alloy 825
    
    Alloy 825
    
    Alloy 825 is a nickel-iron-chromium alloy with additions of molybdenum, copper and titanium (NiCr21Mo), supplied in the hot worked and annealed condition. It achieves good mechanical properties from cryogenic to medium-high temperatures (5400C) and can be significantly strengthened through cold working.
  - Alloy 825 (Tube)
    
    Alloy 825 (Tube)
    
    Alloy 825 is a nickel-iron-chromium alloy with additions of molybdenum, copper and titanium (NiCr21Mo). Langley Alloys can supply the unique metal in the hot worked and annealed condition. It achieves good mechanical properties from cryogenic to medium-high temperatures (5400C) and can be significantly strengthened through cold working.
  - Alloy 825 HS110
    
    Alloy 825 HS110
    
    Alloy 825 HS110 is a high strength nickel-iron-chromium alloy with additions of molybdenum, copper and titanium (NiCr21Mo). We supply the metal in the hot worked, annealed and cold worked condition. Controlled cold working ensures that the product achieves significantly increased yield strengths over the annealed product, whilst retaining good ductility and toughness.
  - Alloy 925
    
    Alloy 925
    
    Alloy 925 is a precipitation-hardenable Nickel-Iron-Chromium Alloy with additions of Molybdenum, Copper, Titanium and Aluminium, supplied in the solution annealed and aged condition.
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TP038 The Influence of Specific Alloying Elements in Control of Pitting of 25% Cr Duplex Steels

Project Overview:

Market Sector: All
Authors: C. Tuck, Sykes, L. Garfias,
Company: Langley Alloys, Oxford University, TWI
Publication Date: 1994
Download: Download PDF

Description:

This paper reviews the resistance of Ferralium (UNS32550) to corrosion in sulphuric acid and chloride-containing medium. The benefits of Cu and N additions is considered, and an argument for reducing the perceived benefit of Mo in the calculation of the pitting resistance equivalent number (PREN) in sulphuric acid is proposed.