Below are the most frequently asked questions about SAF™ 2707 HD hyper-duplex stainless steel.
- What is a hyper-duplex material?
- What is the chemical composition of SAF™ 2707 HD?
- What product forms are available?
- Are there any matching welding consumables?
- Are the stress corrosion cracking properties of SAF™ 2707 HD similar to those of SAF™ 2507?
- Can SAF™ 2707 HD be used as an alternative to nickel alloys?
- What references are available?
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What is a hyper-duplex material?
It is a duplex stainless steel grade with even better corrosion resistance than the super-duplex grade SAF™ 2507 super-duplex stainless steel. That is why we call it 'hyper-duplex'. Generally, it behaves as a super-duplex stainless steel, but SAF™ 2707 HD can be used in much more aggressive environments. The nominal PRE value for SAF™ 2707 HD hyper-duplex stainless steel is min. 48 (valid for tube and pipe).
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What is the chemical composition of SAF™ 2707 HD?
Chemical composition (nominal), % C
maxSi Mn P
maxS
maxCr Ni Mo Others 0.030 0.3 1.0 0.035 0.010 27 6.5 4.8 N=0.4
Co=1.0 -
What product forms are available?
Today, we can offer tubular products in SAF™ 2707 HD hyper-duplex stainless steel, with a focus on heat exchanger tubes.
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Are there any matching welding consumables?
Yes, welding products have been developed in parallel with the base material. Welding wire Exaton 27.7.5.L for GTAW (TIG) is available from ESAB.
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Are the stress corrosion cracking properties of SAF™ 2707 HD similar to those of SAF™ 2507?
Yes, results show that SAF™ 2707 HD is at least on the same high level or better than SAF™ 2507.
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Can SAF™ 2707 HD be used as an alternative to nickel alloys?
One of the targets with developing SAF™ 2707 HD hyper-duplex stainless steel has been to produce a duplex grade with performance on a similar level to nickel alloys. However, SAF™ 2707 HD is more attractive economically in terms of material and life cycle costs.
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What references are available?
SAF™ 2707 HD hyper-duplex stainless steel has been evaluated over the last couple of years in a variety of industrial heat exchanger applications, for example, refinery overhead condensers and seawater coolers.