Lean duplex stainless steel (D4)

Even better product, even better value!

Technically speaking, it was already far superior to the austenitic materials A4, A5 and A4L in terms of strength, durability and value. But now we can offer an even better alloy with a price/performance ratio that is second to none.

In collaboration with our civil engineering partner, ASTATEC GmbH & Co. KG, who specialise in fastening systems, we provide support and retaining anchors for masonry and precast concrete components and natural stone façades for prestigious projects throughout Europe.

The advantages of Modersohn:

1. significant reduction of thermal bridges, thanks to the low thermal conductance of lean duplex stainless steel "D4" - γ = 15 (W/m*k) compared to non-alloyed steel (incl. galvanised or coated!) γ = 50 (W/m*k) and aluminium γ = 150 (W/m*k).
2. As a further step towards reducing thermal conductance, the civil engineers exploit the steel's high strength of up to S450 to achieve a slim design and reduced fastening points, thus leaving the wall construction as undisturbed as possible.
3. The use of lean duplex stainless steel materials also considerably cuts the cost of material acquisition due to the very low content of expensive nickel and molybdenum in the special duplex alloy. The low alloy surcharge compared to the A4/A5 steels also means they are less vulnerable to price fluctuations, thus offering greater price stability, a major advantage for longer-term offers.
4. Lean duplex stainless steel "D4", at S400 and S450 (yield strength Rp_0,2 at least 450 N/mm²), has double the basic strength of A4/A5 steels (1.4401/1.4404/1.4571), thus enabling our civil engineers to produce designs with considerably reduced material thickness.
5. In terms of corrosion resistance, lean duplex stainless steel "D4" is also ideal for safety-relevant fastenings. In contrast with the aforementioned austenitic A4/A5 steels, it is resistant to chloride or hydrogen-induced stress corrosion cracking up to temperatures of 50°C .
   "Stress corrosion cracking" occurs when a material is subjected to the simultaneous effect of purely static tensile stresses, or low-frequency pulsating tensile stress, and a corrosive environment. This causes fine hair cracks that can considerably weaken the cross-section of a component.

Please feel free to contact us for further information on this topic:

• Prof. Dr.-Ing. Wolf Berend Busch, material expert and CEO of DVS BV, East Westphalia-Lippe
  Email: prof.busch(at)modersohn.de
• Wilhelm Modersohn, a member of the Executive Board of the Stainless Steel Information Office, at the German Steel Centre in Düsseldorf.
  Email: modersohn(at)modersohn.de