For fastening solutions in chloride containing and aggressive media

Fire hazard, dynamic loads and aggressive environmental media: The difficult conditions in tunnel construction place high demands on the building material, especially on the steel. For example, it plays a supporting role in fastening elements. With Acidur 4529, Deutsche Edelstahlwerke (DEW) offers the right steel solution for such complex applications. Thanks to good mechanical properties and excellent corrosion resistance, superaustenite is a reliable and durable material - not only for tunnel construction.

Acidur 4529: Corrosion resistant against chloride containing and aggressive media

The materials used in road construction and especially in tunnelling must withstand particularly difficult conditions with good corrosion properties. Chlorides from de-icing agents and a high sulphur dioxide content due to car exhaust gases attack tunnel structures. There are high dynamic loads that promote stress corrosion cracking. With Acidur 4529, Deutsche Edelstahlwerke covers such requirements in building construction and civil engineering well.

High molybdenum content for improved resistance

Thanks to its alloy composition, the stainless superaustenitic steel has a high resistance to numerous organic and inorganic acids. It is significantly more resistant to corrosion than conventional chromium-nickel-molybdenum steel. In addition, the high molybdenum content offers improved resistance to pitting and stress corrosion cracking. Compared with standard austenite, Acidur 4529 has a higher tensile strength of at least 800 MPa, which can be specifically adjusted by additional cold processing of the raw material.

Contact and expert advice

Simone Ermert
Deutsche Edelstahlwerke
+49 2302 29-2565
Send e-mail
Advantages at a glance

  • Superaustenitic steel
  • High resistance to pitting and stress corrosion cracking
  • Good combination of strength and toughness
  • tensile strength of at least 800MPa
Available products

  • Wire rod
  • Bright bars
  • Bright wire
  • Bars
Available grades

  • Acidur 4404
  • Acidur 4529
  • Acidur 4571
  • Duplex steel Acidur 4362
  • Duplex steel Acidur 4462

A stainless grade for many applications in the construction industry

Due to its special chemical composition, this steel grade is suitable for all applications where halogenated or chloride-containing media have to be tolerated: in swimming pool construction, in the chemical industry or in sea and brackish water applications.

Acidur 4529: Technical data

Mechanical properties

Min. yield strengths (Rp0.2) expressed in N/mm²

Ø in mm Hardness in HB Rp0,2 in MPa Rp1,0 in MPa Rm in MPa A5 in % AV in J
160 250 300 340 650 - 850 ≥ 40 longitudinal ≥ 100 longitudinal
160 ≤ 500 350 300 340 650 - 850 ≥ 35 transversal ≥ 60 transversal
Physical properties
Density in kg/dm2 Electrical resistance at 20°C in (Ω mm2)/m Magnetisa-bility Thermal conductivity at 20°C in W/(m K) Specific heat capacitiy at 20°C
in J/(kg K)
Young's modules in GPa at »20°C Mean thermal expansion coefficient in 10-6K-1 »20°C
 - 100°C
8.1 1.00 no 12 450 195 15.8
Chemical composition (in % by weight)
    C Si Mn P S Cr Ni Mo N Cu
min.  -  -   -  -  - 19,0 24,0 6,0 0,15 0,5
max. 0,02 0,5 1,0 0,03 0,01 21,0 26,0 7,0 0,25 1,5
Delivery options
Type Acidur 4529
  Wire rod Ø 5,5 - 30,0 mm
  Bright steel, bars Ø 2,0 - 20,0 mm
  Bright steel, coils Ø 2,0 - 20,0 mm
  Steel bars on demand

Swiss tunnel construction with stainless steel Acidur 4529

The material solution has proven itself in various tunnel construction projects. In the concrete example of a road tunnel in Switzerland DEW supplied more than 100 tons of long steel with a dimension of 27.6 mm round. The client used the steel in fastening elements for the suspension of the suspended ceiling in the tunnel.

Since this construction is located behind the outer formwork and is not accessible for regular inspections, the steel must be reliably durable. In addition, it is used here in the critical area of load-bearing structures and, with its high heat resistance, also fulfils the criteria for fire protection. While it is ultimately the responsibility of the client and designer to fulfil the safety-related requirements, DEW experts provide comprehensive advice and support with their materials expertise.



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