G-TECH 413

SMAW
  • COPPER ALLOYS
CuNi 70-30

Description

Special basic coated electrode, with alloyed core
Suitable for welding Cupronickel alloys (up to 30% Ni). The deposited metal has exceptional resistance to marine corrosion and shows good corrosion resistant fatigue. Therefore it is suitable also for joining and build-up welding in desalination plants, naval accessories, water treatment plants, heat exchangers and chemical industry equipments. Preheating is not necessary and avoid continuous welding, keep the interpass temperature under 100ºC. The arc length should be short as possible and adopt straight bead method.
Specifications
AWS A5.6
ECuNi
DIN 1733
EL-CuNi30Fe
Shielding
-
Positions
PA, PB, PC, PD, PF
Current
DC+
Packaging Type
Carton box
Asme qualifications
F-No (QW432)
34
A-No (QW442)
-

Hardness

90HB
Chem. Comp. %
DEFAULT
Mn
1.3
Ni
30
Si
0.15
Fe
0.7
Mechanical Properties
min
variant
Tensile strength Rm MPa
350
370
Yield strength Rp0.2 MPa
-
230
Elongation A (L0=5d0) %
20
30
Impact Charpy ISO-V
-
-
Impact Charpy ISO-V
-
-
Welding Parameters
2.5 mm
3.2 mm
4.0 mm
Ampere
80A - 120A
100A - 140A
150A - 200A
Voltage
-
-
-
Packaging
pcs/kg
pcs/kg
pcs/kg
Packaging Type
Carton box
Carton box
Carton box
Description

Application

The CuNi 70-30 consumable is particularly suitable for overlay and cladding operations, provided a buttering layer is created. This is commonly done using alloy 400 or pure nickel. The 70/30 consumables are ideal for welding 70/30, 80/20, and 90/10 base materials. They match the 70/30 base materials in terms of strength and color, and allow for overmatched welding on 90/10 alloys for optimal strength. This material is widely used in offshore constructions, desalination plants, evaporators, condensers, and systems for treating saline and marine water. No preheat is required, and the maximum interpass temperature is 150°C, with no need for PWHT. It is crucial to avoid contamination in the weld area with foreign materials, particularly sources of lead, tin, or zinc, to prevent cracking in the weld metal.

Alloy Type

70/30 copper-nickel alloys.

Microstructure

Solid solution, single phase alloy.

Materials

  • EN W.Nr.: 2.0872 (CuNi10Fe), 2.0882 (CuNi30Mn1Fe), 2.0883 (CuNi30Fe2Mn2)
  • ASTM: C71500, C96400 (cast)
  • UNS: C71500, C96400, C70600, C96200
  • PROPRIETARY: Cunifer 30 (VDM), Cunifer 10 (VDM), Osna®-30 (KME), Osna®-10 (KME)

Welding & PWHT

Particularly suitable for welding applications that require high resistance to corrosion in aggressive environments. This includes systems exposed to saline and seawater, where long-term durability is critical.

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