1Ni

For welding higher-strength steel structures in situations where post-weld heat treatment (PWHT) is impractical, requiring welds with a suitable level of toughness and crack resistance. The addition of approximately 1% Ni contributes to microstructural refinement, enhancing tolerance to procedural variations compared to plain carbon-manganese (CMn) weld metal. Nickel also improves resistance to atmospheric weathering and enhances electrochemical balance between the weld and base metal, minimizing preferential corrosion in marine environments. In cases of offshore oilfield sour service, a maximum of 1.0% Ni is often required (NACE MR0175). This consumable is recommended for applications where design specifications mandate toughness testing of higher-strength low-alloy steel welds down to –50°C, such as in offshore construction, pipelines, and pressure vessels. Preheat requirements will depend on the grade and thickness of the base material.

Low alloy steel alloyed with nominally 1%Ni for improved toughness. Actual Ni content is kept below 1% to ensure conformance with NACE MR0175.

In the as-welded condition the microstructure is ferritic with a component of acicular ferrite for optimum toughness.

Low temperature applications, fine-grained steels that contain 1 % Nickel.
EN W.Nr.: S460N (1.8901), S355N (1.0545), S460NL (1.8903), S460QL (1.8906).
ASTM: A333 & A334 gr. 6, A350 gr. LF2 & LF5, A352 gr. LCB & LCC (cast), A572 gr.50.
API: 5L X65.