Nickel-Core Stick Electrode for Lower-Cost High-Nickel Welding
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Solution Overview
Problem
Current stick electrodes for forming weld metal with nickel composition that satisfies AWS A 5.15-90 for ENiFe-CI and ENiFe-CI-A classes are difficult and expensive to produce, especially for use in both continuous arc welding and stick welding operations due to the high cost and difficulty in obtaining nickel sheets of desired alloy composition.
Innovation Solution
A consumable electrode with a nickel-containing core and an iron alloy sheath, where the core comprises at least 50 wt.% nickel and the sheath is formed from an iron alloy with minimal nickel content, optionally coated with a flux layer to generate shielding gases and protect the weld pool, allowing for the creation of a weld metal with a nickel content greater than 35 wt.%, suitable for both continuous arc welding and stick welding processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a nickel-containing sheath is used to form weld metal with high nickel content, then the weld metal composition satisfies AWS A 5.15-90 for ENiFe-CI and ENiFe-CI-A classes, but the manufacturing cost and difficulty increase significantly
Solution Approach 1:
The electrode is divided into two functional parts: a nickel-rich core (≥50 wt.% nickel) that provides the necessary nickel content for the weld metal, and an iron alloy sheath with minimal nickel content that provides structural integrity and protects the core. This segmentation allows the nickel to be concentrated where needed in the core rather than distributed throughout the entire electrode structure, significantly reducing the total nickel required and manufacturing complexity.
Solution Approach 2:
The electrode structure implements local quality by concentrating high nickel content (≥50 wt.%) specifically in the core region where it is most needed for weld metal composition, while the outer sheath contains minimal nickel content. This localized distribution of nickel ensures the weld pool receives sufficient nickel alloying elements while avoiding the need to manufacture and handle expensive nickel sheets for the entire electrode structure.
2Adaptability or versatility
If nickel sheets of desired alloy composition are used to form the sheath, then the electrode can be used for both continuous arc welding and stick welding operations, but the cost and difficulty of obtaining and processing nickel sheets increase
Solution Approach 1:
The electrode is segmented into a nickel-rich core and an iron alloy sheath with minimal nickel content. This segmentation allows the core to provide nickel for weld metal composition in both continuous arc and stick welding operations, while the iron alloy sheath provides mechanical protection and structural integrity. This eliminates the need to obtain and process expensive nickel sheets for the entire electrode structure.
Solution Approach 2:
The electrode employs a composite structure combining a nickel-rich core material with an iron alloy sheath material. This composite construction provides the dual functionality needed for both continuous arc welding and stick welding operations while using materials that are easier and less expensive to obtain and process than solid nickel sheets, particularly for the sheath portion.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The proposed electrode solution provides a cost-effective means to produce weld metal with high nickel content, suitable for various welding operations, by utilizing a nickel-rich core and an iron alloy sheath, enhancing the efficiency and affordability of nickel-containing weld metal production.
Implementation Method 1
coalescence is produced by heating with an electric arc between a bare-metal electrode and the metal being worked
Implementation Method 2
The welding operation is started by striking an arc beneath the flux to produce heat to melt the surrounding flux
Implementation Method 3
A flux is generally coated on the outer surface of the sheath... The molten filler metal displaces the flux pool and forms the weld
Data Source
Figure 1
Figure 2
AI summary
A metal-cored electrode for welding to form a weld bead on a ferrous material, which weld bead includes at least 35 wt.% nickel. The metal-cored electrode includes a metal sheath surrounding a core. The core includes greater than 35 wt.% nickel.