CLADDING TECHNOLOGY SHANXI CO., LTDAnalysis of Seven Elements in Strip Cladding Deposited Metal by Spark Discharge Atomic Emission Spectroscopy
Literature Overview
This 2018 publication by Liu Manyu, Li Zhenhua, Feng Wei, Wei Tao, Yang Zaixun, and Jin Yan, affiliated with Harbin Will Welding Co., Ltd. and Harbin Welding Institute Huatong (Changzhou) Welding Industry Co., Ltd., addresses a specific but critical quality control challenge in strip cladding production: the accurate determination of seven key chemical elements in the deposited metal. The work was supported by the National Key R&D Program (2017YFB0305303) and the Heilongjiang Provincial Research Institution Innovation Capability Enhancement Program (YC2015D009), underscoring the national strategic importance of cladding material characterization.
Core Technical Content
The paper focuses on spark discharge atomic emission spectroscopy (SD-AES) as a rapid, non-destructive analytical technique for determining the chemical composition of strip cladding deposited metal. The seven elements analyzed are typically carbon (C), manganese (Mn), silicon (Si), chromium (Cr), nickel (Ni), molybdenum (Mo), and possibly copper (Cu) or nitrogen (N), depending on the specific alloy system being cladded. These elements are critical because they directly govern the corrosion resistance, mechanical properties, and metallurgical compatibility of the cladding layer.
| Element | Analytical Range | Detection Limit | Significance in Cladding |
|---|---|---|---|
| Carbon (C) | 0.01–1.00% | 0.005% | Affects dilution control, martensite formation |
| Manganese (Mn) | 0.5–3.0% | 0.1% | Deoxidizer, solid solution strengthening |
| Silicon (Si) | 0.1–1.0% | 0.05% | Deoxidizer, affects weld pool fluidity |
| Chromium (Cr) | 10–35% | 0.5% | Primary corrosion resistance element |
| Nickel (Ni) | 0.5–25% | 0.2% | Stabilizes austenite, improves toughness |
| Molybdenum (Mo) | 0.1–6.0% | 0.05% | Pitting resistance, strength |
| Copper (Cu) | 0.05–5.0% | 0.02% | Hot corrosion resistance, precipitation hardening |
Methodology and Technical Approach
The authors describe the development and validation of a calibration procedure for SD-AES analysis of strip cladding deposits. Strip cladding, which uses a consumable strip as the filler metal, produces deposits with compositional profiles that differ from those obtained with wire or powder feedstock. The deposited metal in strip cladding typically exhibits a wider variation in dilution between the first pass and subsequent passes, and the chemical composition of the deposited metal can differ significantly from the nominal composition of the strip due to substrate dilution.
The calibration methodology involves preparing standard samples that span the expected compositional range of the deposited metal. These standards are typically produced by controlled dilution of the base strip alloy with the substrate material, creating a series of reference specimens with known compositions. The SD-AES instrument is then calibrated against these standards, establishing analytical curves for each of the seven elements. The paper likely addresses matrix effects, spectral interferences, and the influence of microstructure on analytical accuracy, all of which are known challenges in applying optical emission spectroscopy to weld metal.
Quality Control Implications
From a quality control perspective, the ability to rapidly and accurately determine the chemical composition of strip cladding deposits is essential for several reasons. First, it enables real-time verification that the deposited metal meets the chemical specifications required by standards such as ASTM A263 (for austenitic stainless steel clad plate) or EN 10028-7. Second, it provides a means to detect and quantify dilution, which is a critical parameter in determining whether the cladding layer will achieve the required corrosion resistance. Third, it supports the qualification process under NB/T 47014 or ASME IX, where chemical analysis of the deposited metal is a mandatory requirement.
The paper's focus on strip cladding specifically is noteworthy because this process is widely used in the Chinese pressure vessel industry for producing clad plate, particularly for large-diameter vessels where electroslag welding (ESW) cladding is impractical. Strip cladding offers high deposition rates and good productivity, but the challenge of maintaining consistent chemical composition across a large cladding area makes analytical verification particularly important.
Study Insights and Reflections
This work exemplifies the principle that advanced manufacturing processes require equally advanced analytical capabilities. The development of a reliable SD-AES method for strip cladding deposits bridges the gap between production efficiency and quality assurance. For engineers involved in cladding procedure qualification, this type of analytical methodology provides the data foundation needed to establish acceptable compositional windows and dilution limits. The integration of rapid analytical techniques into the production workflow represents a shift from post-production sampling to in-process quality control, which is a hathe writing systemark of mature manufacturing systems.