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Run your analysis now →https://www.patsnap.com/resources/blog/rd-blog/continuous-hot-dip-galvanizing-lines-patent-landscape/ · Patsnap · data cut-off 2026-07-31 · downloaded from the live page
Patent Landscape · Coated Steel SheetContinuous Hot Dip Galvanizing Line Patents: Who Leads and Where the Claims Sit
- Concentrated at the top. The five leading assignees hold 41.2% of all 1,059 records in scope, and the top ten hold 59.7% — this is a field with a short list of gatekeepers, not a fragmented one.
- Filing has cooled from its 2019 peak. Output ran from 39 records in 2021 down to 15 in 2024, a -62% swing over that span, after peaking at 70 records in 2019.
- Coating claims dominate the class mix. C23C coating and surface deposition appears in 69.3% of records, more than double the next most common class, C21D heat treatment at 30.1%.
1,059
Published Records
41%
Top-5 Share of All Records
-62%
Filing Growth 2021→2024
US
Leading Jurisdiction
Filing growth compares 2021 (39 records) with 2024 (15) — a three-year span. 2024 is the most recent year we treat as complete: publication lags filing by roughly 18 months, so 2025 onwards are still filling in and any growth rate that ends there would understate the field. Top-5 share is the combined record count of the five largest assignees divided by all 1,059 records in scope (CR5), not by the ranked leaders only.
Published byPatsnap Research··7 min readSourced from Patsnap Eureka
Field Overview
What this landscape covers
Continuous hot dip galvanizing lines sit at the intersection of metallurgy and process control: strip enters a molten zinc pot, passes through air knife wiping to set coating weight, and exits through cooling and temper stages that fix spangle appearance and mechanical properties. The dataset behind this page pulls 1,059 published records filed between 2015 and mid-2026 that combine core process terms — zinc pot management, dross formation, strip temperature — with the galvanizing line itself, rather than galvanized steel generically.
That framing narrows the field to line-level process and equipment claims rather than downstream coating chemistry alone, which is why furnace, control-system and coating-apparatus classes show up as meaningful minorities alongside the two dominant coating and heat-treatment classes.
Records by filing year, 2015–2026
Source: Patsnap Eureka. Assignee ranking and totals. Derived from a Patsnap search on Continuous Hot Dip Galvanizing Lines covering 2015–2026, data cut-off 2026-07-31. Counts reflect published records only and shift as new filings publish.Run this in Eureka MCP
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The Data
Filing trend and technology composition
Two views of the same 1,059-record corpus: how filing volume has moved year on year, and how records distribute across IPC subclasses. Because a single record can carry several IPC codes, the class shares below sum to well over 100% of the record total.
Filing trend, 2017-2026
Annual output climbed to a peak of 70 records in 2019, then fell across the following years; the -62% drop from 39 records in 2021 to 15 in 2024 is the clearest complete-year signal, since 2025 and 2026 are still filling in under normal publication lag.
IPC subclass distribution
C23C (coating and surface deposition) touches 69.3% of the 1,059 records, C21D (heat treatment) 30.1%, and C22C (alloys) 17.5%; smaller but persistent minorities sit in B21B rolling, G05B control systems, B05C/B05D coating apparatus and process, and F27B furnaces, each around 3-4%.
Shares are the percentage of the 1,059 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Source: Patsnap Eureka. Filing trend and technology composition. Derived from a Patsnap search on Continuous Hot Dip Galvanizing Lines covering 2015–2026, data cut-off 2026-07-31. Counts reflect published records only and shift as new filings publish.
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Most-cited records in the corpus
Representative Filing
US6761936B1 — Method and installation for hot dip galvanizing hot rolled steel strip
SMS DEMAG AG
Filed by SMS Demag AG, this record specifies a full line sequence: a pickling station that strips scale and reaction products from the strip surface, a rinsing station that removes pickle residues before drying, and a furnace stage that brings the strip to galvanizing temperature under a protective gas atmosphere ahead of the zinc pot.Abstract condensed from the original filing.
Highest-citation records
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | WO2006002843A1 | Steel sheet with hot dip galvanized zinc alloy coating and process to produce it | 116 |
| 2 | WO2008102009A1 | Cold rolled and continuously annealed high strength steel strip and method for producing said steel | 78 |
| 3 | US4845332A | Galvanneal induction furnace temperature control system | 62 |
| 4 | EP1621645A1 | Steel sheet with hot dip galvanized zinc alloy coating | 61 |
| 5 | US4330574A | Finishing method for conventional hot dip coating of a ferrous base metal strip with a molten coating metal | 60 |
| 6 | US4135006A | Automatic coating weight controls for automatic coating processes | 59 |
| 7 | WO2007146161A1 | High-aluminum alloy for general galvanizing | 54 |
| 8 | US6180933B1 | Furnace with multiple electric induction heating sections particularly for use in galvanizing line | 54 |
| 9 | US20040050323A1 | Apparatus for controlling coating weight on strip in continuous galvanizing process | 48 |
| 10 | US4369211A | Process for producing a hot dip galvanized steel strip | 48 |
Citation counts inside this corpus skew toward older filings simply because they have had longer to accumulate citations; treat the ranking as a signal of influence on later filings, not of current commercial relevance.
Each row carries its publication number; clicking a row searches Eureka by that number.
Source: Patsnap Eureka. Citation counts and representative records. Derived from a Patsnap search on Continuous Hot Dip Galvanizing Lines covering 2015–2026, data cut-off 2026-07-31. Counts reflect published records only and shift as new filings publish.Run this in Eureka MCP
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What the numbers say about the field
Three patterns stand out once the records are ranked and classified: a concentrated ownership structure, a cooling filing trend that predates the publication-lag window, and a claim landscape weighted heavily toward coating over control.
Concentration
41.2%
of 1,059 records held by top 5
A short list of gatekeepers
The five leading assignees account for 41.2% of all records in scope, and the top ten extend that to 59.7%. New entrants are filing against a claim space that a small group of steelmakers and equipment builders has already staked out over more than a decade.
Based on the full 100-company assignee ranking.
Filing momentum
-62%
2021 to 2024 change
Output down from its 2019 peak
Annual filings peaked at 70 records in 2019 and dropped from 39 in 2021 to 15 in 2024. That is a real, complete-year decline; figures for 2025 and 2026 are not yet comparable because publication typically lags filing by around 18 months.
2024 is the most recent year treated as complete.
Claim weighting
69.3% vs 30.1%
C23C vs C21D share of records
Coating claims outweigh heat treatment more than 2 to 1
C23C coating and surface deposition touches 69.3% of the 1,059 records, against 30.1% for C21D heat treatment. Control-system claims under G05B sit at just 3.4%, suggesting the automation layer of these lines is comparatively under-claimed relative to the metallurgy.
Shares sum above 100% because records carry multiple IPC codes.
Collaboration
10 pairs
co-assignee pairs identified
Filing partnerships are narrow and stable
Only ten co-assignee pairs appear in the corpus, and the strongest of them link the same handful of steelmakers and heavy-industry equipment suppliers repeatedly rather than spreading across new partners.
Counted by co-listed assignee pairs on shared records.
Eureka AI Agent
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Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to continuous hot dip galvanizing lines, with the prior art for and against each one.
Source: Patsnap Eureka. Co-assignee relationships and derived observations. Derived from a Patsnap search on Continuous Hot Dip Galvanizing Lines covering 2015–2026, data cut-off 2026-07-31. Counts reflect published records only and shift as new filings publish.Run this in Eureka MCP
Players
Who holds the claim space
The assignee ranking spans 100 companies drawn from the full 1,059-record corpus. Ownership is front-loaded: a handful of Japanese, European and American steelmakers and line-equipment builders hold the bulk of the ranked total, with a long tail of single- or few-filing entrants behind them.
Leader
125 records
leading assignee
The top filer sits well clear of the field
The leading assignee holds 125 records against 53 for the fifth-ranked company and 31 for tenth place, a steep drop-off that marks this as a leader-plus-pack structure rather than an even spread.
Counted in patent families across the ranking.
Recent momentum
1 filing
latest-year record, top assignee
Even leaders have gone quiet recently
Nippon Steel shows just 1 record in the latest year, and several other historically active filers, including Tata Steel Ijmuiden, show 0 with a -100% year-on-year change. This tracks the broader cooling trend rather than signalling exit from the field.
Momentum reflects publication-lag-affected recent years.
Partnerships
20 shared records
strongest co-assignee pair
Joint filings cluster around equipment integration
The strongest co-assignee pairing links a steelmaker with a heavy-industry equipment maker, consistent with lines being engineered and patented jointly by the mill operator and the furnace or coating-equipment supplier.
Based on the 10 co-assignee pairs identified in the corpus.
Recent-year filing momentum by assignee
| Assignee | Recent year | YoY |
|---|---|---|
| Nippon Steel Corporation | 1 | — |
| JFE Steel Corporation | 0 | — |
| Tata Steel Ijmuiden BV | 0 | -100% |
| Kawasaki Steel Corporation | 0 | — |
| ArcelorMittal SA | 0 | — |
| Mitsubishi Heavy Industries, Ltd. | 0 | — |
| SMS Group GmbH | 0 | -100% |
| Nippon Kokan KK | 0 | — |
Source: Patsnap Eureka. Assignee-level momentum. Derived from a Patsnap search on Continuous Hot Dip Galvanizing Lines covering 2015–2026, data cut-off 2026-07-31. Counts reflect published records only and shift as new filings publish.Run this in Eureka MCP
What's Next
Where to take this analysis
The dataset points to a field with concentrated ownership and a cooling but not collapsing filing rate. The next steps depend on whether the goal is freedom-to-operate, competitive tracking, or identifying a filing gap.
Run a freedom-to-operate check on the gate chips
The under-claimed sub-areas above — dross detection, air knife feedback control, in-line spangle sensing — are worth a targeted search before committing engineering resources to them.
Explore in EurekaTrack the leading assignees' next moves
With several top filers at zero in the latest year, watch for renewed activity that could signal a new product line or process generation entering the patent record.
Set up assignee trackingMap claims against US6761936B1 and the other cited records
The most-cited records define the process sequence competitors have already staked out; a claim chart against them clarifies what a new filing needs to design around.
Build a claim chartSource: Patsnap Eureka. Forward-looking reading of the same dataset. Derived from a Patsnap search on Continuous Hot Dip Galvanizing Lines covering 2015–2026, data cut-off 2026-07-31. Counts reflect published records only and shift as new filings publish.Run this in Eureka MCP
FAQ
Common questions about this landscape
Ownership is concentrated: the leading assignee holds 125 records, and the five leading assignees together account for 41.2% of the 1,059 records in this dataset. The top ten extend that to 59.7%. The leaders are a mix of established steelmakers and heavy-industry equipment builders, and the drop-off from the top few names to the rest of the ranked 100 companies is steep rather than gradual, so a small group effectively sets the claim environment for the whole field.
Filing peaked at 70 records in 2019 and has declined since, with a documented -62% drop from 39 records in 2021 to 15 in 2024. That 2021-2024 window is the most reliable recent signal because publication typically lags filing by around 18 months, so 2025 and 2026 figures are still incomplete and should not be read as a continuation of decline or a sign of recovery either way.
Coating and surface deposition, IPC class C23C, appears in 69.3% of the 1,059 records, making it by far the most heavily claimed area. Heat treatment (C21D) follows at 30.1% and alloy composition (C22C) at 17.5%. Control and regulating systems (G05B) sit at only 3.4%, which is a much lower share than the metallurgical classes despite automation being central to modern line operation.
US6761936B1, assigned to SMS Demag AG, describes a full hot dip galvanizing sequence for hot-rolled strip: a pickling station that removes scale, a rinsing station that clears pickling residues before drying, and a furnace stage that brings the strip to temperature under a protective gas atmosphere ahead of the zinc pot. It is useful as a reference point for the baseline line architecture that later, more specific coating-weight and control claims build on, rather than as a narrow point claim to design around in isolation.
The class data points toward automation and sensing as comparatively under-claimed relative to coating chemistry and heat treatment: control and regulating systems (G05B) sit at just 3.4% of records against 69.3% for coating claims. Specific candidates include closed-loop air knife pressure control, automated dross detection, and in-line spangle appearance sensing, all of which show up as adjacent but lightly claimed branches next to the dense core coating and furnace classes.
Answers are grounded in the same dataset. Derived from a Patsnap search on Continuous Hot Dip Galvanizing Lines covering 2015–2026, data cut-off 2026-07-31. Counts reflect published records only and shift as new filings publish.Run this in Eureka MCP
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Disclaimer. This page is generated from Patsnap Eureka data drawn from a limited snapshot of global patent and scientific-literature records, and is provided for general information and reference only.
Patent data carries inherent limitations: recent filings (typically the most recent 18–24 months) are under-counted due to standard publication lag; counts may be reported at either a patent-family or a patent-record basis and are not always directly comparable; classification, applicant-name, and citation data may contain errors, duplicates, or omissions; and the underlying search query defines and constrains the scope shown. As a result, the analysis may be incomplete or inaccurate and may not reflect the full technology landscape.
Nothing on this page constitutes an exhaustive prior-art, novelty, freedom-to-operate, or validity search, nor does it constitute legal, financial, investment, or professional advice, and it should not be relied upon as such. Any patent, commercial, or strategic decision should be verified independently and reviewed with qualified patent, legal, and domain professionals. Patsnap makes no warranties, express or implied, as to the accuracy, completeness, or fitness for any particular purpose of the information presented.
Machine translation. Assignee and organisation names originally recorded in Chinese, Japanese or Korean have been rendered into English by an AI translation step so that the tables stay readable. These renderings are best-effort and may not match a company's registered English name; the original name is what the underlying patent record carries, and it is what any Eureka query launched from this page uses.