Blast Furnace Ironmaking Patents: Who Leads, Where Gaps Are 2026
- 54.5% concentration at the top. The top 5 of 74 ranked assignees combined account for 132 of 242 records in scope — over half the field sits with a small group.
- Filing has cooled since 2020. Filings peaked at 27 in 2020 and had fallen back toward single digits by 2026, with the 2022 midpoint at 12 — growth here is flat or declining, not accelerating.
- Almost no branch diversification. Every record in scope carries the core C21B class; the next largest branch, F27D, appears in only 5.4% of records, meaning most inventive activity is staying inside the core furnace process rather than spreading into adjacent systems.
What the blast furnace ironmaking patent record shows
Blast furnace ironmaking is a mature, capital-intensive process, and the patent record reflects that: filings cluster tightly around core furnace operation rather than spreading across a wide technology tree. The search scope here spans 242 records published between 2015 and the 2026 cut-off, filtered to documents that combine blast furnace operation or hot metal production language with specific operational terms such as coke rate, pulverized coal injection, burden distribution, hearth erosion or top gas recycling, and classified under the core iron-production IPC group. That filter produces a corpus weighted toward operational control and process-parameter claims rather than broad furnace design.
Because publication lags filing by roughly 18 months, the most recent year of the trend is always undercounted relative to how it will eventually settle. Treat the apparent 2026 figure as a floor, not a ceiling, and read the multi-year pattern rather than the last data point alone.
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Filing trend and technology composition
Two views of the same 242-record corpus: how filing activity has moved year over year, and how those records distribute across IPC subclasses.
Filing trend, 2017-2026
Filings rose to a peak of 27 in 2020, had fallen back to a midpoint of 12 by 2022, and stood at 2 in the partial 2026 year — from 4 in 2017. The shape is a rise-and-cool pattern rather than sustained growth, consistent with a process area where the core inventive questions have largely been claimed.
IPC subclass composition
Every record in scope carries the core C21B iron-production classification by construction of the search. Beyond that, F27D furnace details (5.4%), C01B inorganic compounds (4.1%) and G06Q data processing (4.1%) are the largest secondary branches, followed by C10J gasification, C22B metal extraction and F27B furnaces, each around 3.7%. These are class shares against the 242-record total, and because records can carry multiple classes they sum to more than 100%.
Shares are the percentage of the 242 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Blast Furnace Ironmaking with Eureka
This page is one run against one query. Ask Eureka your own question about blast furnace ironmaking and every answer comes back with the patent numbers behind it.
Try EurekaMost-cited records and a recent representative filing
Process control method, blast furnace operation method, hot metal production method, process control device, and program (US20260218321A1)
The filing describes a process control method that predicts future hot metal temperature with a physical model and, when the predicted value deviates from a target beyond a threshold, determines operation amounts for pulverized coal rate and blast moisture using an evaluation function balancing that deviation against reducing-agent rate. It is a closed-loop control scheme built directly on the operational parameters — coke rate, pulverized coal injection, blast conditions — that define the search scope itself.Filed by JFE Steel Corporation, published 2026-07-30 — among the most recent records in scope.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | JP1987263906A | Method for blowing pulverized coal from blast furnace tuyere | 43 |
| 2 | WO2019057930A1 | Method for producing hot synthesis gas, in particular for use in blast furnace operation | 30 |
| 3 | JP1999061284A | Evaluation test method of reduction degradation characteristic of sintered ore | 22 |
| 4 | US4976780A | Blast furnace operation management method and apparatus | 22 |
| 5 | GB1218912A | Blast furnace operation | 17 |
| 6 | CN1043745A | 高炉操作管理方法和装置 | 16 |
| 7 | US4381938A | Multi-purpose zone controlled blast furnace and method of producing hot metal, gases and slags | 16 |
| 8 | EP0641863A1 | Blast furnace operation management method and apparatus | 15 |
| 9 | US5437706A | Method for operating a blast furnace | 14 |
| 10 | CN106191350A | 基于定点雷达的高炉下部风口工作状况评估方法 | 13 |
Citation counts favour older documents simply because they have had more time to accumulate citations inside the searched corpus — read this as a signal of influence on the field's prior art, not as a ranking of current commercial importance.
Patent titles are shown in the language they were filed in, not translated, so that each record stays verifiable against the original filing — a translated title will not match in Eureka or in any national register. Each row carries its publication number; clicking a row searches Eureka by that number.
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Browse MCP servers →What the numbers mean for a filing decision
Three read-throughs of the concentration, trend and citation data, framed around where a new filing would actually land.
Core process claims are already crowded
Just over half of all records in scope sit with the five leading assignees, out of a ranked list of 74 companies total. That level of concentration in a 242-record field means the central operational-control claims around coke rate, pulverized coal injection and burden distribution are heavily occupied, and a new entrant filing on the same core parameters is filing into dense prior art rather than open ground.
Momentum has passed its peak
The filing trend rose from 4 in 2017 to a peak of 27 in 2020, then eased back to a midpoint of 12 by 2022. That pattern is more consistent with a technology area where the highest-value control and operational claims were staked out early in the cycle, and later filings are refining rather than opening new ground.
Older tuyere and process-management patents anchor prior art
The most-cited records in this corpus include a 1987 pulverized-coal tuyere method and a 1990s-era blast furnace operation management patent, both with high citation counts. That skew toward older documents is typical of citation data in a searched corpus and should be read as a marker of foundational influence, not as evidence those approaches remain the frontier.
Filing activity is spread across major steel-producing jurisdictions
South Korea, the EPO route, China, India, Japan and the UK all register meaningful filing volumes in this corpus, reflecting where blast furnace capacity and steel R&D investment are concentrated. A freedom-to-operate check for this technology needs to span multiple receiving offices rather than a single home jurisdiction.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to blast furnace ironmaking, with the prior art for and against each one.
Assignee concentration and collaboration patterns
The ranked list covers 74 companies across the full 242-record corpus. Filing is concentrated at the top, with a long tail of single- or few-filing entrants below.
One assignee holds a clear lead
The top-ranked assignee holds 55 of the 242 records in scope, well ahead of fifth place at 13 and tenth place at 6. That gap between first and fifth position indicates a single dominant filer rather than a tightly bunched group at the top.
Joint filing is rare and mostly intra-group
Only four co-assignee pairs appear in this corpus, and the strongest pair — a major steelmaker filing jointly with a furnace-technology specialist — recurs eight times. The next pairs involve a steelmaker filing with its own research institute, suggesting most collaboration is internal group activity rather than cross-company partnership.
Recent-year activity has gone quiet even among leaders
Every one of the six assignees tracked for recent-year momentum, including the corpus leader, shows zero filings in the latest year, with one showing a -100% year-on-year change. Given the 18-month publication lag, this likely understates true recent activity, but it is consistent with the broader cooling trend since the 2020 peak.
| Assignee | Recent year | YoY |
|---|---|---|
| JFE Steel Corporation | 0 | -100% |
| Pohang Iron & Steel Co., Ltd. (POSCO) | 0 | — |
| Nippon Steel Corporation | 0 | — |
| Kobe Steel, Ltd. | 0 | — |
| Paul Wurth S.A. | 0 | — |
| Midrex Technologies, Inc. | 0 | — |
| Nippon Kokan K.K. | 0 | — |
| Hyundai Steel Co., Ltd. | 0 | — |
Where to take this analysis
The dataset points to a mature, concentrated field with a cooling filing trend — the next step is usually a closer look at specific claim sets or a freedom-to-operate check before committing R&D spend.
Check freedom to operate against the top assignees
With 54.5% of 242 records held by the top 5 of 74 ranked assignees, any new filing on core operational-control claims should be checked against that group's existing claim scope first.
Explore assignee claims in EurekaLook for openings in secondary IPC branches
Branches such as F27D, C01B and G06Q carry far fewer records than the core C21B class, which is where claim space is more likely to still be open.
Run a white-space search in EurekaCommon questions about blast furnace ironmaking patents
One assignee leads the ranked list with 55 of the 242 records in scope, well ahead of the fifth-ranked company at 13 and the tenth-ranked at 6. The top 5 of 74 ranked assignees together hold 132 records, or 54.5% of the full 242-record corpus, so filing activity is concentrated among a small group of major steelmakers and furnace-technology suppliers rather than spread evenly. Anyone assessing competitive position in this space should look closely at that leading group's existing claims before filing on core operational parameters.
The filing trend rose from 4 records in 2017 to a peak of 27 in 2020, then eased back toward single digits by 2026, with a midpoint of 12 in 2022. That is a flat-to-declining pattern rather than sustained growth, suggesting the core inventive questions around coke rate, pulverized coal injection and burden distribution were largely staked out during the earlier part of the period. Because publication lags filing by around 18 months, the most recent year's low count understates true activity somewhat, but the overall cooling trend predates that lag effect.
By construction of the search, every one of the 242 records carries the core C21B iron-production classification. Beyond that core, the next largest branches are F27D furnace details and accessories at 5.4% of records, and C01B inorganic compounds and G06Q data processing each at 4.1%, followed by C10J gasification, C22B metal extraction and F27B furnaces around 3.7% each. Because a single record can carry several IPC classes, these percentages add up to more than 100% and should be read as coverage shares against the 242-record total, not as a breakdown that sums to one.
South Korea is the leading receiving office with 50 filings in this corpus, followed closely by the European Patent Office route at 48 and China at 46. India, Japan and the United Kingdom follow at 26, 20 and 13 respectively. That spread across major steel-producing economies means a freedom-to-operate review for this technology needs to cover several jurisdictions rather than relying on a single home-country search.
The clearest signal is the gap between the core C21B class, present in 100% of the 242 records, and every secondary branch, none of which exceeds 5.4% of records. Branches such as furnace-gas gasification, data-driven burden optimization, and furnace accessory retrofits carry far fewer filings than the core process claims, which points to comparatively open claim space for combinations that pair blast furnace operation with those adjacent systems. Co-assignee data also shows only 4 identified collaboration pairs across the whole corpus, suggesting cross-company joint development in these adjacent areas remains rare.
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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.