Blast-Furnace Ironmaking Patents: Top Companies & Filing Trends 2026
- 25.8% concentration at the top. The top 5 assignees hold 238 of 924 records in scope — a fifth-place company still files 33, so the field narrows fast after the leader's 68.
- Filings grew 43% from 2021 to 2024. Activity rose from 40 records in 2021 to 57 in 2024, with 2022 the peak year so far at 60 — before the usual 18-month publication lag understates the most recent years.
- C21B dominates, but C22C alloy claims stay thin. 68.6% of records sit in core blast-furnace class C21B, while only 4.9% touch C22C alloy composition — a narrow band relative to the furnace-process crowding above it.
Filing growth compares 2021 (40 records) with 2024 (57) — 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 924 records in scope (CR5), not by the ranked leaders only.
What this landscape covers
This dataset tracks 924 published patent records filed between 2015 and 2026 that describe blast-furnace ironmaking processes, hot metal production, reduction furnace operation, and related alloy composition and microstructure control claims. The scope spans core furnace mechanics through to downstream metallurgical quality control, so a single record can carry multiple IPC classes at once. Family counts, not raw document counts, drive the assignee ranking, which keeps continuation filings and multi-jurisdiction duplicates from skewing who looks active.
Filing offices skew toward the United States and Europe, with India, Australia, the WIPO PCT route and Canada rounding out the receiving-office spread. That mix points to a technology still being filed defensively across steelmaking's traditional manufacturing and export markets, rather than consolidating around a single jurisdiction.
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Filing trends and technology composition
Two views of the same 924-record set: how filing volume has moved year over year, and how records distribute across IPC subclasses.
Growth phase, not a plateau
Filings climbed from 9 in 2017 to a peak of 60 in 2022, then held in a high band — 40 in 2021 rising to 57 in 2024, a 43% increase over that span. 2025 and 2026 figures will rise as publications catch up to filing dates already on record.
Where the claim density sits
C21B (iron production, blast furnace) appears in 68.6% of the 924 records, far ahead of C22B metal extraction (22.0%) and C21C steelmaking (20.8%). Furnace hardware classes F27D and F27B together cover a meaningful share of records, while C22C alloys (4.9%) and C10L fuels (3.1%) are the thinnest bands — these percentages overlap because records carry more than one class.
Shares are the percentage of the 924 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 Patent Landscape with Eureka
This page is one run against one query. Ask Eureka your own question about blast-furnace ironmaking patent landscape and every answer comes back with the patent numbers behind it.
Try EurekaA recent filing that shows where the claims are heading
Method for controlling a process, method for operating a blast furnace, method for producing hot metal, and apparatus for controlling the process (EP4541910A1)
The filing acquires hot metal temperature, hot metal production rate, and gas permeability of a blast furnace via observed or calculated values, then controls all three simultaneously against target values through a single process control unit.The claim's novelty sits in simultaneous multi-variable control rather than in any one measured parameter alone.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US5695130A | Method and apparatus for the dry grinding of solids | 102 |
| 2 | US4363654A | Production of reducing gas for furnace injection | 65 |
| 3 | US20230020752A1 | Producing biocarbon pellets with high fixed-carbon content and optimized reactivity, and biocarbon pellets ob… | 57 |
| 4 | US3928023A | Method of treating off gases from iron processes | 57 |
| 5 | US20230015387A1 | Processes for producing biocarbon pellets with high fixed-carbon content and optimized reactivity, and biocar… | 51 |
| 6 | US5234490A | Operating a blast furnace using dried top gas | 50 |
| 7 | US4504043A | Apparatus for coal-gasification and making pig iron | 50 |
| 8 | US4087274A | Method of producing a partially reduced product from finely-divided metal sulphides | 48 |
| 9 | US4072504A | Method of producing metal from metal oxides | 48 |
| 10 | US5259864A | Method of disposing of environmentally undesirable material and providing fuel for an iron making process e.g… | 45 |
Citation counts favour older records simply by being in the corpus longer; treat them as a signal of influence rather than of current importance. The two biocarbon-pellet filings among the most-cited records point to a citation cluster forming around alternative reductant feedstock.
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Browse MCP servers →What the numbers mean for a filing decision
Three findings that change where a competent team should look next, drawn directly from the concentration, growth and class-mix figures above.
The top of the field is narrow, the tail is long
Five assignees hold a quarter of all records, with the leader alone at 68. Below tenth place at 22, the ranking thins into single- and low-digit filers, meaning most technical variations in this space are held by companies with only a handful of families each.
Activity is still climbing, not cooling
The rise from 40 records in 2021 to 57 in 2024 came after an even sharper peak of 60 in 2022, suggesting the field went through a filing surge and has settled into a higher sustained rate rather than a one-off spike.
Alloy composition claims are thin relative to furnace process claims
C21B blast-furnace process claims cover 68.6% of records, but C22C alloy composition claims cover only 4.9%. That gap is wide enough to suggest alloy-side microstructure and impurity-control claims are comparatively open next to the crowded furnace-operation space.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to blast-furnace ironmaking patent landscape, with the prior art for and against each one.
Assignee landscape and collaboration patterns
The ranked leaders show a steep drop-off from the top filer to the rest of the field, with a small number of recurring co-assignee partnerships pointing to structured joint R&D rather than one-off collaboration.
One filer sets the pace
The top-ranked assignee's 68 records are roughly double the fifth-place count of 33, a gap wide enough to suggest a deliberate, sustained filing programme rather than incidental output.
The middle of the field flattens quickly
Between fifth place at 33 and tenth place at 22, the gap narrows considerably compared with the drop from first to fifth — a sign that mid-tier filers are competing on comparable footing.
A small number of tight partnerships stand out
Ten recurring co-assignee pairs appear in the data, with the strongest pairing filing jointly 21 times — evidence of structured joint development between a small group of steelmakers and research institutes rather than broad industry-wide co-filing.
| Assignee | Recent year | YoY |
|---|---|---|
| JFE Steel Corporation | 3 | +200% |
| Pohang Iron & Steel Co., Ltd. (POSCO) | 0 | — |
| Kobe Steel, Ltd. | 0 | — |
| Nippon Steel Corporation | 0 | — |
| Carbon Technology Holdings, LLC | 0 | — |
| ArcelorMittal SA | 0 | -100% |
| Technological Resources Pty Ltd | 0 | — |
| Praxair Technology, Inc. | 0 | — |
Where to take this analysis
The figures above establish who files and what they claim. The next step is testing a specific claim idea against the records that actually crowd or leave open a given sub-area.
Check freedom-to-operate on a specific claim
Run a targeted search against the C22C alloy composition and off-gas treatment records before drafting, since the thin class shares here can hide a small number of very specific blocking claims.
Explore in Patsnap EurekaTrack the leader's recent filing pace
The leader's momentum has shifted sharply in the latest year; monitoring their newest filings shows whether the multi-variable control approach in EP4541910A1 is becoming a pattern.
Monitor assignee activity in Patsnap EurekaCommon questions about this landscape
The ranked leader in this dataset holds 68 of the 924 records in scope, well ahead of the fifth-ranked assignee at 33 and the tenth-ranked at 22. The top five assignees combined account for 25.8% of all records, and the top ten for 40.2%, showing a field that is concentrated at the very top but still leaves more than half of filings spread across a long tail of smaller filers. Anyone assessing competitive risk should look past the single leader to the mid-tier cluster, since the gap between fifth and tenth place is much narrower than the gap between first and fifth.
Yes, based on complete-year data: filings rose from 40 records in 2021 to 57 in 2024, a 43% increase, with 2022 standing as the peak year so far at 60. Figures for 2025 and 2026 will look lower in the raw count, but that reflects the roughly 18-month lag between filing and publication rather than a genuine slowdown. Treat any apparent dip in the most recent one to two years as incomplete data, not a trend reversal.
C21B, the core iron-production and blast-furnace class, appears in 68.6% of the 924 records in scope, making it by far the most heavily claimed area. C22B metal extraction and refining (22.0%) and C21C steelmaking (20.8%) follow at a distance, with furnace hardware classes F27D and F27B covering smaller but still notable shares. Because a single record can carry several IPC classes, these percentages overlap rather than sum to 100%, so they describe density within each class, not a market breakdown.
The clearest gap sits in C22C alloy composition claims, which cover only 4.9% of the 924 records despite the furnace-process classes above them being heavily claimed. C10L fuels and firelighters is similarly thin at 3.1%. That imbalance suggests alloy-side microstructure and impurity-control work, along with alternative fuel and reductant formulations, are comparatively open relative to core furnace-operation claims, though any specific filing plan still needs a targeted freedom-to-operate check against the exact wording of nearby records.
EP4541910A1, filed by JFE Steel Corporation and published 2025-04-23, claims a method and apparatus that acquires hot metal temperature, hot metal production rate, and blast-furnace gas permeability, then controls all three simultaneously against target values through one process control unit. The novelty is in the simultaneous multi-variable control approach rather than in measuring any single parameter alone, which narrows what a competitor can safely claim around integrated blast-furnace control loops. Anyone building a similar control system should map their claim language against this simultaneous-control mechanism specifically, not just against hot-metal temperature control in general.
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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.