Continuous Casting EM Stirring Patents: Who Leads, Where Gaps Are 2026
- Filing activity peaked in 2020 at 114 records and has since eased to 89 in 2024, an 18% decline over that three-year span — a maturing but still active claim space, not a collapsing one.
- The ranked field is a long tail the top 5 assignees hold just 12.9% of all 2,476 records in scope, and the top 10 only 18.2% — no single filer controls the core mold-flow or stirrer-placement claims.
- Metal casting (B22D) anchors 45.2% of records while control-specific classes like H02P (motor/generator control) sit at just 4.0%, pointing to where stirring hardware is claimed heavily but control logic is not.
Filing growth compares 2021 (108 records) with 2024 (89) — 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 2,476 records in scope (CR5), not by the ranked leaders only.
What this landscape covers
Electromagnetic stirring and braking in continuous casting spans a mix of hardware (stirrer placement, coil design, induction sources) and process control (mold flow pattern, meniscus stability, argon bubble distribution, equiaxed zone ratio). This landscape draws on 2,476 published records filed or published between 2015 and mid-2026, searched against title and title/claim/description fields for electromagnetic stirring or braking combined with the process parameters that define how a stirring system is tuned and evaluated. Because publication lags filing by roughly 18 months, the most recent one to two years in any trend chart will read lower than eventual filings will show.
The dataset is dominated by steelmakers and casting-equipment builders rather than component suppliers, and the technology composition below shows a field still organised primarily around casting hardware rather than control software.
Filing trends and technology composition
Two views of the same 2,476-record dataset: how filing volume has moved year over year, and how records distribute across IPC subclasses.
Filing trend: rise, peak, plateau
Annual filings ran from 102 in 2017 to a peak of 114 in 2020, then eased to 89 by 2024 — an 18% decline across 2021–2024. Treat 2025 and 2026 figures as provisional; they will revise upward as later publications land.
Technology composition by IPC subclass
B22D (metal casting) covers 45.2% of the 2,476 records, far ahead of C22C alloys (12.3%) and H02K electric motors and generators (7.0%). Because records can carry multiple IPC classes, these shares sum to more than 100%; the pattern nonetheless shows casting-hardware claims outnumbering motor-control claims (H02P, 4.0%) by a wide margin.
Shares are the percentage of the 2,476 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Continuous Casting Electromagnetic Stirring with Eureka
This page is one run against one query. Ask Eureka your own question about continuous casting electromagnetic stirring and every answer comes back with the patent numbers behind it.
Try EurekaA representative record
Controlled casting of in-mold large steel ingot with induced variable power and variable frequency applied to the top surface of molten metal in-mold
Large steel ingot casting is accomplished with a top suspended induction heating device supplied with variable power and variable frequency from a power source. By the induction heating and stirring provided by the top suspended induction heating device, metal solidification advances progressively upwards from bottom to top, and the upper molten metal in a riser part compensates for shrinkage of the lower solidified metal in the main part. Inclusions are selectively moved out of the molten metal by a variable electromagnetic stirring force and the formation of casting defects is suppressed.Filed by Inductotherm Corp., published 2024-03-12.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US5517464A | Integrated modulator and turbine-generator for a measurement while drilling tool | 333 |
| 2 | US20200008990A1 | A reconfigurable wheeled personal mobility device | 94 |
| 3 | US5709347A | Device for electromagnetically braking and clutching a spool | 92 |
| 4 | US4701653A | Disk drive with internal brake and static discharge | 79 |
| 5 | EP0681090A2 | Measurement while drilling tool | 69 |
| 6 | US5699850A | Method and apparatus for control of stirring in continuous casting of metals | 67 |
| 7 | JP2009274686A | Electric power steering device | 66 |
| 8 | CN101391290A | 一种磁场与超声场耦合作用下熔体反应合成金属基复合材料的方法 | 65 |
| 9 | CN101032788A | 一种电磁复合场熔化极堆焊方法、设备及其拓展应用 | 62 |
| 10 | CN103252496A | 一种含非晶纳米晶高熵合金粉末及其制备方法 | 54 |
Citation counts favour older records simply because they have had longer to accumulate citations inside this corpus — read them as a signal of influence, not current relevance.
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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The top 5 assignees hold a modest share
The five most active filers together account for 320 records, 12.9% of everything in scope. That is meaningful presence, not control — the remaining 87% is split across a long tail of steelmakers, equipment builders and research institutes.
Volume has eased from its 2020 peak
Filings peaked at 114 in 2020 and fell to 89 by 2024, an 18% decline over that three-year window. That reads as a field settling into its established claim boundaries rather than one still expanding rapidly.
Filing activity is concentrated in China
China accounts for 1,192 records, well ahead of Japan (358) and the United States (195). Europe (EPO, 163), India (82) and WIPO/PCT (76) filings trail further behind, suggesting most defensive and enforcement activity should be checked first in Chinese filings.
Casting hardware outweighs control claims
B22D covers 45.2% of the 2,476 records, while H02P (motor and generator control) sits at just 4.0%. The gap suggests the mechanical and process side of stirring is heavily claimed while the control-algorithm layer is comparatively open.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to continuous casting electromagnetic stirring, with the prior art for and against each one.
Who is active, and where the gaps sit
The ranked field spans 100 companies counted by patent family. It is a long tail: strong at the top, but far from a duopoly.
The leading filer sits well ahead of fifth place
The top-ranked assignee holds 113 records versus 35 at fifth place and 23 at tenth — a steep drop-off after the leader, then a flatter tail across the rest of the ranking.
Even the top 10 hold under a fifth of the field
The ten most active assignees combined account for 451 records, 18.2% of the 2,476 in scope. That leaves the large majority of filing activity distributed among smaller, often single-country filers.
Co-filing is limited but consistent among Japanese steelmakers
Only 10 co-assignee pairs appear in the dataset, the strongest being a pairing tied to legacy Japanese steel groups. This points to mostly independent filing strategies rather than joint development programmes.
| Assignee | Recent year | YoY |
|---|---|---|
| Angang Steel Co., Ltd. | 1 | 0% |
| Nippon Steel Corporation | 0 | — |
| Kobe Steel, Ltd. | 0 | — |
| Sumitomo Metal Industries, Ltd. | 0 | — |
| Rotelec SA | 0 | — |
| NIPPON STEEL & SUMITOMO METAL CORP | 0 | — |
| Danieli & C. Officine Meccaniche SpA | 0 | — |
| Jiangsu University | 0 | — |
Where to take this
The dataset points to a field with occupied hardware claims and comparatively open control-layer claims. Two directions follow from that.
Map the control-layer white space
H02P control claims sit at just 4.0% of records against B22D's 45.2%. A focused search on variable-frequency and closed-loop stirring control could surface a genuinely open filing position.
Explore in EurekaTrack the leading filer's recent activity
With the top filer holding 113 records against a fifth-place total of 35, understanding what that assignee has filed in the last two published years matters more than the aggregate trend.
Run an assignee monitor in EurekaCommon questions
The ranking covers 100 assignees measured by patent family, and the leader holds 113 records compared with 35 at fifth place and 23 at tenth. That is a steep drop after the top filer, but even combined, the top 5 assignees account for only 12.9% of the 2,476 records in scope. Filing activity is dominated by large steelmakers and casting-equipment builders, but no single company controls the field outright.
Filings rose from 102 in 2017 to a peak of 114 in 2020, then declined to 89 by 2024, an 18% drop over that three-year span. That points to a field consolidating around established claim boundaries rather than one in early-stage expansion. Figures for 2025 and 2026 should be read as provisional since publication typically lags filing by around 18 months.
China leads by a wide margin with 1,192 records, followed by Japan at 358 and the United States at 195. Europe via the EPO holds 163, India 82, and WIPO/PCT filings account for 76. Anyone assessing freedom to operate should prioritise Chinese-language prior art and filings first, given the scale of the gap.
B22D, the metal casting classification, covers 45.2% of the 2,476 records, making it by far the largest single IPC subclass in this dataset. C22C alloys (12.3%) and H02K electric motors and generators (7.0%) follow well behind. Control-specific classes like H02P sit at only 4.0%, suggesting casting hardware and mechanical stirrer design are far more heavily claimed than the control-algorithm layer.
The clearest gap sits in control logic rather than hardware: H02P motor and generator control claims cover only 4.0% of records versus 45.2% for B22D casting hardware. Sub-areas tied to meniscus stability control, argon bubble distribution modelling, and variable-frequency power control for stirrers show comparatively thin filing density. These are process-parameter-driven claims layered on top of well-established hardware, which is typically a narrower and faster path to a defensible position than re-claiming stirrer geometry itself.
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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.