Flatness and Profile Control Patents: Who Leads, Where the Gaps Are 2026
- 43.7% concentration. The top 5 assignees combined account for 289 of the 662 records in scope — the field's core flatness and shape-control claims sit with a small group.
- Filing has cooled from its 2017 peak. Volume ran 34 records in 2017, and the confirmed 2021–2024 span shows a 70% drop (10 to 3); 2025–2026 are still filling in under publication lag.
- B21B dominates, but adjacent classes are thin. 86.6% of records sit in metal rolling (B21B), while control systems (G05B, 5.1%) and force measurement (G01L, 4.1%) trail well behind — a gap between mechanical claims and closed-loop control claims.
Filing growth compares 2021 (10 records) with 2024 (3) — 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 662 records in scope (CR5), not by the ranked leaders only.
What this landscape covers
Flatness and profile control spans the mechanisms rolling mills use to keep strip shape within tolerance: work roll bending, roll shifting (including CVC-style continuously variable crown profiles), edge drop compensation, flatness measurement systems and the closed-loop control logic that ties actuators to shape feedback. This dataset covers 662 published records filed between 2015 and mid-2026, drawn from a search string that pairs mechanical flatness terms with actuator-interaction and measurement terms — so it captures the intersection of hardware and control claims rather than either alone.
The picture that emerges is one of a mature mechanical core — work roll bending and shifting claims sit on dense prior art dating back decades, visible in citation counts running into the hundreds for foundational patents — layered with a thinner, more recent set of measurement and control claims. Family-level counting is used throughout so that multi-jurisdiction filing by the same applicant does not inflate any single technology's apparent weight.
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Filing trend and technology composition
Two views of the same 662-record set: how filing activity has moved year over year, and how records distribute across IPC subclasses. Because a single record can carry several IPC classes, the composition shares add up to more than 100%.
Filing trend
Filings peaked at 34 in 2017. The confirmed comparison point — 2021 at 10 records against 2024 at 3 — shows a 70% decline over that three-year span. 2025 and 2026 figures are not yet a reliable read on real filing activity: publication typically lags filing by around 18 months, so recent-year counts will keep rising as more records publish.
Technology composition
B21B (metal rolling) covers 86.6% of the 662 records, confirming that most activity is claimed as rolling-mill hardware rather than as standalone instrumentation or control. G01B measurement (10.3%), B22D casting (5.6%), G05B control systems (5.1%) and G01L force measurement (4.1%) each cover a meaningfully smaller slice, with B21C, B24B and B21D trailing further behind.
Shares are the percentage of the 662 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Flatness and Profile Control with Eureka
This page is one run against one query. Ask Eureka your own question about flatness and profile control and every answer comes back with the patent numbers behind it.
Try EurekaMost-cited records and a representative filing
US8096161B2 — Method for rolling strips in a roll stand
Filed by SMS Siemag, this patent claims a method for rolling strips where two axially displaceable work rolls carry a CVC-style ground contour expressed as a third-order-or-higher polynomial curve. The method forces increased cyclic shifting of the work rolls through cyclic variation of the setting values applied to the working cylinders from one strip to the next, aimed at homogenising work roll wear while retaining fine control over profile and flatness.Abstract text drawn directly from the published filing.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US6306007B1 | Rolling mill equipped with on-line roll grinding system and grinding wheel | 109 |
| 2 | US6769279B1 | Multiroll precision leveler with automatic shape control | 64 |
| 3 | US4274273A | Temperature control in hot strip mill | 60 |
| 4 | US6119500A | Inverse symmetrical variable crown roll and associated method | 59 |
| 5 | US6286349B1 | Flatness measurement system for metal strip | 48 |
| 6 | US3818743A | Rolling mills | 46 |
| 7 | US4369646A | Rolling mill and method for rolling a sheet material | 41 |
| 8 | JP1980077903A | Rolling method for shape control | 41 |
| 9 | US7181822B2 | Method and apparatus for controlling strip shape in hot rolling mills | 39 |
| 10 | US5174144A | 4-High rolling mill | 37 |
Citation counts reflect influence within the searched corpus and skew toward older filings; treat them as a signal of foundational importance rather than current commercial weight.
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-outs from the dataset that matter more for strategy than the raw counts alone.
The core claims are held by a small group
With 289 of 662 records concentrated among five assignees, work roll bending and shifting mechanisms are well-claimed ground. A new entrant filing on the core mechanical actuator geometry is filing into dense prior art, not open space.
Confirmed filing volume has fallen from its peak
The 2017 peak of 34 records has not been repeated. The 2021-2024 comparison, the last span with reliable publication coverage, shows filing volume down 70% — a real decline, not an artefact of publication lag.
Mechanical rolling claims dominate over control claims
Metal rolling (B21B) covers the large majority of records, while control and regulating systems (G05B) cover only 5.1% and force measurement (G01L) 4.1%. Closed-loop control logic that ties measurement to actuator response is comparatively lightly claimed relative to the mechanical hardware it governs.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to flatness and profile control, with the prior art for and against each one.
Who holds the ground, and where the collaboration sits
The ranked leaders list returns 100 companies, not a top-50 or top-100 cut by design — it is the full set the data endpoint returns for this search. Ranked first with 73 records, the leader sits well ahead of fifth place at 40 and tenth place at 22, and the top 10 combined account for 67.2% of all 662 records in scope.
A clear leader, then a fast taper
The leading assignee holds 73 records against 40 at fifth place and 22 at tenth — a steep drop-off rather than a flat plateau, meaning the gap between first and mid-table is wider than between mid-table and the long tail.
Two-thirds of the field sits with ten companies
445 of 662 records belong to the top 10 ranked assignees. The remaining 90 ranked companies plus unranked filers split the last third, which is where single-filing entrants and research institutes tend to sit.
Co-filing is limited but concentrated
Only 10 co-assignee pairs appear in the dataset, and the strongest of them recur across multiple filings rather than being one-off joint ventures — consistent with equipment suppliers and mill operators partnering repeatedly rather than broadly.
| Assignee | Recent year | YoY |
|---|---|---|
| Nucor Corporation | 0 | — |
| Hitachi, Ltd. | 0 | — |
| SMS Group GmbH | 0 | — |
| IHI Corporation | 0 | — |
| ABB AB | 0 | — |
| Nippon Steel Corporation | 0 | — |
| Kawasaki Steel Corporation | 0 | — |
| Novelis Inc. | 0 | — |
Where to take this from here
The landscape points to a mechanically dense core and thinner control-layer coverage. The next step is usually a closer read of specific claim sets before committing engineering time to a design.
Check freedom to operate against the cited core patents
The most-cited records in this set carry citation counts running into the hundreds and define the mechanical baseline for roll bending and shifting. Any new actuator or crown-control design should be checked against these claims before prototyping.
Explore citation trees in EurekaProbe the control-layer white space
G05B and G01L coverage trails B21B by a wide margin, suggesting closed-loop control and force-feedback integration are less thoroughly claimed than the mechanical hardware they operate. A first claim there would pair a specific sensor input with a specific actuator response rule.
Run a white space search in EurekaQuestions practitioners ask about this field
The ranked leader in this dataset holds 73 records, well ahead of fifth place at 40 and tenth place at 22. The top 5 assignees combined account for 43.7% of all 662 records in scope, and the top 10 account for 67.2%. This is a concentrated field: a handful of rolling-mill equipment suppliers and steelmakers hold most of the core work roll bending, shifting and crown-control claims, with a long tail of single-filing entrants behind them.
Filing peaked at 34 records in 2017 and has not returned to that level since. The most recent reliable comparison, 2021 against 2024, shows a 70% decline from 10 records to 3. Figures for 2025 and 2026 are still incomplete because publication typically lags actual filing by around 18 months, so those years will rise as more records publish, but the confirmed 2021-2024 trend is a genuine slowdown, not a lag artefact.
The large majority of records, 86.6%, sit in IPC class B21B, metal rolling, covering work roll bending, shifting and crown-profile hardware. Measurement systems (G01B) appear in 10.3% of records, casting-related claims (B22D) in 5.6%, control and regulating systems (G05B) in 5.1%, and force or pressure measurement (G01L) in 4.1%. Because a record can carry multiple IPC classes, these shares add up to more than 100% and should be read individually against the 662-record total, not summed.
US6306007B1, titled 'Rolling mill equipped with on-line roll grinding system and grinding wheel,' is the most-cited record in this dataset at 109 citations. High citation counts inside a searched patent corpus tend to favour older filings simply because they have had longer to accumulate references, so this reflects the patent's foundational role in on-line roll grinding rather than current commercial dominance. Anyone designing an on-line grinding or roll-maintenance system should review it as part of a freedom-to-operate check.
Relative to the dense mechanical core in B21B, the control and measurement layers are thinner: G05B (control and regulating systems) covers only 5.1% of the 662 records and G01L (force and pressure measurement) covers 4.1%. That gap suggests closed-loop logic tying specific sensor readings to specific actuator responses, and integrated force-measurement sensing, are less thoroughly claimed than the mechanical hardware they operate on. A first filing there would need to specify a concrete sensor-to-actuator control rule rather than a general control loop.
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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.