Hot Strip Rolling Mills Patents: Who Leads, Where Gaps Are 2026
- Concentrated at the top. the top 5 assignees hold 37.5% of all 251 records in scope, and the top 10 hold 53.8% — a small group controls more than half the field.
- Filings have flattened. activity peaked at 12 records in 2022 after rising from 5 in 2017, with no sign of renewed acceleration through the most recent full year.
- Coverage skews to core rolling and heat treatment. 80.1% of records sit in B21B (metal rolling) and 41.8% in C21D (heat treatment), leaving control-systems classes like G05B at just 1.2%.
What this landscape covers
This dataset tracks 251 published records filed against hot strip mill technology — rolling force models, strip crown and flatness control, coiling temperature regulation, work roll wear, and thermomechanical control — filtered to IPC classes B21B (metal rolling), B21B37, and C21D8. Coverage runs from 2015 through the 2026-07-31 cut-off, so the most recent year is necessarily a partial count.
Filing activity in this field is driven almost entirely by integrated steelmakers and mill-equipment suppliers rather than newer entrants, and the receiving-office mix shows where enforcement and freedom-to-operate questions are most likely to arise in practice.
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Filing trends and technology composition
Two views of the same 251-record dataset: how filing volume has moved year over year, and how records distribute across IPC subclasses.
Filing trend, 2017–2026
Filings rose from 5 records in 2017 to a peak of 12 in 2022, then held flat to declining. Because publication lags filing by roughly 18 months, the final year or two of this trend will read low regardless of true filing activity.
IPC subclass composition
B21B (metal rolling) appears in 80.1% of the 251 records and C21D (heat treatment of metals) in 41.8%, confirming that most filings combine rolling mechanics with a thermal or metallurgical claim. Because records can carry multiple IPC classes, these shares sum to well over 100% and should not be read as a pie that adds to one whole.
Shares are the percentage of the 251 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Hot Strip Rolling Mills with Eureka
This page is one run against one query. Ask Eureka your own question about hot strip rolling mills and every answer comes back with the patent numbers behind it.
Try EurekaRepresentative and most-cited filings
WO2008078908A1 — Temperature controlling method and apparatus in hot strip mill (POSCO, 2008-07-03)
There is provided a method and apparatus for controlling temperature in a hot strip mill. In order to accurately control coiling temperature by using middle temperature, a method of controlling temperature in a hot strip mill includes correcting a learning coefficient of a coil previously processed, collecting finishing delivery temperature, coiling temperature, middle temperature, and moving speed of a strip, calculating an air cooling drop amount of temperature by using the finishing delivery temperature and calculating a water cooling drop amount of temperature by using the air cooling drop amount of temperature and a coiling temperature target value, calculating a first water cooling drop amount target.Abstract truncated as provided in the underlying filing record.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | JP1996252625A | Method for controlling coiling temperature in hot rolling | 41 |
| 2 | JP2005154906A | High tensile strength cold-rolled steel sheet having excellent strain age hardening property, and its product… | 40 |
| 3 | CN102581008A | 一种生产低成本高成形性IF钢的加工方法 | 36 |
| 4 | EP0730916A1 | Hot rolling method and apparatus | 33 |
| 5 | JP1988168211A | Temperature control method for hot rolling process | 32 |
| 6 | CN101456038A | 热轧带钢层流冷却过程板带温度监测方法 | 31 |
| 7 | CN102330023A | 屈服强度500MPa级H型钢用钢及其控轧控冷工艺 | 29 |
| 8 | US4261190A | Flatness control in hot strip mill | 28 |
| 9 | CN102962296A | 一种厚规格X120管线钢热轧卷板的低温卷取方法 | 27 |
| 10 | US20070106400A1 | System and method for online property prediction for hot rlled coil in a hot strip mill | 25 |
Citation counts are drawn from within this searched corpus and favour older filings that have had more time to accumulate citations — treat them as a measure of influence on later filings, not of current commercial 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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Three patterns stand out once concentration, timing and technology mix are read together.
A small group controls the core claim space
The top 5 assignees combined account for 37.5% of all 251 records, and the top 10 push that to 53.8%. New entrants filing in rolling force models or coiling temperature control are filing into ground already claimed by a handful of integrated steelmakers and mill builders.
Filing activity has plateaued
Volume rose from 5 records in 2017 to a peak of 12 in 2022, and recent-year momentum among the largest historical filers shows zero new filings in the latest year for each of the leading assignees tracked. That is consistent with a maturing claim space rather than a growing one.
Control-systems claims are thin
G05B (control and regulating systems) appears in only 1.2% of records and G02B (optical elements) in 3.2%, even though modern flatness and crown control increasingly depends on sensing and control-loop architecture rather than mechanical mill design alone.
Japan and China dominate the receiving-office mix
Japan (86) and China (46) lead the receiving offices tracked, ahead of the EPO (29), the United States (28), South Korea (17) and India (13) — a filer clearing freedom-to-operate needs to check Japanese and Chinese prior art first.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to hot strip rolling mills, with the prior art for and against each one.
Who holds the claim space
The assignee ranking covers 74 companies scored by patent family count across the full 251-record dataset — not a top-50 or top-100 cut, but the complete ranking the data returns.
One filer sits well ahead of the field
The leading assignee holds 34 records, more than triple the count at fifth place (11), which sets the pace for the concentration seen across the top 5 and top 10 combined.
A steep drop-off after the leader
Filing counts fall quickly from the leader to fifth place and again to tenth place, indicating a small set of established filers rather than a broad cluster of similarly sized competitors.
Joint filing is limited but concentrated
Only 8 co-assignee pairs appear in the dataset, and the strongest pair links two entities under the same corporate group, suggesting cross-company joint filing is rare in this field compared with intra-group collaboration.
| Assignee | Recent year | YoY |
|---|---|---|
| Nippon Steel Corporation | 0 | — |
| Kawasaki Steel Corporation | 0 | — |
| Sumitomo Metal Industries, Ltd. | 0 | — |
| Pohang Iron and Steel Co., Ltd. (POSCO) | 0 | — |
| Nippon Kokan KK | 0 | — |
| Primetals Technologies Austria GmbH | 0 | — |
| Tata Steel Ltd. | 0 | — |
| Primetals Technologies Japan, Ltd. | 0 | — |
Where to take this analysis
The dataset points to a mature, concentrated core and a thinner control-systems periphery. Two directions follow from that.
Map freedom-to-operate against the top filers
With 53.8% of records held by the top 10 assignees, any new filing in rolling force models or coiling temperature control should be checked against those portfolios first, particularly filings routed through Japan and China.
Explore assignee portfolios in EurekaTest the control-systems white space
G05B and G02B classes remain thin relative to the B21B core, suggesting sensing and closed-loop control claims around flatness and crown may face less crowded prior art.
Run a white-space search in EurekaCommon questions about hot strip mill patents
The dataset's assignee ranking of 74 companies shows a clear leader with 34 records, well ahead of the fifth-ranked assignee at 11. The leading names are integrated steelmakers and mill-equipment suppliers with long histories in rolling force modelling and coiling temperature control. Because the ranking counts patent families rather than raw documents, it reflects distinct inventions rather than continuation filings or multiple national counterparts of the same invention.
No, filing volume has flattened. Records rose from 5 in 2017 to a peak of 12 in 2022, and have not shown renewed growth since. Recent-year momentum data for the largest historical filers shows zero new filings in the latest year, though this should be read cautiously since publication typically lags filing by around 18 months, which understates the most recent year in any dataset.
B21B, covering metal rolling, appears in 80.1% of the 251 records in scope, and C21D, covering heat treatment of metals, appears in 41.8%. C22C (alloys) and B21C (metal extrusion and drawing) follow at lower shares. Because a single record can carry multiple IPC classes, these percentages add up to more than 100% and should be read as overlapping coverage rather than a market share breakdown.
Control and sensing-related classes are comparatively thin: G05B (control and regulating systems) covers only 1.2% of the 251 records and G02B (optical elements and systems) covers 3.2%, despite modern flatness and crown control depending heavily on real-time sensing and closed-loop architecture. That gap suggests claims tied to control-loop design or optical profile measurement face less crowded prior art than mechanical rolling or heat-treatment claims.
Among the receiving offices tracked, Japan leads with 86 filings, followed by China with 46, the European Patent Office with 29, the United States with 28, South Korea with 17, and India with 13. This distribution reflects where applicants chose to seek protection, not necessarily where the underlying research originated, and it signals where freedom-to-operate checks matter most for anyone commercialising in this space.
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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.