AHSS Microstructure Patents: Who Leads, Where the Gaps Are 2026
- Filing has cooled since its 2019 peak of 50 families, with the 2022 midpoint at 37 and no year since matching the peak — a signal that core claim space is filling up rather than expanding.
- Every major East Asian steelmaker shows 0 filings in the latest year, including drops as sharp as -100% YoY at several named assignees, though the most recent year is always undercounted by publication lag.
- C22C alloy claims and C21D heat-treatment claims dominate at 388 and 371 records respectively, while B23K welding and B22D casting sit at single digits — a gap between microstructure claims and joining/casting integration.
What this landscape covers
This dataset tracks patent families addressing retained austenite control, martensite-bainite microstructure design, grain refinement and phase fraction control in advanced high-strength steel, filtered against IPC classes C21D8, C22C38/00 and C21D6. It spans filings from 2015 through the July 2026 data cut-off, covering 398 published families.
The claim activity concentrates overwhelmingly in alloy composition (C22C) and heat treatment (C21D), with coating, lamination and forming processes trailing well behind. Receiving-office data shows Europe and the United States as the primary filing venues, with India a distant but notable third.
Filing trend and technology composition
Two views of the same 398 families: how filing volume has moved year over year, and which IPC subclasses carry the claim density.
A peak in 2019, then plateau and decline
Filings rose to 26 in 2017 and peaked at 50 in 2019. By the 2022 midpoint, annual volume had settled at 37 — below peak but not collapsing. The trend line through the most recent years should be read cautiously: publication lag of roughly 18 months means the last one to two years will always look thinner than they eventually turn out to be.
Alloy and heat-treatment claims dominate
C22C (alloys) appears in 388 of 398 records and C21D (heat treatment) in 371 — together these two subclasses define almost the entire corpus. C23C (coating) at 80 and B32B (laminates) at 45 form a secondary tier. B21C, B21B, B23K and B22D — extrusion, rolling, welding and casting — each register in the single or low double digits, marking them as adjacent rather than core to how this technology has been claimed so far.
Shares are the percentage of the 398 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Advanced High-Strength Steel Microstructure Control with Eureka
This page is one run against one query. Ask Eureka your own question about advanced high-strength steel microstructure control and every answer comes back with the patent numbers behind it.
Try EurekaRepresentative and most-cited filings
US20190338403A1 — High-strength steel sheet with excellent crashworthiness characteristics and formability
Filed by POSCO, this family claims a steel sheet composition bounded by weight-percentage ranges for carbon, silicon, manganese, molybdenum, chromium, phosphorus, sulfur, aluminum, nitrogen, boron, antimony, titanium and niobium, with an explicit inequality — {(2x(Si+Al))+Mo+Cr}/C ≥ 20 — linking five of those elements to carbon content.Published 2019-11-07.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US20100258219A1 | High-Strength Steel Sheet with Excellent Low Temperature Toughness and Manufacturing Method Thereof | 62 |
| 2 | US20180237877A1 | Mitigating liquid metal embrittlement in zinc-coated press hardened steels | 42 |
| 3 | WO2013007729A1 | Hot-rolled high-strength steel strip with improved HAZ-softening resistance and method of producing said steel | 41 |
| 4 | US20130174941A1 | High-Strength Steel Material Having Outstanding Ultra-Low-Temperature Toughness and a Production Method There… | 37 |
| 5 | US20120282487A1 | High-strength steel sheet having excellent processability and paint bake hardenability, and method for produc… | 25 |
| 6 | WO2021089851A1 | Medium manganese steel product and method of manufacturing the same | 18 |
| 7 | US20190100818A1 | High-strength steel plate for pressure vessel having excellent toughness after post weld heat treatment and m… | 18 |
| 8 | EP2083094A1 | High-strength steel wire excelling in ductility and process for producing the same | 18 |
| 9 | US20180355453A1 | Ultra-high strength steel sheet having excellent phosphatability and hole expandability and method for manufa… | 17 |
| 10 | CN108559917A | 一种屈服强度1100MPa级超细晶高强钢板及其制造方法 | 16 |
Citation counts reflect influence within the searched corpus and skew toward older filings; they are not a measure 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 the raw filing counts and IPC splits are read together.
Growth has flattened, not accelerated
The corpus peaked in 2019 and has not returned to that level since. This is consistent with a technology area where the dominant compositional and heat-treatment approaches have already been staked out by early filers, leaving later entrants to file narrower, more defensive claims.
Two IPC subclasses carry almost the whole corpus
Alloy composition and heat treatment together appear in nearly every record. Coating, lamination and metal-forming processes are present but thin, which suggests that process-integration claims — how the microstructure survives downstream coating or forming — are comparatively open ground.
Major steelmakers show a pause, not an exit
Several long-standing assignees register zero filings in the most recent year, with some down as much as -100% YoY. Given the lag between filing and publication, this more likely reflects filings still working through the pipeline than a genuine withdrawal from the field.
Co-filing is rare and clustered
Only eight co-assignee pairings appear in the corpus, and the strongest pairing is concentrated between two related entities. Most filers in this space patent independently rather than through joint ventures.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to advanced high-strength steel microstructure control, with the prior art for and against each one.
Who holds the claim space
Filing activity concentrates among a small group of integrated steelmakers, with a long tail of single- or few-filing entrants behind them.
Concentration among established steelmakers
The ranking of assignees skews toward vertically integrated steel producers with long-running R&D programs in sheet steel metallurgy, rather than newer specialty-materials entrants.
A cooling period across the leaderboard
Several of the most active historical filers show no filings in the latest year. This pattern is broad enough across multiple unrelated assignees that it is more consistent with publication lag than with a coordinated pullback.
Joint filings are the exception
The strongest co-assignee pairing links two related corporate entities rather than independent competitors, and the remaining pairs are each thin. Most claim positions in this dataset are held solely.
| Assignee | Recent year | YoY |
|---|---|---|
| POSCO Co., Ltd. | 0 | -100% |
| JFE Steel Corporation | 0 | — |
| Tata Steel IJmuiden B.V. | 0 | -100% |
| Baoshan Iron & Steel Co., Ltd. (Baosteel) | 0 | — |
| Nippon Steel Corporation | 0 | -100% |
| SSAB Technology AB | 0 | — |
| Salzgitter Mannesmann Precision GmbH | 0 | — |
| Nakayama Steel Works, Ltd. | 0 | — |
Where to take this analysis
The dataset points to specific next steps depending on whether the goal is freedom-to-operate, whitespace filing, or competitive tracking.
Map claims against the under-claimed branches
Weld-zone and casting-stage microstructure control show far fewer filings than the core alloy claims. A targeted claim search in those branches can surface whether the gap is real or simply unindexed.
Explore in EurekaTrack assignees through the publication-lag window
The zero-filing readings in the latest year need re-checking as 2025-2026 filings continue to publish. Set a watch on the most active historical assignees rather than treating the current numbers as final.
Set up monitoring in EurekaReview the most-cited prior art before drafting
The highest-cited records in this corpus define the compositional boundaries examiners will search against first. Reading them before drafting a new composition claim avoids overlap with well-established prior art.
Review prior art in EurekaCommon questions
In this dataset it means patent families claiming control over retained austenite, martensite-bainite phase mixtures, grain refinement or phase fraction, filtered against IPC classes C21D8 (heat treatment control processes), C22C38/00 (iron alloys) and C21D6 (heat treatment of ferrous alloys). Most records combine a compositional claim with a processing step, such as a specific cooling or annealing schedule, rather than claiming composition alone. This combination is what distinguishes AHSS microstructure claims from general steel alloy claims.
Filing peaked at 50 families in 2019 and had fallen to 37 by the 2022 midpoint, with no year since matching the peak. This is consistent with early filers having already claimed the dominant compositional ranges and processing windows, pushing later filers toward narrower, more defensive claims. It is also important to note that the most recent one to two years in any patent dataset are undercounted because publication typically lags filing by about 18 months, so the true 2025-2026 filing volume is not yet visible.
The corpus is dominated by integrated steelmakers with long-running metallurgy R&D programs, several of which appear repeatedly across the assignee ranking. A number of these same assignees show zero filings in the latest recorded year, which given publication lag likely reflects filings still in the pipeline rather than an exit from the field. The representative filing in this dataset, US20190338403A1, comes from POSCO, one of the more consistently active filers in the space.
The clearest gaps sit outside the core C22C alloy and C21D heat-treatment subclasses, which together cover nearly the entire 398-record corpus. Welding and joining (B23K) and casting (B22D) each register only single-digit record counts, despite being necessary downstream steps for any AHSS component. That gap suggests claims tying microstructure retention to weld-zone behaviour or casting-stage phase control are comparatively under-filed relative to the core composition space.
This POSCO filing claims a specific steel sheet composition defined by weight-percentage ranges across twelve elements, including carbon, manganese, molybdenum, chromium, titanium and niobium, plus an explicit inequality linking silicon, aluminum, molybdenum, chromium and carbon. A composition falling within all of the stated ranges and satisfying that inequality would need to be evaluated against this claim. It does not, on its own, block every high-strength steel composition — only those matching its specific elemental ranges and the stated ratio expression.
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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.