AHSS Testing & Inspection Patents: Leaders & White Space 2026
- Filing has plateaued, not grown. Annual filings ran flat from 2017 through a 2023 peak of 12, then fell back toward zero by 2026 — a mature, cyclical filing pattern rather than an expanding one.
- Heat treatment and alloy claims dominate the IPC mix. C22C (alloys) appears in 173 of 179 families and C21D (heat treatment) in 138, while coating, welding and rolling classes each sit in the low double digits — the claim space is concentrated, not spread evenly across the process chain.
- Europe is the dominant filing venue. 77 of the tracked records route through the EPO, more than double the US total of 34, which changes where freedom-to-operate checks matter most.
Filing growth compares 2021 (6 records) with 2024 (1) — 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 179 records in scope (CR5), not by the ranked leaders only.
What this landscape covers
This landscape tracks 179 patent families published between 2015 and mid-2026 at the intersection of advanced high-strength steel (AHSS) and its testing and inspection methods — tensile testing, formability testing, ultrasonic inspection and hydrogen embrittlement testing, filtered against IPC classes covering alloy composition (C22C), mechanical testing (G01N3) and acoustic/ultrasonic testing (G01N29). The dataset captures both the steel compositions being qualified and the test methods used to qualify them, which is why alloy and heat-treatment classes outnumber pure test-method classes in the composition breakdown.
Because publication typically lags filing by around 18 months, the apparent drop-off in the most recent years understates real filing activity; treat the last one to two years of the trend as provisional rather than a confirmed decline.
Filing trend and technology composition
Two views of the same 179-family dataset: how filing volume moved year over year, and how those filings distribute across the metallurgy and testing IPC subclasses that define this space.
A flat-to-declining filing curve
Filings sat around 11 in 2017, held near the midpoint of 6 in 2022, rose to a peak of 12 in 2023, and have since fallen toward zero in the partial 2026 year. That shape reads as a mature filing cycle with periodic bursts tied to new steel grades, not sustained growth.
Alloy and heat-treatment classes carry the volume
C22C (alloys) and C21D (heat treatment) together anchor almost every family in the set, while coating (C23C), welding (B23K), lamination (B32B), rolling (B21B), drawing (B21C) and electrolytic cleaning (C25F) each appear in a much smaller, secondary share — evidence that most patenting activity qualifies the steel itself rather than the inspection instrumentation.
Shares are the percentage of the 179 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 Testing and Inspection with Eureka
This page is one run against one query. Ask Eureka your own question about advanced high-strength steel testing and inspection and every answer comes back with the patent numbers behind it.
Try EurekaThe prior art doing the most citation work
EP4494799A1 — Spot-welded joint and high-strength steel element for spot welding
A spot-welded joint comprising a high-strength steel sheet portion with a Vickers hardness of 530 HV or higher, joined to another steel sheet portion via a nugget, with a ring-shaped corona bond around the nugget where solid-phase joining occurs and no coating layer present in that bonded region.Filed by Nippon Steel Corporation, published 2025-01-22 — illustrative of how current claims combine hardness thresholds with joint geometry rather than testing method alone.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | EP0969112A1 | Dual-phase high-strength steel sheet having excellent dynamic deformation properties and process for preparin… | 92 |
| 2 | WO2021019947A1 | High-strength steel sheet and method for manufacturing same | 58 |
| 3 | WO2006106591A1 | High-strength steel sheet and high-strength welded steel pipe excelling in ductile fracture performance and p… | 40 |
| 4 | US20110024004A1 | High-strength steel sheet and galvanized steel sheet having very good balance between hole expansibility and … | 37 |
| 5 | EP2264206A1 | High-strength steel sheets which are extremely excellent in the balance between burring workability and ducti… | 28 |
| 6 | EP1146132A1 | Hot-dip galvanized steel sheet having high strength and also being excellent in formability and galvanizing p… | 24 |
| 7 | US20060021682A1 | Ultratough high-strength weldable plate steel | 22 |
| 8 | US20110008648A1 | High-strength steel sheet, strength member for vehicles using the same, and method for producing strength mem… | 20 |
| 9 | EP2083094A1 | High-strength steel wire excelling in ductility and process for producing the same | 18 |
| 10 | WO2017050790A1 | A hot-rolled high-strength roll-formable steel sheet with excellent stretch-flange formability and a method o… | 16 |
Citation counts are drawn from within this searched corpus and skew toward older filings that have simply had more time to accumulate citations — read them as markers of influence on later filings, not as a ranking of current commercial relevance.
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 counts are read against each other: where the claim density sits, where the citations concentrate, and where geography narrows the freedom-to-operate question.
Alloy composition is the crowded core
Almost every family in this dataset makes an alloy-composition claim (C22C), and 138 also claim heat treatment (C21D). New entrants filing on steel chemistry alone are filing into the densest part of the landscape; differentiation is more available in how a composition is tested or qualified than in the composition itself.
One dual-phase steel patent anchors the field
EP0969112A1, on dual-phase high-strength steel sheet, carries far more citations than any other record in the set, with the next tier — WO2021019947A1 and WO2006106591A1 — well behind it. Any freedom-to-operate review in dual-phase steel sheet should start with this lineage before moving to newer filings.
Europe leads filing volume by a wide margin
The EPO route accounts for more than double the US filing count, with India, Canada and Austria trailing further behind. Clearance searches and opposition monitoring built around European filings will catch more of this landscape than a US-only search.
Recent-year activity has gone quiet across the board
Every assignee tracked for recent-year momentum shows zero filings in the latest year, several down 100% year over year. Combined with the 18-month publication lag, this points to a lull that may already be reversing in filings not yet published, rather than an abandoned technology.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to advanced high-strength steel testing and inspection, with the prior art for and against each one.
Who is filing, and where the gaps sit
Filing in this space is led by a small group of steel producers and automakers who co-file with named inventors, alongside a longer tail of single-filing entrants. The strongest co-assignee pairings sit inside a handful of Japanese steelmakers and one automaker's long-running collaboration with named co-inventors.
Steelmaker-to-steelmaker collaboration is the tightest cluster
The strongest co-assignee link in this dataset pairs two major Japanese steel producers, filing together seven times — the densest collaborative link in the set, ahead of automaker-inventor pairings.
One automaker runs a sustained inventor partnership
Honda's two strongest co-assignee links are with individually named co-inventors rather than corporate partners, at six and five joint filings respectively — a pattern more typical of a long-running technical consulting relationship than a joint venture.
Filing strategy is broader than a single home market
With activity split across six receiving offices and no single one taking a majority, applicants in this space are pursuing multi-jurisdiction protection rather than relying on a home-market filing alone.
| Assignee | Recent year | YoY |
|---|---|---|
| JFE Steel Corporation | 0 | -100% |
| Nippon Steel Corporation | 0 | — |
| Tata Steel IJmuiden B.V. | 0 | -100% |
| NIPPON STEEL & SUMITOMO METAL CORP | 0 | — |
| Honda Motor Co., Ltd. | 0 | — |
| Kobe Steel, Ltd. | 0 | — |
| Northwestern University | 0 | — |
| Sumitomo Metal Industries, Ltd. | 0 | — |
Where to take this analysis
The dataset points to a mature, geographically concentrated field with specific under-claimed branches. The next steps depend on whether the goal is clearance, licensing, or identifying a filing opportunity.
Run a freedom-to-operate check on the dual-phase steel lineage
Start with EP0969112A1 and its citing family before evaluating any new dual-phase or multi-phase steel composition claim, given how much later filing traces back to it.
Explore citation lineage in Eureka →Map the white space branches against your own claims
Hydrogen embrittlement test protocols and in-line ultrasonic defect sizing show materially thinner filing density than alloy composition — a first claim there faces less prior art crowding.
Run a white space analysis in Eureka →Watch for the publication-lag rebound
The apparent 2025–2026 drop in filings is partly a reporting artefact; recheck assignee momentum once the current filing year fully publishes.
Track assignee filings in Eureka →Common questions about this landscape
This landscape covers patent families that combine advanced high-strength steel (AHSS) subject matter with a specific test or inspection method — tensile testing, formability testing, ultrasonic inspection, or hydrogen embrittlement testing — identified through IPC classes for alloy composition, mechanical testing, and acoustic testing. It includes both the steel compositions being qualified and the methods used to verify their properties. It does not cover general steelmaking patents that lack any testing or inspection claim.
Filing is concentrated among a small group of major steel producers and automakers, with several Japanese steelmakers showing the strongest co-assignee collaboration in the dataset. One automaker, Honda, shows a distinct pattern of repeated co-filing with named individual inventors rather than corporate partners. Beyond this core group, a longer tail of single-filing entrants accounts for the remainder of the 179 tracked families.
No — the filing trend is flat to declining rather than growing. Annual filings held around 11 in 2017, dipped toward a midpoint of 6 in 2022, spiked to a peak of 12 in 2023, and have since fallen toward zero in the most recent partial year. Because publication lags filing by roughly 18 months, the very latest years understate true activity, but the multi-year shape is a mature filing cycle rather than sustained expansion.
Start with Europe: 77 of the 179 tracked records filed through the EPO, more than double the US total of 34, making European prior art the larger clearance risk. Within that, the dual-phase steel sheet lineage anchored by EP0969112A1 carries by far the most citations in the dataset and should be checked before any new dual-phase or multi-phase composition claim. India and Canada are secondary but non-trivial filing venues worth including in a broader search.
The core alloy-composition and heat-treatment classes (C22C, C21D) are heavily claimed, appearing in the large majority of tracked families, while coating, welding, rolling, drawing and electrolytic cleaning classes are comparatively thin. Specific under-claimed branches include in-line ultrasonic defect sizing for AHSS coils, hydrogen embrittlement test protocols for coated sheet, and non-destructive verification of weld or corona-bond quality. These are areas where filing density is low relative to the crowded alloy core, though thin density does not guarantee an application will grant — it means less prior art to design around.
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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.