Hydrogen Embrittlement Patents: Top Companies & Filing Trends 2026
- Filings have plateaued, not grown. activity peaked at 116 records in 2023 and the field sits flat to declining through the most recent year — this is an occupied space, not a hot one.
- The top five assignees hold 35.5% of the field. 569 of 1,602 records concentrate around a handful of steelmakers, with a long tail of single- and few-filing entrants behind them.
- Alloy composition and heat treatment dominate the claim space. C22C alloy claims and C21D heat-treatment claims each cover roughly a third of all records, while testing and analysis (G01N) sits under 10%.
What this landscape covers
Hydrogen embrittlement — the loss of ductility and delayed cracking that occurs when atomic hydrogen diffuses into a metal lattice under stress — has been a persistent qualification problem for high-strength steel, welded structures and hydrogen-service components. This landscape covers 1,602 patent families published between 2015 and mid-2026 that address embrittlement susceptibility ranking, test methods, coatings, liner mitigation, weld and heat-affected-zone (HAZ) susceptibility, and code qualification. Publication lags filing by roughly 18 months, so the most recent year of data understates real filing activity.
The bulk of the activity sits in metallurgy rather than in testing infrastructure: alloy design and heat treatment together outweigh material-analysis filings by a wide margin, which tells a reader where the claim thicket actually is and where a narrower, testing-side filing might still find open ground.
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Filing trend and technology composition
Two views of the same 1,602-record dataset: filing volume by year, and where those records sit across IPC subclasses. Because a single record can carry several IPC classes, the subclass shares add up to more than 100% of the record total.
Filings rose to a 2023 peak, then eased off
Annual filings moved from 23 in 2017 to a peak of 116 in 2023, sat at 88 by the 2022 midpoint, and stood at 22 in the most recent (partial) year. Read the tail-end drop as a publication-lag artefact, not a real collapse in activity — but the shape from 2022 to 2023 already shows the field is not accelerating.
Alloys and heat treatment carry the claim density
C22C (alloys) appears in 39.2% of the 1,602 records and C21D (heat treatment of metals) in 30.0%, making composition and heat-treatment claims the densest prior art to search around. Coating (C23C, 21.5%) and welding (B23K, 13.9%) form a second tier; testing and analysis (G01N, 8.0%) and corrosion (C23F, 5.2%) are comparatively lightly claimed.
Shares are the percentage of the 1,602 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Hydrogen Embrittlement of Structural Materials with Eureka
This page is one run against one query. Ask Eureka your own question about hydrogen embrittlement of structural materials and every answer comes back with the patent numbers behind it.
Try EurekaThe most-cited records in this space
High Strength Welded Steel Tube Superior in Hydrogen Embrittlement Cracking Resistance of Weld Metal and Method of Production of Same (US20080257008A1)
The filing covers a method of producing a welded steel pipe with hydrogen embrittlement cracking resistance in the weld metal: seam welding from inner and outer surfaces at a tensile strength of 850 MPa or more, followed by expanding or reducing the pipe for correction, with the preceding weld metal's hydrogen concentration held to 0.2 cc or less per 100 g at ordinary temperature.Assigned to Nippon Steel Corporation, published 2008-10-23.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US20120222781A1 | HIGH STRENGTH STEEL PLATE WITH ULTIMATE TENSILE STRENGTH OF 900 MPa OR MORE EXCELLENT IN HYDROGEN EMBRITTLEME… | 89 |
| 2 | US4245698A | Superalloys having improved resistance to hydrogen embrittlement and methods of producing and using the same | 81 |
| 3 | JP2006283131A | High strength cold rolled steel sheet having excellent coating film adhesion, workability and hydrogen embrit… | 72 |
| 4 | US6855217B2 | Method of baking treatment of steel product parts | 71 |
| 5 | WO2013005570A1 | Austenite steel welded joint | 67 |
| 6 | EP1865085A1 | High-strength cold-rolled steel sheet excellent in coating adhesion, workability and hydrogen embrittlement r… | 63 |
| 7 | WO2004110695A1 | Austenitic steel weld joint | 60 |
| 8 | US7491362B1 | Multiple enzyme cleaner for surgical instruments and endoscopes | 58 |
| 9 | EP0398117A2 | Process for rehabilitating internally reinforced concrete by removal of chlorides | 55 |
| 10 | JP1988227748A | High strength steel wire for spring and its production | 55 |
Citation counts favour older filings that have had more time to accumulate citations inside the searched corpus — read them as a signal of influence on later work, not as a marker of current commercial relevance.
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Browse MCP servers →What the data means for a filing or freedom-to-operate decision
Three patterns stand out once the ranking, trend and IPC composition are read together.
The top of the field is settled, the middle is not
The leader alone accounts for 239 records, and the top five combine for 569 of the 1,602 records in scope. Below tenth place (18 records) the ranking thins quickly into single- and few-filing entrants, which is where new claim scope is easiest to find.
Growth has already crested
Filings ran flat to declining from the 2022 midpoint of 88 through the partial most-recent year of 22. Several leading assignees show 0 filings or steep year-on-year drops in the latest year, though the publication lag makes the very last year an unreliable signal on its own.
Composition and heat treatment are the crowded classes
Alloy composition (C22C) and heat treatment (C21D) claims dominate the corpus, while material-analysis and testing methods (G01N, 8.0%) and corrosion mitigation (C23F, 5.2%) are comparatively open. A test-method or susceptibility-ranking claim faces far less prior art than a new alloy composition claim.
Cross-filing is limited and concentrated
Only ten co-assignee pairings appear in the dataset, and the strongest pairs link a steelmaker to a research affiliate rather than to another steelmaker. That points to embrittlement mitigation being filed largely as in-house metallurgy work rather than joint development.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to hydrogen embrittlement of structural materials, with the prior art for and against each one.
Who is filing, and where the gate sits
The ranked leaders are dominated by integrated steelmakers with decades of alloy and weld-metallurgy portfolios; component and OEM filers appear further down the ranking with narrower, application-specific claims.
Integrated steelmakers hold the base patents
The leading assignees are steel producers with filings spanning alloy composition, heat treatment and weld metallurgy — the same three IPC classes that carry the highest overall claim density in this dataset.
A sharp drop-off after the top ten
The top ten assignees combine for 42.3% of all 1,602 records, but the count at tenth place (18) is far below the leader's 239, showing that scale advantage is concentrated in very few hands rather than spread evenly across a mid-tier.
Component and application filers sit in the tail
Bearing, automotive and fastener manufacturers appear with narrower, use-specific claims further down the ranking, often tied to a single component class such as welded tube or coated fastener applications rather than base alloy chemistry.
| Assignee | Recent year | YoY |
|---|---|---|
| JFE Steel Corporation | 2 | -78% |
| Pohang Iron & Steel Co., Ltd. (POSCO) | 2 | — |
| Nippon Steel Corporation | 0 | -100% |
| Kobe Steel, Ltd. | 0 | — |
| NIPPON STEEL & SUMITOMO METAL CORP | 0 | — |
| NTN Corporation | 0 | — |
| The Boeing Company | 0 | — |
| ThyssenKrupp Steel Europe AG | 0 | — |
Where to take this analysis
The dataset points to a field with settled leadership at the top and open ground in testing, coating durability and pipeline liner mitigation.
Map freedom-to-operate against the top five
With 35.5% of all 1,602 records held by five assignees, any new alloy or heat-treatment filing should start with a citation search against those portfolios before drafting claims.
Run a freedom-to-operate search in Eureka →Track the under-claimed branches
Test-method, liner-mitigation and corrosion classes carry markedly lower filing density than alloy composition, suggesting narrower claims there face less crowded prior art.
Explore white space in Eureka →Watch the flattening trend, not just the peak
The 2023 peak of 116 filings followed by a decline toward the present partial year is a signal worth monitoring rather than a one-off; publication lag means the true current-year picture will only firm up over the next 18 months.
Set up a filing-trend alert in Eureka →Common questions about hydrogen embrittlement patents
Filing is concentrated among a small number of integrated steel producers, with the leading assignee alone holding 239 of the 1,602 records in this dataset. The top five assignees combined account for 35.5% of all records, and the top ten for 42.3%. Below the top ten, the ranking thins quickly into a long tail of component makers and single-filing entrants, so most of the durable claim scope sits with a handful of steelmakers rather than being evenly spread.
No — filings rose from 23 in 2017 to a peak of 116 in 2023, then eased back toward 22 in the most recent, still-partial year. The 2022 midpoint of 88 versus the 2023 peak and subsequent decline indicates the field has plateaued rather than continuing to accelerate. Because publication typically lags filing by around 18 months, the very last year of any dataset like this will always look weaker than it eventually turns out to be, so treat the most recent one or two years as provisional.
Alloy composition (IPC class C22C) and heat treatment (C21D) are the two densest areas, appearing in 39.2% and 30.0% of the 1,602 records respectively. Coating and surface deposition (C23C, 21.5%) and welding (B23K, 13.9%) form a second, still-substantial tier. Material analysis and testing methods (G01N, 8.0%) and corrosion mitigation (C23F, 5.2%) are comparatively lightly claimed, which is where a narrower filing is more likely to clear prior art cleanly.
US20080257008A1, assigned to Nippon Steel Corporation, claims a method of producing a high-strength welded steel pipe with improved hydrogen embrittlement cracking resistance in the weld metal, specifically seam welding at 850 MPa or higher tensile strength followed by pipe expansion or reduction for correction, with weld-metal hydrogen concentration held to 0.2 cc or less per 100 g. It blocks that specific combination of weld process parameters and hydrogen-concentration threshold for welded pipe, but it does not cover embrittlement mitigation approaches outside welded tube production, such as coating-based or heat-treatment-based routes, which sit in separate IPC classes with their own prior art.
The lower-density IPC classes point to it directly: material-analysis and test-method claims (G01N) sit at 8.0% of the 1,602 records, corrosion mitigation (C23F) at 5.2%, and sheet-metal working (B21D) at 4.7%, all well below the 39.2% and 30.0% occupied by alloy composition and heat treatment. Liner mitigation for hydrogen service and code-qualification test protocols are named search terms in this dataset but do not dominate any single IPC class, suggesting they are still addressed piecemeal rather than through a dense, defensible patent thicket. A first claim in HAZ-specific susceptibility test protocols or pipeline liner mitigation is more likely to clear prior art than a new bulk-alloy composition claim.
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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.