Vacuum Degassing Patents: Top Steelmakers & Filing Trends 2026
- Concentrated at the top. The top 5 assignees hold 46 of 77 records in scope (59.7%), and the top 10 hold 66 (85.7%) — a long tail of single-filer entrants fills the rest.
- Filing has cooled from its 2022 peak. Filings rose to 5 in 2022 before easing to 1 in 2024, a -50% move from 2021's 2 filings — though 2025-2026 counts are still filling in under publication lag.
- Steelmaking claims dominate the class mix. C21C (steelmaking) appears on 77.9% of records, more than twice the share of the next class, C22C alloys at 28.6%.
Filing growth compares 2021 (2 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 77 records in scope (CR5), not by the ranked leaders only.
What this landscape covers
Vacuum degassing removes dissolved hydrogen, nitrogen and carbon from liquid steel between the ladle metallurgy furnace and continuous casting, using RH (Ruhrstahl-Heraeus) circulation, vacuum tank degassing or ladle vacuum treatment. The claims in this dataset cluster around hydrogen removal, circulation rate control, snorkel refractory design, vacuum decarburization and treatment cycle parameters — the mechanical and process-control layer that sits between bulk steelmaking and finished-grade chemistry control.
The 77 records in scope span 2015 through the 2026 cut-off, with publications concentrated in national steelmaking powers and filed through both national offices and the PCT route. Because publication typically lags filing by around 18 months, the most recent one to two years understate actual filing activity.
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Filing trend and technology composition
Two views of the same 77 records: how filing activity has moved year over year, and which IPC subclasses the claims sit in.
Filing trend, 2017-2026
Filings built toward a peak of 5 in 2022, then eased to 1 by 2024 — a -50% move from 2021's 2 filings. 2025 and 2026 figures are still incomplete under normal publication lag and should not be read as a slowdown yet.
IPC subclass distribution
C21C (steelmaking) covers 77.9% of the 77 records, with C22C alloys (28.6%) and C22B metal extraction and refining (13.0%) the next largest classes. Records can carry more than one class, so these shares sum to well over 100%.
Shares are the percentage of the 77 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Vacuum Degassing Technologies with Eureka
This page is one run against one query. Ask Eureka your own question about vacuum degassing technologies and every answer comes back with the patent numbers behind it.
Try EurekaRepresentative filing and most-cited prior art
US20230323492A1 — Degassing method for manufacturing steel
The disclosure covers a method for producing non-grain-oriented electrical steel: tapping liquid steel from a primary furnace, deoxidizing before or after transfer to a ladle metallurgy furnace, removing sulfur at the LMF with flux additions and slag skimming to prevent sulfur reversion, then transferring to an RH degasser for oxygen-blown carbon removal, with flux added at the RH stage to fortify the slag's bottom layer before oxygen blowing.Filed by United States Steel Corporation, published 2023-10-12.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US20070180955A1 | Recovery of steel from contaminated scrap | 31 |
| 2 | EP2775007A1 | A process for the production of a grain-oriented electrical steel | 24 |
| 3 | US5417739A | Method of making high nitrogen content steel | 18 |
| 4 | WO2005118890A2 | Recovery of steel from contaminated scrap | 16 |
| 5 | US5228902A | Method of desulfurization in vacuum processing of steel | 15 |
| 6 | US20100071509A1 | Method of producing steel for steel pipe excellent in sour-resistance performance | 12 |
| 7 | US5110351A | Method of promoting the decarburization reaction in a vacuum refining furnace | 12 |
| 8 | US5152831A | Method of producing ultra-low-carbon steel | 7 |
| 9 | JP1989091047A | Method and apparatus for analyzing hydrogen in molten metal | 7 |
| 10 | GB2462481A | A method of removing zinc and lead from molten copper matte | 6 |
Citation counts are drawn from within this searched corpus and favour older filings; treat them as a signal of influence rather than of current relevance.
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 ranking, trend and class data that matter more than the raw counts.
Ten assignees hold most of the field
Top 10 assignees account for 66 of 77 records (85.7%), and the top 5 alone hold 59.7%. A ranking this concentrated means new entrants are filing into occupied claim space on the core RH and vacuum-tank mechanics, not into an open field.
Activity has eased from its 2022 high
Filings peaked at 5 in 2022 and fell to 1 by 2024, a -50% move from 2021's level. Because publication lags filing by roughly 18 months, 2025-2026 figures are not yet reliable evidence of a continued decline.
Steelmaking claims dominate, alloys claims trail well behind
C21C steelmaking process claims appear on 77.9% of the 77 records, more than double the 28.6% carrying C22C alloys claims. Smaller classes — C21D heat treatment, F27D furnace details — appear on single-digit percentages, marking them as secondary rather than core claim territory here.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to vacuum degassing technologies, with the prior art for and against each one.
Who is filing, and where the gate sits
The ranked leaders are integrated steelmakers and steel-engineering firms with decades of continuous filing in this space; smaller filers tend to appear once and not return.
A single integrated steelmaker leads the ranking
The top-ranked assignee holds 12 of the 77 records in scope, ahead of a fifth-place holder at 7 and a tenth-place holder at 3. That gap between first and fifth place is the clearest sign of an entrenched leader rather than a crowded top tier.
Beyond the top 10, filing thins quickly
The ranking runs to 22 companies, but the top 10 alone already cover 85.7% of records. The remaining companies in the ranking are filing in single digits, consistent with occasional process patents rather than sustained R&D programmes in vacuum degassing specifically.
Filing activity favours US, EPO and Canadian offices
The United States receives the most filings at 16, ahead of EPO at 13 and Canada at 10; the UK, WIPO/PCT and Japan each sit close together at 7-8. That spread suggests assignees are pursuing protection across multiple major steelmaking and steel-consuming jurisdictions rather than concentrating on one home office.
| Assignee | Recent year | YoY |
|---|---|---|
| Sumitomo Metal Industries | 0 | — |
| Kawasaki Steel Corporation | 0 | — |
| United States Steel Corporation | 0 | -100% |
| WARNER NOEL A | 0 | — |
| USX Engineers & Consultants Inc. | 0 | — |
| LTV Steel Company | 0 | — |
| Voestalpine Stahl GmbH | 0 | — |
| Nippon Steel Corporation | 0 | — |
Where to take this analysis
The dataset points to a mature, concentrated core with a few narrower branches still open. Two directions follow from that.
Check freedom-to-operate against the top 10
With 85.7% of records held by ten assignees, any new RH-degasser or circulation-control filing should be checked against that group's claim scope first, not just the most-cited records.
Run a freedom-to-operate checkWatch the under-claimed branches
Vacuum pump capacity, snorkel refractory wear and wastewater handling from degassing carry noticeably fewer records than core steelmaking claims, and may offer narrower but clearer paths to a grantable claim.
Explore white space with EurekaCommon questions about vacuum degassing patents
One integrated steelmaker leads the ranking with 12 of the 77 records in scope, well ahead of the fifth-ranked assignee at 7 and the tenth-ranked at 3. The top 5 assignees combined hold 59.7% of all records, and the top 10 hold 85.7%. That gap between the leader and the rest indicates a long-established filing programme rather than a recently arrived challenger, so any competitive review should start with that leader's family before looking further down the ranking.
Filings rose to a peak of 5 in the 2022 filing year, then declined to 1 by 2024, a -50% move over that three-year span. It would be premature to call this a lasting decline, however, because publication typically lags filing by around 18 months, so the 2025 and 2026 counts in this dataset are still incomplete. A fairer read is that the field cooled from an unusually active 2022 rather than that interest in the technology has ended.
The dataset's IPC mix is dominated by C21C steelmaking, present on 77.9% of the 77 records, with C22C alloys claims on 28.6% and C22B metal extraction and refining on 13.0%. Smaller classes such as C21D heat treatment and F27D furnace accessories appear on under 11% of records each. Because a single record can carry several IPC classes, these percentages add up to well over 100% and should be read as overlapping claim coverage, not a strict pie chart.
The United States receives the largest count of filings in this dataset at 16, followed by the European Patent Office at 13 and Canada at 10. The United Kingdom, WIPO's PCT route and Japan each sit close together at 7-8 filings. This spread across major steelmaking and steel-importing economies suggests assignees are seeking multi-jurisdiction protection for RH degasser and vacuum tank degassing technology rather than filing defensively in a single home market.
US20230323492A1, assigned to United States Steel Corporation and published 2023-10-12, claims a specific sequence for producing non-grain-oriented electrical steel: deoxidizing at the ladle metallurgy furnace, sulfur removal with flux and slag-skimming steps to prevent sulfur reversion, then transfer to an RH degasser for oxygen-blown carbon removal with a further flux addition before oxygen blowing. Anyone designing a similar LMF-to-RH sequence for electrical steel should check their process order and flux-timing steps against this claim set specifically, since the sequencing and timing of the sulfur-reversion prevention steps appear to be the load-bearing elements of the 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.