Ladle Refractory Patents: Top Companies & Filing Trends 2026
- Concentrated but not locked up. the top 5 assignees hold 40.0% of the 75 records in scope, and the top 10 hold 58.7% — a leader plus a long tail, not a monopoly.
- Casting, not just refractory chemistry, is where the claims sit. B22D metal casting touches 62.7% of records, well ahead of C04B ceramics and refractories at 24.0%.
- Japan dominates the filing map. 28 of the tracked records route through Japan, ahead of the United States (16) and China (15), which shapes where enforcement risk actually lives.
Top-5 share is the combined record count of the five largest assignees divided by all 75 records in scope (CR5), not by the ranked leaders only.
What this landscape covers
Ladle refractory and slag line wear sits at the junction of vessel engineering and materials chemistry: magnesia carbon brick formulations, thermal cycling behaviour, ladle preheating control, purging plug design and relining intervals all show up in the same claim sets because a ladle’s working life is decided by how its lining survives heat and slag attack cycle after cycle. This landscape draws on 75 published records filed between 2015 and mid-2026, indexed by IPC subclass, assignee and receiving office.
Publication typically lags filing by around 18 months, so the most recent filing year in this dataset understates real activity — treat the tail of the trend line as a floor, not a ceiling.
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Filing trend and technology composition
Two views of the same 75 records: how filing activity has moved year over year, and which IPC subclasses carry the claims.
Filing trend
Activity peaked so far at 5 records in 2022. With fewer than four complete years available once publication lag is stripped out, a growth rate cannot be stated reliably from this window.
IPC subclass mix
B22D (metal casting) appears in 62.7% of the 75 records, well ahead of F27D (furnace details, 25.3%) and C04B (ceramics and refractories, 24.0%). Records can carry more than one class, so these shares add up past 100%.
Shares are the percentage of the 75 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Ladle Refractory and Slag Line Wear with Eureka
This page is one run against one query. Ask Eureka your own question about ladle refractory and slag line wear and every answer comes back with the patent numbers behind it.
Try EurekaRepresentative and most-cited filings
GB2341234A — Ladle preheating control system
A system for controlling the preheating of a refractory-lined ladle measures ladle temperature against a set-point and adjusts heat input rate accordingly. It calculates an average slope of heat input versus time to determine when the refractory is fully heated through, and can route the comparison through a programmable logic controller. An alternative version signals full preheat once the second derivative of the heat energy input rate falls below a set threshold.Filed by UEC Technologies LLC, dated 2000-03-08 — included here as a representative filing for its scope over preheat-completion detection logic, a claim area that recurs across the corpus.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US4718643A | Method and apparatus for rapid high temperature ladle preheating | 62 |
| 2 | JP1983221220A | Heating and refining method of molten steel in ladle | 21 |
| 3 | US20090220900A1 | Combustion with variable oxidant low NOX burner | 17 |
| 4 | JP1992055361A | Unburned refractory for molten steel vessel | 15 |
| 5 | US5981917A | Ladle preheat indication system | 14 |
| 6 | US4014532A | Ladle refractory lining preheater | 14 |
| 7 | US7549858B2 | Combustion with variable oxidant low NOx burner | 10 |
| 8 | US20180319710A1 | Lightweight micro-closed-pore alumina composite refractory material and method preparing same | 9 |
| 9 | JP1992021713A | Method for correcting steel tapping temperature with reserving heat quantity in ladle | 9 |
| 10 | JP1987224473A | Preheating apparatus for refractory-made rod-like body for ladle | 9 |
Citation counts favour older filings simply because they have had more time to be cited; read them as a signal of influence within this corpus, not as a ranking of current importance.
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 dataset that matter more for strategy than the raw counts alone.
Leadership is real but not exclusive
The top 5 assignees combine for 40.0% of all 75 records, and the top 10 for 58.7%. That leaves more than 40% of filings spread across a long tail of single- or few-filing entrants — room for a new entrant to stake a claim, provided it avoids the densest classes.
Casting-process claims dominate over pure ceramics
B22D (metal casting) appears in nearly two-thirds of records, ahead of C04B (ceramics, cement and refractories) at 24.0%. Filing volume in B22D signals occupied claim space around casting-integrated wear control, not that the underlying refractory chemistry itself is settled.
Enforcement risk skews toward Japan
Japan accounts for 28 of the tracked filings, ahead of the United States (16) and China (15). A freedom-to-operate review that only checks US and China filings misses the largest single receiving office in this field.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to ladle refractory and slag line wear, with the prior art for and against each one.
Who is filing, and where the gaps sit
The ranked leaders span integrated steelmakers, refractory specialists and gas/burner suppliers, with a leader at 10 records and a fifth-place assignee at 3 — a shallow drop-off that points to a fragmented rather than winner-take-all field.
A single leader, then a fast taper
The top assignee holds 10 records against a fifth-place holder at 3 and a tenth-place holder at 2 — the gap from first to fifth is steep, but from fifth to tenth it flattens out quickly.
Joint filings cluster around specific alliances
Eight co-assignee pairings appear in the dataset, with the strongest repeating three times each — consistent with steelmaker-refractory supplier partnerships and university-industry collaboration rather than broad industry consortia.
Recent-year activity looks flat for named leaders
Every assignee tracked for recent-year momentum shows 0 filings in the latest year in this dataset. Given the roughly 18-month publication lag, this reads as reporting lag rather than an actual halt in R&D.
| Assignee | Recent year | YoY |
|---|---|---|
| Nippon Steel Corporation | 0 | — |
| Nucor Corporation | 0 | — |
| Praxair Technology, Inc. | 0 | — |
| Sumitomo Metal Industries, Ltd. | 0 | — |
| Krosaki Harima Corporation | 0 | — |
| Zibo Langfeng High Temperature Materials Co., Ltd. | 0 | — |
| Zibo City Luzhong Refractories Co., Ltd. | 0 | — |
| Steel Authority of India Limited | 0 | — |
Where to take this analysis
The dataset points to specific next steps depending on whether the goal is filing, freedom-to-operate, or partner scouting.
Map claim scope inside B22D and C04B
With 62.7% of records touching metal casting and 24.0% touching ceramics and refractories, a claim-by-claim read of the densest filings in these two subclasses will show exactly which casting-integrated wear mechanisms are already occupied.
Explore claims in EurekaCheck Japan-heavy freedom-to-operate exposure
28 of 75 records route through Japan, more than the US and China combined counts in this dataset. Any commercialisation plan touching Japanese supply chains should treat this office as the primary FTO check, not a secondary one.
Run an FTO search in EurekaTrack the fragmented long tail for partnership targets
With 48 companies ranked and a fast taper after the top few, the long tail includes refractory specialists and research institutions that may be open to licensing or co-development rather than direct competition.
Screen assignees in EurekaCommon questions on ladle refractory patents
The dataset ranks 48 companies, with the leading assignee holding 10 of the 75 records in scope. The drop-off is steep at first — the fifth-ranked assignee holds only 3 — but flattens quickly, with the tenth-ranked assignee still holding 2. That pattern points to a field with one clear leader surrounded by a fragmented group of steelmakers, refractory specialists and research institutions rather than a small cartel of dominant filers.
Most records sit in B22D, metal casting, which touches 62.7% of the 75 filings in scope — more than double the share in C04B, ceramics, cement and refractories, at 24.0%. F27D, furnace details and accessories, follows at 25.3%. This means the bulk of patent activity is claiming casting-integrated wear control and process steps around the ladle, not standalone refractory material chemistry, which is a narrower and comparatively less-crowded space.
Japan is the largest receiving office in this dataset with 28 filings, ahead of the United States at 16 and China at 15. WIPO PCT filings account for 5, with Canada and India each at 3. A company assessing freedom-to-operate risk in this field should treat Japan as the primary jurisdiction to clear, not an afterthought behind the US and China.
The dataset's peak year so far is 2022 with 5 records, but a reliable growth rate cannot be computed from this window because fewer than four complete years remain once the roughly 18-month publication lag is accounted for. The most recent filing years will understate true activity simply because many of those applications have not published yet, so treat any apparent flattening near 2026 with caution rather than reading it as a real slowdown.
Sub-areas such as purging plug wear sensors, relining interval prediction, and thermal cycling fatigue modelling show materially thinner filing density than the core B22D casting and C04B refractory classes that carry most of the corpus. These are candidates for a first claim precisely because the dense classes — casting-integrated wear control and preheat detection logic — are already well covered by the ranked leaders' filings.
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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.