Heat Treatment & Surface Engineering Patents: Leaders & Trends 2026
- 12.8% concentration at the top. The five most active filers hold 9,728 of 75,925 records — a real lead, but nowhere close to a lock on the field.
- Filing has pulled back from a 2020 peak. Activity peaked at 950 records in 2020; on the last complete comparison, 2021's 857 fell to 505 by 2024, a 41% drop.
- Alloys and heat treatment classes dominate, but thinly. C22C and C21D each cover just over 6% of records — the core is claimed, but no single class approaches saturation.
Filing growth compares 2021 (857 records) with 2024 (505) — 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 75,925 records in scope (CR5), not by the ranked leaders only.
What this landscape covers
This dataset tracks 75,925 published records filed against heat treatment and surface engineering terms — quenching, tempering, surface hardening, thermal cycling and the working-fluid and sensor systems that support them — from 2015 through the 2026 cut-off. The search string pairs core metallurgical heat-treatment language with the process-control vocabulary (temperature sensor, heat flux, thermal cycle, rolling process) that separates a production-grade claim from a laboratory one.
Coverage spans steelmaking giants, semiconductor process-tool makers and oilfield-adjacent filers, reflecting how far heat treatment technique has spread beyond its metallurgical origin. The receiving-office split shows the United States and Europe carrying the bulk of filings, with WIPO PCT, Canada, Australia and the UK forming a secondary tier.
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Filing trends and technology composition
Two views of the same 75,925-record dataset: how filing volume has moved year over year, and which IPC subclasses carry the claim density today.
Filing activity, 2017–2026
Filings rose to a peak of 950 records in 2020, then eased back; the last complete comparison shows 2021's 857 records falling to 505 by 2024, a 41% decline. 2025 and 2026 figures are still incomplete because publication lags filing by roughly 18 months, so the apparent tail-off in the most recent years should not be read as the field cooling further than the 2021–2024 figures already show.
Technology composition by IPC subclass
C22C (Alloys) and C21D (Heat treatment of metals) each sit at just over 6% of the 75,925 records in scope, with C23C (coating and surface deposition) and H01L (semiconductor devices) forming a second tier near 2-3%. Because records can carry multiple IPC classes, these shares add to more than 100% and should be read as claim density per class, not as a partition of the field.
Shares are the percentage of the 75,925 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Heat Treatment & Surface Engineering Patent Landscape with Eureka
This page is one run against one query. Ask Eureka your own question about heat treatment & surface engineering patent landscape and every answer comes back with the patent numbers behind it.
Try EurekaRepresentative filing and most-cited records
US20080197546A1 — Metal heat treatment system hot-gas quenching apparatus and hot-gas heat treatment system
A metal heat treatment method includes quenching a workpiece by blowing an inert gas onto the workpiece, adjusting the temperature of the inert gas to approximately an isothermal holding temperature of the workpiece for transformation of the workpiece, holding the isothermal holding temperature within a margin of error of approximately plus or minus five degrees Celsius for a given period, and performing a metal heat treatment with the isothermal holding temperature kept statically or dynamically by varying the temperature of the hot-gas.Filed by Taniguchi, published 2008-08-21 — a hot-gas quenching architecture that ties inert-gas temperature control directly to isothermal holding tolerance.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US6454781B1 | Feedback control in an ultrasonic surgical instrument for improved tissue effects | 2,269 |
| 2 | US7108695B2 | Feedback control in an ultrasonic surgical instrument for improved tissue effects | 1,974 |
| 3 | US20070010702A1 | Medical device with low magnetic susceptibility | 1,511 |
| 4 | US6147135A | Fabrication of biocompatible polymeric composites | 1,232 |
| 5 | US9614258B2 | Power storage device and power storage system | 1,006 |
| 6 | US6692692B2 | Dental drill sterilization through application of high amperage current | 1,000 |
| 7 | US20060106375A1 | Ablation system with feedback | 910 |
| 8 | US20160045841A1 | New and improved system for processing various chemicals and materials | 860 |
| 9 | US5837960A | Laser production of articles from powders | 788 |
| 10 | US8193129B2 | Refrigerator oil, compressor oil composition, hydraulic fluid composition, metalworking fluid composition, he… | 775 |
Citation counts inside this corpus favour older filings and should be read as a signal of influence within the searched set, not as a ranking of current commercial importance.
Each row carries its publication number; clicking a row searches Eureka by that number.
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Three read-outs from the same figures: where the claim space is genuinely crowded, where momentum has actually gone, and what the citation table is and is not telling you.
The top of the field is real but not dominant
Nine of the ranked leaders' combined 9,728 records equal 12.8% of all records in scope; extending to ten filers adds only another 4.4 points, to 17.2%. That leaves well over 80% of filing activity spread across a long tail — this is a field with recognisable leaders but no gatekeeper.
Volume has pulled back from its 2020 peak
Filings peaked at 950 records in 2020 and eased to 857 by 2021; the last complete year-over-year comparison shows a further drop to 505 by 2024. Several of the most active historical filers show sharply negative year-on-year momentum in the latest tracked year, though that single-year figure is still filling in.
Core classes are claimed but not saturated
C22C and C21D each account for a bit over 6% of the 75,925 records, with coating (C23C), non-ferrous treatment (C22F) and rolling (B21B) trailing well behind at 1-3%. No single class approaches the density that would signal a closed field.
Filing is US- and Europe-anchored
The United States and the European Patent Office together account for the largest receiving-office volumes, with WIPO PCT, Canada, Australia and the UK forming a distinct second tier. That split matters for freedom-to-operate work: clearance in the US and EPO covers most of the documented activity, but PCT filings signal where applicants are keeping options open.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to heat treatment & surface engineering patent landscape, with the prior art for and against each one.
Who is filing, and where activity is cooling
The ranking spans steelmakers, a semiconductor process-tool maker and oilfield-services filers — a wider mix than the search terms alone would suggest, because heat-treatment control technique has migrated across industries.
A steel-sector leader sets the pace
The top-ranked filer holds 3,433 records, well ahead of the fifth-place filer's 850 and the tenth-place filer's 585 — a steep drop-off after the leader rather than a gradual taper.
Historical leaders show sharp pullback
Several of the most historically active assignees — including major steel producers and a semiconductor equipment maker — show latest-year filing counts down 75% or more year-on-year, with some at zero. This tracks the broader 2021-2024 volume decline rather than a single company's retreat.
Co-filing is limited and concentrated
Only ten co-assignee pairs are documented in this dataset, and the strongest of them cluster around a single oil-and-gas research entity and its named inventors — collaborative filing is the exception here, not the norm.
| Assignee | Recent year | YoY |
|---|---|---|
| ArcelorMittal | 2 | -75% |
| Pohang Iron & Steel Co., Ltd. (POSCO) | 1 | -75% |
| Tokyo Electron Ltd. | 1 | -92% |
| Nippon Steel Corporation | 0 | -100% |
| JFE Steel Corporation | 0 | -100% |
| Shell Oil Company | 0 | — |
| NIPPON STEEL & SUMITOMO METAL CORP | 0 | — |
| Semiconductor Energy Laboratory Co., Ltd. | 0 | -100% |
Turning this landscape into a filing decision
The figures above describe where the field has been. Deciding where to file next means testing a specific claim against this same prior art, not re-reading the trend lines.
Stress-test a draft claim
Run a candidate claim — say, an isothermal hold-tolerance control scheme or a working-fluid heat-flux sensor design — against the records underlying this landscape before filing.
Test a claim in EurekaTrack the assignees still active
Filing momentum has diverged sharply across the ranked leaders; set up monitoring on the filers still showing positive year-on-year activity rather than the ones now at zero.
Set up assignee tracking in EurekaMap the white space precisely
The under-claimed sub-areas flagged here are starting points, not conclusions — confirm the gap with a full classification sweep before committing R&D or filing budget to it.
Map white space in EurekaQuestions practitioners ask about this landscape
The ranking returned by this dataset covers 100 companies, led by a steel-sector filer with 3,433 records against a fifth-place figure of 850 and a tenth-place figure of 585 — a steep drop after the leader rather than a gradual taper. The five most active filers together account for 9,728 records, or 12.8% of all 75,925 records in scope, and the top ten reach 17.2%. That leaves the large majority of filing activity spread across a long tail of smaller filers, so leadership in this field is real but far from exclusive.
Filing volume peaked at 950 records in 2020 and has declined since; the last year-over-year comparison that can be treated as complete shows 2021's 857 records falling to 505 by 2024, a 41% drop. Figures for 2025 and 2026 are still incomplete because publication typically lags actual filing by around 18 months, so those recent years understate true activity and should not be read as a continued fall. The honest read is that filing cooled meaningfully through the early 2020s off a 2020 peak, not that it is still falling today.
C22C (Alloys) and C21D (Heat treatment of metals) each cover a little over 6% of the 75,925 records in scope, making them the densest classes in this landscape. C23C (coating and surface deposition) and H01L (semiconductor devices) form a second tier near 2-3%, followed by non-ferrous treatment, welding/brazing and rolling classes each under 2%. Because a single record can carry several IPC codes, these percentages add to more than 100% and describe claim density per class rather than a split of the whole field.
US20080197546A1 describes a metal heat treatment system using hot-gas quenching, where an inert gas is blown onto a workpiece and its temperature actively adjusted to hold an isothermal temperature within roughly plus or minus five degrees Celsius during transformation. It blocks designs that combine inert-gas quenching with tight, actively-controlled isothermal hold tolerances in that specific band. It does not automatically block adjacent approaches — different quench media, looser tolerance bands, or control schemes that hold temperature by a different mechanism — but any new filing in gas-quench isothermal control should be checked against it directly rather than assumed clear.
The clearest gaps sit adjacent to the two most-claimed classes rather than inside them: working-fluid heat-flux sensing, non-ferrous alloy surface hardening, and rolling-process thermal cycle integration all show materially lower filing density than the core alloy and heat-treatment classes. These are not empty fields, but the claim density evidence suggests less crowding for a well-drafted first claim. Any white-space read should be confirmed with a targeted classification sweep before committing filing budget, since low density in an IPC subclass count is a starting signal, not a guarantee of clearance.
Collaboration is limited: the dataset documents only 10 co-assignee pairs across all 75,925 records, and the strongest of these cluster around a single oil-and-gas research entity filing jointly with named inventors. This suggests heat treatment and surface engineering patents in this corpus are filed predominantly by single assignees working independently, with joint filing the exception rather than the norm. Anyone benchmarking partnership strategy in this space should not expect to find dense co-filing networks here.
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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.