Resistance Spot Welding Patents: Leaders & Filing Trends 2026
A data-backed look at resistance spot welding patents: who leads filings, how the technology splits by IPC class, where filing has cooled since 2021, and where white space remains for new entrants.
Filing growth = 2021 (334 records) → 2024 (248); 2024 is the last year we treat as complete. Top-5 share = the 5 largest assignees ÷ all 7,521 records in scope (CR5), not the ranked leaders only.
What the resistance spot welding patent record shows
Resistance spot welding sits at the intersection of process control and materials engineering: joining thin sheet metal, usually steel or aluminium alloys, by clamping electrodes and passing current through a localized nugget. The patent record in scope here — 7,521 published records filed between 2015 and the 2026 data cut-off — reflects that split. The dominant IPC class, B23K (welding, soldering and brazing), covers 79.5% of records, but a meaningful share of activity sits in adjacent classes covering alloy composition, heat treatment and surface coating, which is where dissimilar-metal and high-strength-steel joining problems get claimed.
Filing is led by steelmakers and automakers rather than equipment specialists, which tracks with where the commercial pressure sits: automotive body-in-white assembly is the largest consumer of spot-welded joints, and steel producers have a direct incentive to patent the welding parameters that make their higher-strength grades weldable. Publication lags filing by roughly 18 months, so the most recent one to two years in any trend understate true filing activity.
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Filing trend and technology composition
Two views of the same 7,521-record dataset: the year-by-year filing count, and how records split across IPC subclasses. Because a single record can carry more than one IPC class, the composition shares add up to more than 100%.
Filing peaked in 2018 and has since eased
Annual filings ran from 376 records in 2017 to a peak of 474 in 2018, then declined through the last complete year of data; the 2021-to-2024 window fell 26%, from 334 to 248 records. 2025 and 2026 figures are still filling in as publications catch up to filing dates and should not be read as a continuation of the decline.
Publication lags filing by roughly 18 months, so 2025 onwards are still filling in. Growth rates on this page therefore end at 2024; running them to the last bar would understate the field.
B23K dominates; materials-science classes carry the harder claims
B23K (welding, soldering, brazing) accounts for 79.5% of the 7,521 records in scope. The next-largest classes — C22C alloys (11.4%), C21D heat treatment (7.7%) and C23C coatings (5.0%) — point to where dissimilar-metal joints and advanced high-strength steels are being claimed, rather than in the core welding-process class itself.
Shares are the percentage of the 7,521 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Joining, Welding & Brazing: Resistance Spot Welding Patent Landscape with Eureka
This page is one run against one query. Ask Eureka your own question about joining, welding & brazing: resistance spot welding patent landscape and every answer comes back with the patent numbers behind it.
Try EurekaRepresentative filing and most-cited prior art
US20220088699A1 — Method of resistance spot welding and resistance spot welding apparatus
Filed by Futaba Industrial and published 2022-03-24, this record claims a resistance spot welding method for layered steel plates of different thicknesses, using a first electrode contacting the thicker plate and a second electrode contacting the thinner plate arranged to reduce spatter while improving weld strength across the thickness mismatch.Abstract text is drawn directly from the published filing.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US20090152251A1 | Personalized interface for torch system and method | 255 |
| 2 | US6506997B2 | Spot welding system and method for sensing welding conditions in real time | 199 |
| 3 | US20100040902A1 | Formable light weight composites | 131 |
| 4 | JP2010115706A | Resistance spot welding method for high-strength steel sheet | 129 |
| 5 | US4447700A | Resistance spot welder adaptive control | 126 |
| 6 | JP2015093282A | Method for spot welding high-strength steel plate | 117 |
| 7 | US4650951A | Method of welding laminates each having the structure of metal layer/thermally softenable insulating layer/me… | 113 |
| 8 | US20140360986A1 | Resistance spot welding of steel to pre-coated aluminum | 107 |
| 9 | US20090255908A1 | Weld electrode for attractive weld appearance | 100 |
| 10 | US4329561A | Method of ensuring the maintenance of constant quality of spot welds | 100 |
Citation counts favour older records simply because they have had more time to be cited; treat them as a signal of influence within this corpus, not as a ranking of current technical 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
Four read-outs from the dataset, framed for teams deciding where to file, who to watch and what is still open.
Leadership is real but not exclusionary
The leading assignee alone accounts for 944 records, and the top 5 combined hold 28.2% of all 7,521 records in scope. That leaves more than 70% of filing activity spread across a long tail of steelmakers, automakers and equipment makers — evidence of a field with an established core but room for a differentiated claim to clear.
Activity has eased from its 2018 peak, not collapsed
Filings peaked at 474 records in 2018 and have declined since, with the most recent complete three-year comparison showing a 26% drop. Publication lag means 2025-2026 figures will revise upward, so this is a cooling trend rather than a cliff.
Process claims dominate; materials claims are the secondary layer
B23K covers nearly four in five records, confirming that most filings address the welding process itself — electrode design, current control, nugget formation. The smaller but non-trivial shares in C22C alloys and C21D heat treatment mark where high-strength-steel and dissimilar-metal joining problems get their own claims.
Filing is spread across major manufacturing economies
China leads receiving-office counts at 1,508, ahead of the United States (1,228), Japan (865) and the EPO (724). That spread mirrors where automotive and steel production capacity sits, rather than pointing to a single dominant jurisdiction for enforcement or freedom-to-operate review.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to joining, welding & brazing: resistance spot welding patent landscape, with the prior art for and against each one.
Where to take this next
The dataset points to specific follow-up work rather than a single conclusion.
Map the white space in adjacent classes
C22C, C21D and C23C carry meaningful but secondary filing shares. A claim that couples a specific alloy or coating chemistry to a spot-welding parameter set is less contested than a pure B23K process claim.
Explore white space in EurekaTrack the post-2021 filing pattern by assignee
The 26% drop from 2021 to 2024 is a field-wide figure; it is worth checking whether it holds evenly across the ranked leaders or whether some are filing at a steady rate while others have pulled back.
Run an assignee filing trend in EurekaCheck freedom-to-operate against the most-cited records
The most-cited records in this corpus skew toward older filings, which is expected of citation counts, but several remain in force and worth a direct claim read against any new electrode-control or adaptive-welding design.
Pull citation detail in EurekaCommon questions on resistance spot welding patents
The assignee ranking in this dataset covers 100 companies, and the leader holds 944 of the 7,521 records in scope. The top 5 combined account for 28.2% and the top 10 for 35.2%, with the remainder spread across a long tail of steelmakers, automakers and welding-equipment companies. No single company controls the field outright, so a freedom-to-operate review needs to look well beyond the leading few names.
Filing peaked in 2018 at 474 records and has declined since; the most recent complete comparison, 2021 to 2024, shows a 26% drop from 334 to 248 records. Because publication lags filing by roughly 18 months, the 2025 and 2026 figures in any trend chart are undercounts and will revise upward as more filings publish, so this should be read as a cooling trend rather than a sharp stop.
Nearly 80% of the 7,521 records sit in IPC class B23K, covering welding, soldering and brazing process claims directly. The next largest overlaps are C22C alloys at 11.4% and C21D heat treatment of metals at 7.7%, which reflect claims tied to specific steel or aluminium grades rather than the welding process alone. Smaller shares appear in C23C coatings, B32B laminates and B62D motor vehicles, showing how the technology reaches into materials science and automotive body design.
China's receiving office leads with 1,508 records, followed by the United States at 1,228, Japan at 865 and the European Patent Office at 724, with the Soviet-era SU office and South Korea also represented in the count. This spread lines up with where automotive assembly and steel production capacity are concentrated rather than favouring one office as a sole enforcement venue.
A representative example in this dataset, US20220088699A1 from Futaba Industrial, claims a method for welding layered steel plates of different thicknesses using two electrodes arranged asymmetrically against the thicker and thinner plates, aimed at improving weld strength while reducing spatter. Claims of this type are common in the corpus: they tie a specific electrode or current-control arrangement to a named materials problem rather than claiming spot welding broadly, which is typical of how this crowded process area gets carved into patentable increments.
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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.