The most-cited records in this dataset are concentrated among a small group of major steelmakers, with the earliest and most-cited families dating back over a decade — for example the EP2325346A1 and JP2004332099A families, cited 177 and 164 times respectively, both address high-strength steel sheet with hydrogen embrittlement resistance alongside weldability or ductility trade-offs. High citation counts favour older filings that have had more time to accumulate references, so treat this as a map of foundational prior art rather than a current activity ranking. Newer entrants should check these families' claim scope directly rather than relying on citation rank alone.

No — filing peaked in 2018 at 75 new families per year in this dataset and has declined since, with the 2022 midpoint already down to 55 and the most recent years running much lower. Some of that recent decline is publication lag, since patents typically publish roughly eighteen months after filing, so the last one to two years will always look artificially low. Even accounting for lag, the multi-year trend from 2018 onward points to a field where dominant claim positions are largely established rather than one still expanding.

In this dataset, alloy composition claims (C22C) appear in nearly all 1,116 families, but the majority also carry a heat-treatment claim (C21D, 953 records) and over a third carry a coating or surface-deposition claim (C23C, 422 records). That means most granted protection covers a specific alloy paired with a specific process step or coating, not the base alloy in isolation. A freedom-to-operate review that checks composition alone will miss the process and coating claims that typically control actual commercial use of the steel.

The smaller IPC subclasses in this dataset — electrolytic cleaning (C25F, 71 records), electroplating (C25D, 68), and casting (B22D, 33) — carry an order of magnitude fewer filings than the core alloy, heat-treatment and coating classes. That gap suggests narrower process refinements, such as electrolytic descaling pretreatment or casting-stage inclusion control aimed at corrosion performance, are comparatively under-claimed. Any first claim in these areas should be checked against the dominant alloy-plus-coating families first, since a new process step is often still covered by an existing composition claim.

Recent-year momentum data shows multiple top assignees, including firms holding some of the most-cited historical families, with year-on-year filing declines of 50% to 100%, several dropping to zero new families in the latest year. This pattern is consistent with a mature claim landscape where the core compositions and processes are already protected, so incumbents shift effort toward trade secrets, narrow process tweaks, or other technology areas. It does not necessarily mean the underlying R&D has stopped — but it does mean the публичное patent record for these firms is thinning, which is worth confirming with a freedom-to-operate search before assuming the space is uncontested.