Within this dataset, one assignee leads with 14 of the 24 records in scope, well ahead of the other four ranked companies. Those five companies together account for 100.0% of all records returned by the search, meaning there is no significant unranked long tail of smaller filers to track separately. This concentration makes the field easier to monitor than a fragmented one, since a small number of portfolios cover essentially all relevant prior art.

Filing peaked in 2021 at 8 records and fell to 0 by 2024, a -100% change over that three-year span. However, 2025 and 2026 figures are still incomplete because publication typically lags filing by around 18 months, so it would be premature to call the field dormant based on the most recent years alone. The safest reading is that the post-2021 pullback is real through 2024, with more recent activity still emerging in the data.

Self-tempered martensite refers to the microstructure formed at the rebar’s outer rim when it is quenched rapidly after hot rolling and then allowed to temper using residual heat from the still-hot core – a process central to thermomechanically treated (TMT) rebar. It is the mechanism behind the strength-toughness-weldability balance that seismic-grade rebar needs. Patent claims in this space concentrate heavily in the C21D heat treatment class, which appears in 83.3% of the 24 records analysed here, more than any other IPC subclass.