The corpus of 336 patent families is led by large integrated steel producers and major automakers, reflecting that tailored blanks and hot-stamped steel grades sit at the intersection of materials supply and forming technology. No single assignee dominates the way a monopolist would; instead filings concentrate among a handful of steel and automotive groups with a long tail of single-filing entrants. Checking the current assignee ranking table alongside recent-year momentum is the fastest way to see who is still active versus who filed heavily in the past and has since gone quiet.

No — filing peaked in 2017 at 24 families and had fallen to 21 by the 2022 midpoint, indicating a flat-to-declining trend rather than growth. The most recent one to two years will look artificially low because publication typically lags actual filing by around 18 months, so a genuine slowdown cannot be confirmed until later data arrives. Taken together, the pattern is consistent with a technology area where the core forming mechanics are well claimed and new activity is shifting toward adjacent metallurgy and coatings.

US9901969B2, assigned to Nippon Steel Corporation and granted in February 2018, covers a tailored blank for hot stamping made by butt-welding two aluminum-plated steel sheets, with the weld metal's average aluminum concentration constrained to between 0.3 and 1.5 mass percent and its Ac3 point held at or below 1250 degrees Celsius. The claim also requires an aluminum layer formed during welding to remain present on the welded portion's surface. This is a narrow, parameter-specific claim around weld chemistry in aluminum-coated tailored blanks, not a broad claim over tailored blanks or hot stamping generally.

Filing density is thin relative to the core B21D and C21D classifications in areas such as in-die lubrication monitoring, die wear sensing integrated with press operation, and forming limit diagram prediction tuned to high-strength steel grades. These branches sit adjacent to heavily claimed forming and heat-treatment territory but have not attracted the same volume of dedicated filings. A first claim in these areas would likely combine a sensing or predictive method with a specific forming or hot-stamping step, rather than claiming the sensor or the forming step alone.

The United States leads receiving-office filings at 116, followed by Europe through the EPO at 85, then China at 40, Canada at 31, India at 17 and WIPO PCT filings at 12. This distribution suggests the US and Europe are the primary markets where applicants seek protection and where freedom-to-operate risk is most concentrated. China's growing but still secondary share, alongside a distinct China-based assignee tier, indicates a regional cluster worth tracking separately from the established US-Europe filing base.