Sumitomo AC304: the maker lists AC630M as its successor
Sumitomo Electric puts Sumitomo AC630M against AC304 in its own catalogue material. We publish the pair only because the maker printed it; the source and page are below.
What the maker's document shows
AC304 → AC630M · M / stainless steel turning (CVD)
The table has a "Grade" column and an "Old Grades" column. AC630M is in the Grade column; AC304 is in its Old Grades column.
Source: Sumitomo Electric, General catalogue 2025–2026, coated carbide grade table, printed page A27 (PDF page 27). Open the maker's PDF at that page →
Text line as extracted from the PDF (table columns run together)
AC630M 89.5 2.7 FF Coat 5 and wear resistance for stainless steel machining AC304
What this does and does not mean
It means the maker positions AC630M as the newer grade for the work AC304 was used for. It does not say AC304 is discontinued, and it does not say every insert shape and chipbreaker you buy in AC304 exists in AC630M.
Before you switch:
- Check that your exact insert designation and chipbreaker are offered in AC630M in the maker's current catalogue.
- Start from the maker's recommended cutting speed for AC630M, not the numbers you ran with AC304.
- Run both grades until the edge is worn out on the same part and compare parts per edge. One part is not a result.
Other Sumitomo successor pairs
AC230 → ACP100 · AC405K → AC4010K · AC420K → AC4125K · AC610M → AC6020M · AC700G → AC420K · AC8015P → AC8115P · AC810P → AC8015P · AC830P → AC8035P · ACP100 → ACP2000
Tell the advisor your insert, material and operation. It answers brand-neutral, including options from other makers. To check a whole tool list for older grades, use the free coverage check.