Sumitomo AC700G: the maker lists AC420K as its successor
Sumitomo Electric puts Sumitomo AC420K against AC700G 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
AC700G → AC420K · K / cast iron turning (CVD)
The table has a "Grade" column and an "Old Grades" column. AC420K is in the Grade column; AC700G 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)
AC420K 91.1 2.5 FF Coat 12 · Designed as a grade with emphasis on fracture resistance and chipping resistance, outstanding AC700G
What this does and does not mean
It means the maker positions AC420K as the newer grade for the work AC700G was used for. It does not say AC700G is discontinued, and it does not say every insert shape and chipbreaker you buy in AC700G exists in AC420K.
Before you switch:
- Check that your exact insert designation and chipbreaker are offered in AC420K in the maker's current catalogue.
- Start from the maker's recommended cutting speed for AC420K, not the numbers you ran with AC700G.
- Run both grades until the edge is worn out on the same part and compare parts per edge. One part is not a result.
Grade lineage in the same document
AC700G → AC420K → AC4125K. The maker also lists AC4125K against AC420K, so AC420K is not the newest step in this line.
Other Sumitomo successor pairs
AC230 → ACP100 · AC304 → AC630M · AC405K → AC4010K · AC420K → AC4125K · AC610M → AC6020M · 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.