Sumitomo SPMT090304N-FB AC530U Carbide Turning Insert – Square, R0.4, FB chipbreaker | Steel & Stainless Steel SPMT321

Group P — Carbon & alloy steels

1. Low-carbon / structural steel (HB ≤ 200)
   Vc: 180–320 m/min; f: 0.10–0.40 mm/rev; ap ≤ 4.0 mm
2. Alloy / quenched-and-tempered steel (HB 200–330)
   Vc: 120–240 m/min; f: 0.10–0.35 mm/rev; ap ≤ 3.0 mm

Raise Vc for continuous cuts; lower it and pick a tougher chipbreaker for interrupted cuts.

Group M — Stainless steel

1. Ferritic / martensitic (HB ≤ 220)
   Vc: 120–200 m/min; f: 0.08–0.30 mm/rev; ap ≤ 3.0 mm
2. Austenitic 304 / 316 (work-hardening)
   Vc: 90–160 m/min; f: 0.08–0.25 mm/rev; ap ≤ 2.5 mm

Flood coolant; avoid too low a feed to prevent work hardening.

Group K — Cast iron

1. Grey iron (HB ≤ 240)
   Vc: 120–280 m/min; f: 0.15–0.50 mm/rev; ap ≤ 4.0 mm
2. Ductile / nodular iron (HB 200–300)
   Vc: 100–220 m/min; f: 0.12–0.40 mm/rev; ap ≤ 3.0 mm

Dry or minimal coolant works; mind the entry impact.

Figures are general reference ranges by ISO material group — adjust for tool geometry, machine rigidity and cooling. For exact recommendations refer to the manufacturer's data or contact us for a quote.