Material Machining Views: 10

Differences between machining ferrous and non-ferrous metals, and tool selection: Metals divide into ferrous and non-ferrous families with very different machinability. Ferrous (iron-based): iron, steel, cast iron, stainless, alloy steel. Characteristics: 1) High strength and hardness - high cutting force; 2) Medium thermal conductivity - higher cutting temperature; 3) Chips are ribbon or powdery; 4) Medium work hardening (severe for stainless); 5) High density (7.8-8.0g/cm3); 6) High melting point (1400-1600C). Non-ferrous: aluminum, copper, zinc, magnesium, titanium, nickel etc. Characteristics: 1) Low strength and hardness (except titanium, nickel) - low cutting force; 2) Good thermal conductivity (except titanium) - low cutting temperature; 3) Tacky - welds easily (aluminum, copper, zinc); 4) Low melting point (aluminum 660C, copper 1083C, zinc 420C, magnesium 650C) - melts and welds; 5) Density varies (aluminum 2.7, copper 8.9, zinc 7.1, magnesium 1.7, titanium 4.5); 6) Work hardening varies (severe for titanium, nickel). Tool selection: 1) Ferrous - a) carbon steel, cast iron: standard HSS or cobalt HSS, TiN or TiAlN; b) stainless, alloy steel: cobalt HSS or carbide, AlCrN or TiAlN; c) hardened steel, superalloys: carbide or CBN, AlCrN; d) all-round: cobalt HSS + TiAlN gives best value. 2) Non-ferrous - a) aluminum: cobalt HSS or carbide, DLC recommended (anti-welding) or polished uncoated; b) copper alloys: cobalt HSS or carbide, DLC for anti-welding; red copper MUST use DLC; c) zinc: cobalt HSS, DLC, prevent melt-welding; d) magnesium: cobalt HSS or standard HSS - fire safety first; e) titanium: carbide, AlCrN, low speed, small feed; f) nickel superalloys: carbide or ceramic, AlCrN, very low speed. Parameters: 1) ferrous - medium speed (500-1500rpm), medium feed (0.05-0.15mm/rev), emulsion or semi-synthetic; 2) non-ferrous (aluminum, copper, zinc, magnesium) - high speed (1500-4000rpm), large feed (0.12-0.25mm/rev), semi- or full synthetic, or compressed air; watch welding; 3) hard non-ferrous (titanium, nickel) - low speed (200-500rpm), small feed (0.03-0.08mm/rev), EP fluid, generous cooling. Cutting fluid: 1) ferrous - emulsion, semi-synthetic, EP emulsion all fine, 5%-10%; 2) non-ferrous - a) aluminum, copper, zinc: semi- or full synthetic, 3%-5%; no sulfur-bearing fluids (corrode copper and aluminum); b) magnesium: water- or oil-based; magnesium reacts with water producing hydrogen - keep alkaline; c) titanium, nickel: EP emulsion or dedicated fluid, 10%-15%. Summary: ferrous is strong with high force - wear-resistant tools (cobalt HSS, carbide), medium speed and feed; non-ferrous is soft but tacky - anti-welding tools (DLC), high speed, large feed, watch melting and corrosion. Choose tools and parameters by material - do not generalize. Our countersinks come in multiple grades and coatings for ferrous and non-ferrous work - ask us.