Material number G86200: 8620
G86200 is the Unified Numbering System designation for 8620, nickel-chromium-molybdenum case-hardening steel specified in ASTM A29.
What G86200 means
UNS numbers (ASTM E527 / SAE J1086) use a letter for the alloy family and five digits: G = AISI/SAE carbon and alloy steels (G41400 = 4140), S = stainless and heat-resisting steels (S30400 = 304), K = miscellaneous steels (K02600 = A36), T = tool steels, N = nickel alloys. The UNS number identifies a composition, not a product form or property level, so G86200 appears in several ASTM specifications (plate, bar, pipe) with different mechanical requirements.
8620 at a glance
AISI 8620 is the American standard case-hardening alloy steel: 0.20 % carbon with 0.55 % nickel, 0.5 % chromium and 0.2 % molybdenum, UNS G86200. The triple alloying is 'lean' — no single element above 0.7 % — but together they give enough hardenability for a 25 mm gear to develop a 58–62 HRC carburized case over a tough 30–35 HRC core, plus the nickel toughness that lets gear teeth take shock without spalling. It is the default steel for automotive and truck transmission gears, differential ring and pinion gears, camshafts, piston pins, splined shafts, kingpins, chain sprockets and, in the through-hardened condition, for medium-strength bolts and pins.
8620 is normally bought as 8620H (hardenability-guaranteed band) for gears, machined in the annealed or normalized state, then carburized at 900–930 °C, quenched in oil and tempered at 150–200 °C. Core properties depend strongly on section size — the table gives typical values at 25 mm.
EN 20NiCrMo2-2 (1.6523, ex 21NiCrMo2), JIS SNCM220, GB 20CrNiMo and BS 805M20/EN362 are the same steel; European gear practice more often uses 16MnCr5 or 18CrNiMo7-6, which are functional substitutes.
Full data sheet for 8620 → · Equivalent grades →