8620H/21NiCrMo2/DIN1.6523/805 M20/EN362/SNCM 220H Hot Rolled Steel
Bar ,With Black/peeled surface
8620 is a low nickel - chromium - molybdenum medium hardenability,
case hardening (carburizing) steel, generally supplied in the as
rolled condition with a maximum brinell hardness of 280 (Rc30).
Characterised by good core strength and toughness in small to
medium sections with case hardness up to Rc62 when carburized,
hardened and tempered.
8620 can also be used (uncarburised) as a high tensile steel, which
when suitably hardened and tempered can be utilized for various
applications requiring good tensile strength and reasonable
Pre hardened and tempered (uncarburized) 8620 can be further
surface hardened by nitriding but will not respond satisfactorily
to flame or induction hardening due to its low carbon content.
8620 (carburized) is used extensively by all industry sectors for
light to medium stressed components and shafts requiring high
surface wear resistance with reasonable core strength and impact
AISI 8620 is a common, carburizing alloy steel used for a variety
of medium-strength applications including gears, camshafts,
fasteners, and chains/chain pins. Flexibility in hardening
treatments allow optimization of case/core properties. Typical uses
are: Arbors, Bearings, Bushings, Cam Shafts, Differential Pinions,
Guide Pins, King Pins, Pistons Pins, Splined Shafts, Ratchets,
rocess: EAF+LF+VOD+Rolled+Heat Treatment(optional)
Black, Peeled (K12), Cold Drawn, Turned & Polished (H10, H11),
Precision Ground (H9, H8)
Test: Ultrasonic test according to SEP 1921-84 .
Heat to 1150 oC and hold until temperature is uniform throughout
the section. Soaking time at forging temperature should be as short
as possible to avoid heavy scaling and excessive grain growth. This
will vary depending on furnace conditions but 15 minutes per 25 mm
of section may be used as a guide.Do not forge below 850 oC.
Following completion of forging operation, work piece should be
cooled as slowly as possible in sand or dry lime etc.
Note: Case hardening steels due to their low carbon content are
less susceptible to cracking than medium or high carbon steels, and
may therefore be heated and cooled more rapidly.
8620 in the as rolled as supplied condition, has very good
machinability and all operations such as turning, drilling, milling
and tapping etc. can be carried out satisfactorily as per machine
manufacturers recommendations for suitable tool type - feeds and
8620 is readily weldable in the as rolled as supplied condition.
Following welding, the work piece immediately upon cooling to hand
warm should be stress relieved at 630 oC - 650 oC if possible.
N.B. Welding in the carburized and heat treated condition is not
Welding of 8620 should always be carried out using low hydrogen
electrodes - please consult your welding consumables supplier.