AISI 416 Stainless Steel | X12CrS13 | SUS 416

AISI 416, a martensitic free-machining stainless steel, is made by adding extra sulfur (minimum 0.15%) to 410 stainless steel, which enables it to break chips and lubricate the cutting surface.

With just simple oil quenching and tempering, 416 steel can achieve a hardness of around 38-42 HRC and retain its magnetism in any state.

Therefore, for machined parts requiring high hardness, magnetism, and rapid machining, 416 is often the most economical hardenable stainless steel.

AISI 416 STEEL CHEMICAL COMPOSITION

Grade	C	Si	Mn	P	S	Cr	Mo
416	≤0.15	≤1.0	≤1.25	≤0.06	≥0.15	12.0-14.0	/
X12CrS13	0.06-0.15	≤1.0	≤1.5	≤0.04	0.15-0.35	12.0-14.0	≤0.6

AISI 416 STEEL EQUIVALENT GRADE

Europe	USA	China	Japan
X12CrS13/1.4005	416	Y12Cr13	SUS 416

AISI 416 STEEL PHYSICAL PROPERTY

Density, g/cm3	7.75
Melting point,°C	1480-1530
Thermal conductivity,20℃ W/(m.K)	25
Modulus of elasticity,Gpa	200
Coefficient of thermal expansion,µm/(m·K)	9.9
Magnetic response	Magnetic

AISI 416 STEEL FORGING

416 stainless steel is a free-machining martensitic stainless steel containing sulfur, which easily produces MnS inclusions (the source of cracks). Therefore, it is strictly forbidden to forge at low temperatures or to rapidly cool after forging, and it is not suitable for severe upsetting and large deformation.

Preheating	Initial forging temperature	Final forging temperature	Forging ratio
750–800℃	1150-1200℃	900–930℃	≥4:1

AISI 416 steel requires slow cooling after forging. Full annealing is recommended.

AISI 416 STEEL HEAT TREATMENT

AISI 416 steel Pretreatment: Softening Annealing

AISI 416 steel is heated to 815–900 °C, held for a sufficient time to allow the cross-section to reach that temperature, and then slowly cooled in the furnace. Annealed 416 steel is soft and most easily machined.

AISI 416+A steel Mechanical property

	Tensile strength Rm	Yield strength Rp0.2	Elongation A	Reduction of area	Hardness
AISI 416+A	515–620 MPa	275–345 MPa	15–30%	40–60%	155–190 HB

AISI 416 steel Final Heat Treatment: Quenching & Tempering

Austenitize 416 steel at 925–1010 °C . Hold 30–60 minutes, roughly one hour per 25 mm of section, then quench in oil. Air cooling works for thinner sections, but oil is the safer default.

Temper immediately after quenching. Two temperature ranges are suitable:

205–370 °C gives 38–42 HRC and the best corrosion resistance 416 steel can offer.
595–705 °C gives 24–30 HRC with significantly improved toughness.

Avoid 425–540 °C. Hardness is still high in that band, but impact toughness drops, so parts can fail without much warning. Air cool after tempering.

Typical hardness of 416 after hardening (≈980 °C, oil quench) and tempering.Hardness falls as the tempering temperature rises. The 425–540 °C band keeps hardness up but drops impact toughness, so it is avoided.

AISI 416+QT steel Mechanical property

Tempering	Tensile strength Rm	Yield strength Rp0.2	Elongation A	Hardness
205 °C	≈1310 MPa (190 ksi)	≈1000 MPa (145 ksi)	12–15%	38–42 HRC
538 °C	≈1000 MPa (145 ksi)	≈795 MPa (115 ksi)	13%	321 HBW
595–705 °C	—	—	—	24–30 HRC

AISI 416 STEEL SUPPLY FORM & SIZE & TOLERANCE

Round bar: Dia 6-400mm

Square bar: Dia 6-200mm

Flat bar:2 x 10-20 x 200mm

Hexagonal bar: Dia 6-150mm

Surface Finish	Black-Forged	Black-Rolled	Rough Turned	Cold Drawn	Peeled	Polished	Grinded
Tolerance	0/+5mm	0/+1mm	0/+3mm	Best H11	Best H9	Best H9	Best h8

Heat treatment Supply Conditions

Condition	Hardness	What it is for
A, annealed	≈155–190 HB	machine first, harden and temper after
T, intermediate temper	26–32 HRC	machine and use as-is, common for shafts
H, hard temper	35–42 HRC	used where hardness is needed without further treatment