AISI / SAE 9840 Steel

AISI / SAE 9840 Steel is a nickel-chrome-molybdenum steel  which contains at least 0.85%Ni,0.7%Cr,0.2%Mo as strengthening alloy elements.It is suitable for different heat treatment and shows excellent hardenability, strength,toughness and good cold workability.After annealing,this material  becomes machinable and adjusted for the mechanical cutting.pre-heat and post-weld stress relief are necessary for welding of this alloy,but welding in the hardened and tempered condition is not recommended.

AISI / SAE 9840 Steel Supply Form & Size

Form of Supply	Size(mm)	Length(mm)
Round bar	Φ6-Φ1,000	3,000-10,000
Square bar	100×100-600×600	3,000-6,000
Plate/Sheet	Thickness :20-400 Width:80-1,000	2,000-6,000
Flat bar/Blcoks	Thickness :120-800 Width:120-1,500	2,000-6,000

AISI / SAE 9840 Steel Surface Finish&Tolerance

Surface Finish	Black-Forged	Black-Rolled	Turned	Grinding	Polished	Peeled	Cold Drawn
Tolerance	(0，+5mm)	(0，+1mm)	(0，+3mm)	Best h9	Best h11	Best H11	Best H11

AISI / SAE 9840 Steel Chemical Composition per ASTM A519

GRADE	C	Si	Mn	P	S	Cr	Mo	Ni
9840	0.38-0.42	0.15-0.35	0.70-0.90	≤ 0.040	≤ 0.040	0.70-0.90	0.20-0.30	0.85-1.15

AISI / SAE 9840 Steel Mechanical Property

Diameter d mm	≤ 16	16-40	40-100	100-160	160-250
Yield Strength Mpa	≥900	≥800	≥700	≥600	≥550
Tensile Strength Mpa	1100-1300	1000-1200	900-1100	800-950	750-900
Elongation, %	≥10	≥11	≥12	≥13	≥14
Reduction of area ,%	≥45	≥50	≥55	≥60	≥60
impact,J	≥35	≥40	≥45	≥45	≥45
Hardness,HB	331-380	298-359	271-331	240-286	225-271

AISI / SAE 9840 Steel Forging

Forging AISI 9840 steel between 1100℃-11500℃,and reheat the steel once temperature below 950℃.AISI 9840 has good forging characteristics,but this material is easy to crack when cooling improperly,Cooling in sand or in the furnace after forging is recommended.

AISI / SAE 9840 Steel Heat Treatment

• Normalizing:850℃-880℃,Cool in air
• Soft Annealing:650℃-700℃,Cool in furnace
• Full Annealing:830℃-850℃,Cool in furnace,235HB max
• Hardening:830℃-865℃,water or oil quench
• Tempering:540°C – 680°C, cool in still air

AISI / SAE 9840 Steel Machinability

This material may be readily machined, preferably from a coarse pearlitic structure.

AISI / SAE 9840 Steel Application

This alloy is suitable for production of highly stressed components of large cross section for aircraft, automotive and general engineering applications, such as forged propeller shafts, connecting rods, gear shafts, crankshafts and landing gear components.