817M40/SAE4340 forged steel shaft for mechnical purpose, OD: 80-1200mm

Description:
4340 is a 1.8% nickel - chromium - molybdenum high hardenability high tensile steel - generally supplied hardened and tempered in the tensile range of 930 - 1080 Mpa (condition U) - (Rc 28 - 36).
Characterised by high strength and toughness in relatively large sections.
Pre hardened and tempered 4340 can be further surface hardened by flame or induction hardening and by nitriding.
4340 is used in most industry sectors for applications requiring higher tensile/yield strength than 4140 can provide.

RELATED SPECIFICATIONS:

Australia AS 1444-2007 4340

Great Britain BS970 1955 EN24

BS970 Part 3:1991 817M40

BS EN10083:1-1991 817M40

USA ASTM A29A29M 1991 4340

ASTM A322 4340

UNS G43400

Japan JIS G 4103 SNCM439

JIS G 4103 SNCM8

Werkstoff 1.6565 40NiCrMo6

Chemical Composition(%):

Carbon 0.37-0.44

Silicon 0.17-0.37

Manganese 0.50-0.80

Phosphorus 0.04 max

Sulphur 0.04 max

Chromium 0.60-0.90

Molybdenum 0.15-0.25

Nickel 1.25-1.85

Process: EAF+LF+VD+ Forged+Heat Treatment(optional)

SIZE RANGE:

Round:

Hot Forgedf: 80mm-1200mm

SURFACE FINISHES:

Black, Peeled K12, Cold Drawn, Turned & Polished H10, H11, Precision Ground H9, H8

Test: Ultrasonic test according to SEP 1921-84 3

Forging:
Heat to 1150 oC - 1200 oC maximum, hold until temperature is uniform throughout the section.
Do not forge below 850 oC.
Following forging operation the work piece should be cooled as slowly as possible in sand or dry lime etc.

Heat Treatment
Annealing

Tempering


Machining:
4340 in the hardened and tempered as supplied condition is still regarded as being readily machinable and operations such as turning and drilling etc. can be carried out satisfactorily using machine manufacturers, recommendations for suitable tool type - feeds and speeds.