AISI 4340 Forged Alloy Steel Round Bar

• Type: Alloy Steel Bar
• Standard: AISI, ASTM, DIN, JIS, GB, BS
• Composition: Alloy
• Technique: Rolled or Forged
• Shape: Bar
• Surface Treatment: Polished or Other
• Model NO.: 4340
• Special Use: for Oilfield
• Application: for Oilfield
• Transport Package: Anti-Corrosion
• Specification: 20-600mm
• Trademark: SHUNFU
• Origin: China
• HS Code: 7228600000
• Production Capacity: 100000 Tons Per Year

Product Description

AISI 4340 Alloy Steel

Our supply size :

Diameter : 80 to 600 mm ;
Length : 1000 to 9000 mm ;
 

Our capacity :

Delivery condition : Normalized, or Annealed, or Quenched and Tempered ;
Surface condition : Grounded, or Turned, or Polished
 

Our advantage :

1. High Quality, Reasonable Price
2. Over 40 Years Experience
3. ISO NQA Certificated Factory
4. Worldwide shipping
5. Emergency Orders and Fast Delivery
 

Quality Standard

EN 10277 Bright steel products. Technical delivery conditions. Steels for quenching and tempering
EN 10083 Steels for quenching and tempering. Technical delivery conditions for alloy steels
EN 10269 Steels and nickel alloys for fasteners with specified elevated and/or low temperature properties
EN 10263 Steel rod, bars and wire for cold heading and cold extrusion. Technical delivery conditions for steels for quenching and tempering
EN 10250 Open steel die forgings for general engineering purposes. Alloy special steels
ASTM A29 Standard Specification Steel Bars, Carbon and Alloy, Hot-Wrought, General Requirements
 

All Grades Comparison

Material no.	DIN	BS	ASTM
1.6580	30CrNiMo8	823M30	4340
AFNOR	ISO	GOST	JIS
30CND8	31CrNiMo8	3KH3M3F	SNCM431

 

Chemical Composition(%)

Steel Grade	C	Mn	Si	P	S	Cr	Ni	Mo
4340	0.38-0.43	0.60-0.80	0.15-0.35	0.035 max	0.040 max	0.70-0.90	1.65-2.00	0.20-0.30

 

Mechanical Properties

(T=20°C if not differently stated)

Heat treatment state	Diameter(mm)	Rm (Mpa)	Rp0.2 (Mpa)	Fracture elongation A5 (%)	Notch impact energy ISO-V [J]	Hardness (HB)
SOFT ANNEALED	/	844 min	/	/	/	250 max
ISOTHERMAL ANNEALED	/	615-815	/	/	/	183-242
QUENCHED AND TEMPERED	16 max	880-1080	685 min	16 min	40 min	289-347
QUENCHED AND TEMPERED	16-40	930-1080	735 min	16 min	40 min	275-318
QUENCHED AND TEMPERED	40-100	880-1030	685 min	17 min	40 min	261-303
QUENCHED AND TEMPERED	100-250	785-935	635 min	18 min	35 min	233-276
QUENCHED AND TEMPERED	250-500	735-885	590 min	16 min	35 min	218-262

 

Heat Treatment

Annealing: Heat to 800 ºC - 850 ºC, hold until temperature is uniform throughout the section and cool in furnace.
Hardening: Heat to 830 ºC - 860 ºC, hold until temperature is uniform throughout the section, soak for 10 - 15 minutes per 25 mm section, and quench in oil, water, or polymer as required.
Stress Relieving: Heat to 600 ºC - 650 ºC, hold until temperature is uniform throughout the section, soak for 1 hour per 25 mm of section, and cool in still air.
Tempering: Re-heat to 450 ºC - 660 ºC as required, hold until temperature is uniform throughout the section, soak for 1 hour per 25 mm of section, and cool in still air. N.B. Tempering should be avoided if possible within the range 250 ºC - 450 ºC due to temper brittleness.
 

Introduce

4340 Steel is a heat treatable, low alloy steel containing nickel, chromium and molybdenum. It is known for its toughness and capability of developing high strength in the heat treated condition while retaining good fatigue strength. A very popular, versatile steel. It can be heat-treated to produce a wide range of tensile strength in moderate sections.
 

Application

High voltage bolts and nuts, crankshafts, cam shafts, transmission axles, torsion bars, drive shafts, pump shafts, worm shafts, conveyor rollers, stems, pins, tie rods, clutch discs. Large-mass dies for hot stamping. 4340 Steel is widely used in the aerospace industry for structural parts of flaps assembly, fuselage and landing gear, propeller plane axles.
 

Machinability

4340 steel 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.
 

Welding

Welding of 4340 steel in the hardened and tempered condition (as normally supplied), is not recommended and should be avoided if at all possible, as the mechanical properties will be altered within the weld heat affected zone. It is preferred that welding be carried out on 4340 steel while in the annealed condition, and that the work piece, immediately on cooling to hand warm, is then stress relieved at 640 ºC - 660 ºC prior to hardening and tempering.
If welding in the hardened and tempered condition is really necessary, then the work piece, immediately on cooling to hand warm, should be if possible stress relieved at 15 ºC below the original tempering temperature (if known).
 

Mill′s test certificate

EN 10204/3.1 with all relevant data reg. chem. composition, mech. properties and results of testing.