Project 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 :
- High Quality, Reasonable Price
- Over 40 Years Experience
- ISO NQA Certificated Factory
- Worldwide shipping
- 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 ℃ – 850 ℃, hold until temperature is uniform throughout the section and cool in furnace.
Hardening: Heat to 830 ℃ – 860 ℃, 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 ℃ – 650 ℃, 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 ℃ – 660 ℃ 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 ℃ – 450 ℃ 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 ℃ – 660 ℃ 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 ℃ 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.
We are committed to integrate steel resources in china and serve the global steel market. Our company has more than 15 years of experience in steel researching, production, managing and sales. And our team mostly are based on and worked in national famous steel enterprise before. In the aspect of resources and information, we have established cooperative relationship with nearly hundred enterprises, either state-owned or private owned in China.
What’s more, we have built long, deep and close business relationship with dozens of steel company, Sharing and holding equities with several steel enterprises. Because of the close cooperation with steel companies and our pioneering spirit, which can ensure us stay at the top competition, and ensure our customers get what they really want. We provide preffesional one-stop service to the Contractors of follows project:
- Oil and Gas Pipeline Construction
- Onshore and Offshore
- Boiler Manufacturers
- Oil Refining Equipment
- Petroleum and Chemical Plant Construction
- Fire Protection
- Heating & Air Conditioning
Our ability to purchase materials directly from leading mills at the best possible price will give you the competitive edge. This coupled with a skilled workforce dedicated to embracing the demands of the markets we serve. Just give us a call +86-731-89903933.
