4340 1.6580 30CrNiMo8 SNCM439 Forged Alloy Steel Round Bar

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

Chemical Composition(%)

Mechanical Properties

(T=20°C if not differently stated)

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.