40CrNiMoA Steel Round Bar AISI 4340 Alloy Steel

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$2.77 - $5.77 / Kilogram | 200 Kilogram/Kilograms (Min. Order)
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Quick Details
Steel Grade:
Place of Origin:
Liaoning, China
Brand Name:
Model Number:
AISI 430
Hot Rolled
Tool Steel Bar
Alloy Or Not:
Is Alloy
Special Use:
Cold Heading Steel
Alloy Steel Bar
Tensile strength:
Yield strength:
Product Name:
40CrNiMoA Steel Round Bar AISI 4340 Alloy Steel
Similar Grade:
Black Or Polished Bright
According to your request.
Supply Ability
Supply Ability:
20000 Ton/Tons per Year
Packaging & Delivery
Packaging Details
Usually in wooden case or according to your request.
Lead Time :

40CrNiMoA Steel Round Bar AISI 4340  Alloy Steel

Product Description


Alloy steels are designated by AISI four-digit numbers. They comprise different kinds of steels having composition exceeding the limitations of B, C, Mn, Mo, Ni, Si, Cr, and Va set for carbon steels.AISI 4340 alloy steel is a heat treatable and low alloy steel containing chromium, nickel and molybdenum. It has high toughness and strength in the heat treated condition.

AISI 4340 Chemical Composition Table%
Min 0.38 0.15 0.6   0.70.2 1.65 
Max0.43  0.350.8 0.04 0.035  0.90.3  2.0


AISI 4340 Typical Physical Property
Tensile strength σb (MPa): ≥980 (100)
Yield strength σs (MPa): ≥835 (85)
Elongation δ5 (%): ≥12
Section shrinkage ψ (%): ≥55
Impact energy Akv (J): ≥78            


AISI 4340 Heattrement:
(Quenching 850 degrees; coolant: oil; tempering temperature of 600 degrees; Coolant: water, oil)
Annealing or tempering steel supply state Brinell hardness less GBW 269


AISI 4340 alloy steel can be welded using fusion or resistance welding methods. Preheat and post heat weld procedures are followed while welding this steel by established methods.

Heat Treatment

AISI 4340 alloy steel is heat treated at 830°C (1525°F) followed by quenching in oil.


AISI 4340 alloy steel is forged at 427 to 1233°C (1800 to 2250°F).

Cold Working

AISI 4340 alloy steel can be cold worked using all conventional methods in the annealed condition. It has high ductility.


AISI 4340 alloy steel is annealed at 844°C (1550°F) followed by cooling the furnace.


AISI 4340 alloy steel should be in the heat treated or normalized and heat treated condition before tempering. Tempering temperatures depend upon the desired strength level.


AISI 4340 alloy steel can be hardened by cold working or heat treatment.

AISI 4340 Application:
With so requires good toughness, high strength, as well as the large size of the important pieces of quenched and tempered, high loads such as heavy machinery shafts, turbine diameter greater than 250mm of control shaft, rotor shaft helicopter turbojet turbine shaft, blade, high load transmission parts, crank fasteners. Gear and so on; also be used for operating temperatures over 400 ℃ rotor shaft and blades; you can also post nitriding process used to make special performance requirements of important parts in the after quenching and tempering or the like can be used for ultra-high temperature strength steel.
Quality Assurance

After Processing And Before Packing

1. Chemical Compositon Inspection

2.Nondestructive Inspection

3.Metallurgical Microscope Inspection.

4.Physical Property Inspection

5.Hardness Inspection

6.Heterogeinity Of Carbides



Q:Do you accept the sample order?
A: Yes, we accept the sample order. If you order the small piece in stock, it is free.

     But we do not pay for the freight cost.

 Q: How long is your delivery time?
A: Usually 45 to 60 days after your down payment, it also according to the material requirement
     and  the quantity you ordered.

Q: What is your terms of payment.
A: Payment less or equal 10000USD,100% T/T in advance. Payment more than 1000USD, 
30% T/T in advance, balance before shippment. Also accept the L/C at sight.

Q:What is your working time?
A:Monday-Friday : 8:00AM-17:00PM (Beijing time, GMT+08.00) 
While by whatsapp you can contact me anytime if I am awake up.

Why US & Contact US

1) Honest: we will strictly adhere to the contract, you will get the exact quality and quantity

    from us. We never receive any complain from the clients for the quantity and weight. 
2) Competitive price with shipment in time.
3) Strictly control on the quality.
4) More than 16 years experience in the export.
5) Best service after sale: We will be responsible for any disputes and problems occured after    

    shipment, we assure  you that we will be responsible to the end once our service starts.