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AISI4340 Alloy Steel Round Bar with Polished Surface for Mold Steel Application in 13-300mm Diameter

Minimum Order Quantity	1 Ton
Price	US $952-1,058 / Ton

Product Details

Diameter Range	13 - 300mm	Length	6m
Steel Grade	4340 Alloy Steel	Carbon Content	0.38-0.43%
Silicon Content	0.15-0.35%	Manganese Content	0.60-0.80%
Phosphorus Content	≤0.035%	Sulfur Content	≤0.04%
Nickel Content	1.65-2.00%	Chromium Content	0.70-0.90%
Molybdenum Content	0.20-0.30%	Tensile Strength	1282 MPa (186 Ksi)
Yield Strength	862 MPa (125 Ksi)	Elongation	12.2%
Hardness	363 HB
Highlight	AISI4340 Alloy Steel Round Bar , Polished Surface Steel Round Bar , Mold Steel Application Alloy Steel Bar

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Product Description

AISI4340 Alloy Steel Round Bar

Diameter: 13 - 300mm | Length: 6m or custom cutting | Grade: 4340 Alloy Steel

Product Specifications

Diameter	13 - 300mm
Length	6m or custom cutting as request
Grade	4340 Alloy Steel
Our Service	Cutting, polishing, packing, heat treatment
Brand	BAOSTEEL, XINGCHENG, DSS, CHONGQING, XNSS, HLXT, etc.
Standard	GB, ASTM, JIS, EN, DIN
Company Type	Storage company and process service

Material Overview

AISI 4340 steel (UNS G43400) is an ultra-high strength medium carbon low alloy steel that combines deep hardenability, high ductility, toughness and strength. It features high fatigue resistance and creep resistance, is not particularly affected by tempering and embrittlement, exhibits good strength retention at high temperatures, and is not easily softened. In thin sections, this steel is air-hardened, though in practice it is usually oil quenched.

Chemical Composition

ASTM	Steel Grade (UNS)	C	Si	Mn	P (≤)	S (≤)	Ni	Cr	Mo	Notes
ASTM A29/A29M	4340 alloy steel (UNS G43400)	0.38-0.43	0.15-0.35	0.60-0.80	0.035	0.04	1.65-2.00	0.70-0.90	0.20-0.30	Steel Bars, Carbon and Alloy, Hot-Wrought

Mechanical Properties

Condition	Tensile strength, MPa (ksi), ≥	Yield strength, MPa (ksi), ≥	Elongation in 50 mm (2 in.), ≥	Reduction in area, %, ≥	Hardness, HB, ≤
Normalized at 870 °C (1600 °F)	1282 (186)	862 (125)	12.2	36.3	363
Annealed at 810 °C (1490 °F)	745 (108)	470 (68)	22.0	50.0	217
Oil quenched from 800 °C (1475 °F) and tempered at 540 °C (1000 °F)	1207 (175)	1145 (166)	14.2	45.9	352

Applications

SAE AISI 4340 steel is used in applications with severe conditions and heavy parts requiring high strength. It can be widely used as billet, bar, forging, sheet, pipe and welding wire, and can also be produced as light plates and castings. Typical applications include:

Bolts, screws and other fasteners
Gears, pinions, shafts and similar mechanical components
Crankshafts and piston rods of engines
Landing gear and other key structural components of aircraft

International Equivalents

US	European Union	China	Japan	ISO
AISI, SAE, ASTM A29/A29M, ASTM A322, ASTM A519/A519M, ASTM A646/A646M - 4340 (UNS G43400)	SAE AMS6414	GB/T 3077 40CrNi2Mo	JIS G 4053 SNCM439

Company Capabilities

We specialize in various types of round steel and are designated agents for major steel mills including Professional, Handan, Laigang, Jiyuan steel and others. Our monthly sales volume ranges from 40,000-60,000 tons of various steel types.

4+ warehouses for stock management
30+ product grades maintained in stock
800+ sizes available for quick delivery
Dedicated processing warehouse for cutting, polishing, and heat treatment
Global sales network serving machinery, automotive, forging, and hardware industries

Available Steel Grades

We manufacture a comprehensive range of steel grades including EN series, C series, S series, SAE/AISI standards, BS970, EN 10088-3, ASTM specifications, DIN standards, GOST standards, and many others to meet diverse industrial requirements.

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