Description

Alloy steel round bars are long, cylindrical steel round bars made from carbon steel as the base material, with one or more alloying elements (such as chromium, nickel, molybdenum, manganese, silicon, etc.) added, and formed through smelting, rolling, or forging.

Alloy steel round bars are important semi-finished raw materials in machinery manufacturing. By adjusting the composition and heat treatment process, they can achieve higher strength, toughness, wear resistance, or corrosion resistance than ordinary carbon steel. They are mainly used to manufacture mechanical parts that withstand high loads, impacts, or fatigue.

Alloy steel round bars can be classified as follows:

1. By application: Alloy steel round bars are divided into alloy structural steels (such as 42CrMo, 20CrMnTi, 40Cr, 38CrMoAl, used for mechanical parts, shafts, gears, etc.), alloy tool steels (such as Cr12, 9SiCr, Cr12MoV, 6542, used for cutting tools, molds, measuring tools), and special performance steels (such as stainless steel round bar, heat-resistant steel, wear-resistant steel round bars, containing Cr-Ni series, precipitation hardening type, etc.).

2. Classification by Total Alloy Element Content: Alloy steel round bars are classified into low-alloy steel (total alloy element content <5%, such as Q345B round bars), medium-alloy steel (5%~10%, such as 40CrNiMo round bars), and high-alloy steel (>10%, such as high-speed steel 6542 and heat-resistant steel 310S round bars).

Additionally, they can be further subdivided by metallographic structure (martensite, austenite, bainite, etc.) or delivery condition (black skin, bright, cold-drawn, forged), but classification by application and total content is the most common and provides engineering guidance. Note: Stainless steel, high-temperature alloys (such as GH4169), and cemented carbide (such as tungsten carbide), although often collectively referred to as “alloy steel round bars,” strictly belong to special performance steels or cermets and are not classified as traditional alloy steels.

Features of Alloy Steel Round Bars:

1. Balance of High Strength and Toughness: Compared to ordinary carbon steel, Alloy Steel Round Bars, after heat treatment such as quenching and tempering, exhibit significantly improved tensile strength and yield strength while maintaining good impact toughness, making them suitable for bearing complex loads.

2. Excellent Heat Treatment Response: Alloying elements improve the hardenability of the steel, enabling even large-section round bars to achieve uniform microstructure and properties. Hardness and strength can be precisely controlled through quenching and tempering.

3. Corrosion/Heat Resistance in Specific Environments: Alloy Steel Round Bars possess specific advantages depending on the added elements. For example, chromium-nickel alloy steels are resistant to atmospheric or chemical corrosion; molybdenum- and tungsten alloy steels maintain high strength (hot strength) at high temperatures.

4. Good Processing Performance: Most Alloy Steel Round Bars possess good forging and machining properties, and some grades have excellent cold heading or cold drawing properties, facilitating the manufacture of precision parts such as bolts and shafts.

5. High dimensional accuracy: Commonly cold-drawn or ground round bars have high surface finish, small diameter tolerances (up to H7/h6 grade), good straightness and concentricity, reducing subsequent machining allowances.

6. Diverse states: Supply states include hot-rolled black bars (low cost, large size), cold-drawn bright bars (high precision, good surface finish), and forged bars (dense internal structure, used in critical components).

7. Wide range of specifications: Diameters typically range from a few millimeters to hundreds of millimeters, and lengths can be customized to meet different mechanical structure design requirements.

Applications of Alloy Steel Round Bars:

1. Shafts and transmission components: Alloy steel round bars are used in applications such as crankshafts, drive shafts, gear shafts, and connecting rods in automobiles and construction machinery, where high fatigue strength and toughness are required (e.g., 30NC11, 42CrMo).

2. Gears and Fasteners: Alloy steel round bars, after tempering or carburizing, are used for gearbox gears, high-strength bolts, and nuts (e.g., 30CrNiMo8).

3. Dies and Wear-Resistant Parts: Used for punches, wire drawing dies, and roll mandrels, utilizing their wear resistance and deformation resistance (e.g., some high-carbon alloy steels).

4. Pressure Vessels and Hydraulic Components: Alloy steel round bars are used to manufacture high-pressure valve bodies and hydraulic cylinder rods, requiring pressure resistance and sealing performance (e.g., 30NC11 in hydraulic systems).

5. Aerospace and Energy Equipment: Aircraft landing gear, gas turbine fasteners, and key structural components for nuclear power plants, using alloy steels with excellent high/low temperature toughness (e.g., certain nickel-chromium-molybdenum steels).

6. Bearings and Pins: Alloy steel round bars, after surface hardening, are used in high-wear-resistance, low-deformation applications (e.g., bearing rollers and pins).

Specifications of the Steel Round Bar:

Carbon Structural Steel Bright Round Bar	C10 C20 C35 C45 c55 St37-2 St37-3 St44-2 St44-3 St52-3	S10C S20C S25C S35C S45C S48C S50C S55C	1010 1020 1035 1045 1055	10# 20# 25# 35# 45# 20Mn 45Mn
Low – Alloy High – Strength Structural Steel Bright Round Bar	S235JR S235J0 S235J2 S275JR S275J0 S275J2 S355JR S355J0	S355J2 S275J0G3 S275J2G4 S355J2G3 S355J2G4 S355k2G3 S355K2G4 S355K2 S355J2G4	S275N S355N S355NL S420N S420NL S460N S460NL	Q355B Q355D Q390B Q390D
Alloy Structural Steel Bright Round Bar	20Mn2 30Mn2 40Mn2 20Cr 40Cr 15CrMo 20CrMo 30CrMo 42CrMo 41Cr4 16MnCr5 42CrMoS4	12Cr1MoV 20CrMnTi 20CrNiMo 40CrNiMo SAE1541 4120 4135 4140 4320 4340 8620H SCM415 SCM420	SCM430 SCM435 SCM440 SCr420 SCr420H SCr435 SCr440 34CrMo4 SNCM439 34Cr4	42CrMo4 39NiCrMo3 34CrNiMo6 18CrMo4 20NiCrMo2-2
Inconel Alloy Superalloys	Inconel601 InconeX750 Inconel600 Incoloy825 Inconel718	Incoloy800H Incoloy 800H Incoloy800 Inconel625 Inconel625 Inconel690	GH4099 GH128 GH145 GH169 GH605 GH3536 GH4033 GH99 GH625 GH4080AGH2132	GH132 GH500 GH600 GH536 GH4141 GH141 GH3625 GH2747 GH188 GH2696 GH747 GH3030

Diameter (mm)	Theoretical Weight (kg/m)	Diameter (mm)	Theoretical Weight (kg/m)
5.5	0.186	13	1.04
6	0.222	14	1.21
6.5	0.26	15	1.39
7	0.302	16	1.58
8	0.395	17	1.78
9	0.499	18	2
10	0.617	19	2.23
* 11	0.746	20	2.47
12	0.888	21	2.72
22	2.98	63	24.5
* 23	3.26	* 65	26
24	3.55	* 68	28.5
25	3.85	70	30.2
26	4.17	75	34.7
* 27	4.49	80	39.5
28	4.83	85	44.5
* 29	5.18	90	49.9
30	5.55	95	55.6
* 31	5.92	100	61.7
32	6.31	105	68
* 33	6.71	110	74.6
34	7.13	115	81.5
* 35	7.55	120	88.8
36	7.99	125	96.3
38	8.9	130	104
40	9.86	140	121
42	10.9	150	139
45	12.5	160	158
48	14.2	170	178
50	15.4	180	200
53	17.3	190	223
* 55	18.6	200	247
56	19.3	220	298
* 58	20.7	250	385
60	22.2

Products	Round Steel bar
Dia	5.5mm~650mm
Length	3m,6m,9m,12m
Standard	ASTM A 615 Gr 40/60,BSS4449 Gr460B,500B etc
Material	3Cr2Mo/1.2311/1.2312/P20/1.2738/718H/P20+Ni/1.2316/1.2083/4Cr13 /sus420j2/420/S136/NAK80H13/1.2344/SKD61/5CrNiMo/SKT4/1.2714 Cr12/D3/1.2080/Cr12MoV/D2/1.2379/SKD11/9CrWMn/O1/1.2510/SKS3 /DC53 40Cr/5140/35CrMo/42CrMo/4140/1.7225 C45/C50/1045/1050/S50C/S45C/T10/T8 M2/1.338/SKH51
Surface	ASTM，AISI，JIS，GB， DIN，EN
Technique	Hot rolled / cold rolled
Surface	Black Finish ,Oiled,Shot Blasted,Spray Paint,Coated,Galvanized,
Surface	Or as Your Request
Package	In bundle, no other package or wrapped with waterproof, or as customers’ requirement
Payment Term	T/T, L/C at sight,West Union,Paypal
Price Term	FOB,CRF,CIF,EXW all acceptable

S45C	0.42~0.48	0.60~0.90	0.15~0.35	≤0.03	≤0.03	≤0.20	≤0.20	≤0.30	_	_	JIS G4051-2005
S20C	0.18~0.23	0.30~0.60	0.15~0.35	≤0.03	≤0.035	≤0.20	≤0.20	≤0.30	_	_	JIS G4051-2005
ASTM A36	≤0.22	0.50~0.90	≤0.40	≤0.040	≤0.050	≤0.20	≤0.20	≤0.30	≥250	400~500	ASTM A36/A36M-03a
ASTM A105	≤0.35	0.6-1.05	≤0.35	≤0.050	≤0.040	≤0.20	≤0.20	≤0.30	≥310	485~620	ASTM A105/A105M
SAE1013	0.11~0.16	0.50~0.80	_	≤0.040	≤0.050	≤0.20	≤0.20	≤0.30	_	_	ASTM A568/A568M-91a
SAE1015	0.13~0.18	0.30~0.60	_	≤0.040	≤0.050	≤0.20	≤0.20	≤0.30	_	_
SAE1017	0.15~0.20	0.30~0.60	_	≤0.040	≤0.050	≤0.20	≤0.20	≤0.30	_	_
SAE1018	0.15~0.20	0.60~0.90	_	≤0.040	≤0.050	≤0.20	≤0.20	≤0.30	_	_
SAE1020	0.18~0.23	0.30~0.60	_	≤0.040	≤0.050	≤0.20	≤0.20	≤0.30	_	_
S235JR	0.15~0.20	≤1.4	_	≤0.035	≤0.035	≤0.20	_	_	≥235	400~510	EN10025
S275JR	≤0.22	≤1.4	_	≤0.035	≤0.035	≤0.20	_	_	≥275	490~610	EN10025
ST37-2	0.17~0.20	≤1.4	_	≤0.045	≤0.045	≤0.20	_	_	≥235