Structural Alloy Steel Bar

Multi‑form supply: round, square, hex, flat bar, full‑size coverage
Multiple delivery conditions: annealed, cold‑drawn, pre‑hardened quenched & tempered
Complete cross‑standard grade system for global engineering procurement
High strength, good toughness and wear resistance for heavy‑load service scenarios

Product Overview

Structural Alloy Steel Bar is a high-strength alloy structural long bar produced to GB/T 3077, ASTM A322, ASTM A108, EN 10263 and DIN EN 10083 standards. It is available in round, square, hexagonal and flat bar forms, with round bar sizes from Φ10–350 mm, square bar from 10–200 mm, and hexagonal bar from S10–S100. The product is intended for demanding mechanical and structural applications requiring a combination of strength, toughness and wear resistance. A产品简单描述(20260928-023301)

The material portfolio covers multiple international grade systems, including Chinese 40Cr, 42CrMo, 20CrMnTi, 20CrMo, 15CrMo, 12Cr1MoV, 35CrMo, 27SiMn and 45CrNiMoVA, American 4130, 4140, 4340, 8620, 8740 and 5140, and European grades such as 42CrMo4 (1.7225), 34CrMo4 (1.7220), 20MnCr5 and 16CrMo44. This cross-standard grade range supports material selection for different mechanical load and component requirements.

Different delivery conditions are available, including hot-rolled annealed, cold-drawn precision, and quenched-and-tempered pre-hardened conditions. Buyers can therefore select the appropriate material condition according to subsequent forging, machining, dimensional-control and heat-treatment requirements. The supplied product information specifically identifies these three delivery conditions.

Structural Alloy Steel Bar is used for automotive transmission parts, engineering machinery, wind-power equipment, mining equipment, oil-field equipment and heavy mechanical components. Specific applications include gearbox gears, transmission shafts, crankshafts, hydraulic-cylinder piston rods, wind-power main-shaft blanks, mining wear-resistant parts, oil-field down-hole tools, high-pressure valve-body forgings, die blanks, heavy lifting hooks and heavy machinery pins.

Structural Alloy Steel Bar

Chemical & Mechanical Property Snapshot

Grade	Equivalent Standard	C (%)	Si (%)	Mn (%)	Cr (%)	Mo (%)	Yield Strength Min (MPa)	Tensile Strength Min (MPa)	Elongation A5 Min (%)	Key Characteristic
40Cr	GB/T 3077 / ASTM 5140	0.37–0.44	0.17–0.37	0.50–0.80	0.80–1.10	≤0.10	785	980	9	General structural alloy steel, good hardenability
42CrMo	GB/T 3077 / 42CrMo4 (1.7225)	0.38–0.45	0.17–0.37	0.50–0.80	0.90–1.20	0.15–0.25	930	1080	12	High strength & toughness, suitable for heavy-load shafts
20CrMnTi	GB/T 3077	0.17–0.23	0.17–0.37	0.80–1.10	1.00–1.30	—	835	1080	10	Case-carburizing steel, suitable for gears
20CrMo	GB/T 3077	0.17–0.24	0.17–0.37	0.40–0.70	0.80–1.10	0.15–0.25	685	885	12	Low-carbon alloy steel, weldable, suitable for carburized parts
15CrMo	GB/T 3077	0.12–0.18	0.17–0.37	0.40–0.70	0.80–1.10	0.40–0.55	440	440	21	High-temperature creep resistance, suitable for boilers and high-temperature parts
12Cr1MoV	GB/T 3077	0.08–0.15	0.17–0.37	0.40–0.70	0.90–1.20	0.25–0.35	245	490	22	Heat-resistant alloy steel for the power industry
35CrMo	GB/T 3077 / 34CrMo4 (1.7220)	0.32–0.40	0.17–0.37	0.40–0.70	0.80–1.10	0.15–0.25	835	980	12	Good fatigue strength, suitable for heavy-load fasteners and shafts
27SiMn	GB/T 3077	0.24–0.32	1.10–1.40	1.10–1.40	≤0.30	—	835	980	12	High strength, low cost, suitable for hydraulic cylinder tube blanks
45CrNiMoVA	GB/T 3077	0.42–0.49	0.17–0.37	0.50–0.80	0.80–1.10	0.20–0.30	1325	1470	7	Ultra-high-strength alloy for impact and heavy-load applications
4130	ASTM A322 / 20MnCr5	0.28–0.33	0.15–0.35	0.40–0.60	0.80–1.10	0.15–0.25	785	980	12	American-standard alloy steel, versatile for machinery applications
4140	ASTM A322 / 42CrMo4	0.38–0.43	0.15–0.35	0.75–1.00	0.80–1.10	0.15–0.25	930	1080	12	Popular U.S. alloy bar, equivalent to 42CrMo
4340	ASTM A322	0.38–0.43	0.15–0.35	0.60–0.80	1.65–2.00	0.20–0.30	830	980	10	Ni-Cr-Mo alloy with ultra-high toughness
8620	ASTM A322	0.18–0.23	0.15–0.35	0.70–0.90	0.40–0.60	0.15–0.25	620	830	12	Low-carbon Ni-Cr-Mo carburizing gear steel
8740	ASTM A322	0.38–0.43	0.15–0.35	0.75–1.00	0.40–0.60	0.20–0.30	830	980	10	Carburizing & quenching alloy steel
16CrMo44	EN 10083	0.12–0.20	≤0.40	0.60–0.90	0.80–1.10	0.40–0.50	400	600	16	European low-carbon Cr-Mo alloy

Detailed Technical Specifications

Technical Item	Complete Specification
Product Name	Structural Alloy Steel Bar
Product Category	Structural Alloy Steel Bar
Material Type	Alloy Structural Steel
Applicable Standards	GB/T 3077; ASTM A322; ASTM A108; EN 10263; DIN EN 10083
Available Forms	Round Bar; Square Bar; Hexagonal Bar; Flat Bar
Round Bar Size	Φ10–350 mm
Square Bar Size	10–200 mm
Hexagonal Bar Size	S10–S100
Flat Bar	Available; specific dimensions are not stated in the supplied product material
Delivery Condition	Hot-Rolled Annealed
Delivery Condition	Cold-Drawn Precision
Delivery Condition	Quenched & Tempered Pre-Hardened
Chinese GB Grades	40Cr; 42CrMo; 20CrMnTi; 20CrMo; 15CrMo; 12Cr1MoV; 35CrMo; 27SiMn; 45CrNiMoVA
American ASTM Grades	4130; 4140; 4340; 8620; 8740; 5140
European EN / DIN Grades	42CrMo4 (1.7225); 34CrMo4 (1.7220); 20MnCr5; 16CrMo44
Performance Characteristics	High strength; good toughness; wear resistance
Material Selection Basis	Load, impact conditions and working temperature
Quality Documentation	Mill Test Certificate with heat number, chemical composition and mechanical property data
Automotive Applications	Gearbox gears; transmission drive shafts; crankshafts
Engineering Machinery Applications	Hydraulic-cylinder piston rods; heavy machinery pins
Wind-Power Applications	Main-shaft blanks
Mining Applications	Wear-resistant components
Oil-Field Applications	Down-hole tools
High-Pressure Equipment Applications	High-pressure valve-body forgings
Tooling / Die Applications	Die module blanks
Heavy Equipment Applications	Heavy lifting hooks; heavy-duty machinery pins
MOQ	5 Ton
Payment Terms	T/T, L/C at Sight
Package	Waterproof paper + galvanized steel strap + seaworthy export wooden pallet

Size Specifications Table

Product Form	Size Range	Tolerance Reference	Available Surface
Round Structural Alloy Steel Bar	Φ10 mm–Φ350 mm	Hot rolled: ±0.3–1.5 mm; Cold drawn: ±0.05–0.3 mm	Black, Peeled, Polished
Square Structural Alloy Steel Bar	10 mm–200 mm	Hot rolled: ±0.4–1.8 mm; Cold drawn: ±0.06–0.3 mm	Black, Machined
Hexagonal Structural Alloy Steel Bar	S10–S100 (across-flat dimension)	Cold drawn: ±0.08–0.3 mm	Bright / Black
Flat Structural Alloy Steel Bar	Thickness: 4–100 mm; Width: 20–300 mm	Hot rolled: ±0.5–2 mm	Black / Milled

Product Comparison Table

GB Grade	ASTM Equivalent	EN/DIN Equivalent	Density (g/cm³)	Hardenability	Main Feature	Typical Application
40Cr	5140	—	7.85	Medium	General-purpose Cr alloy steel, good strength & wear resistance	Gears, shafts, bolts, machinery structural parts
42CrMo	4140	42CrMo4 (1.7225)	7.85	High	Excellent toughness, high-temperature strength, fatigue resistance	Crankshafts, wind power shafts, heavy gears, hydraulic piston rods
20CrMnTi	—	—	7.85	Medium	Carburizing steel, good surface-hardening performance	Automobile gearbox gears, transmission gears
20CrMo	—	—	7.85	Medium	Low-carbon CrMo steel, good weldability after normalizing	Carburized pins, shafts, high-pressure pipe fitting blanks
15CrMo	—	—	7.85	Low	High-temperature oxidation & creep resistance	Boiler tube headers, high-temperature pipeline components
12Cr1MoV	—	—	7.85	Low	Heat-resistant steel, stable mechanical properties under long-term high temperatures	Power station superheaters, high-temperature pipe parts
35CrMo	—	34CrMo4 (1.7220)	7.85	High	High fatigue strength, impact resistance	Heavy-load bolts, drill rods, engine shafts
27SiMn	—	—	7.85	Medium	High strength, low cost, good hardenability	Hydraulic cylinder blanks, heavy machinery structural blocks
45CrNiMoVA	—	—	7.85	Ultra-high	Ultra-high strength, strong impact resistance	Ultra-heavy-load impact components, artillery parts
—	4130	20MnCr5	7.85	Medium	Good weldability & machinability, preferred for oil & gas applications	Oilfield downhole tools, pressure vessel parts
—	4340	—	7.85	Ultra-high	Ni-Cr-Mo composite alloy, outstanding toughness	Aircraft landing gear, heavy-impact machinery
—	8620	—	7.85	Medium	Low-carbon nickel alloy, easy carburizing	Precision gears, automotive transmission parts
—	8740	—	7.85	Medium	Balanced strength and toughness after heat treatment	Automotive axles, heavy machinery pins

App Market

Reliable Steel Coil Solutions For Diverse Industrial Applications

Wind Turbine Main Shaft Blank

Mining Wear-Resistant Parts

Automotive Transmission Gears

Product Packaging

Secure Export Packaging For Safe Handling And Delivery

FAQs

What is Structural Alloy Steel Bar used for?

Structural Alloy Steel Bar is used for automotive transmission components, engineering machinery, wind-power equipment, mining equipment, oil-field equipment and heavy mechanical components. Specific applications include gears, drive shafts, crankshafts, piston rods, main-shaft blanks and heavy machinery pins.

What sizes are available for Structural Alloy Steel Bar?

Round bar is available from Φ10–350 mm, square bar from 10–200 mm, and hexagonal bar from S10–S100. Flat bar is also available, but a specific dimensional range is not stated in the supplied product material.

Which material grades are available?

The supplied grade portfolio includes GB grades 40Cr, 42CrMo, 20CrMnTi, 20CrMo, 15CrMo, 12Cr1MoV, 35CrMo, 27SiMn and 45CrNiMoVA; ASTM grades 4130, 4140, 4340, 8620, 8740 and 5140; and EN/DIN grades 42CrMo4, 34CrMo4, 20MnCr5 and 16CrMo44.

Which delivery condition should I choose?

The available delivery conditions are hot-rolled annealed, cold-drawn precision and quenched-and-tempered pre-hardened. The selection should be based on the required downstream machining, forging and heat-treatment process.

Which standards does the product follow?

Structural Alloy Steel Bar is specified according to GB/T 3077, ASTM A322, ASTM A108, EN 10263 and DIN EN 10083.

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Structural Alloy Steel Bar