Alloy Structural Steel Round Billet
Introduction:
Alloy structural steel round billet is high-purity continuous casting semi-finished material, integrating low-alloy high-strength steel, manganese alloy steel, boron hardening steel, Cr-Mo tempered steel, carburizing alloy steel series. Produced by EAF smelting + LF ladle refining + VD vacuum degassing + EMS electromagnetic stirring continuous casting process. Strictly restrict S, P harmful impurities and non-metallic inclusions, featuring uniform chemical composition, low central segregation, dense internal metallographic structure, excellent hardenability, balanced strength & toughness, outstanding fatigue resistance and weldability.
Product Overview
Diameter range covers ø150mm–ø1300mm, full mainstream grades: Q355, Q390, Q420, Q460, 20Mn2, 40Mn2, 27SiMn, 37Mn5, 40B, 45B, 42CrMo, 20MnTiB, 20Cr, 40Cr, 20CrMo, 35CrMo, 20CrMnTi, 30CrMnTi.
Available delivery states: as-cast black scale billet, hot-charged hot delivery billet, normalized softening billet, surface scarfing finished billet. It is core upstream raw material for hot rolled round bar, seamless pipe piercing, open-die & closed-die forging. Deep-processed finished products are widely applied to automobile transmission parts, engineering machinery heavy-load components, petroleum drilling & pipeline fittings, wind power main shafts, high-pressure valve bodies and heavy-duty fastener forgings.
Representative Grades
|
Grade |
Executive Standard |
Alloy System |
Core Performance & Application |
|
Q355/Q390/Q420/Q460 |
GB/T 1591-2018 |
HSLA low-alloy high-strength steel |
V/Nb/Ti micro-alloyed, high yield strength, excellent weldability; bridge, factory steel frame, mining support, heavy truck structural parts |
|
20Mn2 / 40Mn2 |
GB/T 3077-2015 |
Mn low-alloy steel |
Mn improves hardenability, cost-effective; medium-load connecting rod blank, general shaft forging, heavy bolt raw material |
|
27SiMn |
GB/T 3077-2015 |
Si-Mn high tensile steel |
High strength & wear resistance; hydraulic cylinder blank, mine heavy structural forgings |
|
37Mn5 |
EN 10294 |
Mn oil pipe special steel |
Stable quenching performance, anti-hydrogen induced cracking; oil casing, drill pipe joint, downhole tool blank, meet API J55 standard |
|
40B / 45B |
GB/T 3077-2015 |
Boron hardening steel |
Trace boron greatly enhances hardenability, replace partial Cr steel; medium-strength shaft, auto fastener forgings |
|
35CrMo / 42CrMo |
GB/T 3077-2015 |
Cr-Mo tempered steel |
Excellent temper stability & low-temperature toughness; crankshaft, wind power main shaft, drill collar, high-pressure valve body |
|
20Cr / 20CrMo |
GB/T 3077-2015 |
Low-carbon Cr carburizing steel |
Hard wear-resistant surface after carburizing, tough core; small gear, piston pin, miniature transmission parts |
|
20MnTiB |
GB/T 3077-2015 |
Ti-B fine grain carburizing steel |
Ultra-fine grain, ultra-high fatigue strength; automobile gearbox gear blank, transmission shaft forging |
|
20CrMnTi / 30CrMnTi |
GB/T 3077-2015 |
Cr-Mn-Ti carburizing steel |
Uniform carburized layer, stable impact resistance; heavy-duty auto gear, gear ring, large reducer gear blank |
Grade Description
-
01
Q series (Q355~Q460): Low-alloy high-strength structural steel, micro-alloyed with V, Nb, Ti, yield strength 355~460MPa, good weldability for large engineering load-bearing structures.
-
02
Mn-series steel (20Mn2,40Mn2,37Mn5): Manganese element optimizes hardenability; 37Mn5 is European standard oil pipe special billet, matching API oil & gas downhole pressure components.
-
03
Boron steel (40B,45B): Trace boron sharply improves hardenability, lower cost than chromium alloy steel, substitute 40Cr for medium-strength structural parts.
-
04
Cr-Mo tempered steel (35CrMo,42CrMo): Chromium-molybdenum composite alloy, outstanding high-temperature creep resistance, preferred material for heavy-load power core components.
-
05
Carburizing steel (20Cr,20CrMo,20MnTiB,20CrMnTi,30CrMnTi): Low carbon alloy, after carburizing heat treatment to form hard wear-resistant surface while retaining high-toughness core, raw material for all types of transmission gears.
Product Specifications
|
Item |
Specific Parameters |
|
Product Form |
Continuous casting alloy round billet |
|
Standard Diameter Range |
ø150mm ~ ø1300mm |
|
Standard Length |
3m / 6m / 9m / 12m; customized fixed-length cutting available |
|
Production Technology |
EAF + LF refining + VD vacuum degassing + EMS electromagnetic stirring continuous casting |
|
Delivery Condition |
As-cast black oxide scale / Hot-charged hot delivery / Normalized softening / Surface scarfing finished billet |
|
Surface State |
Original casting oxide skin; surface grinding, shot blasting optional |
|
Dimensional Tolerance |
Diameter tolerance ±1.2%~±1.3%D (YB/T 2011-2014) |
|
Ovality |
≤2.0% of nominal diameter |
|
Length Tolerance |
±50mm |
|
Straightness |
≤4mm/m standard grade |
|
Internal Quality Standard |
Low center segregation, minimal shrinkage cavity & looseness, fine uniform grain, strictly limited non-metallic inclusions |
Core Advantages
1. Complete Alloy Grade Matrix: Cover low-alloy high-strength steel, manganese steel, boron steel, Cr-Mo tempered steel, Cr-Mn-Ti carburizing steel, fully match carburizing, quenching & tempering, nitriding all heat treatment processes, one-stop supply for construction, auto, petroleum, machinery multi-industry raw material demand.
2. Ultra-High Metallurgical Purity: Triple smelting EAF+LF+VD removes gas and harmful impurities; EMS electromagnetic stirring suppresses central segregation, stable internal metallographic structure, tiny mechanical performance fluctuation between different heats and batches.
3. Balanced Comprehensive Mechanical Performance: Scientific alloy matching realizes high strength, high toughness, excellent fatigue resistance and temper stability; large-diameter billets maintain uniform hardness after secondary forging & rolling without layer separation.
4. Full Diameter Coverage ø150–400mm: Small ø150–240mm billet for small round bar & seamless pipe raw material; large ø250–400mm heavy round billet for heavy seamless pipe, large crankshaft, wind power gear ring and heavy load forging blank, realize one-stop procurement for steel processing factories.
5. Wide Downstream Process Adaptability: Suitable for hot rolling, open die forging, closed die forging, piercing multiple processing routes; hot-charged billet saves secondary heating energy consumption for downstream manufacturers and cuts production cost.
6. Diversified Custom Deep Processing: Support surface scarfing & grinding, softening normalization, fixed-length cutting, batch ultrasonic flaw detection, customized special length delivery.
Main Application Fields
-
Construction & Heavy Engineering Machinery
Q355/Q390/Q420/Q460 round billets for bridge steel, factory building steel frame, mining equipment support parts, heavy transport vehicle structural components.
-
Automobile Manufacturing Forging Raw Material
20CrMnTi/20MnTiB gear blanks, 42CrMo/35CrMo crankshaft & connecting rod blanks, 40B/45B medium-strength fastener forgings, steering knuckle semi-finished products.
-
Petroleum & Energy Equipment
37Mn5 billets for oil casing, drill pipe joints matching API standard; Cr-Mo series for drill collars, wind power main shaft, hydraulic piston rod blanks.
-
General Machinery Manufacturing
40Cr/20CrMo shaft blanks, reducer gear forgings, 27SiMn hydraulic cylinder blanks, heavy-duty pin and mold blank raw material.
-
Seamless Pipe Production
Round billets for piercing high-pressure fluid pipeline, hydraulic cylinder tube, oil & gas delivery steel pipe.
-
Large Heavy-Duty Forging
ø250–400mm large round billet for large gear ring, marine structural forging, wind power bearing blank, heavy engineering machinery load-bearing shaft raw material.
Packaging & Services
- 1. Executive Standards: GB/T 1591-2018 Low-alloy high-strength steel, GB/T 3077-2015 Alloy structural steel, YB/T 2011-2014 Continuous casting round billet, EN 10294 (37Mn5).
- 2. Full Inspection Items: Melting chemical composition analysis, dimensional inspection, surface defect detection, macrostructure low-fold examination, non-metallic inclusion rating, grain size test; optional ultrasonic flaw detection (UT) for large-diameter round billets.
- 3. Certification Documents: EN10204 MTC 3.1 mill test certificate attached per batch, complete heat number composition & mechanical property reports; SGS/BV/TÜV third-party inspection certification available.
- 4. Packaging & Shipment: Steel wire bundled, waterproof tarpaulin covering; support bulk cargo vessel and full container transportation.
- 5. MOQ: 10 tons per single grade; mixed grades & mixed diameter sizes container loading acceptable.
- 6. Value-added Services: Surface scarfing & grinding, softening normalizing, fixed-length cutting, hot-charged delivery, full-set non-destructive flaw detection.
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- WhatsApp: +86-185 9567 2991
- Email: martinliu@rongtianmetal.com
- Tel: +86-185 9567 2991
- Address: 8F, Bldg 2, Jinke Zhihui Valley No. 65 Hongyuan Rd., Jinshui Dist. Zhengzhou, China.
