Alloy Structural Steel Square Billet
Introduction:
Alloy structural steel square billet is semi-finished continuous casting steel raw material, integrating low-alloy high-strength steel, manganese alloy steel, boron steel, chromium-molybdenum steel, carburizing alloy steel series. Adopt EAF smelting, LF ladle refining, VD vacuum degassing + EMS electromagnetic stirring continuous casting process, strictly control harmful S, P impurities and non-metallic inclusions, with uniform chemical composition, low center segregation, dense internal metallographic structure, excellent hardenability, balanced strength & toughness, fatigue resistance and weldability.
Product Overview
Standard cross-section specifications: equal square billets 150×150mm, 180×180mm, 240×240mm; large rectangular bloom 400×500mm. Cover full mainstream grades: Q355, Q390, Q420, Q460, 20Mn2, 40Mn2, 27SiMn, 37Mn5, 40B, 45B, 42CrMo, 20MnTiB, 20Cr, 40Cr, 20CrMo, 35CrMo, 20CrMnTi, 30CrMnTi.
Delivery states: as-cast black scale, hot-charged hot delivery, normalized softening, surface scarfing finished billet. Widely used as upstream raw material for hot rolling round bars, flat steel, seamless pipe piercing, die forging; downstream finished products applied to automobile transmission parts, engineering machinery heavy-load components, petroleum drilling fittings, wind power structural parts and high-strength fasteners.
Representative Grades
|
Grade |
Executive Standard |
Alloy System |
Core Performance & Application |
|
Q355/Q390/Q420/Q460 |
GB/T 1591-2018 |
Low-alloy high-strength HSLA steel |
Micro-alloy V/Nb/Ti, high yield strength, good weldability; bridge, construction, heavy machinery support frame, mining equipment |
|
20Mn2 / 40Mn2 |
GB/T 3077 |
Mn-series low alloy steel |
Mn improves hardenability, low cost; medium-load connecting rod blanks, general shaft forgings, heavy bolt raw material |
|
27SiMn |
GB/T 3077 |
Si-Mn high-strength steel |
High tensile strength & wear resistance; hydraulic cylinder blank, mine heavy structural parts |
|
37Mn5 |
DIN EN 10294 |
Mn alloy oil pipe steel |
Good quenching performance, anti-hydrogen cracking; oil casing, drill pipe joint, downhole tool blank |
|
40B / 45B |
GB/T 3077 |
Boron alloy steel |
Trace boron greatly promotes hardenability, replace partial Cr steel; medium-strength shaft, automobile fastener forgings |
|
35CrMo / 42CrMo |
GB/T 3077 |
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 |
Low carbon Cr carburizing steel |
Surface hardening after carburizing, tough core; small gear, piston pin, miniature transmission parts |
|
20MnTiB |
GB/T 3077 |
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 |
Cr-Mn-Ti carburizing steel |
Uniform carburized layer, stable impact resistance; heavy-duty automobile gear, gear ring, reducer large 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, excellent weldability for large engineering structures.
-
02
Mn-series steel (20Mn2,40Mn2,37Mn5): Manganese element optimizes hardenability; 37Mn5 is European standard oil pipe special steel, suitable for oil & gas downhole components.
-
03
Boron steel (40B,45B): Trace boron element sharply improves hardenability, cost lower than chromium alloy steel, replace 40Cr for medium-strength parts.
-
04
Cr-Mo tempered steel (35CrMo,42CrMo): Chromium-molybdenum compound alloy, outstanding high-temperature creep resistance, heavy-load power core components preferred material.
-
05
Carburizing steel (20Cr,20CrMo,20MnTiB,20CrMnTi,30CrMnTi): Low carbon alloy, carburizing heat treatment to form hard wear-resistant surface while retaining tough core, all kinds of transmission gear blanks.
Product Specifications
|
Item |
Specific Parameters |
|
Product Form |
Equal square billet;Rectangular bloom |
|
Standard Cross-Section Sizes |
Square billet: 150×150mm、180×180mm、240×240mmRectangular bloom: 400×500mm |
|
Standard Length |
3m / 6m / 9m / 12m; customized fixed-length cutting available |
|
Production Technology |
EAF+LF+VD+EMS electromagnetic stirring continuous casting |
|
Delivery Condition |
As-cast black surface / Hot-charged hot delivery / Normalized softening / Surface scarfing finished |
|
Surface State |
Original casting oxide scale; surface grinding, shot blasting optional |
|
Section Tolerance |
Square billet ±2.0mm；400×500 rectangular bloom ±3.0mm (YB/T 2011-2014) |
|
Length Tolerance |
±50mm |
|
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, meet construction, auto, petroleum, machinery multi-industry demand.
2. Ultra-High Metallurgical Purity: Triple smelting EAF+LF+VD removes gas and harmful impurities; EMS electromagnetic stirring suppresses central segregation, stable internal structure, small mechanical performance fluctuation between batches.
3. Balanced Comprehensive Mechanical Performance: Scientific alloy matching realizes high strength, high toughness, excellent fatigue resistance and temper stability; large cross-section bloom maintains uniform hardness after secondary forging & rolling.
4. Complete Size Coverage: Small 150 square billet for small bar & seamless pipe raw material; 400×500 large bloom for heavy plate, large crankshaft and heavy gear forging blank, realize one-stop procurement for steel processing factories.
5. Wide 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 factories.
6. Diversified Custom Deep Processing: Support surface scarfing, softening normalization, fixed-length cutting, batch ultrasonic flaw detection, customized special length delivery.
Main Application Fields
-
Construction & Heavy Machinery
Q355/Q390/Q420/Q460 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; Cr-Mo series for drill collars, wind power main shaft, hydraulic piston rod blanks.
-
General Machinery Manufacturing
40Cr/20CrMo shaft blanks, reducer gear forgings, hydraulic cylinder blanks (27SiMn), heavy-duty pin and mold blank raw material.
-
Seamless Pipe Production
Square & rectangular billets for piercing high-pressure fluid pipeline, hydraulic cylinder tube, oil delivery steel pipe.
-
Large Forging & Plate Rolling
400×500 rectangular bloom for large gear ring, marine structural plate, heavy engineering machinery load-bearing forging blank.
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 square & rectangular billet, DIN EN 10294 (for 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-section bloom.
- 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 cross-section 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
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