Carbon Structural Steel Square Billet
Introduction:
Carbon structural steel square billet is semi-finished continuous casting steel, divided into ordinary carbon structural steel and high-quality carbon structural steel, produced by EAF smelting, LF ladle refining and continuous casting with electromagnetic stirring. It features stable chemical composition, low segregation, dense internal structure, excellent weldability, cold/hot forming performance and outstanding cost performance.
Product Overview
Carbon structural steel square billet is semi-finished continuous casting steel, divided into ordinary carbon structural steel and high-quality carbon structural steel, produced by EAF smelting, LF ladle refining and continuous casting with electromagnetic stirring. It features stable chemical composition, low segregation, dense internal structure, excellent weldability, cold/hot forming performance and outstanding cost performance. Available cross-section specifications: 150×150mm, 180×180mm, 240×240mm equal square billets and 400×500mm rectangular bloom. Cover full mainstream grades: Q195, Q215, Q235, Q275 (ordinary carbon steel, GB/T 700); 20, 35, 45, 20Mn, 25Mn, 65Mn (high-quality carbon steel, GB/T 699). Delivered in as-cast black surface state, optional surface scarfing, annealing and hot charging. Main raw material for downstream hot rolling, forging, seamless pipe piercing, widely applied in construction steel, hardware fasteners, general machinery shafts, auto small parts, spring blanks and engineering structural components.
Representative Grades
|
Grade |
Executive Standard |
Material Category |
Core Characteristic & Application |
|
Q195 / Q215 / Q235 / Q275 |
GB/T 700-2006 |
Ordinary carbon structural steel |
Low carbon, excellent plasticity & weldability, low cost; rebar, wire rod, stamping parts, building brackets, common fasteners |
|
20 / 35 / 45 |
GB/T 699-2015 |
High-quality carbon steel |
Strict control of S/P impurities; 20# for carburized small parts; 35# for medium-strength shafts; 45# for general quenched & tempered mechanical parts |
|
20Mn / 25Mn |
GB/T 699-2015 |
Manganese-series carbon steel |
Increased manganese improves hardenability and tensile strength; medium-load forgings, bolt blanks, mining small shaft parts |
|
65Mn |
GB/T 699-2015 |
Carbon-manganese spring steel |
High elastic limit & fatigue resistance; spring washers, miniature coil springs, agricultural machinery vibration damping parts |
Grade Description
-
01
Q series (Q195~Q275): Q stands for yield strength, the number represents minimum yield strength value, low impurity control, mainly for low-load structural stamping and building steel rolling raw materials.
-
02
Digital grades (20/35/45): Figures mean average carbon mass fraction ×100; higher number = higher carbon content, higher strength, lower plasticity; strict limit on S, P harmful elements.
-
03
Mn series (20Mn/25Mn): Extra manganese element to optimize hardenability, suitable for medium-strength forged structural parts without expensive alloy elements.
-
04
65Mn: Medium-high carbon manganese spring steel, balance of elasticity and wear resistance, special blank for all kinds of small elastic components.
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 |
Continuous casting with electromagnetic stirring |
|
Delivery Condition |
As-cast black surface (AC)/ Hot-charged hot delivery / Annealed softening |
|
Surface Treatment |
Original casting oxide skin; surface scarfing, grinding & shot blasting optional |
|
Section Tolerance |
±2.0mm for square billet; ±3.0mm for 400×500 bloom |
|
Length Tolerance |
±50mm |
|
Internal Quality Standard |
Low center segregation, minimal shrinkage cavity & looseness, uniform grain structure |
Core Advantages
1. Complete Grade Matrix: Cover low-carbon plastic steel, medium-carbon adjustable quenching steel, manganese strengthened steel and spring special carbon steel, match all downstream rolling, forging, piercing production lines.
2. Stable Internal Metallurgical Quality: EAF+LF refining + EMS electromagnetic stirring effectively reduce center segregation, shrinkage and looseness, consistent mechanical performance after secondary processing.
3. Balanced Process Performance: Low-carbon Q series with outstanding cold stamping & welding performance; medium-carbon high-quality carbon steel supports quenching & tempering to reach medium-high strength; Mn series & 65Mn meet wear-resistant and elastic component demands.
4. Wide Cross-Section Coverage: Small 150 square billet for wire rod & small round bar; large 400×500 bloom for heavy plate, large forging blank, realize one-stop procurement for steel processing factories.
5. Ultra-High Cost Efficiency: No expensive alloy elements, lower raw material cost than alloy steel billets, sufficient stock and short delivery cycle.
6. Diversified Custom Processing: Support surface scarfing, annealing, fixed-length cutting, hot charging delivery and batch ultrasonic flaw detection.
Main Application Fields
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Construction Steel Rolling
Q195/Q215/Q235/Q275 billets for hot rolled rebar, wire rod, angle steel, channel steel, H-beam, building steel structure auxiliary materials.
-
General Hardware & Standard Fasteners
20#/35#/45# billets rolled into round bars for bolts, nuts, rivets, positioning pins and cold heading parts.
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Machinery Manufacturing Forgings
45#/20Mn/25Mn as blank for motor shafts, pump shafts, gear blanks, connecting rod small forgings, engineering machinery light-load structural parts.
-
Spring & Elastic Components
65Mn square billet for coiled springs, spring washers, retaining rings, agricultural machinery shock-absorbing elastic accessories.
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Seamless Pipe Production
Square & rectangular billets for piercing into low-pressure fluid pipeline tubes, civil water delivery steel pipes.
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Medium & Heavy Plate Processing
400×500 rectangular bloom raw material for building plates, container plates, general machinery structural plates.
Packaging & Services
- 1. Executive Standards: GB/T 700-2006 Ordinary Carbon Structural Steel, GB/T 699-2015 High-Quality Carbon Structural Steel.
- 2. Full Inspection Items: Chemical composition melting analysis, dimensional inspection, surface defect test, macrostructure low-fold inspection, non-metallic inclusion rating; optional ultrasonic flaw detection (UT) for large section bloom.
- 3. Certification Documents: EN10204 MTC 3.1 mill test certificate with each batch, provide complete heat component & mechanical property reports; SGS/BV third-party inspection 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 annealing, fixed-length cutting, hot charging delivery, non-destructive testing.
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Contact Us
- 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.
