Carbon Structural Steel Round Billet
Introduction:
Carbon structural steel round billet is continuous casting semi-finished steel, divided into ordinary carbon structural steel and high-quality carbon structural steel. Adopt EAF smelting, LF ladle refining, EMS electromagnetic stirring continuous casting process, strictly control S, P harmful impurities and internal segregation, featuring uniform chemical composition, dense internal metallographic structure, excellent weldability, cold & hot forming performance and ultra-high cost performance.
Product Overview
Standard round billet diameters: ø150-1300mm. Complete mainstream grade series: Q195, Q215, Q235, Q275 (ordinary carbon steel GB/T 700); 20, 35, 45, 20Mn, 25Mn, 65Mn (high-quality carbon steel GB/T 699).
Available delivery states: as-cast black oxide surface, hot-charged hot delivery, soft annealing, surface scarfing finishing. It is core raw material for downstream hot rolling round bars, seamless pipe piercing, open-die & closed-die forging, widely applied in construction steel, hardware fasteners, general machinery shafts, auto small structural parts, spring blanks and fluid pipeline steel production.
Representative Grades
|
Grade |
Executive Standard |
Material Category |
Core Feature & Application |
|
Q195/Q215/Q235/Q275 |
GB/T 700-2006 |
Ordinary carbon structural steel |
Low carbon, outstanding plasticity & weldability, low cost; wire rod, construction support, stamping parts, common bolts & pins |
|
20 / 35 / 45 |
GB/T 699-2015 |
High-quality carbon steel |
Strictly limited 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 carbon steel |
Manganese improves hardenability & tensile strength; medium-load forgings, heavy 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 damping elastic parts |
Grade Description
-
01
Q series (Q195~Q275): Q represents yield strength, figures mean minimum yield strength value, low impurity control, mainly for low-load structural stamping and construction steel rolling raw materials.
-
02
Digital grades (20/35/45): Numbers stand for average carbon mass fraction ×100; higher number = higher carbon content, higher strength, lower plasticity; S, P harmful elements are strictly restricted.
-
03
Mn series (20Mn/25Mn): Extra manganese element optimizes hardenability, no expensive alloy elements, suitable for medium-strength forged structural parts.
-
04
65Mn: Medium-high carbon manganese spring dedicated carbon steel, balanced elasticity and wear resistance, special blank for various small elastic components.
Product Specifications
|
Item |
Specific Parameters |
|
Product Form |
Continuous casting round billet |
|
Standard Diameter Sizes |
ø150-1300mm |
|
Standard Length |
3m / 6m / 9m / 12m; customized fixed-length cutting available |
|
Production Technology |
EAF + LF refining + EMS electromagnetic stirring continuous casting |
|
Delivery Condition |
As-cast black oxide scale / Hot-charged hot delivery / Soft annealing / Surface scarfing finished |
|
Surface State |
Original casting oxide skin; surface grinding, shot blasting optional |
|
Dimensional Tolerance |
Diameter tolerance ±2.0mm; ovality ≤85% of diameter tolerance (YB/T 2011-2014) |
|
Length Tolerance |
±50mm |
|
Straightness |
≤4mm/m standard grade |
|
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 quenching steel, manganese strengthened steel and spring special carbon steel, fully match downstream wire rod, round bar rolling, seamless pipe piercing, die forging production lines.
2. Stable Internal Metallurgical Quality: EAF+LF refining + EMS electromagnetic stirring effectively suppress center segregation, shrinkage and looseness, consistent mechanical performance after secondary processing.
3. Balanced Process Performance: Low-carbon Q series with superior 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 production demands.
4. Standard Diameter Range Coverage: small round billet for wire rod & small finished round bar; large round billet for heavy seamless pipe, large shaft and gear forging blanks, realize one-stop procurement for steel processing factories.
5. Ultra-High Cost Efficiency: No expensive alloy elements, raw material cost far lower than alloy steel billets, sufficient stock and short delivery cycle.
6. Diversified Custom Processing: Support surface scarfing, softening annealing, fixed-length cutting, hot-charged delivery and batch ultrasonic flaw detection.
Main Application Fields
-
Construction Steel Rolling
Q195/Q215/Q235/Q275 round billets for hot rolled wire rod, rebar, small section steel, building steel structure auxiliary raw materials.
-
General Hardware & Standard Fasteners
20#/35#/45# round billets rolled into finished round bars for bolts, nuts, rivets, positioning pins and cold heading parts.
-
Machinery Manufacturing Forgings
45#/20Mn/25Mn as blank for motor shafts, pump shafts, gear blanks, small connecting rod forgings and light-load mechanical structural parts.
-
Spring & Elastic Components
65Mn round billet for coiled springs, spring washers, retaining rings and agricultural machinery shock-absorbing elastic accessories.
-
Seamless Pipe Production
Round billets for piercing low-pressure fluid pipeline tubes, civil water delivery steel pipes, small hydraulic cylinder tubes.
-
Medium & Heavy Shaft Forging
Large round billet for heavy-duty machinery transmission shafts, large gear blanks and engineering equipment load-bearing forgings.
Packaging & Services
- 1. Executive Standards: GB/T 700-2006 Ordinary Carbon Structural Steel, GB/T 699-2015 High-Quality Carbon Structural Steel, YB/T 2011-2014 Continuous Cast Square & Round Billet.
- 2. Full Inspection Items: Melting chemical composition analysis, dimensional inspection, surface defect test, macrostructure low-fold inspection, non-metallic inclusion rating; 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 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 annealing, fixed-length cutting, hot-charged delivery, non-destructive flaw detection.
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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.
