Alloy Structural Steel Bright Bar
Introduction:
Alloy structural steel bright bar is a high-precision, high-surface-quality finished steel product. It integrates domestic low-alloy high-strength steel, manganese-boron alloy steel, silicon-manganese high-strength steel, chromium-molybdenum tempered steel, carburizing alloy steel and European standard equivalent grades.
Product Overview
Alloy structural steel bright bar is a high-precision, high-surface-quality finished steel product. It integrates domestic low-alloy high-strength steel, manganese-boron alloy steel, silicon-manganese high-strength steel, chromium-molybdenum tempered steel, carburizing alloy steel and European standard equivalent grades. Adopting EAF smelting, LF ladle refining and VD vacuum degassing process, the raw steel features ultra-high metallurgical purity and stable internal structure. The final bright bar can be finished by optional cold drawing, centerless turning (peeling) and centerless grinding according to customer precision requirements. With rationally added Mn, Si, Cr, Mo, B, Ti, V and other micro-alloy elements, the material delivers excellent hardenability, balanced strength & toughness, outstanding fatigue resistance, stable temper resistance and reliable comprehensive mechanical properties. The diameter range covers ø12–300 mm, covering a full range of mainstream grades. It is widely used for high-precision automobile components, heavy-duty shaft parts, precision gear forgings, engineering machinery load-bearing accessories, petroleum and new energy equipment parts, and export mechanical supporting components requiring tight tolerance and smooth surface.
Representative Grades
|
Grade |
Executive Standard |
Alloy Classification |
Core Performance & Application |
|
Q355/Q390/Q420/Q460 |
GB/T 1591-2018 |
Domestic HSLA low-alloy high-strength steel |
V/Nb/Ti micro-alloyed, high yield strength, good cold bending & weldability; workshop frames, bridge supports, mining equipment, heavy truck structural parts |
|
St52-3 / S355Jo |
DIN 17100 / EN 10025-2 |
European low-alloy structural steel |
S355Jo guarantees 0℃ impact toughness ≥27J; St52-3 performance equivalent to Q355B; overseas engineering frames, cold-formed load-bearing parts |
|
30Mn2 / 40Mn2 / 40MnB |
GB/T 3077-2015 |
Mn-B low-alloy steel |
Trace boron greatly improves hardenability, cost-effective alternative to partial Cr steel; medium-load connecting rod blanks, general shaft forgings, heavy bolt raw materials |
|
27SiMn |
GB/T 3077-2015 |
Si-Mn high tensile wear-resistant steel |
High tensile strength and impact resistance; hydraulic cylinder blanks, heavy mining structural forgings |
|
35CrMo / 42CrMo / 42CrMo4 |
GB/T 3077 / EN 10083-3 |
Cr-Mo tempered steel |
Excellent temper stability & low-temperature toughness; crankshafts, wind power main shafts, drill collars, high-pressure valve bodies |
|
20CrMo / 41Cr4 |
GB/T 3077 / EN 10083-3 |
Medium-low carbon Cr alloy steel |
Dual-purpose for carburizing and quenching & tempering; miniature gears, piston pins, export high-strength fasteners |
|
20MnVB / 20MnTiB |
GB/T 3077-2015 |
Fine-grain B-Ti carburizing steel |
Ultra-fine grain, ultra-high fatigue strength; automobile gearbox gear blanks, transmission shaft forgings |
|
20Cr / 40Cr |
GB/T 3077-2015 |
General chromium alloy structural steel |
Stable comprehensive mechanical properties, wide applicability; conventional gears, steering knuckles, half shafts, fixture blanks |
|
20CrMnTi / 30CrMnTi |
GB/T 3077-2015 |
Cr-Mn-Ti carburizing steel |
Uniform carburized layer, stable impact resistance; heavy-duty automobile gears, gear ring forgings, large reducer gears |
|
30CrMnSi / 35CrMnSi |
GB/T 3077-2015 |
Multi-alloy ultra-high strength steel |
Outstanding impact resistance; high-pressure precision forgings, aerospace structural components, heavy shock-resistant parts |
Grade Description
-
01
Low-alloy high-strength series (Q355~Q460, St52-3, S355Jo): Micro-alloyed with vanadium, niobium and titanium, high yield strength, good cold bending and welding performance, mainly used for large load-bearing engineering structures and export mechanical frames.
-
02
Mn-B series (30Mn2,40Mn2,40MnB): Manganese improves basic strength, trace boron sharply enhances hardenability, can partially replace chromium alloy steel to cut production costs.
-
03
Cr-Mo tempered steel (35CrMo,42CrMo,42CrMo4): Chromium improves hardness and wear resistance, molybdenum eliminates temper brittleness, suitable for heavy-load power core components under high temperature and alternating stress.
-
04
Carburizing steel (20Cr,20CrMo,20MnTiB,20CrMnTi,30CrMnTi): Low carbon alloy steel, after carburizing heat treatment to form hard wear-resistant surface while retaining high-toughness core, special raw material for all kinds of transmission gears.
-
05
30CrMnSi/35CrMnSi: Silicon-chromium-manganese composite multi-alloy steel with ultra-high strength and strong impact resistance, used for special high-pressure and shock-resistant precision forgings.
Product Specifications
|
Item |
Specific Parameters |
|
Product Form |
Hot rolled round bar;Forged round bar;Peeled precision bright bar |
|
Diameter Range |
ø12 mm – ø300 mm |
|
Standard Length |
3m / 6m / 9m / 12m; customized fixed-length cutting available |
|
Delivery Condition |
Hot rolled black oxide scale / Normalized / Full annealing / Quenched & tempered / Peeled & ground finished |
|
Surface State |
Mirror bright, oxide-free, scratch-free, burr-free, smooth finish |
|
Size Tolerance |
Comply with GB/T 702, EN 10060 standard dimensional tolerance requirements |
|
Straightness |
Standard hot rolled ≤3mm/m；Precision peeled bar ≤1.5mm/m |
|
Internal Quality Standard |
Low central segregation, minimal shrinkage cavity & looseness, fine uniform grain, strictly limited S/P and non-metallic inclusions |
Core Advantages
1. Complete Global Grade Matrix: Cover domestic HSLA steel, Mn-B alloy, Cr-Mo tempered steel, Cr-Mn-Ti carburizing steel and European standard equivalent grades, fully compatible with carburizing, quenching & tempering and nitriding processes, realizing one-stop precision raw material supply for automobile, petroleum, machinery and export manufacturing.
2. Ultra-High Metallurgical Purity: EAF+LF+VD triple smelting removes internal gas and harmful impurities, ensuring stable metallographic structure and extremely small performance fluctuation between batches.
3. Balanced Comprehensive Performance: Scientific alloy ratio achieves high strength, high toughness, excellent fatigue resistance and temper stability. Finished bright bars maintain uniform hardness without internal delamination after secondary processing.
4. Flexible Optional Precision Processing: Support three optional finishing processes including cold drawing for precise dimension control, centerless turning (peeling) for defect removal, and centerless grinding for mirror ultra-smooth surface, meeting different precision and surface requirements.
5. Wide Process Adaptability: Suitable for hot forging, cold bending, CNC precision machining and welding. Normalized and annealed delivery states save secondary heating cost for downstream precision manufacturing.
6. Full-size Coverage & High Stability: ø12–300mm full diameter range covers miniature precision parts and heavy-duty large forgings, with reliable consistency for high-end precision equipment manufacturing.
Main Application Fields
-
High-precision Engineering & Construction
Q355/Q390/Q420/Q460/St52-3/S355Jo bright bars for high-standard factory frames, bridge precision support parts and overseas engineering cold-formed components.
-
Automobile Precision Forging Parts
20CrMnTi/20MnTiB precision gear blanks, 42CrMo/35CrMo crankshaft and connecting rod blanks, 40Cr medium-strength fastener and steering knuckle semi-finished parts.
-
Petroleum & New Energy Precision Equipment
Cr-Mo series bright bars for drill collars, wind power main shaft blanks, hydraulic piston rods and high-pressure valve bodies; 27SiMn for high-precision hydraulic cylinder blanks.
-
General Mechanical Precision Components
40Cr/20CrMo precision shaft blanks, reducer gear forgings and mold blanks; 30CrMnSi/35CrMnSi for aerospace high-pressure impact-resistant structural parts.
-
Export Mechanical & Auto Supporting Parts
European standard grades 42CrMo4, 41Cr4, S355Jo, St52-3 for overseas high-standard mechanical and automobile supporting precision raw materials.
-
Heavy-duty Precision Machining Forgings
Medium and large diameter alloy bright bars for large gear ring forgings, shock-resistant mechanical parts and high-precision load-bearing structural blanks.
Packaging & Services
- 1. Professional Exclusive Packaging for Bright Bars: Adopts special scratch-proof and rust-proof precision packaging for bright bars, wrapped with thickened waterproof film on the outer layer and firmly bundled and fixed. High-precision and long-size products can be customized with solid wooden box packaging, completely avoiding collision, scratches, deformation and rust during transportation, suitable for long-distance sea and land transportation.
- 2. Full Inspection Items: Melting chemical composition analysis, dimensional inspection, surface defect detection, tensile test, impact test, hardness test, macrostructure low-fold examination, non-metallic inclusion rating; optional ultrasonic flaw detection (UT), magnetic particle inspection (MPI).
- 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. MOQ: 1 ton per single grade; mixed grades & mixed diameter sizes container loading acceptable.
- 5. Value-added Services: Optional cold drawing, centerless turning (peeling), centerless grinding, fixed-length cutting, softening normalization, shot blasting rust removal, full-set non-destructive flaw detection and customized heat treatment processing.
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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.
