4130 Chromoly Molybdenum Hot Rolled Steel Bar

4130 Chromoly molybdenum Hot Rolled Bar

4130 Hot-Rolled Steel Bar Comprehensive Introduction

4130 chromoly hot-rolled bars deliver exceptional as-forged performance through optimized metallurgical design, combining chromium's hardening capability (0.80-1.10%) with molybdenum's tempering resistance (0.15-0.25%). Produced via controlled thermomechanical processing at 1150-1250°C (2100-2280°F), these bars develop refined pearlitic-ferritic microstructures offering unique advantages:

Structural Integrity : Achieves yield strength of 435-670 MPa (63-97 ksi) in as-rolled condition - 40% stronger than A36 carbon steel while maintaining ≥22% elongation, enabling direct machining without intermediate annealing for components like hydraulic cylinder rods and gear shafts.

Forging Compatibility : Retains uniform grain flow (ASTM 5-6) during hot working at 980-1150°C (1800-2100°F), permitting 30% greater upset ratios than standard alloy steels for manufacturing flanged couplings and bearing races.

Economic Efficiency : Raw material cost 25% lower than cold-finished alternatives with tolerance class (±1% diameter per ASTM A29), ideal for high-volume production of truck axle components and construction machinery pins.

These bars demonstrate remarkable thermal stability: surface oxide layers (Fe₃O₄) formed during rolling provide natural corrosion resistance (>500h salt spray protection), while 400°C (750°F) heat resistance enables service in engine exhaust systems. Standard diameters from 20-300mm serve diverse sectors: φ50mm bars for oil drill stabilizers withstand 10,000psi bore pressures; φ150mm stock for marine propeller shafts endures seawater corrosion at 5-knot abrasion rates.

4130 Hot Rolled SBQ Rebar
Grade 4130 steel offers many advantages, including good weldability and mechanical properties. Eaton Rebar stocks 4130 hot rolled rebar in a variety of diameters to meet market demands.

4130 Hot Rolled Rebar Applications
This grade of steel is widely used in the oil and gas and firearms industries. Typical applications for 4130 rebar include:
Highly stressed parts such as pumps
Valve bodies
Accessories
Chassis
Body panels for aircraft and automobiles

4130 Chromoly Hot-Rolled Bar Technical Specification Table

Property	Specifications
Dimensions
• Diameter	20–300 mm (Common: 50/80/100/150 mm)
• Length	3m/6m/12m (Custom: 1–18m)
Tolerances
• Diameter Tolerance	±1% or ±0.5mm (whichever is greater) (ASTM A29)
• Length Tolerance	±150mm (±0.5% for >6m)
Surface Condition
• As-Rolled	Mill scale coverage (thickness ≤0.2mm) / Removable by pickling (HRP)
• Defect Control	Surface cracks ≤0.3mm depth (ASTM A484)
Physical Properties
• Density	7.85 g/cm³
• Hardness	197-229 HB (as-rolled)
• Decarburization	≤0.4mm (AMS 2759)
Mechanical Properties
• Tensile Strength	670 MPa (as-rolled) / 930 MPa (Q&T)
• Yield Strength	≥435 MPa (as-rolled) / ≥795 MPa (Q&T)
• Elongation	≥22% (50mm gauge length)
Composition
• Chemical Composition	C:0.28-0.33% Cr:0.80-1.10% Mo:0.15-0.25% Mn:0.40-0.60% Si:0.15-0.35% (AMS 6371)
• International Grades	UNS K23030 / EN 1.7218 / JIS G4105 SCM430
Standards
• General Standards	ASTM A29 / EN 10083-1
• Special Certifications	AMS 6371 (Aerospace) / NACE MR0175 (Sour Service)
Heat Treatment
• Normalizing	870°C×1h → AC (ASTM Grain Size No. 7)
• Quenching & Tempering	850°C Oil Quench + 430°C Temper (32 HRC)
Applications
• Industrial Equipment	Hydraulic piston rods (Ø80mm) / Gear shafts (Ø120mm)
• Energy Sector	Drill pipe connectors (Ø150mm) / Wind turbine main shafts (Ø250mm+)
• Transportation	Truck axles (Ø90mm) / Railway axles (Ø130mm)
• Mold Manufacturing	Large forging die bases (200×200mm)

Standard "4130 Grade" Chemical Composition

Carbon	0.28-0.33
Manganese	0.40-0.60
Phosphorus (max)	0.035
Sulfur (max)	0.040
Silicon	0.15-0.35
Chromium	0.80-1.10
Molybdenum	0.15-0.25

4130 Chromoly Hot-Rolled Bar Market Standard Size Chart

Nominal Diameter (mm)	Tolerance	Surface Condition	Standard Length	Theoretical Weight (kg/m)
Φ30	±0.5mm	Mill scale covered	6m	5.55
Φ50	±0.6mm	Pickled	6m	15.41
Φ80	±0.8mm	As-rolled	6m	39.48
Φ100	±1.0mm	Mill scale retained	6m/12m	61.65
Φ150	±1.5mm	Sandblasted	12m	138.70
Φ200	±2.0mm	Pickled & phosphated	12m	246.58

Imperial Sizes (North America)

Diameter (inch)	Metric Equivalent (mm)	Standard Length (ft)	Price ($/lb)
1.25"	Φ31.75	20ft	0.85-1.00
2"	Φ50.80	20ft	0.80-0.95
3.5"	Φ88.90	20ft	0.78-0.90
6"	Φ152.40	40ft	0.85-1.05

GNEE Group 4130 Hot Rolled Steel Bar Factory Environment

GNEE Group 4130 Chromoly molybdenum Bar Packaging

GNEE Group 4130 Chromoly Bar Testing

1. What is AISI 4130?

AISI 4130 is a chromoly steel, also known as chrome moly steel. It's a medium-carbon, low-alloy steel popular for its balance of strength, toughness, and machinability.
2. Is chrome-molybdenum steel better than steel?
What distinguishes chrome-molybdenum steel from other types of steel is its higher tensile strength. This means it can withstand greater forces without breaking or deforming. It also has better corrosion resistance, making it ideal for applications exposed to harsh environments or moisture.
3. Will 4130 chrome-molybdenum steel rust?
Both 4140 and 4130 steels are low-alloy steels that have excellent strength, toughness, and corrosion resistance.

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