Rebar Bending Mandrel Sleeves

High-Precision Rebar Bending Mandrel Sleeves Full Range of Sizes

Technical Features

• Comprehensive Selection: Multiple outer diameters (OD) to achieve standard 4D, 5D bending radii for all rebar thicknesses.

• Premium Material Options: Forged from high-tensile Cr12MoV or 40Cr alloy steel, both resisting structural deformation under extreme lateral pressure for different processing needs.

• Vacuum Quenched: Every sleeve is vacuum quenched for superior wear resistance during long-term on-site use.

• Standard & Custom Sizes: Standard diameters (30mm-100mm) and bespoke sleeves made to your machine’s center pin dimensions.

Material Options: Cr12MoV & 40Cr (Chemical Composition & Key Properties)

1. Cr12MoV Alloy Steel

Chemical Composition (Weight Percentage)

• Carbon (C): 1.45% - 1.70% – Boosts hardness and wear resistance

• Chromium (Cr): 11.50% - 13.50% – Improves corrosion and wear resistance

• Molybdenum (Mo): 0.40% - 0.60% – Reduces internal stress; improves toughness

• Vanadium (V): 0.15% - 0.30% – Refines structure; enhances hardness and stability

• Silicon (Si): 0.20% - 0.40% – Increases strength and deoxidation

• Manganese (Mn): 0.20% - 0.40% – Improves hardenability and toughness

• Phosphorus (P): ≤ 0.030% – Minimized to avoid brittleness

• Sulfur (S): ≤ 0.030% – Controlled to prevent defects

Core Mechanical Properties (After Vacuum Heat Treatment)

• Hardness (HRC): 60 - 64 – Uniform throughout; no soft core

• Tensile Strength (σb): ≥ 2000 MPa – Handles extreme pressure without cracking

• Impact Toughness (αk): ≥ 25 J/cm² – No brittle fracture in cold or high-speed use

• Wear Resistance: Superior to common alloys – Longer service life

• Dimensional Stability: ≤ 0.005mm/m – Precise fit; consistent bending

• Corrosion Resistance: Resists rust and oil – Suitable for harsh job sites

2. 40Cr Alloy Steel

Chemical Composition (Weight Percentage)

• Carbon (C): 0.37% - 0.44% – Provides basic hardness and strength

• Chromium (Cr): 0.80% - 1.10% – Enhances wear resistance and hardenability

• Silicon (Si): 0.17% - 0.37% – Improves strength and deoxidation performance

• Manganese (Mn): 0.50% - 0.80% – Boosts hardenability and toughness

• Phosphorus (P): ≤ 0.035% – Minimized to avoid brittleness

• Sulfur (S): ≤ 0.035% – Controlled to prevent internal defects

• Nickel (Ni): ≤ 0.30% – Residual content, no obvious impact on performance

• Copper (Cu): ≤ 0.30% – Residual content, ensures processing performance

Core Mechanical Properties (After Quenching & Tempering)

• Hardness (HRC): 32 - 36 (After tempering); up to 55 HRC after surface quenching

• Tensile Strength (σb): ≥ 980 MPa – Handles regular bending pressure stably

• Yield Strength (σs): ≥ 785 MPa – Good load-bearing capacity without deformation

• Impact Toughness (αkv): ≥ 47 J – Excellent toughness, avoids brittle fracture

• Wear Resistance: Good – Suitable for regular rebar processing scenarios

• Processability: Excellent – Easy to forge, machine and heat treat

Definition and Principle of Rebar Bending Mandrel Sleeves

Definition

Working Principle

• Rebar is clamped tightly between the central and positioning rollers (fixed support points).

• The machine drives the movable roller to rotate and apply uniform bending pressure.

• Rebar undergoes plastic deformation around the central roller to complete bending.

• Adjust the central roller’s diameter to change the bending radius.

• Control the bending angle (0-180° stepless adjustment) via the working disc’s rotation angle.

Main Specifications of Rebar Bending Mandrel Sleeves

Classification by Function

• Central Roller: Fixed at the work plate center. Its diameter determines the minimum bending radius—core for all bending operations.

• Movable Roller: Applies bending force via rotation. Adjustable position; key for controlling bending angle.

• Positioning Roller: Auxiliary support. Prevents rebar displacement/warping during bending for stable processing.

Classification by Adapted Rebar Specifications

• Small: For 6-16mm rebar (stirrups, small prefabricated components).

• Medium: For 18-28mm rebar (main structural rebar in beams, slabs).

• Large: For 32-50mm rebar (columns, shear walls, heavy components).

• Special: Custom-made for irregular rebar, high-strength threaded steel, HRB500 grade steel.

Core Specification Parameters

• Roller Diameter: 25-120mm (1.5-5x the processed rebar diameter; affects bending radius).

• Roller Width: 15-50mm (depends on rebar diameter and quantity per bend; wider = more stable).

• Shaft Hole Diameter: 16-40mm (matches bender’s working disc shaft; ensures stable installation).

Material Selection and Manufacturing Process

Core Material Options: Cr12MoV & 40Cr

Key Precision Manufacturing Processes

• Precision Forging: Densifies internal metal structure; improves strength and impact resistance.

• Vacuum Heat Treatment: Uniform quenching avoids deformation; ensures hardness and dimensional accuracy.

• Precision Grinding: Controls roller diameter tolerance within ±0.02mm; ensures fit and bending accuracy.

Applications and Purchasing Considerations

Application Scenarios

• Building Construction: Bending rebar for beams, columns, slabs, shear walls (residential/commercial buildings).

• Bridge Engineering: Precise bending of prestressed and irregular rebar for complex structures.

• Tunnel Engineering: Bending rebar for arched structures and grid steel frames.

• Rebar Processing Plants: Mass production of standard rebar components (boosts efficiency).

• Precast Component Factories: Processing rebar frameworks for prefabricated beams, slabs, stairs.

Purchasing Considerations

• Compatibility: Match the bender model; confirm shaft hole diameter and installation method.

• Rebar Fit: Choose roller size based on daily rebar diameter range.

• Material: Select Cr12MoV for heavy-duty, high-wear scenarios; choose 40Cr for regular-duty, cost-effective needs.

Maintenance and Life Extension Techniques

Daily Use and Maintenance

• Before use: Check installation; clean rebar fragments, rust, and oil.

• During use: Follow size limits; avoid overloading to prevent deformation/chipping.

• After use: Clean stains; apply anti-rust oil to shaft hole and mating surfaces.

Regular Maintenance Procedures

• Disassemble rollers; clean impurities and rust.

• Inspect for wear, cracks, or deformation; check mating surface accuracy.

• Lubricate shaft holes and rotating parts; replace old lubricant.

• Polish minor wear; store in a dry, ventilated area after maintenance.

Wear Repair and Replacement Standards

• Slight wear/scratches: Repair by polishing or welding/grinding.

• Severe wear, cracks, deformation, or shaft hole misalignment: Replace promptly.