Cone Crusher head

Detailed Introduction to the Cone Crusher Head Component

1. Function and Role of the Cone Crusher Head

2. Composition and Structure of the Cone Crusher Head

• Head Body (Core Structure): A conical or frustoconical casting made of high-strength cast steel (e.g., ZG35CrMo) or ductile iron (QT600-3). It serves as the structural support for the wear liner and connects to the eccentric shaft via a central bore. The body’s inner cavity is designed to fit the eccentric bushing, with keyways or bolts to secure the connection and transmit torque.
• Wear Liner (Mantle): A replaceable outer layer made of high-chromium cast iron (Cr20-Cr26) or alloy steel with high hardness (HRC 55-65). It is attached to the head body via bolts, dovetail grooves, or wedge blocks, ensuring tight fitting to prevent movement during crushing. The liner’s surface is often designed with a concave or convex profile (e.g., standard, coarse, or fine crushing profiles) to optimize material gripping and crushing efficiency.
• Bearing Bore: A central cylindrical or tapered hole in the head body that accommodates the upper end of the eccentric shaft. The bore is precision-machined to ensure a stable fit with the shaft, with lubrication channels drilled to deliver oil to the contact surface, reducing friction and wear.
• Mounting Flange or Bolt Holes: Located at the base of the head body, these features secure the wear liner to the body. Dovetail grooves on the liner’s inner surface mate with corresponding protrusions on the head body, enhancing connection strength under impact loads.
• Ventilation and Weight Reduction Cavities: Some large-sized heads have internal hollow structures to reduce weight, improve heat dissipation, and avoid excessive inertia during oscillation. These cavities are designed to not compromise the body’s structural integrity.

3. Casting Process for the Head Body

1. Material Selection:

• Cast steel (ZG35CrMo) is preferred for large crushers due to its high tensile strength (≥785 MPa) and impact toughness, suitable for heavy-duty crushing.

• Ductile iron (QT600-3) is used for medium-sized heads, offering good castability and cost-effectiveness while maintaining sufficient strength.

2. Pattern Making:

• A full-scale pattern is created using wood, foam, or 3D-printed materials, replicating the head’s external shape, internal cavity, and mounting features. For lost foam casting, the foam pattern includes integrated runners and risers.

• Shrinkage allowances (2-3% for cast steel) and draft angles (3-5°) are added to compensate for post-casting contraction and facilitate pattern removal.

3. Molding:

• For sand casting: Resin-bonded sand is packed around the pattern to form the mold cavity, with a sand core inserted to create the central bore and internal cavities. The mold is cured to ensure hardness and dimensional stability.

• For lost foam casting: The foam pattern is coated with a refractory slurry (ceramic or zirconium-based) to form a 3-5 mm thick shell, then embedded in dry sand.

4. Melting and Pouring:

• Cast steel is melted in an electric arc furnace at 1500-1600°C, with alloying elements (Cr, Mo) added to achieve the required chemical composition. The molten metal is deoxidized and desulfurized to reduce impurities.

• Pouring is performed at a controlled rate (50-100 kg/s for large heads) to avoid turbulence and ensure complete filling of the mold. For lost foam casting, the molten metal vaporizes the foam pattern, replacing it in the mold cavity.

5. Cooling and Cleaning:

• The casting is allowed to cool slowly (over 24-48 hours) to prevent thermal cracking, then removed from the mold. Sand or refractory material is cleaned via shot blasting or water jetting.

• Risers and gating systems are cut off, and rough edges are ground to prepare for machining.

6. Heat Treatment:

• Cast steel heads undergo normalization (850-900°C, air-cooled) to refine grain structure, followed by quenching and tempering (600-650°C) to achieve hardness of 220-260 HBW, balancing strength and machinability.

• Ductile iron heads are subjected to annealing (900-950°C) to eliminate carbides and improve toughness.

7. Casting Inspection:

• Surface defects (cracks, pores, shrinkage) are checked via visual inspection and dye penetrant testing (DPT).

• Internal flaws are detected using ultrasonic testing (UT) and magnetic particle testing (MPT), with strict standards (no defects larger than φ3 mm in critical load-bearing areas).

4. Machining and Manufacturing Process

1. Head Body Machining:

• Rough Machining: CNC lathes or boring machines are used to rough-turn the outer surface, base flange, and central bore, leaving 2-3 mm finishing allowance. Keyways and bolt holes are pre-drilled and tapped.

• Heat Treatment: Stress relief annealing (550-600°C) is performed after rough machining to eliminate residual stresses from casting and initial cutting.

• Finish Machining: The central bore is precision-ground to IT7 tolerance, with a surface roughness of Ra1.6-3.2 μm to ensure a tight fit with the eccentric shaft. The base flange and mounting surfaces are milled to achieve flatness (≤0.1 mm/m) for secure liner attachment.

2. Wear Liner Manufacturing:

• Casting: High-chromium cast iron liners are sand-cast, with alloying elements (Cr, Mo, Ni) added to enhance hardness and wear resistance. The casting is subjected to quenching and tempering to achieve HRC 55-65.

• Machining: The liner’s inner surface (mating with the head body) is machined to fit the dovetail grooves or bolt holes, ensuring a snug connection. The outer crushing surface is ground or polished to remove casting burrs and achieve the designed profile.

3. Assembly:

• The wear liner is mounted onto the head body using high-strength bolts (grade 8.8 or 10.9) or wedge blocks, with torque applied uniformly (200-500 N·m, depending on size) to prevent loosening.

• Gaskets or sealants are applied between the liner and body to prevent material ingress, which could cause abrasion between the two components.

5. Quality Control Processes

1. Material Testing:

• Chemical composition analysis (via spectrometry) ensures cast steel/iron meets alloy standards (e.g., ZG35CrMo: C 0.32-0.40%, Cr 0.8-1.1%, Mo 0.15-0.25%).

• Mechanical property tests (tensile strength, impact toughness, hardness) are conducted on test coupons from each casting batch.

2. Dimensional Accuracy Checks:

• Coordinate Measuring Machines (CMM) verify the head body’s outer diameter, bore size, and liner profile, ensuring compliance with design drawings (tolerance ±0.5 mm for critical dimensions).

• The concentricity between the head body’s outer surface and central bore is measured, requiring ≤0.05 mm/m to avoid imbalance during oscillation.

3. Wear Resistance Testing:

• Wear liner samples undergo abrasive wear testing (e.g., ASTM G65) to measure weight loss under standardized conditions, ensuring wear rate ≤0.1 g/h under rated load.

• Hardness testing (Rockwell C scale) is performed on liner surfaces to confirm HRC 55-65, with no soft spots (≤HRC 50) allowed.

4. Assembly and Performance Testing:

• Liner fitment tests ensure no gaps between the liner and head body (checked via feeler gauges, with maximum gap ≤0.1 mm).

• Dynamic balance testing is conducted on the assembled head to ensure vibration amplitude ≤0.1 mm/s at operating speed, reducing stress on the eccentric shaft.

5. Non-Destructive Testing (NDT):

• The head body is re-inspected via UT and MPT after machining to detect any cracks introduced during processing.

• Liner surfaces are checked for casting defects (porosity, cracks) via visual inspection and DPT, with defective liners rejected or repaired.