Cone Crusher clamping ring

Concave Fixation: Applying radial and axial pressure to clamp the concave segments tightly against the bowl’s inner surface, preventing displacement or vibration during crushing, which could lead to uneven wear or material leakage.

Adjustment Locking: Securing the adjustment ring in its set position after gap adjustments, ensuring the crushing gap remains consistent during operation and avoiding unintended changes that affect product size.

Load Transfer: Distributing the clamping force evenly across the concave and bowl, reducing localized stress concentrations and extending the service life of mating components.

Sealing Enhancement: Creating a tight seal between the adjustment ring and lower frame, minimizing the ingress of dust, ore particles, and moisture into internal mechanisms, thus reducing wear and lubricant contamination.

Ring Body: A circular frame made of high-strength cast steel (e.g., ZG35CrMo) or forged steel, with an outer diameter ranging from 800 mm to 3000 mm depending on the crusher size. The body thickness is 40–100 mm, with a radial width of 100–300 mm to withstand clamping forces.

Clamping Surface: A precision-machined, inclined or flat surface on the inner circumference that interfaces with the concave’s outer flange or the adjustment ring. This surface has a roughness of Ra1.6–3.2 μm to ensure uniform force distribution.

Threaded Holes/Bolt Slots: Circumferentially spaced holes (12–36, depending on size) or elongated slots that accommodate clamping bolts. These are positioned to apply even pressure, with hole diameter tolerance H12 and positional accuracy (±0.5 mm) relative to the ring’s center.

Lifting Lugs: Integrally cast or welded protrusions on the outer surface to facilitate installation and removal using lifting equipment, designed to withstand the ring’s weight (often 500–5000 kg).

Locating Features:

Alignment Pins: Small cylindrical protrusions on the lower surface that fit into corresponding holes in the lower frame, ensuring radial positioning.

Grooves/Notches: Circumferential grooves that mate with ribs on the adjustment ring, preventing rotational slippage under load.

Reinforcement Ribs: Radial or circumferential ribs on the outer or inner surface that enhance rigidity without excessive weight, positioned to resist deformation under clamping pressure.

Wear-Resistant Coating (Optional): A hard chromium plating (50–100 μm thick) or weld overlay on the clamping surface to reduce wear from repeated contact with the concave or adjustment ring.

Cast Steel (ZG35CrMo): Preferred for its balance of strength (tensile strength ≥650 MPa, yield strength ≥380 MPa) and castability. Chemical composition: C 0.32–0.40%, Cr 0.8–1.1%, Mo 0.15–0.25%.

Forged Steel (35CrMo): Used for crushers with extreme loads, offering higher toughness (impact energy ≥40 J) and fatigue resistance.

A full-scale pattern is created using 3D-printed resin, wood, or foam, replicating the ring’s outer diameter, width, bolt holes, and lugs. Shrinkage allowances (1.8–2.2%) are added, with larger allowances for thick sections like ribs.

A resin-bonded sand mold is prepared with split patterns to form the annular shape. Cores are used to create bolt holes and internal features, ensuring dimensional consistency. The mold cavity is coated with a zirconium-based refractory wash to improve surface finish.

Cast steel is melted in an electric arc furnace at 1530–1570°C, with strict control of sulfur (≤0.035%) and phosphorus (≤0.035%) to avoid brittleness.

Pouring is performed at 1490–1530°C using a ladle with a tundish to control flow, ensuring the mold fills evenly and minimizes porosity in critical areas like bolt hole bosses.

Normalization: Heating to 860–900°C for 3–5 hours, followed by air cooling to refine the grain structure and reduce internal stress.

Tempering: Heating to 550–600°C for 4–6 hours to achieve a hardness of HB 200–250, balancing strength and machinability. For forged rings, quenching (850–880°C, oil-cooled) plus tempering is used to enhance toughness.

The cast or forged ring is mounted on a CNC vertical lathe to machine the outer diameter, inner diameter, and top/bottom surfaces, leaving 3–5 mm finishing allowance. Key dimensions (e.g., outer diameter) are controlled to ±1 mm.

The inner clamping surface is precision-machined using a CNC turning center or grinder to achieve flatness (≤0.1 mm/m) and roughness Ra1.6 μm. Inclined surfaces (if present) are cut to an angle tolerance of ±0.1°.

Threaded holes or slots are drilled and tapped using a CNC machining center with a rotary table, ensuring positional accuracy (±0.5 mm) and thread quality (class 6H for tapped holes). Hole bosses are reinforced to prevent stripping under high torque.

Lifting lugs are machined to remove casting flash and ensure safe lifting, with radiused edges to reduce stress concentration.

Locating pins or grooves are milled to precise dimensions, with tolerance ±0.1 mm for alignment features.

The clamping surface is optionally coated with hard chromium (50–100 μm) via electroplating, achieving a hardness of HRC 60–65 to resist wear.

Non-mating surfaces are blast-cleaned and painted with epoxy paint (100–150 μm thick) to resist corrosion.

Chemical composition analysis (spectrometry) verifies compliance with ZG35CrMo or 35CrMo standards.

Tensile testing on cast/forged samples confirms mechanical properties (e.g., tensile strength ≥650 MPa, elongation ≥15%).

A coordinate measuring machine (CMM) inspects critical dimensions: outer/inner diameter, clamping surface flatness, and bolt hole positions.

A laser tracker verifies the ring’s circularity (≤0.2 mm) and concentricity between inner and outer diameters (≤0.1 mm).

Ultrasonic testing (UT) detects internal defects in the ring body and bolt hole bosses, with any cracks or pores >φ3 mm rejected.

Magnetic particle testing (MPT) checks for surface cracks in lugs, clamping surfaces, and bolt holes, with linear defects >1 mm resulting in rejection.

Clamping Force Test: The ring is installed with bolts torqued to 120% of rated value, with strain gauges measuring deformation (limit: ≤0.2 mm/m).

Fatigue Testing: Samples undergo cyclic loading (10⁶ cycles) at 80% of yield strength to ensure no cracking, simulating long-term use.

Trial assembly with the adjustment ring and concave segments verifies proper fit: clamping force is evenly distributed, and there is no excessive clearance between mating surfaces.