Jaw Crusher teeth plate

Material Crushing: Directly contacting and compressing raw materials (ore, rock, aggregate) between the fixed and movable teeth plates, applying shear and bending forces to reduce material size from tens of centimeters to millimeters.

Wear Resistance: Withstanding intense abrasion and impact from hard materials, ensuring long service life under harsh working conditions (e.g., mining, quarrying).

Material Guidance: The toothed surface design guides materials into the crushing chamber, preventing slippage and ensuring efficient crushing. The tooth shape (e.g., sharpness, spacing) also influences product particle size distribution.

Protection of Jaw Bodies: Acting as a replaceable wear layer, shielding the fixed and movable jaw structures from direct wear, reducing maintenance costs for the main frame.

Plate Body: A thick (50–200 mm) rectangular or curved plate made of high-chromium cast iron (Cr15–20), manganese steel (ZGMn13), or alloy cast iron (HT350). Its length ranges from 500 mm to 2000 mm, matching the jaw crusher’s 规格 (e.g., 600×900, 1200×1500).

Working Surface (Teeth): A series of evenly spaced protrusions (teeth) and grooves on the crushing surface. Key parameters include:

Tooth Height: 20–50 mm, with larger teeth for coarse crushing and smaller teeth for fine crushing.

Tooth Spacing: 30–80 mm, designed to prevent material bridging and ensure uniform crushing.

Tooth Profile: Triangular, trapezoidal, or curved, with rounded tips to reduce stress concentration and avoid premature chipping.

Back Surface: A flat or slightly curved surface with mounting features (e.g., T-slots, bolt holes) for attaching to the jaw body. It is often reinforced with ribs to prevent bending deformation.

Mounting Features:

T-Slots: Longitudinal slots on the back surface for bolts or clamps to secure the plate to the jaw, allowing quick replacement.

Bolt Holes: Circular holes (φ20–50 mm) for high-strength bolts (grade 8.8+), distributed along the edges or centerline.

Locating Pins: Protrusions or holes that align the teeth plate with the jaw body, ensuring precise positioning.

Reinforcement Ribs: Transverse or longitudinal ribs on the back surface (height 30–80 mm) to enhance rigidity, preventing warping under crushing loads.

Material Selection: Cr15–20 offers excellent wear resistance (hardness HRC 55–65) due to chromium carbide precipitates. Chemical composition: C 2.8–3.5%, Cr 15–20%, Si 0.5–1.2%, Mn 0.5–1.0%, with trace elements (Mo, Ni) to improve toughness.

Pattern Making: A full-scale foam or wood pattern is created, including teeth, ribs, and mounting features. Shrinkage allowances (1.5–2.0%) are added to account for cooling contraction.

Molding: Resin-bonded sand molds are prepared, with cores for bolt holes and T-slots. The mold cavity is coated with a zirconium-based refractory wash to prevent sand inclusion and improve surface finish.

Melting and Pouring:

Molten iron is melted in an induction furnace at 1450–1500°C, with chromium and alloys added to achieve target composition.

Pouring is performed at 1400–1450°C, with a controlled flow rate to fill thin sections (e.g., tooth tips) without cold shuts.

Heat Treatment:

Solution Annealing: Castings are heated to 950–1000°C for 2–4 hours, then air-cooled to dissolve carbides and reduce brittleness.

Aging: Reheated to 250–300°C for 4–6 hours to precipitate fine carbides, enhancing hardness.

Material Selection: ZGMn13 provides superior toughness (impact energy ≥200 J) and work hardening under impact, suitable for crushing large, hard rocks.

Casting Process: Similar to high-chromium iron, but with higher pouring temperature (1500–1550°C) to ensure fluidity.

Heat Treatment: Water quenching from 1050–1100°C to form austenitic microstructure, which work-hardens during use (surface hardness increases from HB 200 to HB 500+ after wear).

The cast plate is mounted on a CNC milling machine to trim the back surface and edges, removing 3–5 mm of excess material. This ensures flatness (≤1 mm/m) for proper mounting.

T-Slots/Bolt Holes: Machined using CNC milling or drilling, with T-slot dimensions (width, depth) controlled to ±0.5 mm and bolt holes tapped to thread class 6H.

Locating Surfaces: The back surface is ground to flatness (≤0.5 mm/m) to ensure tight contact with the jaw body, reducing vibration during crushing.

For high-chromium plates, tooth tips may be polished to remove casting burrs, preventing premature chipping.

For manganese steel plates, no additional treatment is needed, as work hardening occurs during operation.

Laser etching or stamping adds part numbers, material grades, and manufacturing dates for traceability.

A final visual inspection checks for casting defects (e.g., cracks, porosity) on the tooth surface.

Material Testing:

Chemical composition analysis (spectrometry) verifies compliance with Cr15–20 or ZGMn13 standards.

Hardness testing (Rockwell/Brinell) confirms surface hardness: Cr15–20 (HRC 55–65); ZGMn13 (HB 200–250 before work hardening).

Dimensional Accuracy Checks:

A coordinate measuring machine (CMM) inspects tooth height, spacing, and plate dimensions, ensuring tolerances (±1 mm for length/width, ±0.5 mm for tooth height).

A straightedge and feeler gauge check back surface flatness, requiring ≤0.5 mm/m to prevent uneven loading.

Structural Integrity Testing:

Ultrasonic Testing (UT): Detects internal defects (e.g., shrinkage pores) in the plate body, with defects >φ5 mm rejected.

Magnetic Particle Testing (MPT): Checks for surface cracks in tooth roots and ribs, with linear defects >1 mm resulting in rejection.

Performance Testing:

Abrasion Test: ASTM G65 dry sand/rubber wheel testing measures wear resistance, with Cr15–20 showing weight loss ≤0.8 g/1000 cycles.

Impact Test: Charpy V-notch testing ensures toughness: Cr15–20 (≥15 J/cm² at 20°C); ZGMn13 (≥200 J/cm²).

Field Validation:

Prototype plates undergo trial runs in a jaw crusher, with service life tracked (typically 500–2000 hours, depending on material hardness). Excessive wear or chipping indicates design or material adjustments.