Why material selection is the most important thing?

According to statistics, the replacement cost of the wear parts of the crusher accounts for more than 40% of the production cost. The cost of replacement mainly includes the cost of new parts, the cost of replacing workers, and the marginal cost of downtime. Unsuitable material parts will cause the parts to not wearable and increase the frequency of replacement parts. It is a big loss. So it is important to select the right material for your jaw plates.

Material types for jaw plates

There are 4 types of jaw plates materials:

1. Manganese steel. Manganese steel, also called Hadfield steel or mangalloy, is a steel alloy containing 12-14% manganese. Renowned for its high impact strength and resistance to abrasion in its hardened state, the steel is often described as the ultimate work hardening steel.There are some grades for manganese steel jaw plates:
   • Mn14Cr2 Jaw Plates. Mn14cr2 jaw plates are used in crushing soft stones. For example, it has a good life when crushing the easy and non-abrasive blasted rock, non-abrasive gravel, and non-abrasive round rock.
   • Mn18Cr2 Jaw Plates. Mn18Cr2 is the most popular material for casting jaw crusher jaw plates. This Mn18Cr2 jaw plates widely in crushing difficult and non-abrasive blasted rock, medium and non-abrasive,non-abrasive gravel, and non-abrasive round rock.
   • Mn22Cr2 Jaw Plates. Mn22Cr2 jaw plates are widely used in crushing hard and abrasive stones. Under our technology, span life is much better than normal.
2. Alloy steel. Alloy steel to cast small jaw crusher jaw plates. Normally, the weight of alloy steel jaw plates less than 2 tons. After the jaw plate is energized, it can achieve the function of magnetic separation of raw materials.
3. Microalloy steel. By adding some rare elements into manganese steel, the manganese steel jaw plate gets more good wearable and hardness. This kind of material is widely used in crush copper mine.
4. TIC inserts jaw plates. Qiming Casting uses some titanium carbide rods to insert the manganese body.

Crush different kinds of stones or ores, it needs different jaw crusher tooth types to suit. There are some popular jaw plate tooth profiles and uses.

•  Standard Tooth. It is suitable for both rock and gravel crushing; Wear life, power requirements, and crushing stresses in good balance; Typical factory installation.
• Quarry Tooth. Suitable for crushing Shot Rock in quarries; The flat teeth perform better with abrasive materials; (more wearable tooth material); Cause higher stresses and increase power requirements.
• Super Tooth. Suitable for general use and especially a good choice for gravel crushing; the Large mass and special design of the teeth gives long wear life and allows fine material flow down through the cavity along the grooves without wearing the teeth.
• Corrugated Recycling Tooth. Suitable for crushing concrete; Fine material flows easily through the cavity along the large grooves.
• Wavy Recycling Tooth. Suitable for crushing Asphalt, Material flows easily down through the cavity along the grooves without packing; Normally used in the small setting range with the intermediate plate.
• Super Grip Tooth. Suitable for hard and round natural rock crushing; Provides better grip and capacity; Fine material flows easily through the cavity along the large grooves; Wear life of the fixed and movable jaw dies in good balance.
• Wedge & Standard Tooth. Suitable for both rock and gravel crushing; Thicker lower end of the jaw die and the thinner upper end of the jaw die; Maximizes size of the maximum feed size of the cavity with the maximum nip angle; Wedge jaw die is the fixed one and the Standard jaw die is the movable one.
• Anti Slab Tooth. Special jaws designed to crush slabby sedimentary rock; Can also be used when recycling concrete and asphalt slabs.
• TIC Inserts Tooth. Special jaws designed to crush hard rock; Can also be used when recycling concrete, asphalt slabs, and the mining industry.

There are 4 tips for prolonging jaw plates working life.

1. To install the right material jaw plate. Based on crush material, you need to select the right material. Such as the Mn22Cr2 jaw plates suit for crushing hard stone.
2. To install the jaw plate correctly. When installing the jaw plate, we must make sure that the jaw plate is installed correctly and stable to make it contact well with the machine surface. Otherwise, the jaw plate is easy to be shifted during the working process, causing the jaw plate to collide with the inner wall of the machine and seriously damaged.
3. No blocking of materials. When the material jams the jaw crusher, the sliding of materials squeezed by the jaw plate is increased, which increases the jaw plate abrasion, and enlarges the nip angle that the materials blocking situation becomes more serious, forming a vicious cycle.  Therefore, it is necessary to forbid the blockage of the material in the machine and find the blockage to be cleaned in time.
4. The feeding size must be controlled strictly. The abrasion of material properties to jaw plate is obvious, so we should strictly control the feeding size. The oversized particles are forbidden to enter the machine. In addition, the feeding must be evenly, or else, it may lead the angle of discharging hopper of crushing cavity to become big, and the movable plate indirectly contacts with materials to damage the jaw plate.

There are two situations that need to change the jaw plates.

1. Economic benefits and costs. After a long time of running, productivity will decrease because of the wear of jaw plates. So we need to calculate the ratio of economic benefits and cost. If the loss can cover the jaw plate’s price, we need to consider changing jaw plates.
2. In order to prevent damage to the crusher parts, jaw plates need to be changed before they are worn through. Different kinds of jaw crushers have different situations. In some kinds of jaw crushers, jaw plates with a wedge retention design can wear to a thickness of 20-25 mm until they must be changed; In some other jaw crushers, jaw plates with locking wedges in the back can wear to a thickness of 60-65 mm until they must be changed. When to change jaw plates? It based on your jaw crusher wedge retention design.

Jaw Crusher Flywheel

The flywheel is the main part of the jaw crusher. In addition to balancing the weight of the sheave, the flywheel can also accumulate energy. There are two flywheels on the jaw crusher. One flywheel is used to connect the triangle belt and the eccentric shaft, and the other one does not seem to have any effect on the appearance.

The jaw crusher flywheel material: HT200-HT400

A pitman of a jaw crusher comprising an upper part, which comprises an upper supporting point for supporting the pitman in the body of the jaw crusher, and a lower part comprising a lower supporting point for supporting the pitman in the body of the jaw crusher through a toggle plate.

The pitman is rigidly connected with the frame, and the movable jaw is directly hung on the suspension shaft; the lower part of the movable jaw is hinged with the eccentric shaft and the back wall of the frame through a connecting rod and a thrust plate to form a movable swing system.

The material for pitman: 35 steel, 45 steel, 20Mn, or 35CrMo.

The eccentric shaft is the main shaft of the jaw crusher. It is subjected to huge bending and torsion forces and is made of high carbon steel. The eccentric part shall be finished, heat-treated, and the bearing bush shall be cast with Babbitt alloy. One end of the eccentric shaft is equipped with a belt wheel, and the other end is equipped with a flywheel.

The material for the jaw crusher shaft are: 42CrMo or 42CrNiMo

The jaw crusher frame is the installation basis for the entire crusher components. It bears a great impact load during work, and its quality accounts for a large proportion of the whole machine (about 50% for the casting frame and about 30% for the welding frame), and the processing and manufacturing workload is also relatively large. The strength and rigidity of the frame have a great influence on the performance of the whole machine and the life of the main parts.

The jaw crusher frame is divided into structure, there are integral frame and combined frame.

Due to the difficulty of manufacturing, installation, and transportation, the overall frame is not suitable for large-scale crushers and is mostly used by small and medium-sized crushers. It is more rigid than the combined frame, but it is more complicated to manufacture.

The combined frame is used for large-scale crushers. It has two forms: one is the combination of pins and bolts between the frame walls. For example, the 1200×1500 jaw crusher frame is divided into upper and lower parts, the upper frame and the lower frame. It is connected by bolts, and the keys and pins between the joint surfaces bear strong shearing force. The keys and pins also play the role of assembly and positioning.

The other is to use a welding combination, such as a 900×1200 jaw crusher frame. Its rigidity is better than that of a combined frame connected by an insert pin, and it is also more convenient to process, assemble, and disassemble. The 1500×2100 jaw crusher adopts a welded combined frame.

From the point of view of the manufacturing process, the integral frame is divided into an integral casting frame and an integral welding frame. The former is more difficult to manufacture, especially single-piece small batch production, while the latter is easy to process and manufacture, and the machine is lighter, but requires relatively high welding technology and welding quality, and requires the elimination of internal stress after welding.

In addition, cast steel is a process with high energy consumption, and from the perspective of energy saving, the welding frame should also be vigorously developed. There is no doubt that the jaw crusher adopts a welding frame in the development direction.

The toggle plate of the jaw crusher is a cast iron piece that has passed accurate accounting. It is not only a force transmission component but also a safety part of the jaw crusher. The toggle plate will be broken immediately and the crusher will stop working to prevent damage to the entire machine  When the unbreakable material falls into the crusher and the machine exceeds the normal load.

The toggle plate and toggle plate pad use the rolling contact method, and there is little friction under normal use. Only a layer of grease is applied to the contact surface. The whole part is used to adjust the size of the discharge port and compensate for the wear between the jaw plate, the toggle plate, and the toggle pad.

The material for the toggle plate is Q235A.