Railway brake block

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We produce cast iron railway brake block and composite railway brake block.  

Cast iron brake block:

There’re two types of cast iron brake block, normal type and high phosphorous cast iron brake shoe.  The difference lies in the content of the phosphorus.  The P content in normal type is 0.7-1.0%, while in high phosphorous cast iron brake block, the P content is above 10%.

The wear resistance of high phosphorus cast iron brake is 1 times bigger than normal type. Practice shows that the life span of high-phosphorus brake block is 2.5 times of the normal type.

High phosphorus brake block is also characterized by little spark.

The friction coefficient increases with the increasing of phosphorus content, so the friction coefficient of high phosphorus brake brake is greater than the normal type.

However, the high phosphorus content will increase the brittleness, so when the phosphorus content is above 1%, there may be crack, so it requires a backing plate for high phosphorous brake block.

Cast iron brake block has been in use on railway vehicles for more than a century in history. The main advantages of cast iron brake block are:

1. a small friction coefficient affected by the environment and more stable, so it is "all-weather" operational;

2. good thermal conductivity, low thermal damage to the wheels;

3. The coarsening of the wheel surface can obtain more adhesion, which can reduce the mechanical abrasion of the wheel;

4. Durable, low prices.

But the friction coefficient of ordinary gray cast iron brake shoe is small, and with the increase of friction velocity, friction coefficient decreased rapidly especially when it is in high-speed running.

So ordinary cast iron brake shoes are generally used for low-speed operation of passenger trains.

For cast iron brake used in high speed train, we can improve the performance by increase the content of phosphorus or add some alloy element.

In fact, it is the high phosphorus cast iron brake block that is widely used now, to avoid the crack, a backing plate is used to reinforce.

Composite brake block:

The composite brake block is more widely used currently.

It is the following advantages:

1. Friction property can be adjust according to requirement.

2. Good wear resistance and long life span.

3. Saving of the cast iron material

4. Small wear to the wheel which can prolong the lifespan of the wheel

5. Light weight, normally it is only 1/2-1/3 of the cast iron brake block

6. To avoid iron stain and abrasion due to brake injection spark caused fires, and to mitigate the adverse effects on electrical equipments.

7. The friction coefficient is relatively stable and can ensure sufficient braking force.

8. Due to the friction coefficient can be sufficiently improved, the use of composite brake block and small diameter brake cylinder can save compressed air, thus can shorten refillable time when it needs continuous braking in high slope areas, so that the security of running in ramp area is improved.

The materials of composite brake block is asbestos free, it contains resins, elastomers, friction modifiers and mineral fibers reinforcing its structure.  It contains no lead, zinc or any other toxic materials, it is environmental friendly, and causes no bad smell in friction.

The wear of the composite material is very low. The advantage of this material is a stable coefficient of friction in variable atmospheric conditions and high thermal resistance.

The composite brake block is particularly beneficial in those situations where cast iron brake block would cause a safety hazard. Spark free brake blocks are essential in oil refineries, chemical works and ordinance factories. The composite brake block has much to offer in the braking of passenger rail, minimizing braking shocks by its smooth action and permitting higher load factor.