Introduction to the wear mechanism and influencing factors of the pump cobbler

The pump cobbler plate, also called the wear plate, is an important part of the concrete pump truck, so named because of its shape like glasses. It is a part of the pump truck pumping distribution valve and is connected to the concrete conveying cylinder. The moving part S pipe is driven by the swing cylinder and swings from one side of the concrete cylinder mouth to the other side of the concrete cylinder mouth, the cutting ring swings with the S pipe against the spectacle plate and forms a cutting friction with the spectacle plate. Due to the rapid oscillation of the cutting ring the spectacle plate is strongly rubbed against the concrete and at the same time has to withstand the impact force generated by the cut-off stones. The spectacle plate must therefore withstand impact forces, shear forces and very strong friction in its normal working condition.

The main forms of failure of the spectacle plate are wear and tear and chipping and block failure. The wear between the spectacle plate and the cutting ring belongs to the abrasive wear, the first manifestation is the cutting ring and the spectacle plate orifice angle wear blunt, and the formation of a small circular wedge-shaped mouth, with the participation of the abrasive particle size of wear, wear gap also increases, when the gap is large to a certain value will affect the construction due to serious leakage. As the pumping height increases, the impact shear of the cobalt plate will increase, and the wear will be more intense, and it is easy to break and crumble.

Introduction to the wear mechanism of the pump cobalt plate and the influencing factors.

The concept of abrasive wear and the mechanism of cobalt plate wear and the influencing factors.

1. Concept

The loss or material loss caused by the extrusion of hard particles or hard micro-convex bodies on the surface of the friction sub-surface and movement along the surface during the friction process.

2. Wear mechanism

(1) Cutting: Sharp hard abrasive particles cut soft surfaces and the material cut off becomes abrasive particles.

(2) Fracture: The hard particles cause micro-cracks to sprout, expand and fracture off the surface of the material.

(3) extrusion flaking: abrasive in the role of load pressed into the friction surface and produce indentation, the surface of the plastic material extruded laminar or scale-like flaking debris.

(4) fatigue: the friction surface in the abrasive generated by the cycle of contact stress, so that the surface material due to fatigue and flaking.

3. Influencing factors

(1) The higher the material hardness, the lower the abrasive hardness, the better the wear resistance. When the abrasive grain hardness is between 0.7 and 1.0 of the material hardness, no abrasive grain wear is produced or only slight abrasive grain wear is produced. In the working environment of spectacle plates, the abrasive grains are concrete, including cement, stone and sand, etc. Their hardness is basically stable and difficult to reduce, so upgrading the material hardness of spectacle plates is an effective way to reduce abrasive wear.

(2) Abrasive wear is also related to the shape, size and sharpness of the abrasive particles, which is not easy to control when pumping concrete, so do not delve into it.

(3) The degree of line wear is directly proportional to the pressure on the surface of the material. When the pressure reaches the turning value, the line wear degree becomes flat with the increase of pressure, which is due to the transformation of the abrasive wear form. Various materials have different values of turning pressure. During the oscillation of the spectacle plate, the oscillation angle and the design construction of the plate itself will have an effect on the surface pressure, and the shape of the plate can be designed to reduce friction by optimising the structure and designing the plate to be more in line with the mechanical construction.

(4) The number of repetitions of friction and the speed of relative movement will also affect the degree of abrasive wear of the material. The spectacle plate will swing back and forth in the concrete during work, with long working hours, high intensity, many repetitions and fast relative movement, so the wear is particularly serious. However, this is difficult to avoid without reducing production efficiency.

From the above analysis, it can be concluded that, without increasing the workload and reducing production efficiency, to enhance the service life of alloy spectacle plates and reduce wear and tear, enhancing the material hardness, impact resistance and surface smoothness of spectacle plates is an economical and feasible measure.