Ways to Improve the Service Life of Cemented Carbide Anvil and Press Cylinder of Six-sided Top Press

To improve the service life of cemented carbide top hammer and pressure cylinder, thereby reducing hammer consumption:

1. Improve the performance of cemented carbide

(1) Increasing the cobalt content can improve the strength of the cemented carbide. From the comprehensive consideration of economic benefits, the cobalt content in a certain part can only be increased. Experiments show that increasing the cobalt content can improve the service life of the cemented carbide anvil and the pressure cylinder.

(2) The grain size of tungsten carbide has obvious influence on the performance of cemented carbide. With the increase of WC particle size, the compressive strength, hardness and elastic modulus decreased, while the flexural strength increased. Therefore, controlling the particle size of tungsten carbide is an effective way to improve the life and reduce the plastic deformation.

(3) If the structure of the cemented carbide is defective, it will cause stress concentration during synthesis, accelerate the fatigue failure of the anvil, and reduce its life. In order to improve the life of the top hammer, some alloying elements (such as niobium carbide, titanium carbide, vanadium carbide, tantalum carbide, etc.) The service life of the top hammer is greatly improved.

2. Change the shape of the top hammer

Some researchers suggested that if the flat-bottomed top hammer is changed to a spherical bottom, the strength of the spherical top hammer is better than that of the plane, because the uniformity of the force on the spherical top hammer is better, and the maximum tensile stress value acting on the 46° slope of the top hammer, The spherical surface is smaller than the flat surface, the maximum shear stress value acting on the central axis at 1/3 of the top hammer height from the top surface, the spherical surface is smaller than the flat surface, and the maximum compressive stress value on the 46° inclined surface is larger than that of the flat surface Small, changing the shape can also reduce the height of the anvil, save alloys, and reduce the "size effect". Therefore, changing the top hammer to a ball bottom can not only improve the stress distribution state in the top hammer body, reduce the peak value of external stress and thermal stress, improve the life of the top hammer, but also save alloy materials and reduce the "scale effect".

3. Carbide heat treatment

Heat treatment can improve the bending strength, impact toughness and durability of the top hammer, reduce brittle fracture, reduce porosity, increase density, reduce the source of fracture, and thus increase the service life of the top hammer. Heat treatment can change the magnetic properties, increase the coercive force and reduce the magnetic permeability. After heat treatment of fine-grained cemented carbide, the toughness will be improved, the loading deformation energy will be increased, and the durability in the high-pressure chamber will be improved.

4. Appropriately increase the thickness of the gasket

Increasing the thickness of the gasket is beneficial to prolong the life of the anvil. However, increasing the thickness is not arbitrary, and should be limited to not reducing the stability of the gasket and reducing the deformation of the gasket.

In order to achieve sufficient sealing conditions, improve the utilization rate of external load pressure and protect the function of the top hammer, it is required that the side length of the top hammer surface and the width of the chamfer and the side length of the pyrophyllite block have a certain proportional relationship, and the angle of the top hammer chamfer Be suitable. This is mainly to ensure that the pyrophyllite gasket has an appropriate width and thickness, an important condition for forming sufficient sealing force and reducing the influence of thermal stress, so as to achieve the effect of maintaining a constant pressure in the cavity and prolonging the service life of the anvil.

5. Improve the neutrality of the equipment, and adjust the anvil in place

Before starting up, check the centering synchronization of the equipment, ensure the accuracy of the pressure holding performance and the stability of the heating system, check whether the various parts of the press are normal, and the anvil must be accurately installed and debugged in place.

6. Cooling water cooling

Adding appropriate cooling water during synthesis can effectively lower the temperature and reduce thermal stress concentration.

7. Reduce synthesis pressure and temperature, shorten synthesis time

While ensuring the synthesis effect, try to reduce the pressure and temperature of the synthesis and shorten the synthesis time.

8. In order to eliminate the internal stress of the top hammer, it is recommended to put the top hammer and steel ring on hold for two or three months, and then use them after the internal stress is released to reduce longitudinal splitting or top hammer cracks and crushing.

9. The baking process of auxiliary materials such as pyrophyllite should be strictly controlled.

10. Adding a layer of protective metal Mo, Ti, etc. on the surface of the conductive top hammer can improve the temperature distribution of the top hammer, make the top hammer evenly heated, improve thermal stress concentration, and reduce hammer consumption.

11. Classify and use the top hammer, such as using ultrasonic and magnetic flaw detection to inspect the quality of cemented carbide molds. Those with micro defects are used for non-electric heating hammers, and those without defects are used for electrified heating hammers. This will prolong the service life of the top hammer Clearly there are benefits.

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