Measures to prevent surface and internal cracks in forgings

To prevent surface and internal cracks in forgings, the following countermeasures must be taken:

1) Select high-quality original blank, and all defects on the surface of the blank should be completely removed. For example, extruded billets often require carskins. When forging the small bar material that is not convenient for the car on the hammer, it is necessary to strike lightly at first, break the coarse crystal ring, and then gradually increase the blow;

2) Ingots should be sufficiently homogenized at high temperature to eliminate residual internal stress and intracrystalline segregation to improve metal plasticity. Forging heating, to ensure that the specified heating temperature for heating and full insulation;

3) Choose the best forging temperature range according to different alloys. For example, the best forging temperature range of LC4 alloy ingot is: about 440X: heating insulation, and then slowly cooling to 410-390t: about forging, good plasticity;



4) Aluminum alloy due to poor liquidity. The forging process with intense deformation (such as rolling), and the deformation degree should be appropriate, the deformation speed should be as low as possible;



5) Forgings forging operation should be paid attention to prevent bending, folding, and timely rectification or elimination of defects in the produced. When rolling round, can not be 20% small dry, and the number of rolling can not be too much.

6) The tools used for forging and die forging should be fully heated, and the heating temperature should be close to the forging temperature, generally 200-420, in order to improve the fluidity.

here are real pictures of ring type forgings produced by Tongxin precision forging company with good price and stable quality.