Inspection results and analysis of forgings entering and leaving the factory

Forging surface quality and size

After inspection, the size of the forgings developed in the first batch did not meet the requirements of the forging drawings, the local filling of the forgings was not good, the dimension in the height direction was over-negative, and there was a phenomenon of forging wrong molds, resulting in uneven machining allowances for forgings, and there were many places.

The typical folding defects of the first batch of integral frame forgings for forging folded cracks The second batch of forgings was delivered after being repaired and improved by the manufacturer. The surface quality was good. Except for various points, the forgings were well filled and met the technical requirements of forgings. ; And, the trial processing of the parts shows that the forging allowance is uniform, and the external dimensions meet the requirements of the forging drawing.

The chemical composition of the forgings, after inspection, the chemical composition inspection results of the forgings all meet the requirements of the technical standards for forgings, and the specific data are shown in Table 1. As can be seen from Table 1, although the test values of some elements in the two batches of forgings are quite different, they meet the standard requirements, which may be related to factors such as the instruments and equipment used by the two test units, testing methods and measurement errors.

Mechanical properties of forgings

After inspection, the mechanical property inspection results of the two batches of forgings all meet the requirements of the technical standards for forgings. The numerical distribution of the room temperature tensile properties of the forgings is shown in Figures 12 to 15.

The room temperature impact toughness values are 40 to 78.9 J/cm, and the average value is about 55.8 J/cm; the high-temperature tensile strength at 500 °C is 635 ～675MPa, the average value is about 654.3MPa; the high temperature lasting tensile properties at 500℃ all meet the requirements of strength 470MPa and ≥50h; the measured fracture toughness is 70～98.8MPa, and the average value is about 85MPa.

It can be seen from Figure 12 to Figure 15 that the ultimate strength of the forging is basically in a normal distribution state, and is in the middle of the middle and lower parts of the standard range, its peak point is 970~975MPa, the average value is 978MPa, and the minimum value is 930MPa; The yield strength of forgings is also basically in a normal distribution state, with an average value of 924MPa, and most of its values are greater than the standard longitudinal minimum value of 30MPa.

The longitudinal minimum value of 10 is higher than the standard requirement, and the average value is 16.6; the area reduction ratio distribution of the forging is irregular, and the numerical dispersion is relatively large, but the minimum value is still higher than the longitudinal minimum value of 25 required by the standard. , the average value is 47.7, and most of the values have enough standard richness. Because this forging is directly press-formed with a simple shape blank, the metal deformation is very large, and the actual flow direction of the metal in the forging die is very different from the main flow direction of the raw material; therefore, the actual flow line of the metal material of the forging It is difficult to determine the direction and its mechanical properties.