Powder forging process design points

(1) Powder forging process (liú chéng)

     Metal powder-mixed powder-cold pressed billet-sintering-heating-forging (die forging)-heat treatment (chǔ lǐ)-machining-finished product.

     At present, the advanced method can realize one heating, that is, the sintering (the process of converting the powdery material into a dense body) and the heating process are combined into one heating. However, some of the sintering temperature and the forging heating temperature are far apart, or due to the process specifications such as sintering, heating and insulation, it is usually reasonable to use the sintered billet to reheat for forging. Attention oxidation prevention measures should be taken during sintering and heating.

(2) Design of powder forgings

     Powder smelting metals can obtain preforms of various complex shapes and then forge into shaped parts, which is superior to other precision pressure processing processes. In order to achieve a particularly low output speed, the hardened gear reducer can be realized by means of two gear reducers. When using this transmission scheme, the power of the configurable motor must depend on the ultimate output torque of the reducer, and the output torque of the reducer cannot be calculated from the motor power. Therefore, the key to the design of powder forgings is the design of preformed blanks. The principles to be noted in the design are as follows:

    
　　(1) The shape of the preform ensures that the blank is in a three-direction compressive stress state when forged, and is formed by the combination of the squeezing and squeezing to avoid the tensile stress of the blank, and the shape is as close as possible to the final forging shape, and the shape should be as smooth as possible. To avoid dead ends that are not conducive to flow. The efficiency of planetary gear reducer transmission is the most efficient of all transmissions, and its efficiency is much higher than that of worm drive. The efficiency of the gear reducer is mainly determined by the friction of the gear and the bearing. Gear reducer motor 1, R series coaxial helical gear reducer combined with international technical requirements, with high technology content 2, space saving, reliable and durable, with high overload capacity, power up to 132KW; 3, low energy consumption, Excellent performance, the speed reducer efficiency is up to 95%; 4, low vibration, low noise, high energy saving; 5, high-quality forged steel material, steel cast iron box, gear surface after high-frequency heat treatment; 6, after precision machining, ensure Shaft parallelism and positioning bearing requirements, the reducer that forms the helical gear transmission assembly is equipped with various types of motors, combined into mechatronics, which fully guarantees the quality characteristics of the product.    
　

      (2) It is best to adopt the two-way compaction method when pressing the preform blank to ensure uniform density of each part. The powder loading and compaction quantity are controlled in the same way. The weight and volume automatic monitoring device can be used; the compaction process should be Good lubrication conditions for complete demolding.

      (3) The sintering process is an important step to increase the bonding strength and forgeability of the preformed blank. The sintering can make the alloy component uniformly diffuse and reduce the gas content in the workpiece.

      (4) Powder forging density (unit: g/cm3 or kg/m3) stress uniformity (jūn yún), the preform should avoid sharp corners as much as possible, because the density of the sharp corner is low, and it is impossible in forging ( Maybe) improvement, when designing forgings, the right angle should be designed as a chamfer or rounded transition, and the density and performance are uniform after forming.

(3) Forging process (guò chéng)

      (1) Forging equipment (shèbèi) generally uses a friction press, a mechanical press or a high speed hammer for powder forging.

      (2) Generally, it is required to heat in a protective atmosphere, and an electric resistance furnace or an intermediate frequency induction heating furnace can be used; some use a glass material lubricant (action: can reduce or avoid friction and wear) and prevent oxygen (Oxygen) heating. The heating temperature is the same as that of ordinary die forging.

     (3) The mold (title: the mother of the industry) needs to be preheated to a relatively high temperature (temperature) for die forging to avoid the mold wall chilling the forging blank, affecting the forging plasticity and the uniformity of the internal structure. Forged forgings are required to be cooled in a protective atmosphere, and forgings with high complex shapes and precision requirements can be shaped and refined.

     (4) Post-processing

    Powder forged forgings can be annealed, tempered or pre-treated, and subjected to various surface treatments as in conventional die forgings. After the annealing of individual high-demand forgings, it is required to re-sinter (transform the powdery material into a dense body) or hot isostatic pressing to fully diffuse and combine the alloy components to improve the mechanical properties of the forgings, especially toughness.