influence of deformation speed
Generally speaking, the raising and deformation speed will reduce the malleability of the boat, even if the metal plastic part 1; Array, deformation resistance increases.
The deformation speed will also affect the forging penetration. In the plant with large deformation degree, the smaller the deformation speed is, the more light the forging permeability is, which is more conducive to the refinement and reconstitution of the product, and thus is also conducive to the improvement of process plasticity.
. effect of heating speed
For the billets with large section size and high thermal conductivity, the heating speed of covering is too fast, and the holding time is too short, which often makes the temperature difference; It is uneven and causes thermal stress. Crack of the blank at noon. For example, cracks often occur in bars, alloy tool steels, high-temperature alloy ingots and forgings due to improper heating. Billet temperature; Even, it will also cause deformation and uneven structure. The wall attached Liu u is stressed, resulting in good internal cracking.
. effect of cooling rate
Improper cooling rate often causes thermal stress, microstructure wind force and precipitation of the second phase. Martensite; Rusty steel and ledeburite steel (high-speed steel and times 12 section steel), if the cooling rate after plating is too fast, the transformation of internal ten martensite structure often causes structural stress, resulting in surface crack of forgings. However, the slow cooling of some materials after forging will cause the degradation of properties by analyzing the T ratio along the product boundary in the second phase. For example, the slow cooling of bearing steel after forging will precipitate network carbides along the product boundary.
. effect of stress state
The stress state has some influence on the weldability and metal flow. The three-dimensional compressive stress state can improve the plasticity of corrosion metal and increase the deformation resistance. This is because the compressive stress can prevent the destruction of intergranular contact, which is conducive to the development of intragranular slip intersection. The average compressive stress along the moving surface improves the plastic deformation ability of the material.