What are the technical requirements for large-scale annealing equipment?

1. Actual Processing Technology of Spheroidizing Annealing in Large Drawing Annealing Device

(1) Generally (slow cooling) spheroidizing annealing, slow cooling is suitable for most alloy structural steels, especially in the case of large furnace loading, convenient operation, but long production period;

(2) Isothermal spheroidizing annealing is suitable for most alloy structural steels, very difficult to spheroidize and steels with high spheroidizing quality (such as roller bearing steels); its production cycle time is shorter than that of general spheroidizing annealing, only a furnace which can control the cooling rate of water before eutectoid change is necessary;

(3) Cyclic time spheroidizing annealing is suitable for steel with initially lamellar mylonite ferrite mechanism. Its production cycle time is shorter than that of general spheroidizing annealing. It is impossible to change the temperature according to the operating regulations only under the standard of large furnace loading of machinery and equipment, so it is not widely used in production and manufacturing.

(4) Ultra-low temperature spheroidizing annealing is suitable for steel produced and processed by cold deformation and steel hardened by heat treatment (the latter is generally called high temperature softening quenching).

_Deformation spheroidizing annealing and deformation production processing can accelerate spheroidizing. Combining deformation production processing with spheroidizing can reduce spheroidizing time. It is suitable for cold and hot deformed cast iron castings and stainless steel sheets (such as steel sheets).

2. Work Hardening Annealing Process

This quenching method is applied to metal materials and aluminium alloys which have undergone cold deformation. Aim To make the internal mechanism of metal materials into fine equiaxed crystals, remove deformation hardening, repair the plastic deformation and deformation ability of metal materials or aluminium alloys (response and work hardening). If the surface of metal or aluminium alloy is bright, work hardening and quenching can be carried out in controllable atmosphere furnace or vacuum sintering furnace.

Removing in-situ stress, quenching casting, forging and welding parts cause thermal stress due to different water cooling rates at different locations. Metal materials and aluminium alloys also cause thermal stress in cold deformation production and processing, as well as steel parts in drilling production process. If the thermal stress is too large to be removed immediately, it often causes deformation and even cracks in steel parts. Removal of in-situ stress quenching is a slow heating of steel parts to a lower temperature (for example, gray cast iron is 500-550 C, steel is 500-650 C), heat insulation for a period of time, so that the metal material internal relaxation, and then slow down. It should be emphasized that removing in-situ stress quenching can not completely remove thermal stress, but only partially remove it, thereby eliminating its harmful effects.