： Forging temperature and heating specifications of alloy structural steel ingot
Alloy structural steel is widely used in various fields. Material properties such as strength, toughness, and plasticity are related to forging temperature. The forging temperature and heating specifications of alloy structural steel need to be properly determined, otherwise causing the quality of the material to be affected, which will affect its overall performance.
Forging temperature
Forging temperature refers to the temperature of the metal before it is subjected to plastic deformation. Generally, as the forging temperature increases, the plasticity of the metal increases, while the strength and hardness of the metal decreases. If the forging temperature is too low, deformation resistance will increase, resulting in cracking and splitting of the forged billet. It can also lead to added difficulty during subsequent processing, reduced quality and increased costs.
The general conception of the forging temperature of alloy structural steel is: the temperature of hot forging should exceed the recrystallization temperature of the material, while hot rolling should not exceed the thermal stability range. Generally, the recrystallization temperature of alloy structural steel is generally higher than the room temperature. In order to improve the mechanical properties of the material, duplex means is generally used for forging, that is, semi-hot forging, intermediate warm forging and cold forging. Semi-hot forging means that the forging temperature is between the recrystallization temperature of the material and its thermal stability range. Generally, it is between 800～900℃. Intermediate warm forging means that the forging temperature is lower than the recrystallization temperature, usually between 500～800℃, while cold forging means that the forging temperature is lower than the recrystallization temperature, usually between 0～450℃.
Heating specifications
Heating specifications are the technical requirements for heating middle and low carbon alloy steels during heat treatment. The heat treatment of low alloy structural steel mainly refers to annealing, normalizing, quenching and tempering. In order to obtain some of the desired properties of the alloy structural steel, it is necessary to specify the heating specifications for heat treatment.
The heating specifications mainly include the same aspects as forging temperature, such as preheating temperature, heating temperature, soaking time, cooling method and so on. Generally, the preheating temperature should be lower than the subsequent heating temperature, while the heating temperature should be lower than the thermal stability range. If the preheating temperature is too high, the surface of the sample will be softened and cause its subsequent performance to be affected. It is more suitable to control the heating temperature in the intermediate warm forming range. In addition, different materials have different requirements for soaking time and cooling rate, so they should be carefully considered when forming.
Therefore, in the process of alloy structural steel forging, it is necessary to determine the forging temperature and heating specifications according to the properties of the material, so as to obtain satisfactory performance, quality and stability.
