Author: Claire Publish Time: 2024-04-30 Origin: www.train-wheels.com
Forged train wheels according to the steel type and process requirements, often use the following heat treatment methods: annealing, normalising, tempering, quenching and low temperature tempering, quenching and aging. Next, we were to see exactly how it is.
Train wheel forgings annealing process has a complete annealing, spheroidal annealing, low-temperature annealing and isothermal annealing and other forms, according to the train wheel forgings material and deformation to be selected.
Train wheel forgings after annealing, due to recrystallisation refinement of the grain, eliminating or reducing the residual stress, thereby reducing the hardness of the train wheel forgings, improve its plasticity and toughness, improve the cutting performance.
Normalising is generally the train wheel forgings heated to the GSE line above 50-70 ℃, some high-alloy steel train wheel forgings heated to the GSE line above 100-150 ℃, after appropriate insulation and then cooled in the air. If the train wheel forgings after normalising is high hardness, in order to reduce the hardness of train wheel forgings, should also be high temperature tempering, general tempering temperature of 560-660 ℃.
Quenching is done to obtain an unbalanced organisation to increase strength and hardness. Heat the steel train wheel forgings to 30-50°C above the Ac1 line. After holding, cool sharply.
Tempering is to eliminate quenching stress, to obtain a more stable organisation, the train wheel forgings are heated to a certain value below a certain temperature, held for a period of time, and then air-cooled or fast-cooled.
High-temperature alloys and alloys that can be strengthened by heat treatment are often quenched and aged after forging. One of the quenching is the alloy is heated to the appropriate temperature, after full insulation, so that the alloy in some organisational generators dissolved into the matrix to form a uniform solid solution, and then rapidly cooled, become supersaturated solid solution, it is also known as solid solution treatment. Its purpose is to improve the plasticity and toughness of the alloy, and for further aging treatment to prepare the organisation.
Ageing treatment is the supersaturated solid solution or after cold working deformation of the alloy at room temperature or heated to a certain temperature, insulation for a period of time, so that the previous dissolved in the matrix of the body of the material, uniformly diffuse precipitation. The purpose of aging treatment is to improve the strength and hardness of the alloy.
