How to improve the hardness of Gost 17375 Butt Welding Pipe Fitting 90 Degree Elbows

　　There are several methods to improve the hardness of hot pressed Gost 17375 Butt Welding Pipe Fitting 90 Degree Elbows

　　Quenching of hot pressed Gost 17375 Butt Welding Pipe Fitting 90 Degree Elbows: Quenching can increase the strength and hardness of steel, but reduce its plasticity. The commonly used quenching agents in quenching include water, oil, alkaline water, and salt solutions.

　　Normalization of hot pressed Gost 17375 Butt Welding Pipe Fitting 90 Degree Elbows: It can pass through the network cementite of eutectoid hot pressed elbows. Normalization of hypoeutectoid hot pressed elbows can refine the lattice and improve comprehensive mechanical properties. It is more economical to use normalization instead of annealing process for parts with low requirements.

　　Tempering of hot pressed Gost 17375 Butt Welding Pipe Fitting 90 Degree Elbows: Tempering is divided into three categories: high temperature tempering, medium temperature tempering, and low temperature tempering. Tempering is often used in conjunction with quenching and normalizing. Its purpose is to reduce the internal stress generated by quenching, reduce hardness and brittleness, and achieve the expected mechanical properties.

　　1. Quenching and tempering: The heat treatment method of high-temperature tempering after quenching is called quenching and tempering. High temperature tempering refers to tempering between 500 and 650 ℃. Quenching and tempering can greatly adjust the properties and materials of steel, resulting in good strength, plasticity, and toughness, and excellent comprehensive mechanical properties.

　　2. Aging treatment: In order to prevent changes in size and shape of measuring tools, molds, and parts during long-term use, the workpiece is often reheated to 100-150 ℃ after low-temperature tempering (low-temperature tempering temperature 150-250 ℃) before precision machining, and maintained for 5-20 hours. This treatment is called aging to stabilize the quality of the workpiece. It is particularly important to perform aging treatment on steel components under low temperature or dynamic load conditions to stabilize the structure and size of hot pressed elbows with residual stress.

　　Annealing of hot pressed Gost 17375 Butt Welding Pipe Fitting 90 Degree Elbows: Heating a hot pressed Pipe Fitting 90 Degree Elbows to temperature and holding it for a period of time, then slowly cooling it is called annealing. Annealing of hot pressed elbows is a heat treatment method that heats steel to a temperature where phase transformation or partial transformation occurs, and then slowly cools it after insulation. The purpose of annealing is to organize defects, homogenize composition and refine grains, improve the mechanical properties of hot pressed elbows, and reduce residual stress; At the same time, it can reduce hardness, improve plasticity and toughness, and improve cutting performance. Therefore, annealing is a semi-finished product heat treatment, also known as pre heat treatment, which is aimed at addressing the structural defects and internal stresses in the previous process and preparing for subsequent processes.