1. Normalizing: normalizing is the heat treatment method that heats the elbow to the critical temperature, transforms the hot bend into homogeneous austenite, and then cools naturally in the air. Fire can eliminate network cementite eutectoid hot pressing elbow, elbow pressing for hypoeutectoid normalizing can refine crystal lattice, improve the comprehensive mechanical properties of the elbow, the demand is not high by normalizing instead of quenching process is more economical.
2: quenching quenching is the elbow is heated to above the critical temperature, holding time, and then quickly into quenching agent, the temperature suddenly reduced to greater than the critical cooling rate of fast cooling, and the heat treater unbalanced organization with martensite based method. Quenching can increase the strength and hardness of steel, but reduce its plasticity. Quenching agents commonly used in quenching are: water, oil, lye and salt solution, etc..
Hot pressing elbow is heated by the tube forming professional equipment, and then cutting the heated to above the critical temperature, holding time quickly into quenching agent, the temperature suddenly reduced, elbow making methods is greater than the critical cooling rate of rapid cooling of A.