Vacuum annealing

Jun. 25, 2024

1. Characteristics of vacuum annealing

Since vacuum heating can degas, degrease and remove rust, the gas dissolved in the metal can be easily discharged, so the surface of the parts after vacuum annealing is clean and bright. During vacuum annealing, the grains deformed by pressure processing are restored, and new grains are formed, so that the organization is uniformly refined, thus changing the mechanical properties of the material. After vacuum annealing, there is no trace of lubricant on the surface of the material, and the surface is dry. It can be directly electroplated without the cleaning process of pickling or sandblasting, so as to achieve the purpose of shortening the process and improving product quality.

2. Vacuum annealing application range

(1) Annealing of refractory metals. Metals such as molybdenum, tungsten, tantalum, cobalt, vanadium, and zirconium have high melting points and are easily oxidized and contaminated by refractory materials. They have high strength and hardness during processing. If they contain gases such as hydrogen, oxygen, and nitrogen, the ductility of the material will deteriorate. In order to turn them into profiles, they must be softened by vacuum annealing before pressure processing.

(2) Annealing of soft magnetic alloys. Soft magnetic alloys are generally obtained by vacuum melting and vacuum rolling. Because they must maintain stable magnetic properties under the action of temperature, pressure, radiation, and mechanical load, vacuum annealing is required.

(3) Annealing of silicon steel sheets. Vacuum annealing is required to remove gases such as hydrogen, carbon monoxide, carbon dioxide, and methane from silicon steel sheets, remove oxides and sulfides, eliminate internal stress and grain boundary distortion, increase magnetic induction intensity, and reduce unit iron loss.

(4) Annealing of iron-nickel alloys and iron-silicon alloys. The purpose is to improve the organizational structure and toughness.

(5) Annealing of electrical steel. The purpose is to improve plasticity and uniform magnetic properties.

(6) Annealing of stainless steel. The purpose is to improve the resistance of stainless steel to intergranular corrosion.

(7) Annealing of structural steel. The purpose is to improve strength and surface brightness.

(8) Annealing of steel wire and thermocouple wire. The purpose is to obtain a bright surface, eliminate processing stress, and remove harmful gases such as nitrogen and oxygen contained in the metal wire.

Vacuum annealing