Heat treatment is a process of improving performance of metal material and products. According to different purposes, the materials and the workpiece is heated to the proper temperature, thermal insulation, followed by cooling in different ways, changing its internal organization in order to get the performance you require. Seamless steel tube heat treatment usually include annealing, normalizing, quenching, tempering, chemical heat treatment and failure and vacuum heat treatment. By heat treatment, can increase the efficiency of steel or life, and in some cases can make cheaper metals instead of the more expensive special materials.
The basic method of seamless steel pipe heat treatment annealing, normalizing, quenching, tempering and their combinations. Technical system of heat treatment process for determining details of the article the seventh chapter sections.
Annealing is a seamless steel tube heating to slightly higher or lower than the critical temperature, a specific period of time (the insulation), and a process of slow cooling. Annealing process of common categories are: diffusion, fully annealed, isothermal annealed, spheroidized annealed, incomplete annealing and recrystallization annealing, stress relieving annealing.
Fire, also known as "often" is the seamless steel pipe is heated to a critical point on (Ac3 or Acm) as high as mesophile temperature or high temperature above, reach the organization fully austenitic and evenly, then baked, and even in the natural circulation of air cooling process.
Normalizing and annealing process of refinement compared with fast cooling, materials, and improved mechanical properties, short production cycle, equipment characteristic of high efficiency and low cost.
Quenching is the seamless steel pipes is heated to the proper temperature, thermal insulation, then rapid cooling (usually cooled in water, oil or air), undercooled austenite into martensite process. Used to increase the hardness and strength of the parts, or to change its physical and chemical properties (such as electrical conductivity, magnetic, corrosion resistance, etc). There are single liquid to quench hardening, double quenching, quenching and isothermal quenching, and so on.
Heating tempered seamless steel is quenched to a tipping point to Ac1 temperature, thermal insulation and heat treatment process of cooling to room temperature again. It is a process of seamless steel tube hardening must be carried out, is also the last process of heat treatment. Tempering aims at improving the ductility and toughness of quenched steel, to reduce and eliminate quenching stress, stable organization and the size and shape of the workpiece. After tempering is usually uses air cooling, however, shows high temperature tempering embrittlement of seamless steel tubes are used rapid cooling. Medium-temperature Tempering Tempering process can be divided into low-temperature tempering, and tempering.