Steel production
Nowadays，steel is used more and more widely. Such as buildings, bridges, ships, boilers, automobiles, agricultural machinery, aviation, chemical machinery, boilers, electricians, welding rods, etc. Therefore, steel is an indispensable part of our lives. As we all know, there are various varieties of steel. So, do you know why there are various varieties? In fact, the main reason for it is the steel delivery status. Popularly speaking, it is the last step in the production process. How you make the final step will determine what type of steel you produce. So let's talk about the delivery status of steel.
The steel delivery process can be divided into six parts. As follows, hot rolled condition, cold pull, normalizing state, annealed state, high-temperature tempering, solution treatment.
The steel is no longer specially heat treated after hot rolling or forging. And then direct delivery after cooling. Its temperature is generally 800~900°C.Due to the surface covered with a layer of iron oxide, it has a certain degree of corrosion resistance. Its storage and transportation requirements are not too strict.
Cold-formed steel that has been cold-drawn, cold-rolled and delivered directly without any heat treatment. Its named cold drew or cold rolled. Compared with the hot rolled state. Its steel has high dimensional accuracy, good surface quality and low surface roughness. And it has high mechanical properties.
But its packaging, storage and transportation have strict requirements. Its surface has no oxide film covering. It generally needs to be kept in the warehouse, and at the same time, should pay attention to the temperature and humidity control in the warehouse.
The steel is subjected to normalizing heat treatment before leaving the factory, and the delivery state is called a normalized state. Its steel structure and performance are uniforms.It has a high comprehensive mechanical property.
Annealing is the process of heating the steel to a sufficiently high temperature to relieve local internal stresses. It does not create a general softening of the product but only locally relieves strains and stresses locked up within the material. Annealing goes through three phases: recovery, recrystallization, and grain growth. The temperature required to anneal a particular steel depends on the type of annealing to be achieved and the alloying constituents.
The steel is then tempered, which is just a specialized type of annealing, to reduce brittleness. In this application, the annealing (tempering) process transforms some of the martensites into cementite or spheroid and hence it reduces the internal stresses and defects. The result is more ductile and fracture-resistant steel.
At last, it is the solution treatment. Through solution treatment, a single-phase austenite structure is obtained. To improve the toughness and ductility of steel and create conditions for further cold working (cold rolling or cold drawing)It can also prepare for further precipitation hardening.
Finally, I make a summary of it. Because of the various delivery conditions, there are various types of steel produced. Because of this, steel can be applied to various fields. Due to the continuous development of steel, we have made great progress in the industry. In other words, steel indirectly promotes social development.
To truly understand what is steel is really important. It could make us get better in the business part.
The steel delivery process can be divided into six parts. As follows, hot rolled condition, cold pull, normalizing state, annealed state, high-temperature tempering, solution treatment.
The steel is no longer specially heat treated after hot rolling or forging. And then direct delivery after cooling. Its temperature is generally 800~900°C.Due to the surface covered with a layer of iron oxide, it has a certain degree of corrosion resistance. Its storage and transportation requirements are not too strict.
Cold-formed steel that has been cold-drawn, cold-rolled and delivered directly without any heat treatment. Its named cold drew or cold rolled. Compared with the hot rolled state. Its steel has high dimensional accuracy, good surface quality and low surface roughness. And it has high mechanical properties.
But its packaging, storage and transportation have strict requirements. Its surface has no oxide film covering. It generally needs to be kept in the warehouse, and at the same time, should pay attention to the temperature and humidity control in the warehouse.
Annealing is the process of heating the steel to a sufficiently high temperature to relieve local internal stresses. It does not create a general softening of the product but only locally relieves strains and stresses locked up within the material. Annealing goes through three phases: recovery, recrystallization, and grain growth. The temperature required to anneal a particular steel depends on the type of annealing to be achieved and the alloying constituents.
The steel is then tempered, which is just a specialized type of annealing, to reduce brittleness. In this application, the annealing (tempering) process transforms some of the martensites into cementite or spheroid and hence it reduces the internal stresses and defects. The result is more ductile and fracture-resistant steel.
At last, it is the solution treatment. Through solution treatment, a single-phase austenite structure is obtained. To improve the toughness and ductility of steel and create conditions for further cold working (cold rolling or cold drawing)It can also prepare for further precipitation hardening.
Finally, I make a summary of it. Because of the various delivery conditions, there are various types of steel produced. Because of this, steel can be applied to various fields. Due to the continuous development of steel, we have made great progress in the industry. In other words, steel indirectly promotes social development.
To truly understand what is steel is really important. It could make us get better in the business part.
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