Introduction
Carbon steel wire, also known as high carbon steel wire, is widely used in spring steel industry because of its good performance and durability. Carbon steel wire is mainly produced by quenching and tempering heat treatment process to improve its strength, toughness, plasticity, hardenability and other mechanical properties. The general process of quenching and tempering of carbon steel wire is as follows:
First of all, the raw material of carbon steel wire must be subjected to mechanical and chemical processes to meet the requirements of the national standard YB/t5103-1993 and the corresponding technical means. After the material meets the requirements, the preheating process for quenching should be carried out. Generally, it is preheated to 750-850℃ for 1.5-2.5h. During the preheating, the carbon steel wire should be protected from oxidation or overheating, and then cooled to room temperature with water or oil.
The second step of the quenching and tempering process is quenching. After preheating, carbon steel wire should be quickly immersed in the quenching liquid till its temperature drops to 1050-1060 ℃. The quenching liquid should be made of mineral oil or water-based emulsion. During this process, in order to ensure the uniformity of hardened steel wire, appropriate agitation should be added in the quenching liquid. And its quenching temperature should be controlled strictly according to the requirements of the drawings.
In the third step of quenching and tempering, the surface of hardened steel wire should be removed of oxide and scale, as well as water droplets. After that, carbon steel wire should be tempered. Generally, the tempering temperature should be about 500-700℃ for 1-2 h. During the tempering, it is necessary to prevent the overheating of carbon steel wire. When its tempering temperature exceeded 700℃, it should be reprocessed or abandoned.
Finally, to check the quality of carbon steel wire, the hardness test should be conducted. Generally, the hardness should be at least 10.5HRC. Besides, it is necessary to inspect the surface quality and check for cracks, burrs and mechanical damages.
Conclusion
In conclusion, carbon steel wire can be used in springs because of its high performance and increased durability after undergoing quenching and tempering heat treatment. The quenching and tempering process requires careful control of temperature and the use of water or oil to maintain the wires integrity. The hardened steel wire must then be tempered and checked for hardness, cracks, and other defects. With proper care and inspection, carbon steel wire can be used effectively in the spring steel industry.
