ASTM A312seamless steel pipe

　　The hardness and strength of high ASTM A312seamless steel pipe are mainly determined by the amount of carbon dissolved in steel and increased with the increase of solid carbon. Solid solution carbon content of more than 0.6%, the hardness after quenching is no longer increased, but the excess amount of carbide increased, the wear resistance of steel increased slightly, while the plasticity, toughness and elasticity decreased. To this end, often according to the use of conditions and the strength of steel, toughness to match to use different steel. For example, the manufacture of small force spring or spring parts, you can choose a lower carbon content of 65 steel. General high-carbon steel available electric furnace, open hearth, oxygen converter production. Requirements of high quality or special quality can be used electric furnace smelting and vacuum self-consumption or electroslag remelting. Smelting, the strict control of chemical composition, especially sulfur and phosphorus content. In order to reduce segregation and improve isotropic properties, the ingot can be subjected to high temperature diffusion annealing (particularly important for tool steels)