High Carbon Steel - Performance Analysis
The advantages of high-carbon steel
1, a high hardness can be obtained (a 65 to HRC60) and better wear resistance after heat treatment.
2, moderate hardness in the annealed condition, has good machinability.
3, readily available raw materials, low production costs.
The disadvantage of high carbon steel
1, hot hardness difference, when the tool operating temperature is greater than 200 ℃, its hardness and wear resistance dramatically.
2, low hardenability. When water quenched completely hardenability diameter is typically only 15 to 18mm; when complete quenching oil quenching maximum diameter or thickness (95% martensite) is only about 6mm, and easy to crack deformation.
High carbon steel hardness, strength depends mainly on the amount of carbon in solid solution in the steel, and with the increase of dissolved carbon content increased. When the solid solution carbon amount exceeds 0.6%, no further increase in the hardness after quenching, but an increase in the number of excess carbides, a slight increase in abrasion resistance of the steel, and ductility, toughness and elasticity decrease. For this reason, often according to the use conditions and the strength of steel, toughness matching selection of different steel. For example, manufacturing discontinuity large parts of the spring or reed, select a lower carbon content of 65 steel. High carbon steel is generally available electric furnace, open-hearth furnace, oxygen converter production. Furnace can be higher quality or special quality plus vacuum consumable smelting or remelting. When the rule of melting, strict control of chemical composition, especially sulfur and phosphorus content. In order to reduce segregation, etc. to improve performance, high-temperature diffusion annealing ingot can be (especially important for tool steel). Thermal processing, eutectoid steel stop forging (rolling) require low temperature (about 800 ℃), after forging rolling timber to avoid precipitation of coarse carbide network, the following should be noted that 700 ℃ slow cooling to prevent heat stress causing cracks. Heat treatment or thermal processing to prevent surface decarbonization (spring steel is particularly important). Have sufficient compression ratio during hot working to ensure the quality and performance of steel.