| 摘要 |
A method consisting in converting a coil of hot-rolled band steel for tools and razor blades into an open coil in which its convolutions are spaced apart from one another, and immersing the open coil in a series of salt baths. First of all, the open coil is immersed for 5 to 30 minutes in a salt bath held at a temperature in a range from 550 DEG to 750 DEG C. to preheat the open coil and cause preliminary precipitation of carbides. The preheated open coil is immersed for 5 to 30 minutes in a salt bath held at a temperature in a range from the temperature immediately above Acl point to the temperature of Acl point plus 50 DEG C. to make the band steel austenitic in structure. The open coil is then immersed for over 10 minutes in a salt bath held at a temperature in a range from the temperature immediately below Arl point to the temperature of Arl point minus 80 DEG C. so that the isothermal transformation may be completed. Finally, the open coil is immersed for 3 to 10 minutes in a salt bath held at a temperature in a range from 600 DEG to 650 DEG C. and air cooled thereafter. The method enables to produce band steels for tools and razor blades which contain carbides occurring in a small spheroidal structure of uniform size, have good cold-workability, have freedom from decarburizing and carburizing, and have high amenability to hardening. |
