Good Workmanship Cutting Tool Spring Steel Alloy Round Bars

Also known as wind steel or front steel, also known as white steel. It means
that when quenched, it hardens even when cooled in air and is sharp. It is a
complex alloy steel containing carbide-forming elements such as tungsten,
molybdenum, chromium, vanadium, and cobalt. The total amount of alloying
elements is about 10 to 25%. It can still maintain high hardness under high
heat generated by high-speed cutting (about 500 ℃), and the HRC can be above
60. This is the most important characteristic of high-speed steel - red
hardness. After quenching and low-temperature tempering, carbon tool steel has
high hardness at room temperature, but when the temperature is higher than 200
°C, the hardness drops sharply, and the hardness at 500 °C has dropped to a
similar level to the annealed state. , completely lost the ability to cut
metal, which limits the use of carbon tool steel to make cutting tools. High-
speed steel, due to its good red hardness, makes up for the fatal shortcomings
of carbon tool steel and can be used to manufacture cutting tools.
High-speed steel generally does not do tensile strength testing, but mainly
metallographic and hardness testing.
After the correct heat treatment of tungsten and molybdenum high-speed steel,
the Rockwell hardness can reach above 63, and the cobalt high-speed steel is
above 65. The acid leached low-magnification structure of the steel shall not
have shrinkage cavities and skin turns visible to the naked eye. The center is
loose, and the general looseness should be less than grade 1.
The content of metallographic inspection mainly includes three items:
decarburization layer, microstructure and carbide inhomogeneity.
1. High-speed steel should not have obvious decarburization. The microstructure
must not have fishbone-like eutectic ledeburite.
2. Carbide inhomogeneity in high-speed steel has the greatest impact on
quality, and the metallurgical and mechanical departments attach great
importance to the level of carbide inhomogeneity. Different grades of carbide
non-uniformity requirements can be put forward according to different uses of
steel, and usually should be less than grade 3.
3. In addition to high hardness, high wear resistance and sufficient toughness,
another important factor is the red hardness of high-speed steel for
manufacturing cutting tools. (Red hardness refers to the ability of the cutting
edge to resist softening under red heat when the tool is cutting at high
speed.)
One way to measure the red hardness is to first heat the steel to 580-650°C,
keep the temperature for 1 hour, then cool it down, and measure its hardness
after repeating this for 4 times. The quenching temperature of high-speed steel
is generally close to the melting point of the steel. After quenching, it is
generally necessary to temper 3 times between 540 and 560 °C. Increasing the
quenching temperature can increase the red hardness of the steel. In order to
improve the service life of high-speed steel tools, the surface can be
strengthened, such as low-temperature cyanidation, nitriding, sulfur-nitrogen
infiltration, etc.
songshunmoldsteel41404340

Minimum Order: 1 tons

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