Comparison of Advantages and Disadvantages of Bearing Steel and Carbon Steel
According
to the investigation and analysis of the research results show that bearing steel and carbon steel shaft although the shape is not very
different, but in essence their respective advantages and disadvantages
are very obvious. The following is a specific survey and analysis results:
First, in terms of service life. Their use of life time is very different, bearing steel, long service
life, many garbage bearings are carbon steel bearings, mainly hardness
and wear resistance are not as bearing steel bearings.
Second, in terms of wear resistance. Low-carbon steel surface hardening only in the surface carburizing, and not all quenching. Many low-grade carbon steel bearings on the market is not quenching hard, very poor wear resistance.
Third, in the process and the use of effects. Bearing
the use of good or bad effects and the use of the environment, not to
say that carbon steel bearing is not good, depending on which machinery
to use, because some do not need high-grade, with carbon steel bearings
on the right week. Of course, better but the cost of steel is much higher, the standard bearing steel is Gcr15.
Fourth, the bearing materials and performance. For
example, the bearing rings and the rolling elements are subjected to
high contact pressure repeatedly, and rolling contact is accompanied by
sliding, while maintaining high-precision rotation. Therefore,
the bearing rings, rolling and cage materials and performance to meet
the following requirements: high elastic limit; high rolling fatigue
strength; have high hardness; good wear resistance; toughness of the
impact load; Dimensional stability. In addition, but also good processing. Proven, bearing steel has the above required performance, but the carbon steel bearings can not be guaranteed. Fifth,
not to say that the advantages of carbon steel bearings have no bearing
steel is good nowhere available, and this depends on where used. Carbon
steel bearing noise, particularly short life expectancy, the pressure
is particularly small, but can be used in the hardness, speed limits are
relatively small place. Surface
strengthening technology can form a variety of classification methods
from different angles, according to the surface layer strengthening
technology of physical and chemical process classification, can be
divided into five categories: surface deformation strengthening, surface
heat treatment strengthening, chemical heat treatment strengthening,
surface metallurgy strengthening, surface film strengthen.
1, the bearing surface deformation strengthening
By
mechanical means to the metal surface layer of plastic deformation,
resulting in high hardness and high strength of the hardened layer, this
method is called surface hardening surface strengthening, also known as
work hardening. Including shot blasting, sandblasting, cold extrusion, rolling, cold grinding and impact, explosion and impact strengthening. Most of its methods have been applied in the bearing industry: the
impact of the surface of the rolling body is the application of such
methods, precision compaction has become a new processing and
reinforcement methods.
2, bearing surface heat treatment to strengthen
The
use of solid-state phase change, by rapid heating of the surface layer
of the quenching treatment known as the surface heat treatment, commonly
known as surface hardening. Including
flame heating quenching, high (medium) frequency induction heating
quenching, laser heating or electron beam heating quenching. These
methods are characterized by: the surface of the local heating
quenching, the workpiece deformation is small; heating speed, high
production efficiency; heating time is short, the surface oxidation
decarburization is very minor. The method is particularly effective for improving the wear resistance
and fatigue strength of large and extra large bearing parts subjected
to a certain impact load.
3, bearing chemical heat treatment to strengthen
The
use of an element of solid-state diffusion infiltration, to change the
chemical composition of the metal surface layer in order to achieve the
surface strengthening method known as the chemical heat treatment
strengthening, also known as the diffusion heat treatment. Carburizing bearing steel parts of the processing technology and
needle roller bearing nitriding surface treatment are enhanced this type
of strengthening method.
4, surface metallurgy to strengthen the bearing
Surface
remelting and solidification of the surface layer metal to obtain the
desired composition or texture is called surface metallurgy
strengthening. Including
surface self-dissolving alloy or composite powder coating, surface
melting and crystallization or amorphous treatment, surface alloying and
other methods. Rolling
bearing industry in the micro-bearing surface of the work done to
strengthen the study of laser heating, the effect is good. In this case,
5, the bearing surface film strengthening
Application
of physical or chemical methods, the metal surface coating in the
matrix material properties of different reinforced film, known as the
surface film strengthening. It
includes electroplating, electroless plating (chrome plating, nickel
plating, copper plating, silver plating, etc.) as well as composite
plating, brush plating or conversion treatment. It also includes the
rapid development of high technology in recent years: CVD, PVD, P-CVD Vapor
deposition thin film strengthening method and ion implantation surface
strengthening technology (also known as atomic metallurgy technology)
and so on. They
are common features are in the work surface to form a specific
performance of the film, to strengthen the surface of the wear
resistance, fatigue resistance, corrosion resistance and
self-lubricating properties. For
example, ion implantation technology to strengthen the bearing surface,
bearing surface can wear, corrosion resistance, and resistance to
contact fatigue performance have been significantly improved, so that
the bearing life will be multiplied.