The research on the sorting technology of ferromagnetic material
Ferromagnetism materials are used widelybut different alloy content of the materials lead to different properties and
applications.For example,if highpressure boiler tubes using the common pipe materials,it will reduce the service life,
even serious accidents.So,different materials must be sorted out in the production of ferromagnetic material.
There are some conventional sorting technologies of materials.Such as artificial spark identification method,
spectroscopy method and chemical analysis method and so on.These methods can sort out materials which can’t
meet the demand,but they are slower in the analysis,vulnerable to emotional impact of testing personnel，not suitable
for high-speed testing of ferromagnetic materials online.I researched a ferromagnetic material sorting technology,
which is based on the initial permeability of the material.The secondary coil reflect to the primary magnetic field through
the ferromagnetic material differ because of different initial permeability of the material.According to the phenomena，we can identify the ferromagnetic material grade and sort it.This technology is more faster,more accurate,less affected
by human compared with the conventional methods.The technology can be used for pipelines,bearings and other steel
products sorting.The technology is important for improving product quality and production efficiency of ferromagnetic material.
The main research work are listed as follows:
1、A study of the principle，the advantages and disadvantages of several conventional ferromagnetic material sorting technology.By analyzing the magnetic properties of
ferromagnetic materials we can know:The composition of the ferromagnetic materials determine the initial permeability，alloy percentage of ferromagnetic material differ from the initial permeability.The technology is ideal for highspeed production
line,sorting online.
2、I researched the principle and structure of comparison sorting system based on the initial permeability principle.
This system is composed of three parts:the reference unit,identification unit,instrument unit.Detection unit and the identification
of identical units have exactly the same mechanical structure and magnetic detection equipment.Tested materials and
standard materials wereidentified through the reference unit and identification unit produces two induce voltage.
Comparativeanalysis between the two voltage signals to achieve material sorting.
3、Designed signal processing hardware circuit with low noise chip AD8221 and TL062，which can effectively
suppress common mode interference，amplify and filter the differences of two signals.In order to achieve
identification of steel grade，we also need to do experiments to obtain different data of the relevant steel
grade and put these data into thedatabase.At the same time,we also give the major technical indicators of
ferromagnetic material sorting system.
4、There are lots of noises existing in the system.These noises can be overcome and reduce by shielding,isolating
and using high performance components.I briefly introduced LMS and NLMS algorithm principle,and then used
the NLMS algorithm for superior performance,using simulation tools to study the adaptive noise canceling system.
