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HOME > Quality
Control |
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| Quality
Control |
Production quality control
at Tiancheng is continuously exercised by specialists
independent of production divisions - Technical
Control Dvi. (TCD). The TCD checks compliance
of production technology as well as the production
quality during all the production phases stipulated
by technological procedures.
Since 2004 an independent Quality Inspection Service
has been working at the Mill; this Service presents
the interests of the main shareholder – Company
“Tiancheng”. The Company holds continuous inspectorial
checks of engineering procedures of tube production,
quality control and technical acceptance of integrated
products in accordance with normative-technical
and technological documentation of ASTMs, TU and
other International Standards. Upon identification
of the defected goods or usage of low-quality
material, the inspectors draw up the Reports of
Checks and send them to the Management of Company
"TIANCHENG".
In accordance with requirements of Technical Documentation
of ASTMs, Engineering Specifications, International
Standards-Specifications all the production of
AISI undergoes the following kinds of checks:
Visual inspection of external and internal tube
surfaces
Visual inspection of external and internal surfaces
is stipulated by the requirements of applicable
Standard Technical Specifications and is obligatory
for all kinds of tubes.
Inner surface control
Instrument check of inner tube surface is carried
out by means of endoscope along the full length
of tube with x4 magnification of section of examined
surface. The tubes small with inner diameter not
permitting endoscope usage are checked at short
samples taken from these tubes and cut along the
generatrix.
Wall thickness control
Check of tube wall thickness is done at both ends
of tube by means of tube micrometer MT-0-25. If
specific Technical requirements are stipulated
by the Customer, such control can be carried out
in a continuous way by automatic ultrasonic devices.
Outside diameter control
External tube diameter is checked in several cross
sections of tube with micrometer MK depending
on tube diameter or by fixed calibrated gauge
not less than in two opposite cross sections.
The automatic control of external tube diameter
is carried out by ultrasonic equipment simultaneously
with the check of wall thickness and tube metal
homogeneity.
Inside diameter control
Check of inside diameter is done at both ends
of tube manually by special gauge, prepared acc.
to the Specification requirements. Automatic control
by ultrasonic equipment is used only for the tubes
with severe applications.
Tube straightness control
Straightness of tubes is insured by production
process used at ASTM.accordance with Standards
or Customer requirements the measurements are
carried out manually by using specific gauges
and inclined plane at which tubes are rolled down.
Tube length control
The length of tube is checked by means of tape-measure,
taking into account the tolerances stipulated
by the Specification, when tubes are cut to fixed
lengths – the measuring is carried out using the
length specimen.
Steel quality control
Correspondence of chemical composition to steel
qualities is guaranteed by the manufacturer of
the billets.
Chemical composition of round billets arriving
to the mill is checked for conformity with steel
quality using two control methods: qualitative
method of styloscoping and quantitative chemical
analysis. |
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