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Surface Treatment Technology for Automotive Parts Dr.-Ing. Patiphan Juijerm Materials Innovation Center, Kasetsart University 1 20-21June 2013 BITEC, Bangkok -Thailand
Surface Treatment Technology for Automotive Parts
Dr.-Ing. Patiphan Juijerm
Materials Innovation Center, Kasetsart University
1
20-21June 2013
BITEC, Bangkok -Thailand
2
Introduction to Surface Treatments
Surface Treatments in Thailand
Interesting Surface Treatments for Automotive Industry
Seriously Required Technology and Knowledge
Contents
3
Introduction
Localized surface
hardening (flame,
induction hardening)
Shot peening
Deep rolling
Laser shock peening
Surface treatment / coating types
Changing the
surface metallurgy Changing the
surface chemistry
Adding a surface
layer or coating
Carburizing
Nitriding
Carbonitriding
Boriding
Aluminizing
TRD / TD
CVD
PVD
Thermal spraying
Plating
4
Objectives of surface treatment
Anti-corrosion
Anti-wear
Anti-fatigue
Main objectives Optical
Electrical
Magnetic
Other objectives
For many automotive parts
Introduction
5
Surface Treatments
Anti-wear surface treatments Flame or induction hardening Carburizing process Nitriding process Carbonitriding process Boriding process
These surface treatment processes are mainly used and well known in Thailand.
6
Surface Treatments
FLAME or INDUCTION HARDENING is a heat-treating process in which a thin surface
shell of a steel part is heated rapidly to a temperature above the critical point of the steel.
After the grain structure of the shell has become austenitic (austenitized), the part is
quickly quenched, transforming the austenite to martensite while leaving the core of the
part in its original state.
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Surface Treatments
CARBURIZING is a case-hardening process in which
carbon is dissolved in the surface layers of a low-
carbon steel part at a temperature sufficient to render
the steel austenitic, followed by quenching and
tempering to form a martensitic microstructure. The
resulting gradient in carbon content below the surface
of the part causes a gradient in hardness, producing a
strong, wear-resistant surface layer on a material,
usually low-carbon steel, which is readily fabricated into
parts. In gas carburizing, commercially the most
important variant of carburizing, the source of carbon is
a carbon-rich furnace atmosphere produced either from
gaseous hydrocarbons, for example, methane (CH4),
propane (C3H3), and butane (C4H10), or from vaporized
hydro-carbon liquids.
Carburized SCM 415
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Surface Treatments
NITRIDING is a case-hardening process
whereby nitrogen is introduced into the
surface of a solid ferrous alloy by holding the
metal at a suitable temperature (below Ac1,
for ferritic steels) in contact with a
nitrogenous gas, usually ammonia.
Quenching is not required for the production
of a hard case. The nitriding temperature for all steels is between 495 and 565 °C.
Because of the absence of a quenching
requirement, with attendant volume changes,
and the comparatively low temperatures
employed in this process, nitriding of steels
produces less distortion and deformation than
either carburizing or conventional hardening.
Nitrided tool steel SKD 61
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Surface Treatments
CARBONITRIDING is a modified form of gas carburizing, rather than a form
of nitriding. The modification consists of introducing ammonia into the gas
carburizing atmosphere to add nitrogen to the carburized case as it is being
produced. Nascent nitrogen forms at the work surface by the dissociation of
ammonia in the furnace atmosphere; the nitrogen diffuses into the steel
simultaneously with carbon. Typically, carbonitriding is carried out at a lower
temperature and for a shorter time than is gas carburizing, producing a
shallower case than is usual in production carburizing.
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Surface Treatments
BORIDING, or boronizing, is a thermo-
chemical surface hardening process that can
be applied to a wide variety of ferrous,
nonferrous, and cermet materials. The process
involves heating well-cleaned material in the range of 700 to 1000 °C, preferably for 1 to 12
h, in contact with a boronaceous solid powder
(boronizing compound), paste, liquid, or
gaseous medium.
Borided tool steel SKD 61
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Surface Treatments
Anti-fatigue surface treatments Shot peening process Deep rolling process Laser shock peening process
These surface treatment processes are not well established in Thailand.
Very interesting and much more required
processes for many automotive parts !!!
12
Surface Treatments
Anti-fatigue surface treatments Shot peening process Deep rolling process Laser shock peening process
Mechanical surface treatment
Very interesting and much more required
processes for many automotive parts !!!
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Surface Treatments
a localized near-surface plastic deformation
lo li lo
-
+
Mechanical surface treatment
- Compressive residual stresses
- Near-surface work hardening
- Increased dislocation densities
- Increased near-surface hardnesses
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Surface Treatments
Crack initiation (surface) Crack propagation
Tensile stress
(Fatigue) failure
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Surface Treatments
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Surface Treatments
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Surface Treatments
Ti6Al4V
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Surface Treatments Shot peening process
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Surface Treatments Shot peening process
Shot peening is a cold working
process used to produce a
compressive residual stress layer
and modify mechanical properties of
metals. It entails impacting a surface
with shot forcing sufficient to create
plastic deformation.
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Surface Treatments Shot peening process
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Surface Treatments Shot peening process
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Surface Treatments Shot peening process
not shot peened
shot peened 98% coverage
23
Surface Treatments Shot peening process
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Surface Treatments Shot peening process
25
Surface Treatments Deep rolling process
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Surface Treatments Deep rolling process
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Surface Treatments Deep rolling process
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Surface Treatments Deep rolling process
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Surface Treatments
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Residual stress
Crack Initiation
Crack Propagation
Crack Initiation
Crack Propagation
against
Seriously Required Technology and Knowledge
Origins of Residual Stress
Effects of Residual Stress
Methods of Measurement
etc.
Tensile Residual Stresses
Compressive Residual Stresses
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Seriously Required Technology and Knowledge
Mechanical Method
Hole Drill Method
Destructive Method
Residual stress
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Seriously Required Technology and Knowledge
Hole Drill Method
Residual stress
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XRD
unstressed
stressed
Residual stress
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XRD
ejy =1+u
Esj sin2y -
u
Es1 +s 2( )
ejy =dy - d0
d0
Residual stress
35
Seriously Required Technology and Knowledge
XRD
Residual stress
36
Hole Drill Method
Materials Innovation
Center
Faculty of Engineering
Kasetsart University
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Hole Drill Method
Dr.-Ing. Patiphan Juijerm (ดร. ปฏิภาณ จุ้ยเจิม)
Head of Materials Innovation Center,
Department of Materials Engineering
Faculty of Engineering, Kasetsart University
Tel: 02-942-8555 ext 2109, 2101-3
Mobile: 081-807-6894
Email: [email protected], [email protected]
Thank You
Thank You 38
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