Steel grades for going further with gas quenching

Steel grades for going further with gas quenching

Steel grades for going further
with gas quenching
Quar terly - no. 6 - July 2008
inside pages
Custom-made
ASCOMETAL grades
45
Steel grades for going
further with gas quenching
40
ecm
,
specialist
in
low
carburizing
"Low-pressure carburizing
is geared to the needs
of the Japanese market"
back page
30
-pressure
Asahi Chiyoda Kogyo, customized
heat treatment specialist
Asahi Chiyoda Kogyo, with its general manager
Kenji Sasaki (center), has convinced its customers
that gas quenching is an efficient technique.
35
Even stronger
25
20
15
The automobile industry deserves
recognition as being the first
to invest substantially in lowpressure carburizing. The growing
role of ICBPs in the aeronautics
industry is a clear sign of approval
by the industrial community,
from hydraulic component
manufacturers to gear motor
specialists.
Usual gear parts
steel grades
1
3
5
15
20
25
Depth (mm)
Custom-made Ascometal grades eliminates
the point of inflection that indicates
heterogeneous structure and hardness.
JOMASCO® steel grades
Cooling curves
900
800
700
Perlite
Austenite
But the most tangible proof that
this technology is expanding is
evident with contract processing
firms. In this service market, the
flexibility of our ICBPs combined
with the quality of treatment give
them a real competitive edge. As a
result, these service-providers are
constantly expanding the use of
low-pressure carburizing into new
industrial sectors, which in turn
benefit from its quality standards
and attractive price.
600
500
Bainite
400
Martensite
300
200
100
0
1
10
100
1000
10000
Time (s) (logarithmic scale)
CCT diagrams: avoiding both ferrite
and perlite phases.
Deflection on gear box shaft
30
25
Maximum range
20
Average
deflection
15
www.agence-arca.com
10
5
Therefore, both directly and
via customized heat treatment
specialists, we are diversifying in
order to strengthen our position,
while the automobile industry
finds us an even stronger partner.
We’ve come full circle…
0
MoCr4
Oil
quenching
350 HV
MoCr4
JOMASCO®20
6 bars gas
6 bars gas
quenching
quenching
280 HV
370 HV
Preserved hardness and reduced
deformation: the end of a dilemma.
Headquarters: ECM France
Technisud
38029 Grenoble cedex 2
France
Tél. : +33/(0)4 76 49 65 60
Fax : +33/(0)4 38 49 04 03
E-mail : [email protected]
International contacts:
ECM USA : +1/262 605 4810
ECM China : +86/10 858 02642
ECM Japan : +81/3 6848 6187
Gilles Roland
ECM chairman
Figure of the Quarter
Hardness and controlled deformation: overcoming the dilemma
Maintaining hardness and drastically
reducing deformation in comparison
with oil quenching – the combination of gas quenching and special
steel grade scores high marks and
deserves a word of explanation.
The JOMASCO® range of grades is
characterized by a Jominy hardenability curve (relating hardness to
depth) that is straight and has an
even gradient. There is no point of
inflection as in the case of curves
for conventional grades, indicating
that their structure and hardness
are heterogenous. For this reason,
the transformation fields visible
on the continuous cooling transformation diagrams are modified
and tend towards a homogeneous
Respective benefits
bainite-martensite structure at the
The measurements performed on these
end of quenching, avoiding both
gearbox shafts, which are extremely subferrite and perlite phases. "These
ject to deformation, give a clear idea of
two curves are the grade’s ID card"
the respective benefits of
explains Olivier Finot.
Choosing
adopting gas quenching
Lastly, to validate
and changing steel grade.
the grade and their tests, ECM
With the original material defining the gas and Ascometal use a
(MoCr4), changing from oil
C-shaped trial sample
quenching
quenching to moderateof varying thickness
procedure go
pressure gas quenching
to measure all the
hand in hand
(6 bar) reduces deflecparameters involved.
tion on average by half and reduces the
maximum range to roughly a third (from
The combination of gas quenching
27 o 10 hundredths of a millimeter). The
and specific steel grade means that
slower cooling kinetics helps to ensure a
it will no longer be necessary to
more consistent temperature throughout
choose between hardness and conthe entire part, particularly during martrolled deformation. This innovative
tensitic transformation, and thus limits
approach is based on a comprehendeformation.
sive process. "Work must start as
early as possible in the process. DeHowever, as shown by the continuous
signing the part, choosing the grade
cooling transformation diagrams relating
and defining the gas quenching
quenching speed, hardness and strucprocedure must go hand in hand"
ture, this slower cooling produces a lower
explains Olivier Finot. It is worth the
level of hardness. The choice of a specific
effort. Controlling deformation after
grade designed for these quenching conquenching significantly reduces the
ditions is therefore justified. "It means
time needed to rectify the shafts
we can achieve the desired hardness"
and slashes the reject rate. These
confirms Olivier Finot. By using a grade
improvements also reduce engine
®
developed by Ascometal, JOMASCO
noise when the vehicle is being used
and ultimately make driving more
20, instead of MoCr4 for these gearbox
comfortable.
shafts it is possible to achieve 370 HV
hardness after gas quenching at 6 bar.
Jominy Curves
50
Design & production
This is in line with the specifications
defined for the reference situation
with oil quenching. At the same time,
deformation is controlled even more:
the average deflection is reduced to
0.02 mm with a maximum of less
than 0.04 mm.
HRC hardness
G
as quenching has led to significant progress being made in
terms of mechanical properties
and deformation control. This is also due
to the flexibility of the process, the intensity of which can be
modulated, enabling
the quenching cycles
to be adapted to the
actual material. It is
also possible for even
greater improvements
to be made by changOlivier Finot, ing the material. This is
technical relations
engineer at Ascometal: the aim of a coopera"Work must start as early tion agreement signed
as possible in the process"
between special steel
maker Ascometal and ECM, which has
led to the development of a range of
specific grades for gas quenching, the
benefits of which have been confirmed
in industrial applications. "By changing
steel grade when it’s converted to gas
quenching, Mercedes reduced the reject
rate for its gearbox shafts from 10% to
virtually nothing" states Olivier Finot, technical relations and development engineer
at Ascometal.
from
Customized heat treatment
specialist TTN devotes a unit
to low pressure
Less deflection on shafts leads
to noise reduction in transmissions.
Temperature (°C)
Gas quenching has major potential for reducing deformation, as the intensity of the process can be modified. The use of specific steel grades, such
as those developed by Ascometal with support from ECM, reveals the
potential of the process and leads to a near-zero rejection rate.
magazine
78 %
of pump bodies
produced for
common rail
diesel injection in the
automobile industry
are treated by ICBP.
The Japanese customized heat treatment specialist Asahi Chiyoda
Kogyo has been using an ICBP oil and gas quenching furnace at
its Toyohashi site since 2000. We take an in-depth look at the
lessons learned and prospects, based on an interview with general
manager Kenji Sasaki.
W
tory. The process offers customized heat
hen Asahi Chiyoda
treatment specialists several advantages
Kogyo installed a douover conventional technologies. In addition
ble-cell horizontal ICBP
to enhancing efficiency in terms of hardat its Toyohashi site in 2000, it beness, it is easier for operators to use: "The
came one of the first Japanese cuscooled walls and absence of oil smells are
tomized heat treatment specialists
real plus points,” explains
to use low-pressure
the manager. “And operators
carburizing. "This soNow
familiar
quickly get to grips with the
lution was rolled out
in collaboration with to components graphical user interface."
manufacturers The high investment cost
one of our customof an ICBP is also offset by
ers, to provide heat
lower operating costs. Preventive maintetreatment for a new type of more
nance is carried out in-house by the treatcompact transmission system with
ment specialist, while annual servicing is
highly exacting hardness requireoutsourced to Parker Netsushori Kogyo,
ments", explains general manager
ECM’s partner in Japan.
Kenji Sasaki. At Toyohashi (Aichi
Prefecture in central Honshu, a major Japanese automobile industry
center), the ECM solution perfectly
complements the five existing traditional batch furnaces: "Atmospheric
carburizing is still our main activity,
but the ICBP is playing an ever greater role in meeting our customers’
increasingly exacting requirements,
especially for batch production", explains Kenji Sasaki.
Low-pressure carburizing is now familiar to Japanese component manufacturers, some of whom have been
to visit Asahi Chiyoda Kogyo’s fac-
Toyohashi
Suite >
APPLICATIONS
a
w
Straightness distortion (x 102 mm)
TECHNOLOGIES
ECM-Ascometal partnership
Continued from page 1
...geared to the needs of the Japanese market.
also be able to increase efficiency
Developing gas quenching
by taking advantage of the ICBP’s
Asahi Chiyoda Kogyo is particularly
modular features, which customaware of the prospects opened up by gas
ers sometimes have difficulty unquenching, which is still very much a niche
derstanding; some request that a
area in Japan. "Gas quenching is a very
given part always be treated in the
interesting alternative to oil quenching,”
same cell, for instance. "Along
explains Kenji Sasaki. “It
with ECM, we have to prove them
eliminates costly washthat the ICBP guarantees highly
ing and post-treatreproducible results from one
ment operations,
cell to another", stresses Kenji
representing
a
Sasaki.
saving of more
than 50% on total
In these conditions, low-pressure
quenching costs."
carburizing is sure to become a
The treatment spestrategic resource on a Japancialist has convinced its
ese market making increasingly
initially skeptical customspecific and exacting demands.
ers that gas quenching is an
Asahi Chiyoda Kogyo is standing
efficient technique. For the time
by for the imminent arrival of the
being the quenching pressure is limitnew-generation hybrid vehicles,
ed to 10 bars, which means this technolwhose transmission parts will
ogy can only be used for certain steels,
no doubt need to
but Asahi Chiyoda Kogyo has
be treated using
every intention of broadenA saving
low-pressure carbuing the use of gas quench
of more than
rizing if they are to
to include all parts treated
50% on total
reach the required
using the ICBP: "ECM Japan
is striving to obtain a Japa- quenching costs performance levels. "Low-pressure
nese certification that will alcarburizing is geared to the
low us to increase quenching pressure to
needs of our market,” Kenji Sa20 bars, which is high enough for most of
saki concludes. “What’s more,
the steels used."
some of our customers have
suggested integrating ICBPs
Productivity levers
on-line at their own plants for
In addition to developing gas quenching,
larger production runs!" The key
the customized heat treatment specialto success for the customized
ist has several levers for optimizing the
heat treatment specialist will
use of its ICBP even further – starting
increasingly depend on its abilwith the heat treatment temperature,
ity to treat the most specialized
currently set at 950°C. "We are considparts with optimum response
ering the possibility of increasing the
times and competitiveness. ICBP
temperature to 980°C. This would enable
makes this possible.
us to reduce the treatment time by 30%,
which will save more than five hours on
certain parts!" Asahi Chiyoda Kogyo will
ICBPs in all sectors
The first quarter of 2008 confirmed
that new sectors are interested in lowpressure carburizing. These include the
aeronautics industry, with Turboméca
(France), gear-motor production with
SEW (also in France) and hydraulics with
Sun Hydraulics in the United States.
Automobile gear assemblies also remain
in the forefront: in India, AVTEC purchased
its first ICBP to produce a very low-cost
vehicle; while in China, SAGW purchased
a new one.
ECM certified by Lloyd’s
Register Quality Assurance
In early 2008, ECM received certification
for compliance with the ISO 9001 v2000
quality standards by Lloyd’s Register
Quality Assurance. This certification bears
witness to our constant efforts in applying
and managing our quality system at all
stages of production in our installations.
Our test facility relocated
to headquarters
In early April 2008, we moved our test
facility a few kilometers to our headquarters
in Grenoble. Reserved for tests on behalf
of our existing and prospective customers,
it features an ICBP fitted with heating
and gas quenching cells, and a laboratory
for measuring and analyzing the results.
A genuine showcase for our technology
incorporating the very latest in our
solutions, it is integrated into our workshop
and can thus be used
for evaluating processes
such as Low Pressure
Carbonitriding® or step
quenching in "real"
conditions.
Discover ECM’s innovations
Step quenching, carbonitriding,
improvements in mechanical properties: after
the success of the 36th heat treatment and
surface treatment congress (A3TS) held from
11th to 13th June this year in Tours (France),
ECM’s innovations continue their world tour
this fall and will be showcased at several
banner events. Book the dates now!
• Europe: HK 2008 – AWT Congress,
Wiesbaden, Germany, 8-10 Oct. 2008
• China: 13th International Exhibition on
Heat Treatment, Shanghai,
28-30 August 2008
• United States:
- ASM – “Quenching & Control of
Distortion in Heat Treated Gears“,
Milwaukee, WI, 24-25 Sept. 2008
- "Furnaces North America" conference,
Nashville, TN, 21-22 Oct. 2008
Standing by for the arrival of the new-generation hybrid vehicles’ transmission parts
• Japan: 17th Congress of the International
Federation of Heat Treatment and
Surface Engineering (IFHTSE),
Tokyo, 27-30 Oct. 2008
Customized heat treatment
specialist TTN devotes
a unit to low pressure
Two years after first investing in low pressure, TTN, one of Italy’s largest
customized heat treatment specialists, is adding a new cell to its facilities.
This increases the capacity of the unit TTN has dedicated to this technology,
betting that the flexibility of the process will satisfy customers.
T
Ernesto Pirovano,
TTN chairman and
founder: "We pushed
ECM to innovate"
excellent product quality - repeathe commissioning of a
ably. That justifies a change in tech3-cell ICBP in June 2006
nology and, although the treatment
marked the launch of lowcost is a bit higher, this is offset by
pressure carburizing at TTN. It
the savings made on the straightenwas an ambitious investment
ing phases". So the customers are
for this Italian customized
satisfied, especially the main ones,
heat treatment group, which
the automobile manufacturers. "We
employs 200 people on six
were heartily congratulated by Mersites and offers a wide range
cedes managers when they came
of traditional services to the
to visit. They were impressed by our
mechanical and metallurgical
site and with our facility set up in
industries. TTN was won over
a dedicated unit," says a delighted
by the technology and made
Excellent product quality - repeatably
Pirovano.
the investment before having
the volumes to treat, gambling
Lights out
that the venture would be a commercial success.
The customized heat treatment specialist has set up
The gamble has paid off, thanks to the flexibility of
its dedicated low-pressure carburizing unit at its site
the processes. TTN is now increasing its treatment
in Nerviano, near Milan. The facility has been incorpocapacities further by installing a fourth heating
rated into a group of automated processes including
cell. Vacuum carburizing now represents 15% of its
tempering and washing. Here again, TTN has gained
activity and 30 to 40% of its customers entrust it
flexibility, which its manager describes with underwith low-pressure treatments, particularly for autostandable pride: "The modular nature of the facility
mobile pinions.
enables us to program complete cycles for several
loads of different types in parallel. And the ICBP has
Pushing ECM to innovate
proved sufficiently reliable for us to operate it at night,
Before taking the plunge, TTN had duly checked
with the lights out and no operators present".
that low pressure could be proposed in as many
cases as possible – a maximum requirement in
With the addition of a fourth cell, TTN appreciates the
terms of flexibility. The faflexibility of the technology from another angle: gradcility selected naturally ofA maximum
ual growth, in line with its strategic objectives. It must
fered a choice of vacuum,
requirement in
be said that the customized heat treatment specialist
propane or acetylene heat
terms
of
flexibility
has no intention of stopping there: "Our ultimate aim
treatment, as well as two
is to have three treatment areas, each equipped with
quenching options, with
six cells", reveals Ernesto Pirovano.
oil or gas. But the heat treatment firm pushed ECM
even further, demanding an industrial capacity never seen before. This commenced the first ICBP capable of swallowing up loads weighing 750 kg and
reaching 1200°C, saving precious time when treating certain steels. "We have chosen a configuration
capable of offering a huge array
of services to satisfy even our
most demanding customers,"
explains Ernesto Pirovano, company chairman and founder.
Pinion, gear box, transmission
and steering components are
where TTN’s ICBP earned its
stripes. "Component manufacturers face serious deformation
problems on this type of part,”
explains Ernesto Pirovano. “On
the other hand, low-pressure
treatment is a means of obtaining
Sufficiently reliable to operate at night, with no operators present
APPLICATIONS
APPLICATIONS
Italy