TPT January 2013

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102 January 2013
Article
SDSF new material is first selected for straightening steel
pipe roll at home and also has full approval in the way of
selecting material for large scale HFW/ERW welding pipe roll
and cold roll formed steel roll at home and abroad.
The chemical composition system of SDSF material is
different from between the chemical composition of forging
steel roll and that of high chromium alloy roll for plate and
strip steel rolling.
4.2 Microstructure
The carbide of SDSF material is mainly M7C3, its
microhardness is up to 1800Hm. The microstructure
appeared as no continuous strip state, block state, particle
state and chrysanthemum state, and the content of carbides
about 20 per cent. According to service condition of various
roll the matrix is selected as austenite, bainite, martensite,
and mixing matrix of austenite, bainite and martensite etc.
The macrohardness is up to HRC 50-65. The matrix of D2,
X155CrVMo121 and SKD11 is martensite and the content of
M7C3 carbide is about 15 per cent.
4.3 Comparing hardness and quenching degree sampled
from product
See table 2.
Table 2: The compared hardness and quenching degree of new roll of SDSF with that of high grade similar roll in the world
Brand State
Average value
of
surface
hardness HRC
Hardness average
value
distanced 30mm
from surface
[HRC]
Hardness average
value
distanced 60mm
from surface
[HRC]
Hardness average
value
distanced 120mm
from surface
[HRC]
D2 Quenching,
tempering 59.5 59.6 59.9 59.8
X155CrVMo121 Quenching,
tempering 58.2 58.8 57.9 57
SKD11 Quenching,
tempering 57.7 57.3 57.1 54.6
SDSF
High chromium
alloy roll
Tempering for
eliminating stress 58.8 58.4 58.6 58
SDSF
High chromium alloy roll
Quenching,
tempering 60.1 59.9 59.5 59.3
Table 3: The compared mechanics property of SDSF new roll with that of high grade similar roll in the world
Brand State Sampled direction Tensile strengthMPa
Impact
toughness
J/cm2
D2 Quenching, tempering radial 733 3.1
X155CrVMo121 Quenching, tempering radial 711 3
SKD11 Quenching, tempering radial 750 3.5
SDSF
High chromium alloy roll Eliminating stress in casting radial 500 13.5
SDSF
High chromium alloy roll Quenching, tempering radial 540 7.5
4.4 Comparing mechanics property sampled from
product
See table 3.
4.5 Comparing wear resistance in the field: The result
is compared using the same equipment and rolled
same steel pipe
Comparing wear resistance on straightening mill of world’s
advanced heat treatment production line, see table 4.
The compare wear resistance on straightening mill of world’s
advanced Ф250MPM mills, see table 5.
4.6 Comparing wear resistance testing sampled from
product in the laboratory
See table 6
5 Summary
Persisting in taking the road of “speciality, precision,
characteristic and new” and “continuous innovation”,
persisting in taking the researching direction of “the problems
of customers and the problems in the field are our researching