Transcript Analiza zmienności wybranych właściwości cyklicznych w

THE EFFECT OF HEAT TREATMENT ON
THE PROPERTIES OF ZIRCONIUM CARBON STEEL BIMETAL PRODUCED
BY EXPLOSION WELDING
Mariusz Prażmowski 1), Henryk Paul 2),
Fabian Żok 1,3)
1) Technical
University of Opole, Mechanical Department,
2) Institute of Metallurgy and Materials Science PAN,
3) ZTW Explomet,
xplomet
Presentation plan
1.
2.
3.
4.
5.
6.
7.
8.
Aim of the study
Research material
Characteristics of the received bonds
Heat treatment parameters
Mechanical properties of the claddings
Changes of hardness profile in the bonding zone
Analysis of the microstructure
Summation
2
Cladding processing operations
Straightening
Forming
Drilling
Welding
Aim of the study
The aim of the study is to analyze the effect of heat
treatment for changes of mechanical properties and
structural strengthening bimetals zirconium alloy steel
bonded by explosive welding method.
5
Research material
Zr 700
(gr.3,175 mm)
The chemical composition[%]
Material
Zr 700
C
Fe, Cr
H
O
Zr+Hf
N
< 0,002
0,05
< 0,0003
0,05
>99,2
< 0,002
Tensile strength
[MPa]
Yield strength
[MPa]
Elongation
[%]
Rm
R0,2
A
280
143
35
The chemical composition [%]
Material
P355LN2
P355NL2 (gr. 20 mm)
C
Mn
0,170
1,13
Si
P
S
Ni
Cr
Mo
Al
N
Nb
0,345 0,008 0,001 0,285 0,150 0,035 0,045 0,004 0,019
Tensile strength
[MPa
Yield strength
[MPa]
Elongation
[%]
Rm
R0,2
A
551
402
26,7
6
Research material
Zr 700 + P355NL2
(3,175 mm)+ (20 mm)
Deotantion velocity VD [m/s]
VD
1,3 VD
1,6 VD
Deotantion velocity VD [m/s]
Distance between plates h [mm]
2200
2800
const
3500
steel
steel
steel
7
The interface parameters for different VD
V [m/s]
Bond
length L
[μm]
Average
wave heigh
H [μm]
Average wave
length
n [μm]
Summary area of
meltins P [μm2]
The
equivalent
thickness of
meltings
RGP [μm]
12 685
58
454
5 596
0,46
1,3 VD
13 648
148
1002
137 484
10.06
1,6 VD
16 823
214
940
912 943
54,30
60
1000
50
800
40
30
RGP
H
n
600
400
20
200
10
0
wave parameters H, n [μm]
melt depth equivalent RGP [µm]
VD
Melt depth equivalent
where: P – summary area of meltings, [ µm2]
L – bondline length [ µm]
n – wave length [ µm]
H – wave heigh [ µm]
0
1,0 VD
1,3 VD
1,6 VD
-1
detonation velocity vD [m•s ]
8
Mechanical properties
Fig. Peel off specimen -RO
Clad + base material
Zr 700+ P355NL2
(3,175 mm)+ (20 mm)
Rys. Shear test
specimen - RS
Plate
Shear strength Rs
Peel off strength Ro
Tensile strength Rm
Rys. Tensile test specimen Rm
VD
1,3 VD
1,6 VD
MPa
Place
351
Zr
321
Zr
281
złącze
MPa
449
144
180
Place
Zr
złącze
złącze
MPa
544
563
184
Tab. Mechanical properties of claddings after joinig
9
The selection of heat treatment parameters
260
steel
zirconium
microhardness HV0,05
230
200
170
140
after cladding
500
650
-0,50
-0,25
400
550
700
450
600
0,00
0,25
110
0,50
distance from interface [mm]
Fig. Microhardness of bimetal for variable heat treatment temperature
10
The selection of heat treatment parameters
Tensile strength Rm [MPa]
500
450
Bimetal after HT
Zr 700
400
steel
350
300
250
400
450
500
550
600
650
700
Temperature HT [o C]
Fig. Tensile strength Rm of the bimetal for a variable heat treatment
temperature
11
The selection of heat treatment parameters
Stage I
temperature HT [oC]
600
Heating wit the furnace until
3000C within 35 min.
500
Stage II
400
Heating up to 6000C with
velocity 1000C/h.
300
Stage III
200
Annealing in 6000C over 90
min.
Stage IV
100
Cooling until 3000C with a
velocity 1000C/h.
0
0
90
180
270
time [min]
360
450
Stage V
Cooling in still air.
Fig. Course of the heat treatment
12
strenght: shear (Rs), stripping(Ro),
tensile (Rm) [MPa]
Testing of mechanical properties
600
562
Rs
Rm
Ro-HT
544
500
30-35%
15 %
449
400
300
396
390
351
387
321
293
340
281
281
200
184
180
159
144
100
0
Ro
Rs-HT
Rm-HT
10%
30%
53
53
1.0 VD
1.3 VD
1.6VD
detonation velocity vD [m•s-1]
Fig. Mechanical properties (strength: shear- Rs, peel off- Ro, tensile- Rm) off caldding
13
metal after joining (solid line) and after heat treatment (dotted line)
Fig. Microhardness distribution in bond
zone for different detonation velocities:
a) 1.0vD, b) 1.3vD, c) 1.6vD,
solid line- materiał w after „cladding”,
dotted line – after heat treatment
320
-0,50
260
1.3 vD HT
HT
1.3vD
45%
230
200
35-45%
-0,25
0,00
0,25
distance from interface [mm]
170
140
0,50
260
1.0vD
1.0 vD HT
HT
230
35%
200
35-45%
-0,25
0,00
170
140
0,50
0,25
zirconium
steel
microhardness HV0,05
microhardness HV0,05
-0,50
1.3 vD
1.3vD
1.0vD
1.0 vD
350
zirconium
290
290
distance from interface [mm]
320
steel
zirconium
steel
microhardness HV0,05
Strengthtening in bond
zone - (microhardness
HV0,05 )
-0,50
320
1.6 vD
1.6vD
1.6vD
1.6 vD HT
HT
290
260
50%
230
35-45%
200
170
-0,25
0,00
0,25
distance from interface [mm]
140
0,50
Strengthening in bond zone - (microhardness
HV0,05 )
steel
microhardness HV0,05
zirconium
1.0 vD
1.0vD
1.0 vD HT
HT
1.0vD
1.3 vD
1.3vD
1.6 vD
1.6vD
1.3 vD HT
HT
1.3vD
1.6 vD HT
1.6vD
HT
340
310
280
250
220
190
160
170 HV
-0,50
-0,25
0,00
0,25
130
140 HV 0,50
distance from interface [mm]
Fig. Microhardness distribution in bond zone for different detonation velocities –
summary graph. Measuring along 3 parallel lines trough the bond line (perpendicular
to the bond). Applied load: 50G.
Microstructular analysis
a
b
steel
c
Fig. Microstructure of bonding zone of
Zr700/P355NL2 bimetal, showing strong
deformation of subsurfaces of combined
plates: a) wave bottom, b) wave edge, c)
structure of bimetal after heat treatment.
steel
16
Summation
In work was analyzed the influence of thermal treatment on the mechanical
properties and structural changes in the bond zone of bimetallic sets of steel
plate P355NL2 (base plate) cladding with zirconium Zr 700 (clad plate)
performed by explosive welding technology.

On the basis of microscopic analyzes, it was observed that the increase in velocity
of detonation increases the height and length of the wave, and favors the growth
of the participation of melted area in the joint areas. This phenomenon has a
significant effect on the mechanical properties of the bimetal.

Analysis of the results of tensile strength tests, shear and ram test leads to the
conclusion that a small share of the intermetallic areas significantly increasing the
strength of the bond, while the increase in the RGP coefficient more than an
acceptable value, i.e. it means when the RGP >> 10um, results in a rapid
decreasing of mechanical properties.

Use of heat treatment causes a decrease in the mechanical properties of the
cladding element. However, in the case of bimetals with relatively small
participation of melted layer showing a relatively high mechanical properties. 17
Summation



The application of thermal treatment affect substantially to the value of
strengthening in the base material.
Reduction of mechanical properties and loss of strengthening near to the interface
after heat treatment is related to the observed in the microscopic study structural
changes in the bond zone.
Heat treatments causes the phenomenon of recrystallization, and lead to the
formation of equiaxed grain structure in the closest zone to border of bond.
18
Thank your for your
attention
“Scientific work financed from the budget for science in the years
2010-2013 as a research project”.
PhD student is a scholar of the project: PhD Scholarships - investment in Opole
province faculty co-financed by the ESF
19