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Effect of Temper Rolling on Tensile Properties of Low-Si Al-Killed Sheet Steel
Available online at www.sciencedirect.com
-'I
-;;, ScienceDirect JOURNAL OF IRON AND STEEL RESEARCH. INTERNATIONAL. 2009. 16(3): 64-67
Effect of Temper Rolling on Tensile Properties of Low-Si AI-Killed Sheet Steel MA Qing-long l
,
WANG Dong-cheng' ,
LIU Hong-min",
LU Hai-rning''
O. Education Ministry Engineering Research Center of Rolling Equipment and Complete Technology, State Key Laboratory of Metastable Materials Science and Technology, Yanshan University. Qinhuangdao 066004, Hebei , China; 2. Cold Strip Factory of Lingyuan Iron and Steel Group Co Ltd, Lingyuan 122500. Liaoning. China) Abstract: The tensile properties of steel after temper rollingare affected by the reduction; low-Si Al-killed sheet steel was taken to study the effect of temper rolling on the tensile properties. The results indicate that the yield strength first decreases with the increase of reduction. and then increases. The relationship between the yield strength and the reduction can be expressed using quadratic function. The tensile strength increases with the increase of the reduction, while the total elongation decreases with the increase of the reduction. and the relationship between them and the reduction can be expressed using power function. Under the same condition, the results also indicate that the yield strength and tensile strength of steels across the rolling direction are all larger than those along the rolling direction; there is no obvious distinction between the total elongation along the rolling direction and that across the rolling direction. Key words: temper rolling; yield strength; tensile strength; total elongation
The essential of temper rolling is a cold rolling process to annealed strip steel with slight reduction (0 - 3 %). The purpose is to improve the flatness, make the strip steel get a certain surface roughness and smoothness, improve the mechanical properties, and erase the yield point ios'". The reduction of temper rolling has significant effects[2-4] , therefore, the preset of reduction is restricted not only by the flatness and surface roughness of strip steel, but also by the mechanical properties. Little effort has been devoted to the relationship between the temper rolling reduction and the tensile properties, and most of them focus on qualitative analysis[5-7]. Low-Si Al-killed sheet steel is taken to study the relationship between the temper rolling reduction and tensile properties of strip steel in this article, which is the main product of Lingyuan Iron and Steel Group Co Ltd, to get the relationship between the reduction and the tensile properties such as yield strength, tensile strength, and total elongation
by regression analysis, and to conclude the mathematical model, which can guide the preset of temper rolling reduction.
1
Experimental Procedure
The low-Si Al-killed steel used in this study is 195LD, which is obtained from Cold Strip Factory of Lingyuan Iron and Steel Group Co Ltd. Its chemical compositions are given in Table 1 (in mass percent). The experiment is performed by WDWI020 electronic tensile machine of Yanshan University, and the load speed is 1 mm/min. The range of test samples reductions is 0 - 3 %, the thickness value of steel is 1. 0 mm , and the gauge length is 50 mrn, To compare, the test samples are cut along the rolling direction (lengthwTable 1 wCC) ~O.
08
%
Chemical composition of steel wCMn)
wCSi)
~O. 45
~O.
07
wCS) ~0.03
wCP) ~O.
Foundation Item: Item Sponsored by National Natural Science Fundation of China (50675186); Important Nature Science foundation of Heibei CE2006001038) Biograpby:MA Qing-longC1977-). Male. Doctor; E-mail: jyqlma@ysu. edu. en; Revised Date: December 11. 2008
025
Issue 3
ays direction) and across the rolling direction (transverse direction), to observe the change of tensile properties
with different reductions. The samples before and after the tensile experiment are shown in Fig. 1.
(a) Before tensile experiment;
Fig. 1
2 2. 1
• 65 •
Effect of Temper Rolling on Tensile Properties of Low-Si AI-Killed Sheet Steel
(b) After tensile experiment
Contrast of samples before and after the tensile experiment
appears. That is same for the variation of the transverse yield strength along with the change of the reduction. The results also indicate that the yield strength of transverse direction is larger than that of lengthways direction for about 25 MPa in the same condition. By regression analysis, the relationships between the yield strength and the reduction of lengthways direction and transverse direction can be expressed as Eqn. (1) and Eqn. (2) , (1:=252.96-27. 48E+13. 36E2 (1) rfi=277. 57-25. 99€+12. 35€2 (2) where, (1: is the lengthways yield strength, rfi is the transverse yield strength, and e is the temper rolling reduction. The first term on the right hand side of Eqn, (1) is 252. 96, which is quite close to the average yield strength of the lengthways direction (258. 62 MPa) without temper rolling. Similarly, the first term on the right hand side of Eqn, (2) is 277.57, which is quite close to the average yield strength of the tran-
Results and Discussion Yield strength
A notable influence of the reduction on the mechanical properties of the strip steel is to change the yield strength; an appropriate reduction can erase the yield point jog, and avoid to appear slip line during machining again[8]. The variation of the lengthways yield strength and transverse yield strength along with the reduction is shown in Fig. 2. When the value of temper rolling reduction is less than 1 %, the lengthways yield strength decreases with the increase of reduction; it decreases by about 12 MPa when the reduction is 1. 0 %, and the yield strength reaches minimal value here. The reason why the yield strength decreases is that the dislocation breaks the bondage of caldwell air mass. When the value of reduction is larger than 1 %, the yield strength increases with the increase of reduction; it is because the dislocation pinning increases gradually with the increase of reduction, and work hardening
t
t os
310
=
=290
~
~rIJ
:g
"0
Qi
">' ~
290
270
a:l
"~ 270 is
!!t
J
•
250 0
•
•
250
~
t =
•
••
~ 230
2.0
1.0
3.0
0
• •
• •
1.0
ReductioIlJ% Fig. 2
Relation between yield strength and reduction
2.0
3.0
• 66 •
Vol. 16
Journal of Iron and Steel Research, International
2. 2
Tensile strength The tensile strength of lengthways direction and transverse direction under different reductions is plotted in Fig. 3. The tensile strength always increases with the increase of reduction; it increases by about 25 MPa when the reduction increases to 3 %. The tensile strength of the transverse direction is larger than that of the lengthways direction for about 4 MPa in the same condition. The relationships between the tensile strength and the reduction of lengthways direction and transverse direction are obtained as Eqn, (4) and Eqn. (5), (4) e1b = 332.08+ 10. 43eo. 77 (5) ~=336. 95+10. 15eo. 84 where, C1b is the lengthways tensile strength, and ~ is the transverse tensile strength.
sverse direction (279. 32 MPa) without temper rolling. Therefore, the relationship between the yield strength and the reduction of 195LD can be expressed as Eqn, (3) . C1. =C1~ K\e+ K 2e 2 (3) where, C1. is the yield strength of strip steel after temper rolling; C1~ is the yield strength of strip steel without temper rolling, and K\ and K 2 are constants. The yield strength of strip steel can reach minimum when the right reduction is adopted, which is relative to the chemical constitution, smelting manner, hot rolling condition, and reduction of cold rolling. Here, the yield strength reach minimum
+
..
w h en t h e re d uction
IS
K1 e= 2K
•
2
t
t:
365
fij 355
~
.t:l
'CII"
'CII"
I
c.:I
~
345
i!l
t
~
~
340
'~"
CII
335
330
co
0
1.0
2.0
3.0
..?S
0
1.0
2.0
3.0
ReductioIll%
Fig. 3
Relation between tensile strength and reduction
The first term on the right hand side of Eqn, (4) is 332. 08, which is quite close to the average tensile strength (332.74 MPa) of lengthways direction; similarly, the first term on the right hand side of Eqn, (5) is 336. 95, which is quite close to the average tensile strength (337.68 MPa) of transverse direction. Thus, the relationship between the tensile strength and the reduction can be expressed as Eqn. (6) , C1b=C1~+KgeK4 (6) where, C1b is the tensile strength after temper rolling; C1~ is the tensile strength without temper rolling, and Kg and K 4 are constants.
2. 3
Total elongation The total elongation of lengthways direction and transverse direction decreases with the increase of reduction; it decreases by about 3. 5 % when the reduction increases to 3% (Fig. 4). There is no obvious difference between the lengthways total elongation and the transverse total elongation. The rela-
tionship between the total elongation and the reduction of lengthways direction and transverse direction can be expressed as Eqn. (7) and Eqn. (8) , 8x = 35. 93-1. 36eo. 8\ (7) o. 88 (8) s, = 35. 89 -1. 43e where, 8x is the lengthways total elongation, and s, is the transverse total elongation. The first term on the right hand side of Eqn. (7) is 35. 93, which is quit close to the average lengthways total elongation (36.23%) of strip steel. Similarly, the first term on the right hand side of Eqn. (8) is 35. 89, which is quite close to the average transverse total elongation (35. 14 %) of strip steel. Thus, the relationship between the total elongation and the reduction of strip steel 195LD can be expressed as Eqn. (9), 8=8o + K s e K6 (9) where, 8 is the total elongation by temper rolling, 80 is the total elongation without temper rolling, and K, and K 6 are constants.
Issue 3
• 67 •
Effect of Temper Rolling on Tensile Properties of Low-Si Al-Killed Sheet Steel
37 . - - - - - - - - - - - - - - - - ,
~36
37
~36
•
'l:l
'l:l
gb ]35
~35
~ ~34
•
QI
~34
•
~33
'~"
~33
io·
1
32
E-< 31 '--
____l
~
o
1.0
2.0
]
32
3.0
0
2.0
1.0
.3.0
Reductiorv%
Fig. 4
Relation between total elongation and reduction
2. 4 Contrast of experimental results and the calculated data The tensile properties under different reductions are forecasted using the formulas, and by contrasting with the experimental data, the results are Table 2
obtained as shown in Table 2. Very good agreement between the experimental results and the calculated data can be seen from Table 2; it indicates that the formula has good practicability and commonality.
Contrast of experimental results and calculated data Reductions/ %
Tensile properties Calculated value of yield strength/MPa
3
0.4
O. 8
1.2
1.6
2.0
2. 4
2.8
244.11
239.53
239.22
243. 19
251. 44
263.96
280.76 278.00
Experimental value of yield strength/MPa
245.00
240.00
234.00
245.00
256.00
260.00
Calculated value of tensile strength/MPa
337.23
340.86
344.08
347.06
349.87
352.55
355. 13
Experimental value of tensile strength/MPa
338.00
340.00
346.00
346.00
350.00
354.00
356.00
Calculated value of total elongation/ %
35.28
34. 79
34.35
33.94
33.55
33.17
32. 80
Experimental value of total elongation/ %
35.60
34.40
34.00
34.20
34.00
33.80
33. 20
References:
Conclusions
[lJ
(l) The yield strength of steel 195LD after
temper rolling decreases with the increase of reduction when the value of reduction is less than 1 %, and then increases; the relationship between them can be described by a, =a~ K t € + K 2€ 2 . (2) The tensile strength of steel 195LD increases with the increase of reduction; the relationship between them can be expressed by ab = a~
[2J [3J
+
+
K 3 € K•• (3) The total elongation of steel 195 LD decreases with the increase of reduction; the relationship between them can be expressed by 8 = 80
[4J
[5J
[6J
+
Ks€K s•
(4) The yield strength and tensile strength in transverse direction are larger than that in lengthways direction; however, there is no obvious difference between the lengthways total elongation and the transverse total elongation.
[7J
[8J
FU Zuo-bao. Production of Cold Rolling Sheet Steel [MJ. Beijing: Enginery Industry Press, 1996. LIAN Jia-chuang , LIU Hong-min. Control of Strip Shape and Thickness [MJ. Beijing: Weapon Industry Press, 1996. LIU Ying , CHEN Da-rong , QIN u. Study of Influence on Topography Duplication During Skin Pass [JJ. Iron and Steel, 2003, 38(5): 36 (in Chinese). Fang X, Fan Z, Ralph B. Effect of Temper Rolling on Tensile Properties of C-Mn Steel [JJ. Materials Science and Technology, 2002, 18: 285. ZHU Xiao-dong , YU Ning-Ieng. Effect of Temper Rolling on the Mechanical Properties of Isotropic Steel Sheets Microalloyed With Ti [JJ. Iron and Steel. 2004, 39(11): 57 (in Chinese). ZHU Xiao-dong , WANG u, YU Ning-feng. Effect ofOver Ageing and Temper Rolling on Mechanical Property and Bake Hardenability of Cold Rolled Dual Phase Steel Sheet [JJ. JournalofIronandSteelResearch, 2003,15(6): 47 (in Chinese). Hoggan E J, Scott R I, Barnett M R. Mechanical Properties of Tension and Skin Passed Steels [JJ. Journal of Materials Processing Technology, 2002, 125: 155. The Institute of West Germany Iron Engineer. Production of Cold Rolling Strip Steel [MJ. Beijing: Enginery Industry Press, 1969.
-'I
-;;, ScienceDirect JOURNAL OF IRON AND STEEL RESEARCH. INTERNATIONAL. 2009. 16(3): 64-67
Effect of Temper Rolling on Tensile Properties of Low-Si AI-Killed Sheet Steel MA Qing-long l
,
WANG Dong-cheng' ,
LIU Hong-min",
LU Hai-rning''
O. Education Ministry Engineering Research Center of Rolling Equipment and Complete Technology, State Key Laboratory of Metastable Materials Science and Technology, Yanshan University. Qinhuangdao 066004, Hebei , China; 2. Cold Strip Factory of Lingyuan Iron and Steel Group Co Ltd, Lingyuan 122500. Liaoning. China) Abstract: The tensile properties of steel after temper rollingare affected by the reduction; low-Si Al-killed sheet steel was taken to study the effect of temper rolling on the tensile properties. The results indicate that the yield strength first decreases with the increase of reduction. and then increases. The relationship between the yield strength and the reduction can be expressed using quadratic function. The tensile strength increases with the increase of the reduction, while the total elongation decreases with the increase of the reduction. and the relationship between them and the reduction can be expressed using power function. Under the same condition, the results also indicate that the yield strength and tensile strength of steels across the rolling direction are all larger than those along the rolling direction; there is no obvious distinction between the total elongation along the rolling direction and that across the rolling direction. Key words: temper rolling; yield strength; tensile strength; total elongation
The essential of temper rolling is a cold rolling process to annealed strip steel with slight reduction (0 - 3 %). The purpose is to improve the flatness, make the strip steel get a certain surface roughness and smoothness, improve the mechanical properties, and erase the yield point ios'". The reduction of temper rolling has significant effects[2-4] , therefore, the preset of reduction is restricted not only by the flatness and surface roughness of strip steel, but also by the mechanical properties. Little effort has been devoted to the relationship between the temper rolling reduction and the tensile properties, and most of them focus on qualitative analysis[5-7]. Low-Si Al-killed sheet steel is taken to study the relationship between the temper rolling reduction and tensile properties of strip steel in this article, which is the main product of Lingyuan Iron and Steel Group Co Ltd, to get the relationship between the reduction and the tensile properties such as yield strength, tensile strength, and total elongation
by regression analysis, and to conclude the mathematical model, which can guide the preset of temper rolling reduction.
1
Experimental Procedure
The low-Si Al-killed steel used in this study is 195LD, which is obtained from Cold Strip Factory of Lingyuan Iron and Steel Group Co Ltd. Its chemical compositions are given in Table 1 (in mass percent). The experiment is performed by WDWI020 electronic tensile machine of Yanshan University, and the load speed is 1 mm/min. The range of test samples reductions is 0 - 3 %, the thickness value of steel is 1. 0 mm , and the gauge length is 50 mrn, To compare, the test samples are cut along the rolling direction (lengthwTable 1 wCC) ~O.
08
%
Chemical composition of steel wCMn)
wCSi)
~O. 45
~O.
07
wCS) ~0.03
wCP) ~O.
Foundation Item: Item Sponsored by National Natural Science Fundation of China (50675186); Important Nature Science foundation of Heibei CE2006001038) Biograpby:MA Qing-longC1977-). Male. Doctor; E-mail: jyqlma@ysu. edu. en; Revised Date: December 11. 2008
025
Issue 3
ays direction) and across the rolling direction (transverse direction), to observe the change of tensile properties
with different reductions. The samples before and after the tensile experiment are shown in Fig. 1.
(a) Before tensile experiment;
Fig. 1
2 2. 1
• 65 •
Effect of Temper Rolling on Tensile Properties of Low-Si AI-Killed Sheet Steel
(b) After tensile experiment
Contrast of samples before and after the tensile experiment
appears. That is same for the variation of the transverse yield strength along with the change of the reduction. The results also indicate that the yield strength of transverse direction is larger than that of lengthways direction for about 25 MPa in the same condition. By regression analysis, the relationships between the yield strength and the reduction of lengthways direction and transverse direction can be expressed as Eqn. (1) and Eqn. (2) , (1:=252.96-27. 48E+13. 36E2 (1) rfi=277. 57-25. 99€+12. 35€2 (2) where, (1: is the lengthways yield strength, rfi is the transverse yield strength, and e is the temper rolling reduction. The first term on the right hand side of Eqn, (1) is 252. 96, which is quite close to the average yield strength of the lengthways direction (258. 62 MPa) without temper rolling. Similarly, the first term on the right hand side of Eqn, (2) is 277.57, which is quite close to the average yield strength of the tran-
Results and Discussion Yield strength
A notable influence of the reduction on the mechanical properties of the strip steel is to change the yield strength; an appropriate reduction can erase the yield point jog, and avoid to appear slip line during machining again[8]. The variation of the lengthways yield strength and transverse yield strength along with the reduction is shown in Fig. 2. When the value of temper rolling reduction is less than 1 %, the lengthways yield strength decreases with the increase of reduction; it decreases by about 12 MPa when the reduction is 1. 0 %, and the yield strength reaches minimal value here. The reason why the yield strength decreases is that the dislocation breaks the bondage of caldwell air mass. When the value of reduction is larger than 1 %, the yield strength increases with the increase of reduction; it is because the dislocation pinning increases gradually with the increase of reduction, and work hardening
t
t os
310
=
=290
~
~rIJ
:g
"0
Qi
">' ~
290
270
a:l
"~ 270 is
!!t
J
•
250 0
•
•
250
~
t =
•
••
~ 230
2.0
1.0
3.0
0
• •
• •
1.0
ReductioIlJ% Fig. 2
Relation between yield strength and reduction
2.0
3.0
• 66 •
Vol. 16
Journal of Iron and Steel Research, International
2. 2
Tensile strength The tensile strength of lengthways direction and transverse direction under different reductions is plotted in Fig. 3. The tensile strength always increases with the increase of reduction; it increases by about 25 MPa when the reduction increases to 3 %. The tensile strength of the transverse direction is larger than that of the lengthways direction for about 4 MPa in the same condition. The relationships between the tensile strength and the reduction of lengthways direction and transverse direction are obtained as Eqn, (4) and Eqn. (5), (4) e1b = 332.08+ 10. 43eo. 77 (5) ~=336. 95+10. 15eo. 84 where, C1b is the lengthways tensile strength, and ~ is the transverse tensile strength.
sverse direction (279. 32 MPa) without temper rolling. Therefore, the relationship between the yield strength and the reduction of 195LD can be expressed as Eqn, (3) . C1. =C1~ K\e+ K 2e 2 (3) where, C1. is the yield strength of strip steel after temper rolling; C1~ is the yield strength of strip steel without temper rolling, and K\ and K 2 are constants. The yield strength of strip steel can reach minimum when the right reduction is adopted, which is relative to the chemical constitution, smelting manner, hot rolling condition, and reduction of cold rolling. Here, the yield strength reach minimum
+
..
w h en t h e re d uction
IS
K1 e= 2K
•
2
t
t:
365
fij 355
~
.t:l
'CII"
'CII"
I
c.:I
~
345
i!l
t
~
~
340
'~"
CII
335
330
co
0
1.0
2.0
3.0
..?S
0
1.0
2.0
3.0
ReductioIll%
Fig. 3
Relation between tensile strength and reduction
The first term on the right hand side of Eqn, (4) is 332. 08, which is quite close to the average tensile strength (332.74 MPa) of lengthways direction; similarly, the first term on the right hand side of Eqn, (5) is 336. 95, which is quite close to the average tensile strength (337.68 MPa) of transverse direction. Thus, the relationship between the tensile strength and the reduction can be expressed as Eqn. (6) , C1b=C1~+KgeK4 (6) where, C1b is the tensile strength after temper rolling; C1~ is the tensile strength without temper rolling, and Kg and K 4 are constants.
2. 3
Total elongation The total elongation of lengthways direction and transverse direction decreases with the increase of reduction; it decreases by about 3. 5 % when the reduction increases to 3% (Fig. 4). There is no obvious difference between the lengthways total elongation and the transverse total elongation. The rela-
tionship between the total elongation and the reduction of lengthways direction and transverse direction can be expressed as Eqn. (7) and Eqn. (8) , 8x = 35. 93-1. 36eo. 8\ (7) o. 88 (8) s, = 35. 89 -1. 43e where, 8x is the lengthways total elongation, and s, is the transverse total elongation. The first term on the right hand side of Eqn. (7) is 35. 93, which is quit close to the average lengthways total elongation (36.23%) of strip steel. Similarly, the first term on the right hand side of Eqn. (8) is 35. 89, which is quite close to the average transverse total elongation (35. 14 %) of strip steel. Thus, the relationship between the total elongation and the reduction of strip steel 195LD can be expressed as Eqn. (9), 8=8o + K s e K6 (9) where, 8 is the total elongation by temper rolling, 80 is the total elongation without temper rolling, and K, and K 6 are constants.
Issue 3
• 67 •
Effect of Temper Rolling on Tensile Properties of Low-Si Al-Killed Sheet Steel
37 . - - - - - - - - - - - - - - - - ,
~36
37
~36
•
'l:l
'l:l
gb ]35
~35
~ ~34
•
QI
~34
•
~33
'~"
~33
io·
1
32
E-< 31 '--
____l
~
o
1.0
2.0
]
32
3.0
0
2.0
1.0
.3.0
Reductiorv%
Fig. 4
Relation between total elongation and reduction
2. 4 Contrast of experimental results and the calculated data The tensile properties under different reductions are forecasted using the formulas, and by contrasting with the experimental data, the results are Table 2
obtained as shown in Table 2. Very good agreement between the experimental results and the calculated data can be seen from Table 2; it indicates that the formula has good practicability and commonality.
Contrast of experimental results and calculated data Reductions/ %
Tensile properties Calculated value of yield strength/MPa
3
0.4
O. 8
1.2
1.6
2.0
2. 4
2.8
244.11
239.53
239.22
243. 19
251. 44
263.96
280.76 278.00
Experimental value of yield strength/MPa
245.00
240.00
234.00
245.00
256.00
260.00
Calculated value of tensile strength/MPa
337.23
340.86
344.08
347.06
349.87
352.55
355. 13
Experimental value of tensile strength/MPa
338.00
340.00
346.00
346.00
350.00
354.00
356.00
Calculated value of total elongation/ %
35.28
34. 79
34.35
33.94
33.55
33.17
32. 80
Experimental value of total elongation/ %
35.60
34.40
34.00
34.20
34.00
33.80
33. 20
References:
Conclusions
[lJ
(l) The yield strength of steel 195LD after
temper rolling decreases with the increase of reduction when the value of reduction is less than 1 %, and then increases; the relationship between them can be described by a, =a~ K t € + K 2€ 2 . (2) The tensile strength of steel 195LD increases with the increase of reduction; the relationship between them can be expressed by ab = a~
[2J [3J
+
+
K 3 € K•• (3) The total elongation of steel 195 LD decreases with the increase of reduction; the relationship between them can be expressed by 8 = 80
[4J
[5J
[6J
+
Ks€K s•
(4) The yield strength and tensile strength in transverse direction are larger than that in lengthways direction; however, there is no obvious difference between the lengthways total elongation and the transverse total elongation.
[7J
[8J
FU Zuo-bao. Production of Cold Rolling Sheet Steel [MJ. Beijing: Enginery Industry Press, 1996. LIAN Jia-chuang , LIU Hong-min. Control of Strip Shape and Thickness [MJ. Beijing: Weapon Industry Press, 1996. LIU Ying , CHEN Da-rong , QIN u. Study of Influence on Topography Duplication During Skin Pass [JJ. Iron and Steel, 2003, 38(5): 36 (in Chinese). Fang X, Fan Z, Ralph B. Effect of Temper Rolling on Tensile Properties of C-Mn Steel [JJ. Materials Science and Technology, 2002, 18: 285. ZHU Xiao-dong , YU Ning-Ieng. Effect of Temper Rolling on the Mechanical Properties of Isotropic Steel Sheets Microalloyed With Ti [JJ. Iron and Steel. 2004, 39(11): 57 (in Chinese). ZHU Xiao-dong , WANG u, YU Ning-feng. Effect ofOver Ageing and Temper Rolling on Mechanical Property and Bake Hardenability of Cold Rolled Dual Phase Steel Sheet [JJ. JournalofIronandSteelResearch, 2003,15(6): 47 (in Chinese). Hoggan E J, Scott R I, Barnett M R. Mechanical Properties of Tension and Skin Passed Steels [JJ. Journal of Materials Processing Technology, 2002, 125: 155. The Institute of West Germany Iron Engineer. Production of Cold Rolling Strip Steel [MJ. Beijing: Enginery Industry Press, 1969.