EP3402906A1 - Warm rolling of steels containing metastable austenite - Google Patents

Warm rolling of steels containing metastable austenite

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Publication number
EP3402906A1
EP3402906A1 EP17706330.2A EP17706330A EP3402906A1 EP 3402906 A1 EP3402906 A1 EP 3402906A1 EP 17706330 A EP17706330 A EP 17706330A EP 3402906 A1 EP3402906 A1 EP 3402906A1
Authority
EP
European Patent Office
Prior art keywords
rolling
steel
metastable
warm
temperature
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP17706330.2A
Other languages
German (de)
French (fr)
Inventor
Amrinder Sigh GILL
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Cleveland Cliffs Steel Properties Inc
Original Assignee
AK Steel Properties Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by AK Steel Properties Inc filed Critical AK Steel Properties Inc
Publication of EP3402906A1 publication Critical patent/EP3402906A1/en
Pending legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
    • C21D8/0231—Warm rolling
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/46—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for sheet metals
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/001—Austenite
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/008—Martensite

Definitions

  • the present invention involves warming the material before or during cold rolling to suppress the transformation of austenite to martensite. This can result in lower mill loads and higher amounts of reduction at similar loads. The ability to reduce material more can also lead to fewer intermediate anneals before material can get to final gauge.
  • as-warm rolled steel has shown enhanced mechanical properties when compared to steel reduced the same amount by cold rolling. Warm rolling followed by subsequent annealing also results in better mechanical properties than those achieved in material cold rolled the same amount and then annealed. Steel that has been warm rolled, on subsequent room temperature rolling (cold rolling), shows enhancement in both strength and ductility.
  • Fig. 1 depicts percent martensite in a metastable steel as a function of percent reduction resulting from warm rolling and cold rolling.
  • Fig. 2 depicts percent elongation in a metastable steel as a function of percent reduction resulting from cold rolling and warm rolling.
  • Fig. 3(a) depicts true stress-true strain curves for a metastable steel that was warm rolled and then cold rolled.
  • Fig. 3(b) depicts true stress -true strain curves for a metastable steel that was cold rolled in two passes.
  • This invention pertains to steels containing significant amount of metastable
  • austenite (10%-100% austenite), referred to as "metastable steel.” Austenite is deemed metastable if it transforms to martensite upon mechanical deformation. Such martensite is called deformation-induced martensite. Steels containing such metastable austenite can be carbon steel or stainless steel.
  • IF Instability Factor
  • Md30 temperature is the temperature above which no martensite is formed upon deformation.
  • Md and Md30 temperatures are well-known in the art. In addition to being empirically determined, the Md30 temperature for a particular steel composition can also be calculated by one of the several equations that can be found in literature, including the following:
  • Md30 temperature of the austenite of a given metastable steel composition the more unstable is the austenite. Md30 temperature in such metastable austenite is above the M s temperature (martensite start temperature of thermal martensite).
  • Steels with a significant amount of metastable austenite work hardens rapidly as the austenite transforms to higher strength martensite. This work hardening, and resulting martensite, can present a challenge when further cold rolling such steels because they can require loads that may exceed a mill's capability. Such metastable steels then need to be annealed to form some or all austenite before they can be cold rolled further.
  • the steel can be rolled to thinner gauges, with lower mill loads.
  • One way to suppress such transformation is to warm the material prior to or during cold rolling. Warm rolling has shown to have additional benefit resulting in better mechanical properties.
  • the methods of the present application involve rolling such metastable steels while the steel is warm. It is considered warm when the metastable steel temperature is above room temperature (typically about 80°F). For certain embodiments, the steel is warmed to a temperature near or above the Md temperature for the particular metastable steel composition. In other embodiments, the steel is warmed to a temperature above the Md30 temperature for the particular metastable steel composition. In other embodiments, the metastable steel is warmed to a temperature less than or equal to 250°F.
  • the metastable steel is melt, cast, hot rolled, and annealed prior to cold rolling (if applicable) in accordance with typical metal-making processing for the particular composition.
  • at least one "cold rolling" pass is a "warm rolling" pass that is performed while the steel is warm, i.e., while the steel is at a temperature above 80°F.
  • the steel is warmed to a temperature no greater than 250°F.
  • the metastable steel is warmed to a temperature near or above the Md temperature for the particular metastable steel composition.
  • the metastable steel is warmed to a temperature near or above the Md30 temperature for the particular metastable steel composition.
  • Such warm rolling passes can be one or more of the first, second, or any subsequent "cold rolling" steps.
  • the metastable steel may be any suitable metal
  • the metastable steel may be warm rolled in a first pass, annealed, and then cold rolled (at room temperature) in a second pass.
  • a metastable steel was prepared by melting a heat with a chemistry that had an
  • Instability Factor of 8.5 and M d 30 (Nohara) 447.6 °F.
  • the heat was continuously cast into slabs.
  • the slabs were re-heated to 2300 °F and hot rolled to a thickness of 0.175", with a coiling temperature of 1000 °F.
  • the hot band was the then pickled to remove the scale. Sections of the pickled hot bands were cold rolled and warm rolled. For purpose of warm rolling, the hot band sections were warmed to desired temperatures in a furnace and rolled to desired gauges.
  • Figure 1 shows the amount of martensite transformation from cold and warm
  • FIG. 1 shows the % elongation of the metastable steel, after warm rolling and cold rolling to different reduction amounts. Surprisingly, warm rolling led to an increase in % elongation till certain amount of reduction before starting to drop.
  • the benefits of warm rolling can be tailored by either varying the amount of reduction performed at a temperature or by varying the temperature. On the other hand, cold rolling at room temperature always leads to a decrease in % elongation for metastable steels.
  • Fig. 3(a) shows true stress strain data from the metastable steel that had been warm rolled 30% and subsequently cold rolled at room temperature to various reductions.
  • "WR” refers to warm rolling
  • RT refers to cold rolling at room temperature.
  • 30% warm rolling followed by additional 10% cold rolling showed an increase in both elongation and strength.
  • UTS ultimate tensile strength
  • the metastable steel of Example 1 above shows the effect of warm rolling on steel containing metastable austenite as further shown by the test data set forth in the Tables 1 and 2 below, which compares properties of the steel containing metastable austenite that has been fully annealed (Coil 1) with steel containing metastable austenite that was 25% warm rolled in the plant (Coil 2).
  • HER Hole Expansion 5%, 10%, 21%, 39%, 45% ! 3.6%, 11.2%, 20.6%, 20.1%,

Abstract

Warming a metastable steel before or during cold rolling suppresses the transformation of austenite to martensite, resulting in lower mill loads and higher amounts of reduction at similar loads. As-warm rolled steel has enhanced mechanical properties when compared to steel reduced the same amount by cold rolling. Warm rolling followed by subsequent annealing also results in better mechanical properties than those achieved in material cold rolled the same amount and then annealed. Metastable steel that has been warm rolled, on subsequent room temperature rolling (cold rolling), also shows enhancement in both strength and ductility.

Description

WARM ROLLING OF STEELS CONTAINING METASTABLE AUSTENITE
PRIORITY
[0001] This application claims priority to U.S. Provisional Application Serial No.
62/278,567, entitled WARM ROLLING OF STEELS CONTAINING METASTABLE AUSTENITE, filed on January 14, 2016, and U.S. Provisional Application Serial no. 62/407,001, entitled WARM ROLLF G OF STEELS CONTAINING METASTABLE AUSTENITE, filed on October 12, 2016, the disclosures of which are incorporated by reference herein.
BACKGROUND
[0002] Cold rolling of steels containing metastable austenite can be challenging due to deformation induced transformation of metastable austenite to a higher strength martensite phase. Cold rolling of such steel leads to a significant increase in mill loads. Steel also needs to undergo annealing(s) to partial or full austenitization before further cold reduction can be performed.
SUMMARY
[0003] The present invention involves warming the material before or during cold rolling to suppress the transformation of austenite to martensite. This can result in lower mill loads and higher amounts of reduction at similar loads. The ability to reduce material more can also lead to fewer intermediate anneals before material can get to final gauge. Surprisingly, as-warm rolled steel has shown enhanced mechanical properties when compared to steel reduced the same amount by cold rolling. Warm rolling followed by subsequent annealing also results in better mechanical properties than those achieved in material cold rolled the same amount and then annealed. Steel that has been warm rolled, on subsequent room temperature rolling (cold rolling), shows enhancement in both strength and ductility. [0004] Previously, warm rolling has been avoided in the production environment because of concern that it may cause damage to rolling equipment as well as present risks related to warming of the oils used as lubricants. The present application shows that the benefits of warm rolling can be achieved at moderate temperatures and without extensive line modifications.
DESCRIPTION OF FIGURES
[0005] Fig. 1 depicts percent martensite in a metastable steel as a function of percent reduction resulting from warm rolling and cold rolling.
[0006] Fig. 2 depicts percent elongation in a metastable steel as a function of percent reduction resulting from cold rolling and warm rolling.
[0007] Fig. 3(a) depicts true stress-true strain curves for a metastable steel that was warm rolled and then cold rolled.
[0008] Fig. 3(b) depicts true stress -true strain curves for a metastable steel that was cold rolled in two passes.
DETAILED DESCRIPTION
[0009] This invention pertains to steels containing significant amount of metastable
austenite (10%-100% austenite), referred to as "metastable steel." Austenite is deemed metastable if it transforms to martensite upon mechanical deformation. Such martensite is called deformation-induced martensite. Steels containing such metastable austenite can be carbon steel or stainless steel.
[0010] There are several ways to characterize the stability of austenite. One way is to calculate an Instability Factor (IF) of the austenite based on its chemical composition. This factor was described in U.S. Patent 3,599,320 (the disclosure of which is incorporated herein by reference), which defines IF as:
[0011] IF=37.193 -51.248(%C) -0.4677(%Cr) -1.0174(%Mn) -34.396 (%N) -
2.5884(%Ni) Equation 1 [0012] Steels with calculated IF values from 0-2.9 are categorized as "slightly metastable" and steels with IF greater than 2.9 are categorized as "moderately metastable". The method of the present invention has the most significance for steel containing metastable austenite with an IF greater than 2.9.
[0013] Another technique to characterize the stability of austenite is to calculate or
measure what is known as the Md30 temperature. For a given metastable steel composition, on deformation to 0.3 true strain at the Md30 temperature, 50% of the austenite transforms to martensite. For a given metastable steel composition, the Md temperature is the temperature above which no martensite is formed upon deformation. Md and Md30 temperatures are well-known in the art. In addition to being empirically determined, the Md30 temperature for a particular steel composition can also be calculated by one of the several equations that can be found in literature, including the following:
[0014] As taught by Nohara, K., Ono, Y. and Ohashi, N. 1977. Composition and Grain-
Size Dependencies of Strain-Induced Martensitic Transformation in Metastable Austenitic Stainless Steels. Journal of Iron and Steel Institute of Japan, 63 (5), pp. 212-222 (the disclosure of which is incorporated herein by reference):
Md30= 551 -462(%C+%N) -68*%Cb -13.7*Cr - 29(%Cu+%Ni) -8.1 *%Mn - 18.5*%Mo -9.2*%Si Equation 2
[0015] As taught by Angel, T. 1954. Formation of Martensite in Austenitic Stainless
Steels. Journal of the Iron and Steel Institute, 177 (5), pp. 165-174 (the disclosure of which is incorporated herein by reference):
Md30= 413 -462*(%C+%N) -13.7*%Cr -8.1 *%Mn -18.5*%Mo -9.5*%Ni - 9 2*%Si Equation 3
[0016] The higher is the Md30 temperature of the austenite of a given metastable steel composition, the more unstable is the austenite. Md30 temperature in such metastable austenite is above the Ms temperature (martensite start temperature of thermal martensite). [0017] Steels with a significant amount of metastable austenite work hardens rapidly as the austenite transforms to higher strength martensite. This work hardening, and resulting martensite, can present a challenge when further cold rolling such steels because they can require loads that may exceed a mill's capability. Such metastable steels then need to be annealed to form some or all austenite before they can be cold rolled further. If during rolling, transformation of austenite to martensite can be suppressed, the steel can be rolled to thinner gauges, with lower mill loads. One way to suppress such transformation is to warm the material prior to or during cold rolling. Warm rolling has shown to have additional benefit resulting in better mechanical properties.
[0018] The methods of the present application involve rolling such metastable steels while the steel is warm. It is considered warm when the metastable steel temperature is above room temperature (typically about 80°F). For certain embodiments, the steel is warmed to a temperature near or above the Md temperature for the particular metastable steel composition. In other embodiments, the steel is warmed to a temperature above the Md30 temperature for the particular metastable steel composition. In other embodiments, the metastable steel is warmed to a temperature less than or equal to 250°F.
[0019] The coils of such material can be warmed in ways that will be apparent to one of skill in the art, including one of or a combination of the following methods:
[0020] I. Warm the coil in a furnace/oven prior to putting it on the rolling line.
[0021] II. Warm the coil on the line by using heaters, before it is cold rolled.
[0022] III. Warm the coolant on the mill before rolling the steel material. This can be performed in several ways. One way is to turn off the cooling tower on rolling mill and run some other material to warm up the coolant prior to rolling the metastable steel. Other methods of warming the coolant prior to rolling will be apparent to those of skill in the art.
[0023] The metastable steel is melt, cast, hot rolled, and annealed prior to cold rolling (if applicable) in accordance with typical metal-making processing for the particular composition. During the cold rolling processing of the metastable steel, at least one "cold rolling" pass is a "warm rolling" pass that is performed while the steel is warm, i.e., while the steel is at a temperature above 80°F. In some embodiments, the steel is warmed to a temperature no greater than 250°F. In other embodiments, the metastable steel is warmed to a temperature near or above the Md temperature for the particular metastable steel composition. And in other embodiments, the metastable steel is warmed to a temperature near or above the Md30 temperature for the particular metastable steel composition. Such warm rolling passes can be one or more of the first, second, or any subsequent "cold rolling" steps.
[0024] In some embodiments of the present invention, the metastable steel may be
annealed after one or more warm rolling step. For example, during the "cold rolling" processing, the metastable steel may be warm rolled in a first pass, annealed, and then cold rolled (at room temperature) in a second pass.
[0025] Example 1
[0026] A metastable steel was prepared by melting a heat with a chemistry that had an
Instability Factor of 8.5 and Md30 (Nohara) = 447.6 °F. The heat was continuously cast into slabs. The slabs were re-heated to 2300 °F and hot rolled to a thickness of 0.175", with a coiling temperature of 1000 °F. The hot band was the then pickled to remove the scale. Sections of the pickled hot bands were cold rolled and warm rolled. For purpose of warm rolling, the hot band sections were warmed to desired temperatures in a furnace and rolled to desired gauges.
[0027] Figure 1 shows the amount of martensite transformation from cold and warm
rolling of such metastable steel. At the same amount of reduction, the amount of martensite in each warm rolled steel is significantly less than in cold rolled steel, which was rolled at room temperature. The benefits of warm rolling can be seen at low temperatures (150 °F in this example) but the higher the temperature during warm rolling (250°F in this example), the lower is the amount of martensite formed. [0028] Figure 2 shows the % elongation of the metastable steel, after warm rolling and cold rolling to different reduction amounts. Surprisingly, warm rolling led to an increase in % elongation till certain amount of reduction before starting to drop. The benefits of warm rolling can be tailored by either varying the amount of reduction performed at a temperature or by varying the temperature. On the other hand, cold rolling at room temperature always leads to a decrease in % elongation for metastable steels.
[0029] Example 2
[0030] Another metastable steel was prepared by selecting a chemistry with an Instability
Factor of 13.11 and Md30 (Nohara) = 227.6 °F. The heat was cast into ingots. After trimming the ingots, four bars of 5.75" (W) x 2.75" (T) x 2.75" (L) were obtained. These trimmed ingots were soaked at 2200 °F and hot rolled to 0.2" with a finishing temperature of 1100 °F. The hot band was then pickled to remove the scale. Sections of the pickled hot bands were cold rolled and warm rolled at different temperatures. For purposes of warm rolling, the hot band sections were warmed to the desired temperatures in a furnace and rolled to desired gauges.
[0031] In such metastable steel, warm rolling followed by cold rolling showed an
increase in both strength and % elongation. Without prior warm rolling, the same steel showed an increase in strength but a decrease in % elongation, as expected. Fig. 3(a) shows true stress strain data from the metastable steel that had been warm rolled 30% and subsequently cold rolled at room temperature to various reductions. In Fig. 3(a) and 3(b), "WR" refers to warm rolling and "RT" refers to cold rolling at room temperature. 30% warm rolling followed by additional 10% cold rolling showed an increase in both elongation and strength. The same material when cold rolled by 30% followed by an additional cold rolling at room temperature of 0-30%, as shown in Fig. 3(b), showed an increase in ultimate tensile strength ("UTS") but a decrease in elongation, as one would expect.
Again, the benefits of warm rolling can be tailored by either varying the amount of reduction performed at a temperature or by varying the temperature. [0032] Example 3
[0033] The metastable steel of Example 1 above shows the effect of warm rolling on steel containing metastable austenite as further shown by the test data set forth in the Tables 1 and 2 below, which compares properties of the steel containing metastable austenite that has been fully annealed (Coil 1) with steel containing metastable austenite that was 25% warm rolled in the plant (Coil 2).
Table 1
Table 2
1 l est Average (Coil 1) Average (Coil 2) i Ultimate Tensile Strength i
Yield Strength @ 0.2% 378 MPa 1197.6 MPa
Offset
1 Elongation i 54.6% 21.8%
Uniform Elongation 51.5% 20.4%
Plastic Strain Ratio 0.80 0.86
LDH (Limiting Dome 2.26" 1.32"
Height)
1 LDR (Limiting Draw Ratio) i 1.9 1.5
HER (Hole Expansion 5%, 10%, 21%, 39%, 45% ! 3.6%, 11.2%, 20.6%, 20.1%,
Ratio) (0.25mm/s, 8mm s. 23.2%
! 28mm/s, 114mm/s, 228mm/s) j
Hardness 98 HRB 46.6 I IRC
[0034] Example 4
[0035] The effect of warm rolling on anistropy was also studied on the metastable steel of Example 1. Anisotropy can have a significant effect on subsequent forming. Warm rolling helpd manage anisotropy in mechanical properties of metastable steels.
[0036] The effect of warm rolling compared to cold rolling is further demonstrated by the data set forth in Table 3 below. The initial hot band was the same for both sets of rolling. One set was warm rolled (@ -250 F) to various reductions (10, 15 and 20%) , the other was cold rolled to similar reductions. In the case of the cold rolled samples, elongations in longitudinal (L) and transverse (T) orientations differ quite a bit. The higher the amount of reduction, the bigger is the said difference. However, in the case of warm rolling, the difference is much smaller. Table 3

Claims

What is claimed is:
1. A method of rolling a metastable steel comprising the steps of:
a. Selecting a metastable steel having an instability factor (IF) greater than or equal to 2.9, wherein IF is calculated by the following equation:
IF=37.193 -51.248(%C) -0.4677(%Cr) -1.0174(%Mn) -34.396 (%N) -2.5884(%Ni)
b. Prior to rolling, warming said metastable steel to a warming temperature greater than 80°F; and
c. Rolling said metastable steel.
2. The method of claim 1, wherein the warming temperature is near or above the Md
temperature for the particular metastable steel composition.
3. The method of claim 1, wherein the warming temperature is near or above the Md30 temperature for the particular metastable steel composition.
4. The method of claim 1, wherein the warming temperature is less than or equal to 250°F.
5. The method of claim 3, wherein the Md30 temperature for the metastable steel is
calculated according to the following equation:
Md30=551-462(%C+%N) -68*%Cb -13.7*Cr - 29(%Cu+%Ni) -8.1 *%Mn -18.5*%Mo -9.2*%Si
6. The method of claim 3, wherein the Md30 temperature for the metastable steel is
calculated according to the following equation:
Md30= 413 -462*(%C+%N) -13.7*%Cr -8.1 *%Mn -18.5*%Mo -9.5*%Ni -9.2*%Si
7. The method of claim 1, 2, 3, 4, 5, or 6, further comprising the step of wherein after
rolling, the metastable steel is rolled at room temperature.
8. The method of clam 7, further comprising the step of wherein the metastable steel is annealed prior to being rolled at room temperature.
9. The method of claims 1, 2, 3, 4, 5, or 6 further comprising the step of wherein after
rolling, the metastable steel is rolled in a second rolling step and prior to the second rolling step, the metastable steel is warmed to a warming temperature greater than 80°F.
EP17706330.2A 2016-01-14 2017-01-17 Warm rolling of steels containing metastable austenite Pending EP3402906A1 (en)

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WO2019177896A1 (en) * 2018-03-13 2019-09-19 Ak Steel Properties, Inc. Reduction at elevated temperature of coated steels containing metastable austenite
CN113088652A (en) * 2021-03-31 2021-07-09 长春工业大学 Preparation method of diffusion-strengthened high-stability medical high-nitrogen nickel-free austenitic stainless steel
CN114273426B (en) * 2022-01-10 2024-04-16 南京理工大学 Method for preparing high-strength high-plasticity 316L stainless steel by high-strain warm rolling

Family Cites Families (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3599320A (en) 1967-12-26 1971-08-17 United States Steel Corp Metastable austenitic stainless steel
JPS6092457A (en) * 1983-10-24 1985-05-24 Daido Steel Co Ltd High strength stainless steel
JPH0768584B2 (en) * 1986-06-09 1995-07-26 日新製鋼株式会社 Manufacturing method of stainless steel for springs having excellent spring characteristics
JPH076858B2 (en) * 1987-11-20 1995-01-30 富士写真フイルム株式会社 Pressure converter
JPH0768584A (en) 1993-09-07 1995-03-14 Asahi Chem Ind Co Ltd Manufacture of molding using crystalline vinyliden chloride resin particle
TWI271438B (en) * 2003-05-09 2007-01-21 Nippon Mining Co Metastable austenite series stainless steel strap with excellent fatigue resistance
JP5286409B2 (en) * 2008-11-05 2013-09-11 本田技研工業株式会社 High strength steel plate and manufacturing method thereof
TWI415954B (en) * 2010-10-27 2013-11-21 China Steel Corp High strength steel and its manufacturing method
WO2012133636A1 (en) * 2011-03-31 2012-10-04 新日本製鐵株式会社 Bainite-containing high-strength hot-rolled steel plate with excellent isotropic workability and process for producing same
JP5856002B2 (en) * 2011-05-12 2016-02-09 Ｊｆｅスチール株式会社 Collision energy absorbing member for automobiles excellent in impact energy absorbing ability and method for manufacturing the same
CN103842541B (en) * 2011-09-30 2016-03-30 新日铁住金株式会社 The high-strength hot-dip galvanized steel sheet of excellent in baking hardenability, high-strength and high-ductility galvannealed steel sheet and their manufacture method

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CA3009514A1 (en) 2017-07-20
WO2017124081A1 (en) 2017-07-20
BR112018013818A2 (en) 2018-12-11
TW201730348A (en) 2017-09-01
US20170204493A1 (en) 2017-07-20

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