A kind of high-strength toughness high-boron stainless steel thin plate and preparation method thereof

Abstract

A high-strength and toughness high-boron stainless steel sheet and a preparation method thereof. The composition of the stainless steel sheet contains B 2.0-2.5%, C<0.01%, Cr 16.0-18.0%, Ni 15.5-17.5%, and Mn 1.0-2.0% in mass percentage. Si 0.5~1.0%, the rest is Fe, of which Nieq>1.1Creq-7.0, the tensile strength is 700~850MPa, and the elongation at room temperature is 12.5~15.5%; the preparation method is: (1) smelting molten steel; (2) entering the molten steel The tundish is continuously cast into a thin strip; (3) air-cooled to 900-1100°C and then hot-rolled in a single pass, with a reduction rate of 15-40%; (4) water-cooled to 600-700°C for coiling; (5) uncoiling Finally, it is annealed under protective atmosphere conditions and then smoothed. The invention improves the degree of segregation of alloy elements and obtains a high-boron stainless steel hot-rolled plate with smooth appearance and no edge cracks. The production process is compact, the manufacturing process is few, and the production cost can be significantly reduced.

Description

technical field

[0001] The invention belongs to the technical field of metallurgical materials, in particular to a high-strength and toughness high-boron stainless steel thin plate and a preparation method thereof. Background technique

[0002] The service environment of thermal neutron absorbing materials used for nuclear power plant spent fuel storage is relatively harsh, so the requirements for its performance are also extremely stringent; for thermal neutron absorbing materials used It has the ability to withstand large radiation doses and strong corrosion resistance; for thermal neutron absorbing materials used in spent fuel transport containers, it may withstand higher temperatures and greater corrosion resistance under normal use or accident conditions. Impact damage, so it should have relatively good mechanical properties; natural boron has 11 B and 10 Two isotopes of B, of which, 10 The thermal neutron absorption cross section of B isotope is 3837 Barn; in additi...

Examples

Embodiment 1

[0036] The composition of molten steel for smelting is: B 2.5%, C 0.006%, Cr 17.9%, Ni 15.8%, Mn 1.5%, Si 0.8%, the rest is Fe and unavoidable impurities, and the element composition meets Nieq>1.1Creq -7.0, where Nieq=15.8+30×0.006+0.5×1.5=16.73, Creq=17.9+1.5×0.8=19.1;

[0037] The molten steel enters the tundish, and then flows into the cavity surrounded by the two crystallization rolls and side sealing plates of the twin-roll continuous casting machine to form a molten pool, in which the two crystallization rolls rotate in opposite directions; the molten steel in the molten pool passes through two The roll gap between the crystallization rolls is solidified and exported to form a thin strip; the morphology of the thin strip and the distribution of each element are as follows: figure 2 with image 3 shown;

[0038] Air-cool the thin strip to 1100°C, and then use a hot rolling mill to perform single-pass hot rolling with a reduction rate of 38%, and the speed during hot r...

Embodiment 2

[0043] Method is with embodiment 1, and difference is:

[0044] (1) Molten steel, its composition by mass percentage is: B 2.1%, C 0.004%, Cr 16.2%, Ni 17.4%, Mn 1.0%, Si 0.6%; Wherein Nieq=17.4+30×0.004+0.5×1.0= 18.02, Creq=16.2+1.5×0.6=17.1;

[0045] (2) The thin strip is air-cooled to 900°C, and then hot-rolled in a single pass with a hot rolling mill, with a reduction rate of 28%, and a speed of 1.0m / s during hot rolling; wherein the microstructure of the thin strip is as follows: Image 6 shown;

[0046] (3) The hot-rolled sheet is water-cooled to 650°C and then coiled;

[0047] (4) The annealing temperature is 1000°C, the annealing holding time is 30min, and the reduction rate during smoothing is 1.0%;

[0048] (5) The thickness of high-strength and toughness high-boron stainless steel sheet is 1.3mm, the tensile strength is 760MPa, the elongation at room temperature is 15.2%, and the impact toughness at room temperature is 246KJ / m 2 The borides with a particle size ...

Embodiment 3

[0050] Method is with embodiment 1, and difference is:

[0051] (1) Molten steel, its composition by mass percentage is: B 2.3%, C 0.007%, Cr 17.5%, Ni 16.0%, Mn1.3%, Si 1.0%; Wherein Nieq=16.0+30×0.007+0.5×1.3= 16.86, Creq=17.5+1.5×1.0=18;

[0052] (2) The thin strip is air-cooled to 1050°C, and then hot-rolled in a single pass with a reduction rate of 20%, and the speed during hot rolling is 0.5m / s;

[0053] (3) The hot-rolled sheet is water-cooled to 650°C and then coiled;

[0054] (4) The annealing temperature is 1100°C, the annealing holding time is 15min, and the reduction rate during smoothing is 1.0%;

[0055] (5) The thickness of high-strength and toughness high-boron stainless steel sheet is 2.4mm, the tensile strength is 800MPa, the elongation at room temperature is 14.5%, and the impact toughness at room temperature is 232KJ / m 2 ; The borides with a particle size smaller than 1.0 μm accounted for 63.2% of the total area, and the borides with a particle size larg...

technical field

[0001] The invention belongs to the technical field of metallurgical materials, in particular to a high-strength and toughness high-boron stainless steel thin plate and a preparation method thereof. Background technique

[0002] The service environment of thermal neutron absorbing materials used for nuclear power plant spent fuel storage is relatively harsh, so the requirements for its performance are also extremely stringent; for thermal neutron absorbing materials used It has the ability to withstand large radiation doses and strong corrosion resistance; for thermal neutron absorbing materials used in spent fuel transport containers, it may withstand higher temperatures and greater corrosion resistance under normal use or accident conditions. Impact damage, so it should have relatively good mechanical properties; natural boron has 11 B and 10 Two isotopes of B, of which, 10 The thermal neutron absorption cross section of B isotope is 3837 Barn; in additi...

Examples

Embodiment 1

[0036] The composition of molten steel for smelting is: B 2.5%, C 0.006%, Cr 17.9%, Ni 15.8%, Mn 1.5%, Si 0.8%, the rest is Fe and unavoidable impurities, and the element composition meets Nieq>1.1Creq -7.0, where Nieq=15.8+30×0.006+0.5×1.5=16.73, Creq=17.9+1.5×0.8=19.1;

[0037] The molten steel enters the tundish, and then flows into the cavity surrounded by the two crystallization rolls and side sealing plates of the twin-roll continuous casting machine to form a molten pool, in which the two crystallization rolls rotate in opposite directions; the molten steel in the molten pool passes through two The roll gap between the crystallization rolls is solidified and exported to form a thin strip; the morphology of the thin strip and the distribution of each element are as follows: figure 2 with image 3 shown;

[0038] Air-cool the thin strip to 1100°C, and then use a hot rolling mill to perform single-pass hot rolling with a reduction rate of 38%, and the speed during hot r...

Embodiment 2

[0043] Method is with embodiment 1, and difference is:

[0044] (1) Molten steel, its composition by mass percentage is: B 2.1%, C 0.004%, Cr 16.2%, Ni 17.4%, Mn 1.0%, Si 0.6%; Wherein Nieq=17.4+30×0.004+0.5×1.0= 18.02, Creq=16.2+1.5×0.6=17.1;

[0045] (2) The thin strip is air-cooled to 900°C, and then hot-rolled in a single pass with a hot rolling mill, with a reduction rate of 28%, and a speed of 1.0m / s during hot rolling; wherein the microstructure of the thin strip is as follows: Image 6 shown;

[0046] (3) The hot-rolled sheet is water-cooled to 650°C and then coiled;

[0047] (4) The annealing temperature is 1000°C, the annealing holding time is 30min, and the reduction rate during smoothing is 1.0%;

[0048] (5) The thickness of high-strength and toughness high-boron stainless steel sheet is 1.3mm, the tensile strength is 760MPa, the elongation at room temperature is 15.2%, and the impact toughness at room temperature is 246KJ / m 2 The borides with a particle size ...

Embodiment 3

[0050] Method is with embodiment 1, and difference is:

[0051] (1) Molten steel, its composition by mass percentage is: B 2.3%, C 0.007%, Cr 17.5%, Ni 16.0%, Mn1.3%, Si 1.0%; Wherein Nieq=16.0+30×0.007+0.5×1.3= 16.86, Creq=17.5+1.5×1.0=18;

[0052] (2) The thin strip is air-cooled to 1050°C, and then hot-rolled in a single pass with a reduction rate of 20%, and the speed during hot rolling is 0.5m / s;

[0053] (3) The hot-rolled sheet is water-cooled to 650°C and then coiled;

[0054] (4) The annealing temperature is 1100°C, the annealing holding time is 15min, and the reduction rate during smoothing is 1.0%;

[0055] (5) The thickness of high-strength and toughness high-boron stainless steel sheet is 2.4mm, the tensile strength is 800MPa, the elongation at room temperature is 14.5%, and the impact toughness at room temperature is 232KJ / m 2 ; The borides with a particle size smaller than 1.0 μm accounted for 63.2% of the total area, and the borides with a particle size larg...

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