阅读说明：本技术 一种因瓦合金箔材的制造方法 (Method for manufacturing invar alloy foil ) 是由 宋红宇 刘海涛 王国栋 于 2019-11-22 设计创作，主要内容包括：一种因瓦合金箔材的制造方法,属于材料技术领域,按以下步骤进行：(1)冶炼钢水,利用双辊薄带连铸装置,制成因瓦合金铸带；(2)以10~100℃/s的降温速度水冷；(3)酸洗后一次冷轧；对一次冷轧板进行中间退火,再次酸洗后二次冷轧；(4)对二次冷轧板进行最终退火,退火温度为600~900℃,退火时间为5~60min。本发明的方法可有效抑制有害元素的偏聚,减少因瓦合金铸带的氧化,显著提高成材率；可以避免因热塑性差导致的开裂问题,因瓦合金箔材具有硬度低、韧性好、热稳定性好、立方织构强的优势。(A process for preparing the invar alloy foil includes such steps as smelting molten steel, conticasting to obtain the invar alloy casting band by dual-roller conticaster, (2) cooling by 10 ~ 100 deg.C/s, (3) pickling, cold rolling, intermediate annealing, pickling, and cold rolling again, (4) final annealing at 600 ~ 900 deg.C for 5 ~ 60 min.)

1. The manufacturing method of the invar alloy foil is characterized by comprising the following steps of:

(1) smelting molten steel by adopting an intermediate frequency vacuum induction furnace, pouring the smelted molten steel into a cavity formed by two crystallizing rollers and two side sealing plates through a tundish by utilizing a double-roller thin strip continuous casting device to form a molten pool, solidifying the molten steel in the molten pool along with the rotation of the crystallizing rollers and leading out the molten steel at the speed of 20 ~ 80m/min to prepare an invar alloy casting strip;

(2) cooling the invar alloy casting belt to room temperature by a cooling unit at a cooling speed of 10 ~ 100 ℃/s to obtain a normal-temperature casting belt;

(3) pickling a normal-temperature cast strip to remove surface iron scales, then carrying out primary cold rolling, wherein the reduction rate of the primary cold rolling is 30.0 ~ 93.0.0%, so as to obtain a primary cold-rolled sheet, carrying out intermediate annealing on the primary cold-rolled sheet, wherein the temperature is 600 ~ 900 ℃, and the time is 5 ~ 60min, so as to obtain an intermediate annealed sheet, pickling the intermediate annealed sheet to remove the surface iron scales, then carrying out secondary cold rolling, wherein the reduction rate of the secondary cold rolling is 85 ~ 98.7.7%, so as to prepare a secondary cold-rolled sheet;

(4) and (3) carrying out final annealing on the secondary cold-rolled sheet at the annealing temperature of 600 ~ 900 ℃ for 5 ~ 60min to prepare the invar alloy foil.

2. The method of claim 1, wherein the invar alloy strip comprises Ni 35 ~ 37.5.5 wt%, C0.001 ~ 0.5.5 wt%, Si 0.6 wt%, Mn 0.9 wt%, Ti 2.5 wt%, Al 1.2 wt%, Zr 0.1 wt%, RE 0.2 wt%, S0.02 wt%, P0.02 wt%, and Fe and inevitable impurities.

3. The method of claim 1, wherein the width of the invar alloy strip is 100 ~ 2000 mm.

4. The method of claim 1, wherein in the step (1), the length of the arc of contact between the molten steel and the surface of the rolls of the crystallizing rolls is 100 ~ 250mm, and the height of the molten bath surface at the time of tapping is 80 ~ 220 mm.

5. The method for manufacturing an invar alloy foil according to claim 1, wherein the intermediate annealing and the final annealing in steps (3) and (4) are performed under an argon atmosphere.

6. The method of claim 1, wherein the invar foil has a thickness of 0.02 ~ 0.1.1 mm.

Technical Field

The invention belongs to the technical field of materials, and particularly relates to a method for manufacturing an invar alloy foil.

Background

The invar alloy is an Fe-Ni alloy containing about 36 percent (mass fraction) of Ni, has extremely low average linear expansion coefficient, and still has better matching of strength, plasticity and toughness at low temperature; therefore, the method is mainly used for manufacturing precise instruments, laser resonant cavities and special transmission cables, and is particularly a core material of a Liquefied Natural Gas (LNG) transport ship. The invar alloy foil has the characteristics of high magnetic saturation strength and small coercive force, has good corrosion resistance, can be used as a magnetic shielding material, and has been widely applied to the electronic and information industries.

The typical production process of invar mainly comprises the following steps: vacuum induction melting, ingot casting, peeling, heating, forging, coping, heating, hot rolling, solution treatment, acid washing, coping, coil splicing, cold rolling, continuous bright heat treatment, cold finish rolling and packaging; production practices show that the production efficiency and the yield are seriously reduced by peeling and grinding treatment, so that the comprehensive yield from steel ingots to cold-rolled strips is only about 50%, a large amount of resources and energy are wasted, and the foil is more unfavorable for preparation. In contrast, electrodeposition has been developed to prepare invar alloy foils; however, the grain size of the invar alloy foil obtained by adopting the electrodeposition method is in the nanometer level, so that the electrodeposited invar alloy foil has high hardness, poor toughness and poor thermal stability, and a gamma fiber texture (preferred orientation <111>// ND) which is unfavorable for the magnetic property can be formed in the product; on the other hand, the method needs to adopt electrolyte to prepare the foil, so that environmental pollution is easily caused, and product performance fluctuation can be caused when the electrolyte performance is unstable; therefore, the two existing production processes of the invar alloy foil do not accord with the green development direction of the metal material industry, and how to optimize the production process, improve the yield, reduce the cost and improve the product performance becomes the pursuit target of the metallurgy workers.

Disclosure of Invention

The invention aims to provide a method for manufacturing an invar alloy foil, which gives full play to the advantages and the potential of a thin-strip continuous casting technology in the regulation and control of the invar alloy structure and the texture, obtains an invar alloy foil product by adjusting a process flow, and has the characteristics of short process flow and high yield.

The method of the invention is carried out according to the following steps:

1. smelting molten steel by adopting an intermediate frequency vacuum induction furnace, pouring the smelted molten steel into a cavity formed by two crystallizing rollers and two side sealing plates through a tundish by utilizing a double-roller thin strip continuous casting device to form a molten pool, solidifying the molten steel in the molten pool along with the rotation of the crystallizing rollers and leading out the molten steel at the speed of 20 ~ 80m/min to prepare an invar alloy casting strip;

2. cooling the invar alloy casting belt to room temperature by a cooling unit at a cooling speed of 10 ~ 100 ℃/s to obtain a normal-temperature casting belt;

3. pickling a normal-temperature cast strip to remove surface iron scales, then carrying out primary cold rolling, wherein the reduction rate of the primary cold rolling is 30.0 ~ 93.0.0%, so as to obtain a primary cold-rolled sheet, carrying out intermediate annealing on the primary cold-rolled sheet, wherein the temperature is 600 ~ 900 ℃, and the time is 5 ~ 60min, so as to obtain an intermediate annealed sheet, pickling the intermediate annealed sheet to remove the surface iron scales, then carrying out secondary cold rolling, wherein the reduction rate of the secondary cold rolling is 85 ~ 98.7.7%, so as to prepare a secondary cold-rolled sheet;

4. and (3) carrying out final annealing on the secondary cold-rolled sheet at the annealing temperature of 600 ~ 900 ℃ for 5 ~ 60min to prepare the invar alloy foil.

The chemical components of the invar alloy casting strip comprise, by mass, 35. 35 ~ 37.5.5% of Ni, 0.001 ~ 0.5.5% of C, less than or equal to 0.6% of Si, less than or equal to 0.9% of Mn, less than or equal to 2.5% of Ti, less than or equal to 1.2% of Al, less than or equal to 0.1% of Zr, less than or equal to 0.2% of rare earth elements, less than or equal to 0.02% of S, less than or equal to 0.02% of P, and the balance of Fe.

The width of the invar cast strip was 100 ~ 2000 mm.

In the above step 1, the arc length of contact between the molten steel and the surface of the crystallization roll was 100 ~ 250mm, and the height of the liquid surface of the molten pool at the time of tapping was 80 ~ 220 mm.

In the above steps 3 and 4, the intermediate annealing and the final annealing are performed under an argon atmosphere.

The thickness of the invar alloy foil is 0.02 ~ 0.1.1 mm.

The width of the invar foil described above is 100 ~ 2000 mm.

The double-roller thin-strip continuous casting is a leading-edge technology which integrates sub-rapid solidification and rolling deformation and directly produces a strip with the thickness of 1 ~ 10mm by using liquid metal as a raw material, can obviously inhibit the segregation of harmful elements and greatly reduce the oxidation of a cast strip billet by utilizing the sub-rapid solidification characteristic of the technology and the rapid secondary cooling after casting, can hopefully eliminate the forging and hot rolling processes because the thickness of the invar alloy cast strip billet is smaller and the plasticity is good, fundamentally avoids the cracking problem caused by poor thermoplasticity, obviously improves the production efficiency and the yield, on the other hand, the grain size of the invar alloy foil prepared by the double-roller thin-strip continuous casting process is in the micron level, can avoid the problems of high hardness, poor toughness, poor thermal stability and the like of the electrodeposited invar alloy foil, and can also hopefully avoid the formation of a gamma fiber texture which is unfavorable for the magnetic performance by exerting the advantages of the double-roller thin-strip continuous casting on the texture control.

Compared with the prior art, the invention has the characteristics and beneficial effects that:

(1) by utilizing the sub-rapid solidification characteristic of twin-roll thin strip continuous casting and the rapid secondary cooling after casting, the segregation of harmful elements can be effectively inhibited, the oxidation of a cast strip is reduced, and the yield is obviously improved; moreover, forging and hot rolling procedures in the traditional flow can be eliminated, the cracking problem caused by poor thermoplasticity is fundamentally avoided, and the cracking phenomenon does not occur under the condition that the width of the cast strip is 2000 mm; the preparation process can be greatly simplified, and the production efficiency is improved;

(2) compared with the electro-deposition preparation flow, the invar alloy foil prepared by adopting the twin-roll thin strip continuous casting has the remarkable advantages of low hardness, good toughness, good thermal stability and strong cubic texture ({ 001} <100> preferred orientation), and can greatly reduce the emission of pollutants.

Drawings

FIG. 1 is a schematic process flow diagram of a method for manufacturing an invar alloy foil according to the present invention;

FIG. 2 shows the texture of the invar foil in example 1 of the present invention;

FIG. 3 is a final annealed sheet texture of a comparative test in example 1 of the present invention;

FIG. 4 shows the texture of the invar foil in example 2 of the present invention;

FIG. 5 is the final annealed sheet texture of a comparative test in example 2 of the present invention.

Detailed Description

The twin roll strip casting apparatus used in the examples of the present invention and the comparative examples had a diameter of the crystallization roll of 500 ~ 1000 mm.

The width of the invar alloy cast strip obtained in the inventive example and the comparative example was 100 ~ 2000 mm.

Texture testing of the annealed sheets in the examples and comparative examples of the present invention was performed on a Bruker D8 Discover type X-ray diffractometer by measuring three incomplete pole figures of {111}, {200}, and {220} of the sample and calculating the Orientation Distribution Function (ODF) by using the series expansion method; the dimension of the sample measured was 22mm (rolling direction) × 20mm (width direction perpendicular to rolling direction).

In the embodiment and the comparative example of the invention, the annealing atmosphere is argon atmosphere, and the purity of the adopted argon is more than 99.99 percent.

The invar alloy foil in the present example had an average grain size of 5 ~ 20 μm.

The hardness of the invar foil in the embodiment of the invention is 120 ~ 180HV and 180 HV.

The invar alloy foil in the embodiment of the invention has good thermal stability, and after annealing at 600 ~ 900 ℃, the average grain size difference is within 15 mu m, so that the phenomenon of obvious grain growth of the electrodeposited invar alloy foil can not occur.

The texture of the invar alloy foil in the embodiment of the invention is strong cubic texture.

The width of the invar cast strip and the invar foil in the examples of the present invention was 100 ~ 2000 mm.

When continuous casting is carried out in the examples of the present invention and in the comparative examples, the contact arc length of molten steel with the roll surface of the crystallization roll is 100 ~ 250mm, and the liquid level height of the molten pool is 80 ~ 220 mm.

In the embodiment of the invention, when continuous casting is carried out, the superheat degree of the upper surface of a molten pool is controlled to be 15 ~ 70 ℃.

The thickness of the invar alloy cast strip in the embodiment of the invention is 2.5 ~ 5 mm.