阅读说明：本技术 一种抗高温氧化的铸造高钨镍基合金及其制备方法 (High-temperature oxidation resistant cast high-tungsten-nickel-based alloy and preparation method thereof ) 是由 吴树森 许嘉雄 郭威 吕书林 于 2021-07-30 设计创作，主要内容包括：本发明提供一种抗高温氧化的铸造高钨镍基合金及其制备方法,合金成分重量百分比为：C 0.1～0.2％,Ni 51～54％,Cr 26～27％,Si 0.8～1.0％,Nb 0.5％,Mn 1.0～1.5％,W5.1～6.9％,余量为Fe,及微量的Ce和La。本发明将合金成分设计和传统铸造方法相结合,通过原材料选择、熔炼工艺、熔体的变质处理工艺、浇注工艺等的合理选择,有效地提高了镍基高温合金材料的抗氧化性能,能够较好地满足轧钢线的高温炉内垫块或辊环、冶金热处理炉、石化高温设备等场合下对镍基合金的性能要求。(The invention provides a high-temperature oxidation resistant cast high-tungsten nickel-based alloy and a preparation method thereof, wherein the alloy comprises the following components in percentage by weight: 0.1-0.2% of C, 51-54% of Ni, 26-27% of Cr, 0.8-1.0% of Si, 0.5% of Nb, 1.0-1.5% of Mn, 5.1-6.9% of W, the balance of Fe and trace Ce and La. The invention combines the alloy component design with the traditional casting method, effectively improves the oxidation resistance of the nickel-based high-temperature alloy material through the reasonable selection of raw material selection, smelting process, melt modification process, pouring process and the like, and can better meet the performance requirements of cushion blocks or roll rings in a high-temperature furnace of a rolled steel wire, a metallurgical heat treatment furnace, petrochemical high-temperature equipment and the like on the nickel-based alloy.)

1. The high-temperature oxidation resistant cast nickel-based alloy is characterized by comprising the following components in percentage by weight:

0.1-0.2% of C, 51-54% of Ni, 26-27% of Cr, 0.8-1.0% of Si, 0.5% of Nb, 1.0-1.5% of Mn, 5.1-6.9% of W, the balance of Fe and trace Ce and La.

2. The high temperature oxidation resistant cast nickel-base alloy of claim 1, wherein: the weight percentage of Ce is less than or equal to 0.05 percent, and the weight percentage of La is less than or equal to 0.05 percent.

3. The method for preparing a high temperature oxidation resistant cast nickel-base alloy according to any one of claims 1-2, comprising the steps of:

step 1, melting the raw materials of Ni, Fe, Cr, W and Nb in the proportion into nickel-based alloy melt at 1500 ℃ by an induction melting electric furnace;

step 2, heating the nickel-based alloy melt obtained in the step 1 to 1580-1630 ℃, adding the Si and Mn raw materials in the ratio, performing pre-deoxidation treatment, and removing surface slag; then, adjusting the temperature of the melt to 1530-1580 ℃;

step 3, adding 0.05-0.15% of mixed rare earth raw material into the melt obtained in the step 2 at 1550 ℃, refining and modifying the melt, and keeping the temperature for 3 minutes;

and 4, removing surface slag from the melt refined in the step 3, and pouring at 1480-1550 ℃ to obtain the nickel-based high-temperature alloy.

4. The method of making a high temperature oxidation resistant cast nickel-base alloy of claim 3, wherein: the rare earth raw material is a mixture of Ce, La, Fe and Si, wherein the sum of Ce and La is more than 50%.

Technical Field

The invention belongs to the field of metal materials, and particularly relates to a high-temperature oxidation resistant cast high-tungsten nickel-based alloy and a preparation method thereof.

Background

The short-flow continuous casting and rolling billet production line integrates a series of high and new technologies such as secondary refining, near-net-shape high-speed continuous casting, tunnel heating, modern hot rolling, online automatic detection, computer process control and the like, realizes continuous and automatic production of hot rolled plates from molten steel to finished products, and has the advantages of compact production process, short period, low energy consumption, high yield, less investment, low cost and the like. The continuous casting and rolling production line needs a tunnel type and roller hearth type heating furnace to heat and convey the steel billet. The roller hearth furnace is an important transition device for connecting a continuous casting machine and a rolling mill. When the billet moves in the heating furnace, the billet is supported by the rotating heat-resistant alloy roll collar and moves above the rotating heat-resistant alloy roll collar. When producing thinner steel billet, the heat-resistant alloy roll collar should bear the high temperature of 1150-1250 ℃ in the heating furnace, and keep higher oxidation resistance and high temperature strength. Thus, some imported lines used Co50 alloy (i.e., containing Co 50% with the balance being primarily Cr and Fe) to make roll collars. However, this material is expensive because of the use of expensive cobalt, and the high temperature performance is still to be improved. Therefore, the development of low-cost nickel-based alloy which can meet the high-temperature performance requirement and has lower cost to replace cobalt-based alloy is of great significance.

In addition, parts such as radiant tubes, elbows and material frames in various high-temperature heat treatment furnaces, and parts such as pendants and pipe fittings in high-temperature devices in the petrochemical industry need to work at high temperature for a long time, and need to be manufactured by adopting materials resistant to high-temperature oxidation. The parts are usually made of a cast steel material such as ZG40Cr25Ni20 and the like, so that the defects such as cracking, deformation, oxidation and the like are easy to occur after the parts are used for a period of time at high temperature, the service life is short, the replacement frequency is high, and the normal operation of equipment is seriously influenced.

The nickel-based high-temperature alloy is a high-temperature alloy which takes nickel as a matrix (the content is generally more than 40 percent), has higher strength within the range of 650-1100 ℃ and has good oxidation resistance. It is developed on the basis of Cr20Ni80 alloy, and has great amount of strengthening elements added to meet the requirement of high temperature resistance and antioxidant performance of Ni-base high temperature alloy at over 1000 deg.c. Tungsten is used as a strengthening element and is often added into the nickel-based high-temperature alloy to play a role in solid solution strengthening, the radius of tungsten atoms is larger and is more than ten percent larger than that of matrix nickel, the solid solution strengthening effect is obvious, and the high temperature resistance and the oxidation resistance of the alloy are obviously improved by combining the addition of elements such as molybdenum, manganese, niobium and the like.

The recent Chinese patent application with the publication number of CN 111575536A, "a high W, Mo content nickel-based superalloy and a preparation method thereof" discloses a nickel-based superalloy, which mainly comprises the following components in percentage by mass: 0.013-0.018 of C, 20-21 of Cr, 7.9-8.1 of W, 7.9-8.1 of Mo, 0.6-0.75 of Al, 0.6-0.75 of Ti, 0.28-0.33 of Mn, 0.15-0.20 of Si, 0.002-0.013 of P, 0.001-0.013 of S, 0.11-0.19 of Fe, 0.002-0.005 of B, 0.02-0.05 of Ce, 0.02-0.06 of Zr and the balance of Ni. The invention is characterized by high Mo content and W content. The patent application with the publication number of CN 111411266A discloses a preparation process of a nickel-based high-tungsten polycrystalline superalloy, which comprises the following components in percentage by mass: cr: 15-18%, Co: 15-20%, Ti: 0.5-1.5%, Al: 3.5-4.5%, W: 7.0-8.5%, Si: less than or equal to 0.5 percent, Mn: less than or equal to 0.5 percent, Nb: 0.5-1.5%, C: 0.03-0.08 percent of Ni and the balance of Ni, smelting under the vacuum degree of 0.3-0.5 Pa and under the protection of argon, and refining by adopting an electroslag remelting process to obtain an ingot; forging and cogging, rolling at high temperature, and finally performing heat treatment. The invention is mainly characterized in that the alloy contains Al, and the compound of Al and Ni is used for improving the strength and oxidation resistance. The alloy of the invention is completely recrystallized after heat treatment, the grain size is 30-50 microns, and Ni is dispersed and distributed in the crystal₃Al phase, and the volume fraction of the Al phase is not less than 35%, and the yield strength of the Al phase is not less than 700MPa at the temperature of 850 ℃.

The steel-making and rolling production line uses a large amount of high-temperature alloy and is mainly used as a cushion block in a heating furnace and a conveying roller of a billet. The metallurgical industry or the petrochemical industry also needs to adopt a large amount of high-temperature oxidation resistant alloy materials, and most of the domestic high-temperature alloys are made of high-alloy cast steel or cobalt-containing high-nickel alloy, so the cost is high. And many of the materials developed can only meet the requirements of lower production temperatures of less than 1100 ℃. There is an urgent need to develop a new alloy for reducing the cost and improving the high temperature performance for the manufacture of nickel base alloy parts for production lines with service temperatures up to about 1200 c.

Disclosure of Invention

Aiming at the problems in the prior art, the invention aims to provide a cast nickel-based alloy with good high temperature resistance and oxidation resistance, good comprehensive performance and low cost and a preparation method thereof.

The technical scheme adopted for solving the problems in the prior art is as follows:

a high-temperature oxidation resistant cast nickel-based alloy comprises the following alloy components in percentage by weight:

0.1-0.2% of C, 51-54% of Ni, 26-27% of Cr, 0.8-1.0% of Si, 0.5% of Nb, 1.0-1.5% of Mn, 5.1-6.9% of W, the balance of Fe and trace Ce and La.

The weight percentage of Ce is less than or equal to 0.05 percent, and the weight percentage of La is less than or equal to 0.05 percent.

A preparation method of a high-temperature oxidation resistant cast nickel-based alloy specifically comprises the following steps:

step 1, melting Ni (nickel 51-54 wt.%), Fe (iron 9.6-14.1 wt.%), Cr (chromium 26-27 wt.%), W (tungsten 5.1-6.9 wt.%), and Nb (niobium 0.5 wt.%) raw materials in the above ratio into a nickel-based alloy melt at 1500 ℃ by an induction melting electric furnace;

step 2, heating the nickel-based alloy melt obtained in the step 1 to 1580-1630 ℃, adding Si (0.8-1.0 wt.% of silicon) and Mn (1.0-1.5 wt.% of manganese) raw materials in the proportion, performing pre-deoxidation treatment, and removing surface slag; then, adjusting the temperature of the melt to 1530-1580 ℃;

step 3, adding 0.05-0.15% of mixed rare earth raw material into the melt obtained in the step 2 at 1550 ℃, refining and modifying the melt, and keeping the temperature for 3 minutes;

the rare earth raw material is a mixture of Ce, La, Fe and Si, wherein the sum of Ce and La is more than 50%;

and 4, removing surface slag from the melt refined in the step 3, and pouring at 1480-1550 ℃ to obtain the nickel-based high-temperature alloy.

The invention combines the design of alloy components with the traditional casting method, effectively improves the oxidation resistance of the nickel-based high-temperature alloy material through the reasonable selection of raw material selection, smelting process, modification process of melt, casting process and the like, and the alloy can be used for manufacturing parts such as nickel-based alloy roll collars, heating furnace cushion blocks and the like of continuous casting and rolling conveying belts.

The invention has the following advantages:

(1) the nickel content of the alloy is 51-54%, and the components do not contain Co, so that the good thermal strength and oxidation resistance of the alloy are ensured, and the cost is reduced compared with the similar Co-containing nickel-based alloy.

(2) The content of carbon element is strictly controlled by the alloy, the selected raw materials are all materials with very little carbon content, carbides are not enriched and distributed, but are uniformly distributed in a matrix in a superfine mode, crystal grains are round and fine, and the mechanical property and the oxidation resistance of the whole casting are improved.

(3) Good melt treatment measures and reasonable melting sequence are adopted, and the silicon and manganese deoxidizers and the rare earth refining agent with obvious effects are added, so that the oxide inclusion in the melt is greatly reduced, and the solid solution strengthening effect of alloy elements is greatly improved.

(4) The element W with higher content can generate fine and evenly distributed carbide with a small amount of carbon atoms in the matrix besides solid solution strengthening, thereby improving the comprehensive properties of the alloy, such as high temperature resistance, oxidation resistance, high strength and the like.

The high-tungsten nickel-based alloy has good normal temperature performance and high temperature performance, and can better meet the performance requirements of cushion blocks or roll collars in high-temperature furnaces of steel rolling wires, metallurgical heat treatment furnaces, petrochemical high-temperature equipment and other occasions on the nickel-based alloy.

Drawings

FIG. 1 is an as-cast metallographic structure drawing (500X) of a high W-Ni based alloy according to example 1 of the present invention;

FIG. 2 is a cross-sectional view (1000X) of the vicinity of the surface of the high tungsten-nickel-based alloy of example 1 of the present invention after the oxidation test at 1200 ℃.

Detailed Description

The technical scheme of the invention is further specifically described by the following embodiments and the accompanying drawings.

A high-temperature oxidation resistant cast nickel-based alloy comprises the following alloy components in percentage by weight: 0.1-0.2% of C, 51-54% of Ni, 26-27% of Cr, 0.8-1.0% of Si, 0.5% of Nb, 1.0-1.5% of Mn, 5.1-6.9% of W, and the balance of Fe, and trace Ce (less than or equal to 0.05%) and La (less than or equal to 0.05%).

The preparation of the nickel-based high-temperature alloy comprises two processes of smelting and modification treatment. The Ni and W elements are added from pure metal raw materials, the Cr element is usually added in the form of micro-carbon ferrochrome, and the Nb element is added in the form of ferrocolumbium. Before the preparation, the raw materials are prepared according to the weight percentage for standby. The deoxidizer Si is ferrosilicon intermediate alloy, and Mn is ferromanganese intermediate alloy. The refining and modifying agent RE is added by the material of mixed rare earth.

Si and Mn in the alloy are added as deoxidizer, and refining and modificator RE is added as refining and modificator to play the role of final deoxidation and grain refinement.

The invention strictly controls the operation temperature of each stage and the pouring temperature. And smelting and pouring by adopting a method of carrying out rapid smelting in an electric induction furnace or a vacuum electric induction furnace.

Example 1

According to the weight percentage of the alloy components, Ni51-Cr27-W5.1-Nb0.5-Si1-Mn1-C0.1, and the balance Fe; pure Ni with the purity of 99.98%, micro-carbon ferrochrome containing 60% of Cr and 0.06% of C and ferrocolumbium containing 75% of Nb are put into an induction furnace and melted into nickel-based alloy melt at 1500 ℃. Then, the alloy melt is overheated to 1580 ℃, and ferrosilicon and ferromanganese are added for deoxidation treatment to remove surface slag. Adjusting the temperature of the melt to 1530 ℃, adding 0.05 percent of RE to carry out refining and modification treatment at 1550 ℃, wherein the content of Ce and La in the RE is 50 percent, and the balance is Fe and Si. Removing slag on the surface of the refined and modified alloy melt, and then directly pouring the alloy melt into a casting mold to obtain a nickel-based alloy with the alloy components of Ni51-Cr27-W5.1-Nb0.5-Si1-Mn1-C0.1 and the balance of Fe; the casting temperature is 1480 ℃. The mechanical property of the alloy casting can reach 525MPa of room temperature strength and 125MPa of 1000 ℃ high temperature strength.

The cast metallographic structure diagram (500X) is shown in figure 1, and the matrix structure of the alloy is austenite, the grains are fine and no large carbide is found in the diagram.

The cross-sectional view of the vicinity of the surface after the 1200 ℃ oxidation test is shown in FIG. 2, and it is clear from FIG. 2 that the oxide film on the upper surface layer is very thin, confirming that the high temperature oxidation resistance is good.

Example 2

According to the weight percentage of the alloy components, Ni54-Cr26-W6.9-Nb0.5-Si0.8-Mn1.5-C0.2, and the balance Fe; pure Ni with the purity of 99.98%, micro-carbon ferrochrome containing 60% of Cr and 0.06% of C and ferrocolumbium containing 75% of Nb are put into an induction furnace and melted into nickel-based alloy melt at 1500 ℃. Then, the alloy melt is overheated to 1580 ℃, and ferrosilicon and ferromanganese are added for deoxidation treatment to remove surface slag. Adjusting the temperature of the melt to 1580 ℃, adding 0.2% of RE to carry out refining and modification treatment at 1550 ℃, wherein the content of Ce and La in RE is 52%, and the balance is Fe and Si. Removing slag on the surface of the refined and modified alloy melt, and then directly pouring into a casting mold to obtain an alloy casting body with the alloy components of Ni54-Cr26-W6.9-Nb0.5-Si0.8-Mn1.5-C0.2 and the balance of Fe; the casting temperature was 1550 ℃. The mechanical property of the alloy casting body can reach 531MPa of room temperature strength and 128MPa of high temperature strength at 1000 ℃.

Example 3

According to the weight percentage of the alloy components, Ni52-Cr26-W6-Nb0.5-Si0.9-Mn1.2-C0.15, and the balance Fe; pure Ni with the purity of 99.98%, micro-carbon ferrochrome containing 60% of Cr and 0.06% of C and ferrocolumbium containing 75% of Nb are put into an induction furnace and melted into nickel-based alloy melt at 1500 ℃. Then, the alloy melt is overheated to 1580 ℃, and ferrosilicon and ferromanganese are added for deoxidation treatment to remove surface slag. Adjusting the temperature of the melt to 1580 ℃, adding 0.10% of RE to carry out refining and modification treatment at 1550 ℃, wherein the content of Ce and La in RE is 52%, and the balance is Fe and Si. Removing slag on the surface of the refined and modified alloy melt, and then directly pouring into a casting mold to obtain an alloy casting body with the alloy components of Ni52-Cr26-W6-Nb0.5-Si0.9-Mn1.2-C0.15 and the balance of Fe; the casting temperature was 1530 ℃. The mechanical property of the alloy casting body can reach 530MPa of room temperature strength and 126MPa of 1000 ℃ high temperature strength.

The results of the tests on the room temperature strength (MPa) and the high temperature strength (MPa) at 1000 ℃ for the alloys of the three groups of examples are shown in Table 1,

TABLE 1 mechanical Properties of the alloys of the two examples

Serial number	Strength at room temperature (MPa)	High temperature strength (MPa) at 1000 DEG C
			Example 1	525	125
Example 2	531	128
			Example 3	530	126

As can be seen from Table 1, the nickel-base superalloy of the present invention has excellent room temperature properties and high temperature properties.

According to HB5258-2000 (determination method for oxidation resistance of steel and high-temperature alloy), the oxidation resistance of the alloy is evaluated, and the oxidation resistance grades of the high-temperature alloy are respectively as follows: complete oxidation resistance, secondary oxidation resistance, weak oxidation resistance and no oxidation resistance. The average oxidation weight gain rate and the oxidation resistance level experiment calculated after the nickel-based superalloy is oxidized for 100 hours in the air medium are carried out, and specific results are shown in table 2.

TABLE 2 Oxidation test results

As can be seen from table 2, the alloy of the present invention exhibits oxidation resistance even at 1200 ℃, confirming its good high temperature oxidation resistance.

The protective scope of the present invention is not limited to the above-described embodiments, and it is apparent that various modifications and variations can be made to the present invention by those skilled in the art without departing from the scope and spirit of the present invention. It is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.