CN102268611A

CN102268611A - Fe-based heat-resisting alloy and preparation method thereof

Info

Publication number: CN102268611A
Application number: CN2011101888971A
Authority: CN
Inventors: 徐振伟; 付占东
Original assignee: Individual
Current assignee: Individual
Priority date: 2011-07-07
Filing date: 2011-07-07
Publication date: 2011-12-07
Anticipated expiration: 2031-07-07
Also published as: CN102268611B

Abstract

The invention relates to an Fe-based heat-resisting alloy 1Cr19Ni12W3NbN, which comprises by weight: 0.10-0.18% of C, 0.4-0.8% of Mn, less than or equal to 0.015% of P, less than or equal to 0.01% of S, 0.4-0.7% of Si, 2.9-3.6% of W, 19.05-21.95% of Cr, 11.50-13.0% of Ni, less than or equal to 0.01% of B, 0.20-0.28% of N, 0.001-0.008% of Mg, less than or equal to 2.0% of Co, less than or equal to 1.0% of V, less than or equal to 0.5% of Mo, and 0.85-1.25% of Nb+Ta%, with the ratio of Cr/N less than or equal to 98. In the invention, nitrogen is employed as an interstitial solid solution for strengthening the alloy, and consequently the sigma b value of the metal material is improved to a degree greater than or equal to 850Mpa. In addition, the Fe-based heat-resisting alloy provided in the invention can replace WR26 Ni-based alloy and be used under the states of anti-corrosion, cold resistance and thermal fatigue at a temperature below 780DEG C, thus both saving the rare metals of Ni and Co and substantially reducing the product cost.

Description

A kind of refractory Fe-base alloy and preparation method thereof

Technical fieldThe present invention relates to a kind of Alloy And Preparation Method.

Background technologyAt present, the flange of gigawatt Large Steam Turbine Sets and fastening piece all adopt nickel based super alloy (WR26).This alloy at high temperature has premium propertiess such as intensity height, solidity to corrosion be strong, but the working conditions of above-mentioned Steam Turbine is middle low-temperature condition (below 780 ℃), nickel based super alloy under this temperature (WR26) fatigue resistance is poor, cause work-ing life short, this cost of alloy height causes Steam Turbine cost height again simultaneously.

Summary of the inventionThe object of the present invention is to provide a kind of not only every performance index to meet technical requirements but also cost is low, the refractory Fe-base alloy of long service life and preparation method thereof.

Refractory Fe-base alloy of the present invention is: 1Cr19Ni12W3NbN, and the weight percentage of its each component is as follows: C 0.10-0.18%, Mn 0.4-0.8%, P≤0.015%, S≤0.01%, Si 0.4-0.7%, W 2.9-3.6%, Cr 19.05-21.95%, Ni 11.50-13.0%, B≤0.01%, N 0.20-0.28%, Mg 0.001-0.008%, Co≤2.0%, V≤1.0%, Mo≤0.5%, Nb+Ta% 0.85-1.25%; And the ratio of chromium and nitrogen: Cr/N≤98.

Preferably calculate chromium equivalent, nickel equivalent according to following formula:

Chromium equivalent=Cr+6Si+4Mo+1.5W+11V+5Nb,

Nickel equivalent=40C+2Mn+4Ni+2Co+30N,

Chromium equivalent and nickel equivalent should be positioned at stainless steel phasor austenite region.

Preparation method of the present invention is as follows:

1, melting: place the induction furnace heating to make it fusing metallic nickel, extra low carbon ferrochromium, chromium nitride, ferro-niobium, before tapping, add ferro-boron, metallic cerium and nickel magnesium alloy.At 1650 ℃ of steel tapping casting Φ 200mm electrode bars.Whether within the limits prescribed to detect its each component percentage composition, and calculate the chromium nickel equivalent whether in stainless steel phasor austenite region.

2, esr: place remelting furnace to carry out electroslag smelting above-mentioned electrode bar, be melt into steel ingot.This electroslag smelting adopts quaternary slag system electroslag, and this quaternary slag system includes: calcium oxide (CaO) 8-12%, Calcium Fluoride (Fluorspan) (CaF2) 63-67%, aluminium sesquioxide (Al2O3) 18-22%, magnesium oxide (MgO) 3-7%.Formula calculated below the quantity of slag adopted: the %G ingot of the quantity of slag=(4-5), wherein the G ingot is that ESR ingot is heavy.

3, forge: place the solid solution stove to heat on above-mentioned steel ingot, temperature is 1140-1160 ℃, forges with pressing machine then, and final forging temperature is greater than 900 ℃, and deflection is swaged into pole or cake greater than 20%.The check grain fineness number is qualified greater than 6 grades.

4, thermal treatment: when finished product forged, steel ingot adopted direct aging technology (DA technology) at 1150 ℃ of deflections more than or equal to 20% o'clock, implemented aging technique 16-20 hour for 750-770 ℃.

5, machining: use lathe can obtain bright as silver pole or cake finished product to surface of steel ingot turning.

The present invention compared with prior art has following advantage:

1, the present invention adopts nitrogen as the interstitial solid solution reinforced alloys, has improved the σ b value of this metallic substance, and it is more than or equal to 850Mpa.Can replace the WR26 nickel-base alloy under anti-corrosion, the anti-cold and thermal fatigue state that is lower than under 780 ℃, to use.

2, replace the nickel cobalt-based products by iron-based, not only save nickel cobalt rare metal but also reduce product cost greatly, the product that adopts alloy of the present invention to make only is 1/4. of a WR26 nickel-base alloy product cost

3, can save finished product thermal treatment solid solution craft commonly used by direct aging technology, not only save energy, reduce cost, and shortened technical process.

4, the user can directly carry out mechanical workout to steel ingot of the present invention, promptly obtains the finished product, need not to heat-treat, and makes following process simple.

Embodiment

Example 1

Add 250 kilograms of nickel plates, 750 kilograms of extra low carbon ferrochromiums, 80 kilograms of chromium nitrides, 94 kilograms of ferrotungstens, 41 kilograms of ferro-niobiums in 2 tons of medium-frequency induction furnaces, power-on then is with the above-mentioned raw materials heat fused.Before tapping, add 1.1 kilograms of ferro-borons, 0.2 kilogram of metallic cerium and 0.75 kilogram of nickel magnesium alloy.At 1650 ℃ of steel tapping casting Φ 200mm electrode bars.Detect its each component percentage composition all within the limits prescribed, and calculate the chromium nickel equivalent also in stainless steel phasor austenite region.The Φ 200mm electrode bar of pouring into a mould is above placed 5 tons of electroslag remelting furnaces, and control current is 7200A, voltage 58V.Adopt the quaternary slag system, wherein calcium oxide is 6 kilograms, 33.5 kilograms in Calcium Fluoride (Fluorspan), and 11 kilograms of aluminium sesquioxides, 3.5 kilograms in magnesium oxide is smelted into Φ 380mm steel ingot to Φ 200mm electrode bar with the quaternary slag system.Each components contents is respectively in this steel ingot: C 0.10-0.18%, and Mn 0.4-0.8%, P 0.015%, S 0.01%, Si 0.4-0.7%, W 2.9-3.6%, Cr 19.05-21.95%, Ni 11.50-13.0%, B 0.01%, N 0.20-0.28%, Mg 0.001-0.008%, Co 2.0%, and V 1.0%, Mo 0.5%, Nb+Ta% 0.85-1.25%.

Above-mentioned steel ingot is placed 24 meters continuous ovens, heat 1160 ℃, use 2500 tons of pressing machinees to forge, final forging temperature is greater than 900 ℃, and deflection is swaged into Φ 120mm pole greater than 20%.The check grain fineness number is greater than 6 grades.When finished product forged, steel ingot adopted direct aging technology 760 ℃ of timeliness 16 hours at 1150 ℃ of deflection 〉=20% o'clock, uses 4 meters pit furnaces of resistance wire heating.The check product performance: σ b 〉=850Mpa, σ 0.2 〉=580Mpa, δ be more than 5 〉=20%, grain fineness number 〉=6 grade.Use the lathe surface to be lathed the bright as silver pole material of Φ 120mm finished product.

Claims

1. refractory Fe-base alloy, it is characterized in that: refractory Fe-base alloy of the present invention is: 1Cr19Ni12W3NbN, the weight percentage of its each component is as follows: C 0.10-0.18%, Mn 0.4-0.8%, P≤0.015%, S≤0.01%, Si 0.4-0.7%, W 2.9-3.6%, Cr 19.05-21.95%, Ni 11.50-13.0%, B≤0.01%, N 0.20-0.28%, Mg 0.001-0.008%, Co≤2.0%, V≤1.0%, Mo≤0.5%, Nb+Ta% 0.85-1.25%; And the ratio of chromium and nitrogen: Cr/N≤98.

2. refractory Fe-base alloy according to claim 1 is characterized in that: calculate chromium equivalent, nickel equivalent according to following formula:

Chromium equivalent=Cr+6Si+4Mo+1.5W+11V+5Nb,

Nickel equivalent=40C+2Mn+4Ni+2Co+30N,

3. the preparation method of the described refractory Fe-base alloy of claim 1 is characterized in that:

1) metallic nickel, extra low carbon ferrochromium, chromium nitride, ferro-niobium are placed the induction furnace heating make it fusing, before tapping, add ferro-boron, metallic cerium and nickel magnesium alloy, at 1650 ℃ of steel tapping casting Φ 200mm electrode bars, whether within the limits prescribed to detect its each component percentage composition, and calculate the chromium nickel equivalent whether in stainless steel phasor austenite region;

2) place remelting furnace to carry out electroslag smelting above-mentioned electrode bar, be melt into steel ingot.

4. this electroslag smelting adopts quaternary slag system electroslag, and this quaternary slag system includes: calcium oxide 8-12%, and Calcium Fluoride (Fluorspan) 63-67%, aluminium sesquioxide 18-22%, magnesium oxide 3-7%, formula calculated below the quantity of slag adopted: the %G ingot of the quantity of slag=(4-5), wherein the G ingot is that ESR ingot is heavy;

3) place the solid solution stove to heat on above-mentioned steel ingot, temperature is 1140-1160 ℃, forges with pressing machine then, and final forging temperature is greater than 900 ℃, and deflection is swaged into pole or cake greater than 20%, and the check grain fineness number is qualified greater than 6 grades;

4) when finished product forges, steel ingot was implemented aging technique 16-20 hour for 750-770 ℃ in 1150 ℃ of deflection 〉=20% o'clock employing direct aging technology;

The preparation method of refractory Fe-base alloy according to claim 3 is characterized in that:

Use lathe can obtain bright as silver pole or cake finished product to surface of steel ingot turning.