Short-process manufacturing method of corrosion-resistant high-temperature gold alloy steel plate

Abstract

The invention provides a short-process manufacturing method of a corrosion-resistant high-temperature gold alloy steel plate. A process route of EAT electric arc furnace-AOD furnace refining-LF furnace refining-VD vacuum refining-ingot mold casting-prefabricated plate blank forging-rolling-heat treatment is adopted. According to the production process of the steel plate, the steel ingot is heated to a certain temperature to be subjected to slab forging and then rolled, heat treatment is carried out after the steel plate is rolled and formed, and good tissue and comprehensive mechanical properties are obtained. The corrosion-resistant high-temperature alloy medium-thickness steel plate product is manufactured by optimizing the composition proportion, casting the steel ingot, forging the plate blank, rolling the steel plate, performing heat treatment and selecting reasonable smelting, forging, rolling and heat treatment processes, and the obtained material has relatively high room-temperature / high-temperature tensile strength, reasonable grain size and hardness and good intergranular corrosion resistance; according to the method, the product quality is improved, the rejection rate is reduced, and compared with the prior art, the method has great practical application value.

Description

Technical Field

[0001] The invention relates to the technical field of corrosion-resistant high-temperature alloys for new energy photovoltaic polysilicon equipment, and in particular to a method for manufacturing corrosion-resistant high-temperature gold alloy medium-thick steel plates by smelting-forging-rolling-heating. Background Art

[0002] As petrochemical and coal resources are increasingly depleted, the world is paying more and more attention to the development of the new energy industry. Solar energy is a new energy product that countries around the world are competing to develop, and it is an effective way to achieve the "dual carbon goals". The production of photovoltaic high-purity polysilicon requires the use of core equipment such as cold hydrogenation reactors. Because it needs to have high temperature and corrosion resistance in the production process of polysilicon, the main material of the design mainly uses corrosion-resistant high-temperature alloy steel plate materials. However, the current preparation method has a long production cycle, high cost, and unstable quality. In order to obtain corrosion-resistant high-temperature alloy medium and thick steel plates with excellent comprehensive performance, stable quality, low cost and high efficiency, it is necessary to optimize the material composition ratio, production process, and preparation method, and reasonably select the smelting, forging, rolling and heat treatment processes and manufacturing processes of the steel plates. Summary of the invention

[0003] The purpose of the present invention is to provide a corrosion-resistant high-temperature gold alloy medium and thick steel plate smelting-forging-rolling-heat treatment manufacturing method, which ensures that the comprehensive properties such as room temperature strength, high temperature strength, hardness, grain size and bending meet the standards and have obvious advantages in product performance.

[0004] The technical solution of the present invention is a short-process manufacturing method for a corrosion-resistant high-temperature gold alloy steel plate, wherein the chemical composition of the steel plate is composed of the following components by weight percentage: C: 0.05-0.10%, Si: ≤1.00%, Mn: ≤1.50%, P: ≤0.03%, S: ≤0.015%, Cr: 19-23%, Ni: 30-35%, Cu: ≤0.75%, Ti: 0.15-0.60%, Al: 0.15-0.60%, and the gas elements [H] ≤2ppm, [O] ≤ 50ppm, [N]≤150ppm, the balance is Fe and unavoidable impurities, and the EAF electric arc furnace-AOD furnace refining-LF furnace refining-VD vacuum refining-die casting process is adopted to smelt and cast steel ingots; the steel ingots are heated to 1220℃, forged into rectangular billets, and the rectangular billets are rolled into plates. The initial heating temperature of rolling is set at 1260℃, and the final forging temperature of the plates in each process is required to be greater than 950℃. In the forming stage of the last fire, the final forging temperature is greater than 900℃, and the rolling ratio is greater than 6; the steel plates are heat treated after rolling.

[0005] The specific steps include the following: Step 1: The raw materials are smelted and cast into steel ingots by using the EAF electric arc furnace - AOD furnace refining - LF furnace refining - VD vacuum refining - mold casting process. The specifications of the steel ingots are H (thickness) × W (width) × L (length); Step 2: Forging of rectangular billet: heat the steel ingot to the initial forging temperature of 1220℃, keep it warm for 7h, widen and draw it to H1 (thickness) × W1 (width) × L1 (length), the final forging temperature is 950℃, and air-cool it after forging; Step 3: The steel plate is rolled for the first time, the initial heating temperature is set at 1260°C, the final forging temperature of each rolling process is required to be greater than 950°C, and the obtained rectangular billet is transversely rolled to H2 (thickness) × W2 (width) × L1 (length); Step 4: The steel plate is rolled for the second time, the initial heating temperature is set at 1260°C, the final forging temperature of each rolling process is required to be greater than 900°C, and the billet obtained in step 3 is axially rolled to the required specifications of H3 (thickness) × W2 (width) × L2 (length); Step 5: Heat treatment of formed steel plate, solution treatment, loading into furnace at ≤400℃, heating to 1150±10℃ at a speed of ≤120℃ / h, keeping at temperature for 2.5h, and cooling quickly after being taken out of furnace; Step 6: Stabilization treatment of formed steel plate: below 400℃, heating speed is not controlled; heating speed from 400℃ to 899℃ does not exceed 100℃ / h; insulation temperature and time: (899±14)℃ constant temperature for 5 hours, cooling speed does not exceed 80℃ / h after insulation, and after cooling to 400℃, take out of the furnace and air cool.

[0006] The chemical composition of the corrosion-resistant high-temperature gold alloy of the present invention is optimized on the basis of the standard requirements: C content is one of the main factors to ensure that the strength meets the requirements of the specification. If the C content is low, the strength cannot meet the requirements; if the C content is high, the precipitation of chromium carbide in the steel plate product will increase, resulting in chromium deficiency in the local area, affecting the intergranular corrosion performance of the steel plate. Considering that the steel belongs to a solid solution-strengthened corrosion-resistant high-temperature alloy, the C content is controlled at 0.6%~0.80%; Mn can improve the strength of the steel and weaken and eliminate the adverse effects of sulfur, so Mn is controlled at 0.6-0.9%; Al+Ti content is the main factor to ensure that the strength meets the requirements of the specification. If the Al+Ti content is low, the strength cannot meet the requirements; if the Al+Ti content is high, the weldability of the steel plate will be reduced. Considering that the steel belongs to a solid solution-strengthened corrosion-resistant high-temperature alloy, the Al+Ti content is controlled at 0.40%~0.70%; Si element is the main element for the formation of ferrite, which is a strengthening factor and also a factor that promotes embrittlement. Si itself does not cause embrittlement, but promotes the embrittlement of P: when P is high, Si often squeezes P to the grain boundary (when the cooling speed of heat treatment after forging is slow, and the tempering parameter Pt value is greater than a certain value due to many tempering times, the embrittlement factor will also precipitate at the grain boundary), and O will also combine with Si to form SiO2-type oxide inclusions and enrich the grain boundary, resulting in embrittlement at the grain boundary, so the Si content is controlled at the middle and lower limits; corrosion-resistant high-temperature gold alloy steel plates have extremely strict restrictions on harmful elements such as Cu, As, Sn, and Sb, and extremely strict control requirements are put forward for the above harmful elements. At the same time, the material is required to have good purity, good plasticity and toughness, so the requirements for harmful elements and gas elements such as S, P, H, O, and N are relatively strict.

[0007] Beneficial effects of the present invention: (1) The present invention optimizes the composition ratio and the smelting, forging, rolling and heat treatment process of steel ingot forging and rolling, so that the medium and thick steel plate has comprehensive properties such as room temperature strength, high temperature strength, hardness, grain size and bending and corrosion resistance. After multiple production verifications, its room temperature / high temperature strength, grain size, intergranular corrosion, cold bending, hardness and other properties meet the standard requirements, and each performance index has a large margin.

[0008] (2) The corrosion-resistant high-temperature alloy steel plate of the present invention is manufactured by adopting the process route of steel ingot smelting + forging + rolling + heat treatment. The manufacturing process of the present invention is easy to implement. The present invention improves the stability of product quality, shortens the production process, and improves production efficiency. Compared with the existing technology, it has great practical application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a production step diagram of corrosion-resistant high-temperature gold alloy steel plate; Figure 2 This is the metallographic micrograph of Example 1 after solid solution + stabilization DETAILED DESCRIPTION

[0010] The present invention is further described in detail below.

[0011] Example 1 A corrosion-resistant high-temperature gold alloy steel plate, the chemical composition of which is composed of the following components by mass percentage: C: 0.07; Si: 0.32; Mn: 0.90; P: 0.005; S: 0.001; Cr: 20.34; Ni: 30.50; Cu: 0.06; Al: 0.27; Ti: 0.28; gas elements [H]: 1.8 ppm; [O]: 38 ppm; [N]: 130 ppm; the balance is Fe and unavoidable impurities.

[0012] Steel plate manufacturing process, the above-mentioned steel plate includes the following manufacturing processes: Step 1: The raw materials are smelted and cast into steel ingots using the EAF electric arc furnace - AOD furnace refining - LF furnace refining - VD vacuum refining - mold casting process. The specifications of the steel ingots are 510mm (thickness) × 1430mm (width) × 1700mm (length); Step 2: Preform forging: heat the steel ingot to the initial forging temperature of 1220°C, keep it warm for 7 hours, widen and lengthen it to 245mm (thickness) × 1600mm (width) × 2800mm (length), the final forging temperature is 950°C, and air-cool it after forging; Step 3: The steel plate is rolled for the first time, the initial heating temperature is set at 1260°C, the final forging temperature of each rolling process is required to be greater than 950°C, and the obtained prefabricated slab is rolled transversely to 205mm (thickness) × 2370 (width) × 2800mm (length); Step 4: The steel plate is rolled for the second time, the initial heating temperature is set at 1260°C, the final forging temperature of each rolling process is required to be greater than 900°C, and the resulting billet is axially rolled to the required specifications of 58mm (thickness) × 2370mm (width) × 9925 (length); Step 5: Heat treatment, solution treatment, loading into furnace at ≤400℃, heating to 1150±10℃ at a rate of ≤120℃ / h, keeping at that temperature for 2.5h, and cooling quickly after exiting the furnace; Step 6: Stabilization treatment: below 400℃, heating rate is not controlled; heating rate from 400℃ to 899℃ does not exceed 100℃ / h; insulation temperature and time: (899±14)℃ constant temperature for 5 hours, cooling rate after insulation does not exceed 80℃ / h, after cooling to 400℃, take out of the furnace and air cool.

[0013] The performance of the corrosion-resistant high-temperature gold alloy steel plate prepared by the above smelting, forging, rolling and heat treatment is tested: After the steel plate was treated with solid solution and stabilization, the samples were taken for mechanical properties, cold bending test, microstructure, non-metallic inclusions and grain size test, and the test results fully met the standard requirements. After the steel plate was treated with solid solution and stabilization, the intergranular corrosion tendency test was carried out according to the A method of ASTM G28-2002 (R2015), and the corrosion rate was 0.071mm / year, which met the technical requirements.

[0014] Solution treatment (1150℃ insulation for 2.5h water cooling) + stabilization treatment (899℃ insulation for 5h) p0.2 / MPa=230, Rm / MPa=534, A%=51, Z%=76, hardness (HB)=160 (≤171), 590℃R p0.2 / MPa=127, 590℃Rm / MPa=434, the microstructure is austenite, the grain size grade is 2.5 (1-5), the non-metallic inclusion grade is no more than 1.5, and A+C≤2.0, B+D≤2.0, the total A+B+C+D+Ds≤4.5.

[0015] Although the present invention is disclosed as above, the protection scope of the present invention is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and these changes and modifications will fall within the protection scope of the present invention.

Claims

1. A short-process manufacturing method for a corrosion-resistant high-temperature gold alloy steel plate, wherein the chemical composition of the steel plate is composed of the following components by weight percentage: C: 0.05-0.10%, Si: ≤1.00%, Mn: ≤1.50%, P: ≤0.03%, S: ≤0.015%, Cr: 19-23%, Ni: 30-35%, Cu: ≤0.75%, Ti: 0.15-0.60%, Al: 0.15-0.60%, gas elements [H] ≤2ppm, [O] ≤50ppm, [N] ≤150ppm, the balance is Fe and unavoidable Impurities, characterized in that the EAF electric arc furnace - AOD furnace refining - LF furnace refining - VD vacuum refining - die casting process is adopted to smelt and cast steel ingots; the steel ingots are heated to 1220°C, forged into rectangular billets, and the rectangular billets are rolled into plates. The initial heating temperature of rolling is set at 1260°C, and the final forging temperature of the plate in each process is required to be greater than 950°C. In the forming stage of the last fire, the final forging temperature is greater than 900°C, and the rolling ratio is greater than 6; the steel plate is heat treated after rolling.

2. The short-process manufacturing method of the corrosion-resistant high-temperature gold alloy steel plate as claimed in claim 1 is characterized in that Forging of rectangular billets: heat the steel ingot to the initial forging temperature of 1220℃, keep it warm for 7h, and then widen and lengthen it to obtain a rectangular billet. The final forging temperature is 950℃, and it is air-cooled after forging.

3. The short-process manufacturing method of the corrosion-resistant high-temperature gold alloy steel plate as claimed in claim 1 is characterized in that The rectangular billet is first rolled and the resulting rectangular billet is transversely rolled.

4. The short-process manufacturing method of the corrosion-resistant high-temperature gold alloy steel plate as claimed in claim 1 is characterized in that The rectangular billet is rolled in the second heat, and the resulting billet is axially rolled to the required specifications.

5. The short-process manufacturing method of the corrosion-resistant high-temperature gold alloy steel plate as claimed in claim 1 is characterized in that Heat treatment of formed steel plates, solution treatment, loading into the furnace at ≤400℃, heating to 1150±10℃ at a speed of ≤120℃ / h, keeping warm for 2.5h, and cooling quickly after being taken out of the furnace.

6. The short-process manufacturing method of the corrosion-resistant high-temperature gold alloy steel plate as claimed in claim 1, characterized in that For stabilization treatment of formed steel plates, the heating rate is not controlled below 400℃; the heating rate from 400℃ to 899℃ does not exceed 100℃ / h; the holding temperature and time are: (899±14)℃ for 5 hours, and the cooling rate after the holding does not exceed 80℃ / h. After cooling to 400℃, take out of the furnace and air cool.

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