CN101845593A - Steel for 20 control Cr nuclear power and production method thereof - Google Patents

Abstract

Translated fromChinese

本发明涉及一种20控Cr核电用钢及其生产方法，钢的化学成分按重量百分比为：C 0.17～0.25％，Mn 0.4～1.0％，Si 0.18～0.25％，Cr 0.18～0.30％，S≤0.005％，Alt 0.020～0.040％，P≤0.015％，其余为Fe及不可避免的杂质。将按化学成分设计冶炼好的钢水浇铸成220～250mm厚板坯；加热炉加热温度1150～1250℃，加热时间3～5h；然后出炉进行两阶段轧制，然后进行正火处理。生产的产品屈服强度350MPa，抗拉强度480MPa，延伸率25％，高温拉伸屈服强度250MPa，-30℃横向冲击均值在100J，冷弯性能良好。本发明具有简化工序、节约成本、良好的高温拉伸性能，产品适应在核电工程中，处于高温紊流状态下的核电管件用钢。The invention relates to a 20-control Cr nuclear power steel and a production method thereof. The chemical composition of the steel is: C 0.17-0.25%, Mn 0.4-1.0%, Si 0.18-0.25%, Cr 0.18-0.30%, S ≤0.005%, Alt 0.020～0.040%, P≤0.015%, the rest is Fe and unavoidable impurities. The molten steel designed and smelted according to the chemical composition is cast into a 220-250 mm thick slab; the heating temperature of the heating furnace is 1150-1250 ° C, and the heating time is 3-5 hours; then it is rolled out of the furnace for two-stage rolling, and then normalized. The yield strength of the produced product is 350MPa, the tensile strength is 480MPa, the elongation is 25%, the high temperature tensile yield strength is 250MPa, the average transverse impact value at -30°C is 100J, and the cold bending performance is good. The invention has the advantages of simplified procedure, cost saving and good high-temperature tensile performance, and the product is suitable for nuclear power pipe fitting steel under high-temperature turbulent flow state in nuclear power engineering.

Description

20 control Cr nuclear powers steel and production method thereof

Technical field

The invention belongs to the qualitative carbon steel technical field of control Cr, product adaptation is in the nuclear power pipe fitting steel under the turbulent state in nuclear power engineering.

Background technology

Along with gradually reducing of traditional Nonrenewable energy resources from now on, pay close attention to the utilization of nuclear energy in countries in the world.The nuclear power that is adapted to third generation nuclear power technology with the exploitation of steel become more and more important.Current to the pressing for of energy strategy deposit in view of China, research and development have the nuclear power Plate Steel of the excellent property of independent intellectual property right, and for improving China's energy system, stand-alone development nuclear energy resource, the assurance national energy security is significant.

Nuclear power is used for the feedwater and the extraction line of low pressure feed water heater system, feed-water deaerator system, condensed water extraction system, electronic main feedpump system with 20 control Cr pipelines.In nuclear power engineering; when pipe fitting is under the turbulent state; because of influencing each other of fluidic flow at high speed, temperature and chemical environment; promoted the dissolving of the zone of oxidation that the carbon steel and low alloy steel tube-surface shields; thereby cause corrosion failure, promptly produce so-called " corrosion of flowing and quickening " phenomenon.According to the data from abroad introduction, the corrosive erosion rate of quickening that flows in the carbon steel depends on: factors such as fluid temperature (F.T.), flow velocity, pH value, electropotential, alloying element, thermodynamics.Wherein the alloying element of tubing is that iron and steel enterprise can control.According to abroad to the correlation test result of " relatively reduction-steel in Cr% relation " research: Cr content is the main alloy element that influences its FAC in the carbon steel tubing.Along with the increase of Cr content in the steel, relatively reduction reduces, when Cr content near 0.20% the time, reduction drops to 0.1% relatively.Because nuclear power is higher to security requirement, and vapour generator is also higher to the requirement of feedwater, and therefore, all system pipelines relevant with feedwater all adopt the high quality carbon steel pipe of control Cr in the nuclear power engineering.Because 20 control Cr steel are used for the high places of level of security such as nuclear power conventional island, are used to carry high-temperature medium, therefore for the molten steel purity, steel plate low power, low-temperature flexibility, performances such as drawing by high temperature all have strict technical requirements.

20 control Cr nuclear powers are produced with the TMCP+ normalizing process with steel.Nuclear power has characteristics such as simplifying working process, save cost and delivery cycle weak point with steel, help reducing investment outlay, improving operating efficiency in building the nuclear power projects process, shorten the construction period.20 control Cr are higher to every index requests such as low-temperature flexibility, high temperature tensile properties.The technical indicators such as low-temperature flexibility, high temperature tensile properties and welding property that improve 20 control Cr are important research directions.

Summary of the invention

The object of the present invention is to provide a kind of 20 control Cr nuclear powers steel and production method thereof.Present 20 control Cr nuclear powers with the subject matter that steel and production technology thereof exist are: the fluctuation of the high temperature tensile properties of (1) as-normalized condition delivery; (2) steel plate macroscopic examination and Control and Inclusion Removal strictness.(3) low-temperature impact work problem on the low side appears easily.

For satisfying every performance requriements, adopt carbon, silicon, manganese to add the composition design of Cr, the interpolation that the composition design is upward passed through carbon, silicon, manganese is as main strengthening element, and the interpolation of Cr is in order to reduce the erosion rate of carbon steel mobile accelerated corrosion in the nuclear power generating equipment use; Lower P, S control is in order to guarantee the requirement of steel plate low-temperature flexibility.The center component segregation of control continuous casting steel billet such as is mingled with at defective in the smelting process, is easy to obtain the continuous casting steel billet of better quality, helps guaranteeing the heart portion quality of thicker specification nuclear power with steel plate, improves product percent of pass.

The present invention relates to a kind of 20 control Cr nuclear powers steel and production method thereof, it is characterized in that, chemical ingredients by weight percentage: C 0.17～0.25%, Mn 0.4～1.0%, and Si 0.18～0.25%, and Cr 0.18～0.30%, S≤0.005%, Alt 0.020～0.040%, P≤0.015%, and all the other are Fe and unavoidable impurities.

CEQ=C+Mn/6+Cr/5 is less than 0.40;

Produce the production method of 20 control Cr nuclear powers, adopt sheet billet continuous casting, heating, controlled rolling, normalizing process with steel; Processing step is:

(1) good molten steel casting becomes 220～250mm heavy slab will according to chemical composition to design smelting; With pack into bar plate heating stove heating of blank, 1150～1250 ℃ of Heating temperatures, heat-up time 3～5h; Come out of the stove then and be rolled;

(2) the roughing start rolling temperature is controlled at 1060～1160 ℃; Intermediate blank is treated temperature thickness 40～80mm; The finish rolling start rolling temperature is controlled at 850～950 ℃; Finishing temperature is controlled at 770～840 ℃:

(3) normalizing temperature is 900 ℃～950 ℃, and soaking time is controlled at 10 ± 5min.

Steel plate thickness range of the present invention is 10～40mm.

Beneficial effect of the present invention is: the product microtexture of explained hereafter of the present invention is ferrite+perlite, product possesses good comprehensive mechanical properties: yield strength 300～350MPa, tensile strength reaches 450～500MPa, unit elongation reaches 25%, drawing by high temperature yield strength 210～250MPa ,-30 ℃ of summers than impact absorbing energy vertical on average more than 100J, cold-bending property is good.

Embodiment

Embodiment 1

20 control Cr nuclear powers with steel design mix by weight percentage are: C 0.18%, Mn0.50%, and Si 0.19%, and Cr 0.20%, and S 0.003%, and Alt 0.035%, and P 0.008%, and all the other are Fe and unavoidable impurities.The steel plate specification is: 10 * 2040 * 12000mm (thickness * width * length).

TMCP technology comprises heating, roughing, finish rolling, normalizing, is specially:

(1) good molten steel casting becomes 220～250mm heavy slab will according to chemical composition to design smelting; With pack into bar plate heating stove heating of blank, 1180 ℃ of Heating temperatures, heat-up time 4h; Come out of the stove then and be rolled;

(2) the roughing start rolling temperature is controlled at 1060 ℃; Intermediate blank is treated temperature thickness 40mm; The finish rolling start rolling temperature is controlled at 880 ℃; Finishing temperature is controlled at 820 ℃;

(3) normalizing temperature is 910 ℃, and soaking time is controlled at 8min.

The product yield strength 330MPa that produces, tensile strength 480MPa, unit elongation 27%, drawing by high temperature yield strength 220MPa ,-30 ℃ of transverse impact averages are at 100J, and cold-bending property is good.

Embodiment 2

20 control Cr nuclear powers with steel design mix by weight percentage are: C 0.21%, Mn0.55%, and Si 0.20%, and Cr 0.21%, and S 0.003%, and Alt 0.035%, and P 0.008%, and all the other are Fe and unavoidable impurities.The steel plate specification is: 20 * 2170 * 12000mm (thickness * width * length)

TMCP technology comprises heating, roughing, finish rolling, normalizing, is specially:

(1) good molten steel casting becomes the 220mm heavy slab will according to chemical composition to design smelting; With pack into bar plate heating stove heating of blank, 1200 ℃ of Heating temperatures, heat-up time 4h; Come out of the stove then and be rolled;

(2) the roughing start rolling temperature is controlled at 1070 ℃; Intermediate blank is treated temperature thickness 45mm; The finish rolling start rolling temperature is controlled at 880 ℃; Finishing temperature is controlled at 830 ℃;

(3) normalizing temperature is 910 ℃, and soaking time is controlled at 10min.

The product yield strength 350MPa that produces, tensile strength 470MPa, unit elongation 25%, drawing by high temperature yield strength 230MPa ,-30 ℃ of transverse impact averages are at 100J, and cold-bending property is good.

Embodiment 3

20 control Cr nuclear powers with steel design mix by weight percentage are: C 0.20%, Mn0.50%, and Si 0.20%, and Cr 0.25%, and S 0.003%, and Alt 0.035%, and P 0.008%, and all the other are Fe and unavoidable impurities.The steel plate specification is: 22.2 * 2325 * 12000mm (thickness * width * length)

TMCP technology comprises heating, roughing, finish rolling, normalizing, is specially:

(1) good molten steel casting becomes the 250mm heavy slab will according to chemical composition to design smelting; With pack into bar plate heating stove heating of blank, 1210 ℃ of Heating temperatures, heat-up time 4h; Come out of the stove then and be rolled;

(2) the roughing start rolling temperature is controlled at 1100 ℃; Intermediate blank is treated temperature thickness 50mm; The finish rolling start rolling temperature is controlled at 870 ℃; Finishing temperature is controlled at 810 ℃;

(3) normalizing temperature is 910 ℃, and soaking time is controlled at 10min.

The product yield strength 350MPa that produces, tensile strength 480MPa, unit elongation 25%, drawing by high temperature yield strength 250MPa ,-30 ℃ of transverse impact averages are at 100J, and cold-bending property is good.

Claims (3)

Translated fromChinese

1.20控Cr核电用钢及其生产方法，其特征在于，按重量百分比的化学成分：C 0.17～0.25％，Mn 0.4～1.0％，Si 0.18～0.25％，Cr 0.18～0.30％，S≤0.005％，Alt 0.020～0.040％，P≤0.015％，其余为Fe及不可避免的杂质。1.20 Cr-controlled nuclear power steel and its production method, characterized in that the chemical composition by weight percentage: C 0.17-0.25%, Mn 0.4-1.0%, Si 0.18-0.25%, Cr 0.18-0.30%, S≤0.005% , Alt 0.020～0.040%, P≤0.015%, the rest is Fe and unavoidable impurities.2.按照权利要求1所述的20控Cr核电用钢及其生产方法，其特征在于，CEQ＝C+Mn/6+Cr/5小于0.40；2. according to the 20-control Cr nuclear power steel described in claim 1 and production method thereof, it is characterized in that CEQ=C+Mn/6+Cr/5 is less than 0.40;3.生产如权利要求1所述的20控Cr核电用钢的生产方法，其特征在于，采用板坯连铸、加热、控制轧制、正火工艺；工艺步骤为：3. produce the production method of 20 control Cr nuclear power steel as claimed in claim 1, it is characterized in that, adopt slab continuous casting, heating, controlled rolling, normalizing process; Processing step is:(1)将按化学成分设计冶炼好的钢水浇铸成220～250mm厚板坯；将坯料装入板坯加热炉加热，加热温度1150～1250℃，加热时间3～5h；然后出炉进行轧制；(1) Cast the molten steel designed and smelted according to the chemical composition into a 220-250mm thick slab; put the slab into the slab heating furnace to heat, the heating temperature is 1150-1250°C, and the heating time is 3-5h; then it is rolled out of the furnace;(2)粗轧开轧温度控制在1060～1160℃；中间坯待温厚度40～80mm；精轧开轧温度控制在850～950℃；终轧温度控制在770～840℃；(2) The starting temperature of rough rolling is controlled at 1060-1160°C; the thickness of the intermediate billet to be warmed is 40-80mm; the starting temperature of finishing rolling is controlled at 850-950°C; the final rolling temperature is controlled at 770-840°C;(3)正火温度900℃～950℃，保温时间控制在10±5min。(3) The normalizing temperature is 900℃～950℃, and the holding time is controlled at 10±5min.