Post-forging dehydrogenation annealing technology of chromium-containing high-nickel alloy steel forged piece

An annealing process and alloy steel technology, which is applied in the field of alloy steel manufacturing process, can solve the problems of poor hydrogen expansion effect, huge manpower cost, failure to achieve hydrogen expansion effect, etc., achieve low hydrogen solubility, fast diffusion speed, and facilitate hydrogen diffusion escape effect

Active Publication Date: 2016-08-10
HENAN ZHONGYUAN SPECIAL STEEL EQUIP MFG CO LTD
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  • Abstract
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  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Therefore, we adopt the current conventional top-down hydrogen expansion annealing process, that is, first normalize and keep warm, then overcool above the martensitic transformation start temperature, then heat up to the pearlite transformation zone for hydrogen expansion annealing or direct slow cooling after forging Hydrogen expansion annealing to the pearlite transformation zone takes a long time for the entire pearlite incubation period and complete transformation zone, and the hydrogen expansion effect is very poor, often spending huge manpower, material and financial resources to fail to achieve the expected hydrogen expansion effect , and cause forgings to form white spot defects due to insufficient hydrogen diffusion

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0017] A post-forging hydrogen expansion annealing process for chromium-containing high-nickel alloy steel forgings. The forging size is φ380mm×4200mm, and the chemical composition mass percentages are: C: 0.25%, Si: 0.20%, Mn: 0.19%, Ni: 3.70% , Cr: 1.80%, Mo: 0.45%, V: 0.12%, the balance is Fe and other unavoidable impurities, using electric furnace ingots.

[0018] After forging, cool the forging furnace to 650°C for heat preservation, heat up to 120°C above the complete austenitization temperature with full power, and use fog cooling to cool to 80°C below the martensitic transformation start temperature for short-term heat preservation; at 45°C / h to the high temperature tempering zone for uniform heat preservation, after the heat preservation is completed, cool in the furnace at 50°C / h to 400°C, and then cool in the furnace at 30°C / h to 50°C below the end temperature of martensitic transformation; at 50°C / h Raise the temperature to the high-temperature tempering zone for ...

Embodiment 2

[0021] A post-forging hydrogen expansion annealing process for chromium-containing high-nickel alloy steel forgings. The specification of the forging is 405mm (thickness) × 960mm (width) × 3000mm (length), and the mass percentage of chemical composition is: C: 0.40%, Si: 0.30 %, Mn: 0.50%, Ni: 4.20%, Cr: 1.30%, Mo: 0.20%, and the balance is Fe and other unavoidable impurities. Electroslag ingots are used.

[0022] After forging, cool the forging furnace to 550°C and keep it warm, heat it up to 100°C above the complete austenitization temperature with full power, and use air cooling to cool to 60°C below the martensitic transformation start temperature for short-term heat preservation; at 40°C / h to the high temperature tempering zone for uniform heat preservation, after the end of the heat preservation, cool in the furnace at 40°C / h to 400°C, and then cool in the furnace at 20°C / h to 40°C below the end temperature of martensitic transformation; at 40°C / h Raise the temperature...

Embodiment 3

[0025] A post-forging hydrogen expansion annealing process for chromium-containing high-nickel alloy steel forgings, the forging specification is 405mm (thickness) × 1250mm (width) × 3200mm (length), the chemical composition mass percentage is: C: 0.10%, Si: 0.60 %, Mn: 0.50%, Ni: 3.50%, Cr: 2.90%, Mo: 0.90%, Cu: 0.45%, Al: 0.85%, and the balance is Fe and other unavoidable impurities. Forged with electroslag ingot.

[0026] After forging, cool the forging furnace to 500°C and keep it warm, heat it up to 150°C above the complete austenitization temperature with full power, and use air cooling to cool to 50°C below the martensitic transformation start temperature for a short time; use 30°C / h to the high temperature tempering zone for uniform heat preservation, after the heat preservation is completed, cool in the furnace at 30°C / h to 400°C, and then cool in the furnace at 25°C / h to 30°C below the end temperature of martensitic transformation; at 35°C / h Raise the temperature t...

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Abstract

The invention relates to a post-forging dehydrogenation annealing technology of a chromium-containing high-nickel alloy steel forged piece. The technology comprises the specific steps of after forging, slowly cooling the forged piece to 500 to 700 DEG C, keeping the temperature, increasing the temperature with full power to a temperature 100 to 150 DEG C above a complete austenitizing temperature, keeping the temperature, cooling to a temperature 50 to 100 DEG C below a martensite transformation starting temperature, and keeping the temperature for a short time; increasing the temperature to a high-temperature tempering zone at the speed of 30 to 60 DEG C/h, keeping the temperature, after temperature keeping, carrying out furnace cooling to 400 DEG C at the speed of 30 to 60 DEG C/h, and carrying out furnace cooling to a temperature 10 to 50 DEG C below a martensite transformation ending temperature at the speed of 10 to 30 DEG C/h; and increasing the temperature to the high-temperature tempering zone at the speed of 30 to 60 DEG C/h, keeping the temperature, after temperature keeping, carrying out furnace cooling to 100 to 150 DEG C at the speed of 10 to 30 DEG C/h, taking the forged piece out of a furnace, and carrying out air cooling. According to the post-forging dehydrogenation annealing technology of the chromium-containing high-nickel alloy steel forged piece, the problems that annealing and dehydrogenation are difficult to carry out on the chromium-containing high-nickel alloy steel forged piece through a conventional method, and ultrasonic flaw detection defects are caused by white dots of forged pieces with relatively large specifications are solved better.

Description

technical field [0001] The invention belongs to the field of alloy steel manufacturing technology, and relates to a post-forging hydrogen expansion annealing process for chromium-containing high-nickel alloy steel forgings. Background technique [0002] One of the most detrimental effects of hydrogen in steel is the production of white spots, often causing forgings to be scrapped. The white spots are metal internal defects, which are shaped as microscopic cracks of different lengths and directions. On the transverse low-magnification test piece of the forging, there are jagged fine cracks; on the longitudinal fracture, there are round or oval spots with clear edges and silvery white luster. Although with the continuous development of vacuum metallurgy technology, the hydrogen content of the internal control of forgings has been effectively controlled, but most of the forgings are still produced by conventional smelting and pouring. Therefore, preventing white spots is s...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21D1/26C21D3/06C21D6/00
CPCC21D1/26C21D3/06C21D6/004C21D6/005C21D6/008
Inventor 周许王兴旺孙振环陈俸军姚伟
Owner HENAN ZHONGYUAN SPECIAL STEEL EQUIP MFG CO LTD
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