Manufacturing process of large 14Cr17Ni2 stainless steel forgings

Abstract

The invention discloses a manufacturing process of large 14Cr17Ni2 stainless steel forgings. The process comprises steps as follows: (1) optimization of chemical components: N elements with the content wt being 0.055%-0.065% are added, the content wt of Ti elements are controlled to be smaller than or equal to 0.010%; (2) forging: the large 14Cr17Ni2 stainless steel forgings are forged and heated at 1,100-1,180 DEG C, and the finish forging temperature is controlled to be larger than or equal to 950 DEG C; (3) thermal treatment: the large forgings are subjected to annealing, quenching and tempering, wherein annealing comprises steps as follows: after forging ends, the forgings are subjected to thermal insulation in a waiting furnace; a gate is closed, the furnace is cooled, and thermal insulation is performed; the temperature is increased to 690 DEG C plus or minus 10 DEG C for thermal insulation; the forgings are cooled and discharged from the furnace, and annealing is completed; quenching and tempering comprises steps as follows: the forgings are heated to 1,020 DEG C plus or minus 10 DEG C for thermal insulation, oil cooling is performed after the forgings are discharged from the furnace, and tempering is performed; the forgings are heated to 600 DEG C plus or minus 10 DEG C for thermal insulation and immediately subjected to oil cooling after being discharged out of the furnace. With the adoption of the manufacturing process, the problem that cracks are easily caused during forging of the large 14Cr17Ni2 forgings can be solved, mechanical properties of the large forgings are remarkably improved, and the use requirements of internal components of nuclear power reactors are completely met.

Description

technical field [0001] The invention relates to a manufacturing process of a large forging of 14Cr17Ni2 stainless steel, in particular to a nitrogen-containing 14Cr17Ni2 stainless steel capable of being used for a large forging of nuclear power reactor internal components and a preparation process thereof. Background technique [0002] 14Cr17Ni2 series ferritic-martensitic stainless steel is a kind of steel with good strength and toughness. It has good corrosion resistance to aqueous solutions of oxidizing acids, most organic acids and organic salts. Its main application field is small forgings. For small forgings, its smelting, forging and heat treatment are easier to control, and the preparation is less difficult. Corrosion-resistant shafts, piston rods, pumps and other parts. [0003] Nuclear power reactor internals are the heart components of high-power nuclear power plants, and are crucial to ensuring the absolute safety and reliability of the reactor pressure vessel ...

AI Technical Summary

Problems solved by technology

[0007] During the forging process, 14Cr17Ni2 stainless steel has poor forgeability due to the coexistence and interaction of delta ferrite and austenite phases. Ring forgings with large forgings with large deformation are prone to cracks during the forging process, resulting in forging failure

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