Grain size controlling forging method for super-large section shaft austenite pipeline

A technology of pipe control and section axis, applied in the field of metal forging, can solve the problems of difficulty in meeting the grain size requirements of forgings, increase the difficulty of forging and increase the smelting defects of steel ingots, etc., so as to improve macrosegregation, reduce product cost, and improve material quality The effect of density

Active Publication Date: 2019-11-19
SHANGHAI ELECTRIC SHMP CASTING & FORGING CO LTD
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Problems solved by technology

With the increase of steel ingots required for CAP1400 main pipe forgings, it not only increases the difficulty of forging and forming, but also increases the smelting defects of the steel ingots themselves, which increases the final flaw detection risk of forgings and makes it difficult to meet the final grain size requirements of forgings
[0005] Therefore, the control of grain size of forgings is still the key technical point of main pipeline forgings, and there is no domestic main pipeline forgings that can meet the requirements of grain size above 2.7

Method used

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  • Grain size controlling forging method for super-large section shaft austenite pipeline
  • Grain size controlling forging method for super-large section shaft austenite pipeline
  • Grain size controlling forging method for super-large section shaft austenite pipeline

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Embodiment 1

[0038] see Figure 1-7 , a forging method for controlling the grain size of a shaft-like austenitic pipe with a super large cross-section, the forging method includes the following steps:

[0039] Step 1: Press the pliers + pre-drawn, heat the stainless steel ingot to 1220°C ~ 1270°C, keep it warm for 37 ± 5h, put the forging billet into the furnace and heat it to 1220°C ~ 1270°C for a period of time, then forge. The amount of deformation changes in a single fire, and the surface of the steel ingot is lightly pressed three times. The single-sided reduction of the press pliers + pre-drawn long middle forging billet A is 50-100mm, and the forging billet A is made, and the columnar crystals on the surface of the steel ingot are broken to promote Dynamic recrystallization of surface grains occurs, which improves surface plasticity and reduces cracking tendency; the external dimensions of the electroslag ingot used in the hot section B of the main pipeline involved in the present i...

Embodiment 2

[0048] The other content of this embodiment is the same as that of Embodiment 1, the difference is that in step 8, the straight sections at both ends of the middle nozzle are elongated step by step, and the nozzle section is flattened at the completion of the fire. forming.

[0049] The invention firstly reduces the component segregation of large-sized steel ingots by keeping the steel ingots at high temperature for a long time. Controlled forging technology is adopted to strictly control the temperature and time of forging heat preservation, and the combination of overall upsetting and wide anvil strong pressure is used to quickly refine the coarse grains inside the steel ingot and the internal defects of welded large steel ingots. At the same time, controlling the single-fire deformation rate and the heat preservation conditions of the furnace, and balancing the forging deformation and dynamic recrystallization process are conducive to maintaining the fine-grained structure....

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Abstract

The invention relates to the technical field of metal forging and discloses a grain size controlling forging method for a super-large section shaft austenite pipeline. The forging method comprises thefollowing eight steps: pincers handle pressing+pre-drawing out; upsetting; drawing out; secondary upsetting; secondary drawing out; blazing and splitting; preliminary drawing out; and drawing out. Bymeans of high-temperature and large-deformation forging techniques, columnar crystals are crushed, macrosegregation is improved, the as-cast structure is crushed, inner holes are welded, reasonable fiber direction distribution is obtained, the compactness of a material is improved, grains are refined and tissues are uniformed. Meanwhile, the single heating number deformation rate of a forging stock is controlled, deformation and recrystallization processes are balanced, and a local forging condition as a result of single heating number is avoided to obtain more uniform grain tissues. By reasonably arranging a forging and forming step, other extra tools are not needed, so that the product cost is lowered effectively. By means of the method, a main pipeline product part which is accurate indimension, qualified in flaw detection and excellent in grain size is obtained.

Description

technical field [0001] The invention relates to the technical field of metal forging, in particular to a forging method for controlling the grain size of a shaft-like austenitic pipe with a super large cross-section. Background technique [0002] The CAP1400 nuclear power plant is one of the landmark projects of my country's construction of an innovative country. It is developed by my country Nuclear Engineering Co., Ltd. on the basis of digesting and absorbing the third-generation nuclear power AP1000 technology introduced in my country, and has my country's independent intellectual property rights and the largest power through re-innovation. Passive large-scale advanced pressurized water reactor nuclear power technology brand. With the continuous upgrading of my country's nuclear power technology, higher requirements are put forward for nuclear power equipment. For example, the main pipeline, as one of the seven key equipment of the nuclear island, has stricter requirements...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B21J5/08B21J5/06
CPCB21J5/06B21J5/08
Inventor 张灵芳李兆银董凯
Owner SHANGHAI ELECTRIC SHMP CASTING & FORGING CO LTD
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