Processing Technology of Large Duplex Stainless Steel Impeller

Abstract

The invention involves a large -scale two -phase stainless steel impeller processing technology, including the deformed protection, solid solution treatment before casting, thermal treatment, coarse polishing, component re -inspection, mechanical performance inspection, RT ray detection, cleaning defect supplement welding and polishing,Crude processing, repair, anti -stress thermal treatment, semi -precision processing, fine polishing, precision processing and balance testing and other steps. The processing of the processing of the invention is small, the size is small, the impeller processing size is good, and the surface is high.The completion size inspection is controlled below 40 ° C; and the processing efficiency is high and the quality is good, which can ensure the size accuracy and position size of the impeller to meet the size of the size and technical requirements of the drawings.

Description

technical field

[0001] The invention relates to a processing technology of an impeller, in particular to a processing technology of a large-scale duplex stainless steel impeller, which is especially suitable for producing a large-scale duplex stainless steel impeller for nuclear power, and belongs to the technical field of material processing engineering. Background technique

[0002] Large duplex stainless steel impellers are mainly used in nuclear power plant volute seawater circulation pumps. Duplex stainless steel impellers are widely used in seawater circulation pumps, seawater booster pumps, seawater desalination and transportation in various nuclear power plants at home and abroad. In the prior art, due to the combined influence of materials and processing steps, especially for large duplex steel impellers with a diameter of more than 2000mm, the processing process is difficult to control, the castings are deformed after casting, and the machining allowance is uneven....

Examples

Embodiment 1

[0039] a. For impeller casting, mix molten steel according to ASTM 890 Gr5A standard, and cast the workpiece, and test block of molten steel in the same furnace; the size of the test block is implemented according to ASTM A370 standard; the cutting cap is cleaned and polished; use zx5-1250 air planer to cut quickly Riser to ensure casting size;

[0040] b. Deformation protection before heat treatment, place the workpiece obtained from the above casting on a flat bracket, and hoist the flat bracket when the workpiece enters and exits the furnace to prevent thermal deformation of the workpiece during hoisting;

[0041] c. Solution treatment, heat the above-mentioned protected workpiece to 1120°C±10°C and keep it warm for 7H, then quickly take it out of the furnace, quench and cool it in water, and re-inspect the test block for heat treatment in the same furnace;

[0042] d. Rough grinding I, cleaning and rough grinding the workpiece after the above solution treatment, and visua...

Embodiment 2

[0057] In the step c, keep warm for 9H, then quickly take out the furnace and quench in water; in the step j, keep warm for 30H, and other steps are the same as in Example 1.

Embodiment 3

[0059] In the step c, keep warm for 5H, then quickly take out the furnace and quench in water; in the step j, keep warm for 36H, and other steps are the same as in Example 1.

[0060] The composition weight percent composition of molten steel in the step a of the present invention is as shown in Table 1, and the remaining composition is iron and unavoidable trace elements.

[0061] The mechanical properties of the present invention are as shown in table 2 after inspection.

[0062] The invention processes and tests the impeller used for the million-kilowatt power generation of the nest-shell type seawater circulation pump of a large nuclear power plant. 100% pass rate for dimension inspection, 100% pass rate for shape and position tolerance, 100% pass rate for surface roughness, 100% reasonable blade outlet width. The drawings and technical requirements are met through acceptance inspection. And when the test is used, the running quality of the whole machine is very good.

...

technical field

[0001] The invention relates to a processing technology of an impeller, in particular to a processing technology of a large-scale duplex stainless steel impeller, which is especially suitable for producing a large-scale duplex stainless steel impeller for nuclear power, and belongs to the technical field of material processing engineering. Background technique

[0002] Large duplex stainless steel impellers are mainly used in nuclear power plant volute seawater circulation pumps. Duplex stainless steel impellers are widely used in seawater circulation pumps, seawater booster pumps, seawater desalination and transportation in various nuclear power plants at home and abroad. In the prior art, due to the combined influence of materials and processing steps, especially for large duplex steel impellers with a diameter of more than 2000mm, the processing process is difficult to control, the castings are deformed after casting, and the machining allowance is uneven....

Examples

Embodiment 1

[0039] a. For impeller casting, mix molten steel according to ASTM 890 Gr5A standard, and cast the workpiece, and test block of molten steel in the same furnace; the size of the test block is implemented according to ASTM A370 standard; the cutting cap is cleaned and polished; use zx5-1250 air planer to cut quickly Riser to ensure casting size;

[0040] b. Deformation protection before heat treatment, place the workpiece obtained from the above casting on a flat bracket, and hoist the flat bracket when the workpiece enters and exits the furnace to prevent thermal deformation of the workpiece during hoisting;

[0041] c. Solution treatment, heat the above-mentioned protected workpiece to 1120°C±10°C and keep it warm for 7H, then quickly take it out of the furnace, quench and cool it in water, and re-inspect the test block for heat treatment in the same furnace;

[0042] d. Rough grinding I, cleaning and rough grinding the workpiece after the above solution treatment, and visua...

Embodiment 2

[0057] In the step c, keep warm for 9H, then quickly take out the furnace and quench in water; in the step j, keep warm for 30H, and other steps are the same as in Example 1.

Embodiment 3

[0059] In the step c, keep warm for 5H, then quickly take out the furnace and quench in water; in the step j, keep warm for 36H, and other steps are the same as in Example 1.

[0060] The composition weight percent composition of molten steel in the step a of the present invention is as shown in Table 1, and the remaining composition is iron and unavoidable trace elements.

[0061] The mechanical properties of the present invention are as shown in table 2 after inspection.

[0062] The invention processes and tests the impeller used for the million-kilowatt power generation of the nest-shell type seawater circulation pump of a large nuclear power plant. 100% pass rate for dimension inspection, 100% pass rate for shape and position tolerance, 100% pass rate for surface roughness, 100% reasonable blade outlet width. The drawings and technical requirements are met through acceptance inspection. And when the test is used, the running quality of the whole machine is very good.

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