A method for repairing defects of investment precision castings for liquid rocket engines

A defect repair and liquid rocket technology, applied in welding equipment, manufacturing tools, welding/cutting media/materials, etc., can solve problems such as uneven distribution of residual stress, achieve control of atomic diffusion speed, avoid grain growth, eliminate The effect of residual stress

Active Publication Date: 2022-04-08
XIAN SPACE ENGINE CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0011] In order to overcome the deficiencies in the prior art, the present inventor has carried out determined research, and provides a method for repairing defects of ZG03Cr13Ni5Co9Mo5 and ZG06Cr14Ni7Mo investment castings for liquid rocket engines. The special welding wire for ZG06Cr14Ni7Mo castings is based on the grade I weld of QJ1842-95 "Technical Conditions for Fusion Welding of Structural Steel and Stainless Steel" as the evaluation standard, and a welding process database based on the initial thickness of the repair welding part of the casting is established to ensure that the welding strength meets the design requirements. , and proposed a special post-weld heat treatment system for ZG03Cr13Ni5Co9Mo5 and ZG06Cr14Ni7Mo castings, which solved the problem of uneven distribution of internal organization and residual stress, thereby completing the present invention

Method used

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  • A method for repairing defects of investment precision castings for liquid rocket engines
  • A method for repairing defects of investment precision castings for liquid rocket engines
  • A method for repairing defects of investment precision castings for liquid rocket engines

Examples

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Effect test

Embodiment 1

[0066] In this example, the investment casting is the primary pump impeller of a certain type of fuel pump, the material is ZG06Cr14Ni7Mo, and the structure is as follows figure 2 and image 3 shown.

[0067] (1) Defect location.

[0068] The internal quality inspection method of the casting is X-ray inspection, the surface quality inspection method is fluorescent inspection, and the inspection level in the design drawing is Class B, and the allowable defects comply with the provisions in Table 2 and Table 3. If the above two inspection methods find defects beyond those specified in Table 2 and Table 3, the results shall be displayed on the X-ray film and the surface, and the position and size of the defects shall be marked on the casting.

[0069] Table 2 X-ray Inspection Standards for Castings

[0070]

[0071] Table 3 Fluorescent Inspection Standards for Castings

[0072]

[0073]

[0074] (2) Defect exclusion. Determine the size and location of the defect ac...

Embodiment 2

[0085] In this embodiment, the investment casting is a certain type of turbine oxygen pump centrifugal wheel, the material is ZG03Cr13Ni5Co9Mo5, and the structure is as follows Figure 8 and Figure 9 As shown, the primary impeller of the fuel pump has the same structure as the centrifugal impeller of the turbo oxygen pump in Embodiment 1 except that the blades rotate in the opposite direction.

[0086] The defect repair method is consistent with that in Embodiment 1, the only difference is:

[0087] The welding wire is wire-cut from the master alloy bar for casting, and the chemical composition should meet the requirements of the casting master alloy GJB7961. The specific chemical composition: 13.0% to 15.0% of Cr element, 6.0% to 8.5% of Ni element, 0.5% to 1.0% % Mo element, the rest is Fe element. The initial thickness of the repair welding part in this implementation is 5mm, and the welding process parameters are selected: the welding current A is 170A, the number of we...

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Abstract

The invention provides a method for repairing defects of investment mold precision castings for liquid rocket engines, including defect positioning; defect removal; groove processing; welding repair part treatment; welding; and post-welding treatment. This defect repair method specifies the welding wire used for ZG03Cr13Ni5Co9Mo5 and ZG06Cr14Ni7Mo castings, and establishes a welding process database based on the initial thickness of the repair welding part of the castings, as well as a post-weld heat treatment system; using the corresponding repair process, the resulting ZG03Cr13Ni5Co9Mo5 weld joint has a tensile strength at room temperature Greater than 1070MPa (matrix strength not less than 1180Mpa), elongation not less than 15%, low-temperature impact toughness at ‑196°C not less than 39J; ZG06Cr14Ni7Mo welded joints at room temperature tensile strength greater than 900MPa (matrix strength not less than 980Mpa ), the elongation rate is not less than 12%, the low-temperature impact toughness at ‑196°C is not less than 31J, and the internal quality and surface quality of the weld joint are both qualified, in line with QJ1842‑95 "Technical Conditions for Fusion Welding of Structural Steel and Stainless Steel" I Class welding seam standard, which can meet the requirements of aerospace products for welding seam joints.

Description

technical field [0001] The invention belongs to the technical field of investment precision casting, in particular to a method for repairing defects of ZG03Cr13Ni5Co9Mo5 and ZG06Cr14Ni7Mo investment precision castings for liquid rocket engines. Background technique [0002] Investment casting has the characteristics of high dimensional accuracy, good surface quality, and unrestricted structure, and is widely used in the production of liquid rocket engine castings. [0003] In order to meet the development needs of a new generation of high-pressure supplementary combustion liquid rocket engines, such as high chamber pressure, high speed, high thrust, and ultra-low temperature, ZG03Cr13Ni5Co9Mo5 and ZG06Cr14Ni7Mo martensitic stainless steel for investment casting have been developed, both of which are carbon-free (or ultra-low carbon) ) Martensite-based ultra-high-strength steel, through low-carbon martensitic phase transformation and aging precipitation of intermetallic compo...

Claims

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Application Information

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Patent Type & AuthorityPatents(China)
IPC IPC(8): B23P6/04B23K9/04B23K9/23B23K9/235B23K35/30
CPCB23P6/04B23K9/04B23K9/235B23K9/23B23K35/3086
Inventor吴晓明王玉杨欢庆彭超纪艳卿王琳高斌
OwnerXIAN SPACE ENGINE CO LTD