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Casting process of ultralow-temperature valve casting

A casting process and ultra-low temperature technology, which is applied in the field of casting technology of ultra-low temperature valve castings, can solve the problems of material stress deformation and metamorphosis, and achieve the effect of improving ductility and toughness, improving purity and avoiding differences.

Active Publication Date: 2019-06-14
JIANGSU EVALVE GRP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] In order to avoid martensite transformation in low temperature environment, control the content of ferrite in austenitic stainless steel, and solve the problem of material undergoing stress deformation during cooling, the invention proposes a casting process for ultra-low temperature valve castings

Method used

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  • Casting process of ultralow-temperature valve casting
  • Casting process of ultralow-temperature valve casting
  • Casting process of ultralow-temperature valve casting

Examples

Experimental program
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Effect test

Embodiment 1

[0031] A casting process for ultra-low temperature valve castings, comprising the following steps:

[0032] S1: Casting design: including modeling design of valve castings, calculation of shrinkage rate of valve castings, and selection of parting surfaces, etc., to ensure the dimensional accuracy and quality of valve castings.

[0033] S2: Production preparation: Combining with the casting design in step S1, the preparation includes material preparation and production machinery equipment for producing valve castings, and core making work is performed at the same time.

[0034]S3: Smelting: According to the design, material and production requirements of the valve castings in steps S1 and S2, carry out the proportioning of furnace charges, select a suitable melting method, set a reasonable melting temperature and time, and control the material composition content of the valve castings; The charge ratio is mainly to use 90-95% of the high-alloy steel return material of this stee...

Embodiment 2

[0041] Performance inspection of ultra-low temperature valve castings in low temperature environment:

[0042] The castings produced by the casting process of Example 1 were placed in an environment of minus 196°C to carry out the impact test. The number of samples was 5, and the experiment was repeated. The test results are shown in Table 1:

[0043] Table 1. Impact test report of ultra-low temperature castings at -196°C

[0044]

Embodiment 3

[0046] The casting sample Z3 described in Example 2 will be used for gold sample analysis, the test method is GB / T13298-2015 metal microstructure inspection method, and the detection equipment is a metallographic microscope MS03, and the test results are as follows: figure 1 shown.

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Abstract

The invention discloses a casting process of an ultralow-temperature valve casting. The casting process comprises the steps of production preparation, smelting, casting, sand removing, finishing and the like. The content of ferrite in austenite is reduced by reducing the chromium / nickel equivalent ratio so as to avoid or reduce the ferrite embrittlement and martensite transformation of austeniticstainless steel. The element nitrogen is introduced to reduce the content of harmful elements sulfur and phosphorus. Silicon-calcium alloy and rare earth elements are introduced during molten steel deoxidation, so that the oxygen content and the impurity ratio are reduced. Measures such as the outage of a slagging process are adopted to improve the low-temperature impact resistance of the casting. In addition, more improvements have been made in the wall thickness difference of the casting, molten steel purification, a casting system, casting dead head cutting, shot blasting operation, heat treatment and the like since the start of the design of the casting process. Check results indicate that the valve casting produced by the casting process is stable in size stability and sealing performance after being subjected to treatment at the temperature of -196 DEG C, has the plasticity and toughness in a low-temperature environment, and is better in comprehensive usability.

Description

Technical field [0001] The invention relates to a casting process, specifically a casting process for ultra-low temperature valve castings. Background technique [0002] According to the requirements of my country's energy structure adjustment, the proportion of natural gas in energy supply will increase significantly. After years of efforts, important progress has been made in the localization of major equipment for natural gas liquefaction units and receiving stations. However, key equipment such as cryogenic valves, cryogenic pumps and loading and unloading arms have always relied on imports. In order to ensure national energy security and adapt to the "interconnection" needs of the natural gas pipeline network, the China General Machinery Industry Association and Kunlun Energy Plan organized and carried out follow-up localization research on key equipment based on the design and manufacturing requirements of the LNG project. [0003] Currently, austenitic stainless stee...

Claims

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Application Information

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IPC IPC(8): B22C9/02C22C33/06C21C7/06C21C7/00B22D31/00B22C9/08C21D9/00
Inventor 钱玉峰
Owner JIANGSU EVALVE GRP
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