Bainite isothermal heat treatment method for medium carbon silicon manganese chromium nickel series low alloy steel

A medium-carbon silicon-manganese-chromium-nickel system and carbon-silicon-manganese-chromium-nickel system technology, applied in the field of warm heat treatment, can solve problems such as failure to meet the high strength and toughness requirements of key components, unqualified product performance, and hindering the progress of aircraft manufacturing. Excellent stress corrosion resistance, improved comprehensive mechanical properties, and good plasticity and toughness

Active Publication Date: 2016-12-28
CAPITAL AEROSPACE MACHINERY +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, when this traditional process is applied to the cross shaft of an aircraft engine, the performance of many batches of products is unqualified, lower than the performance indicators of σb≥1570MPa, σ0.2≥1285MPa, and δ5≥9%, which cannot meet the requirements of key components. High strength and toughness requirements seriously hinder the progress of aircraft manufacturing

Method used

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  • Bainite isothermal heat treatment method for medium carbon silicon manganese chromium nickel series low alloy steel
  • Bainite isothermal heat treatment method for medium carbon silicon manganese chromium nickel series low alloy steel
  • Bainite isothermal heat treatment method for medium carbon silicon manganese chromium nickel series low alloy steel

Examples

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Effect test

Embodiment 1

[0025] The bainite isothermal heat treatment of 40SiMnCrNiMoV series medium carbon silicon manganese chromium nickel series low alloy steel is achieved through the following steps:

[0026] Step 1) Austenitizing the medium-carbon silicon-manganese-chromium-nickel low-alloy steel. Described austenitizing temperature is A of medium carbon silicon manganese chromium nickel series low alloy steel. c3 Above 30℃~50℃, the holding time is 10min~30min, where A c3 is the final temperature when the ferrite is completely transformed into austenite during heating;

[0027] Step 2) performing isothermal quenching at a temperature of 5°C to 60°C above the martensitic transformation starting point Ms of the medium carbon silicon manganese chromium nickel series low alloy steel, and the holding time is 120 to 180 minutes;

[0028] Step 3) Temper the medium carbon silicon-manganese-chromium-nickel-based low-alloy steel treated in step 2) at 10°C to 60°C higher than the austempering temperatur...

Embodiment 2

[0035] The difference between this example and Example 1 is that the holding time in step 2) is 180-240 min. Others are the same as in Example 1.

Embodiment 3

[0037] The bainite isothermal heat treatment method for the carbon-silicon-manganese-chromium-nickel-based low-alloy steel in the 40SiMnCrNiMoV series of the present embodiment is achieved through the following steps: heat the carbon-silicon-manganese-chromium-nickel-based low-alloy steel in the 40SiMnCrNiMoV series at 850° C. to 900° C. After the austenitizing treatment is completed under heat preservation for 15 to 20 minutes, isothermal quenching is performed at a temperature of 250 to 300 degrees, and the temperature is maintained for 120 to 180 minutes, and then tempered at 10 to 60 degrees above the quenching temperature, and the holding time is 30 to 150min.

[0038] The beneficial effects of the heat treatment method for the carbon-silicon-manganese-chromium-nickel low-alloy steel in the 40SiMnCrNiMoV series of the present embodiment are verified through the test in Table 2.

[0039] The metallographic photo of 40SiMnCrNiMoV steel after treatment in test 2 is as follow...

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Abstract

A bainite isothermal heat treatment method of medium-carbon silicomanganese nickel-chromium-series low-alloy steel aims to solve a problem that performance requirements of some key components cannot be satisfied since yield strength is significantly low when a temper temperature is lower than an isothermally quenching temperature in a conventional isothermal heat treatment technology. The method includes following steps: performing austenitizing treatment to the medium-carbon silicomanganese nickel-chromium-series low-alloy steel; carrying out isothermal oil-quenching or isothermal gas-quenching at a temperature which is higher than a martensite transformation temperature by 5-60 DEG C with the temperature being maintained for 120-180 min; and performing tempering at a temperature which is higher than an isothermal quenching temperature by 10-60 DEG C for 30-150 min. Through treatment by the method, the medium-carbon silicomanganese nickel-chromium-series low-alloy steel has a tensile strength reaching 1590-1980 MPa, a yield strength reaching 1350-1770 MPa and a ductility being 14-25%.

Description

technical field [0001] The invention relates to a bainite isothermal heat treatment method for medium-carbon silicon-manganese-chromium-nickel low-alloy steel. Background technique [0002] Medium-carbon silicon-manganese-chromium-nickel low-alloy steel is a low-alloy high-strength steel. Its carbon content is generally between 0.25-0.5%, and the total content of alloying elements is not higher than 5%. The role of hardenability; the addition of Mo and V elements can refine the grains, improve the microstructure of the steel, and improve the tempering ability of the steel. Because of its high strength, medium carbon silicon-manganese-chromium-nickel low-alloy steels have been used in aircraft landing gear, rocket shell materials and engine pump cross shafts. With the development of aerospace technology, higher and higher requirements are also put forward for the comprehensive strength and toughness of medium-carbon silicon-manganese-chromium-nickel low-alloy steels. [000...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C21D1/20C21D1/22
CPCC21D1/20C21D1/22C21D2211/001C21D2211/002C21D2211/008C22C38/02C22C38/04C22C38/08C22C38/12
Inventor 孙秀京朱景川叶茂来忠红王淑青崔玉玲王月肖抓王慧田堂振白文勇
Owner CAPITAL AEROSPACE MACHINERY
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