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Ferritic stainless steel and preparation method and application thereof

A technology of stainless steel and ferrite, applied in the field of mold steel, can solve the problems of distribution shape affecting plasticity and toughness, poor plasticity, failure, etc., and achieve the effect of improving intrinsic plasticity and toughness, improving plasticity and toughness, and considerable economic benefits

Active Publication Date: 2022-05-27
SHANGHAI JIAO TONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, in the specific service process, high-strength die steels often crack and cause premature failure under repeated fatigue loads
The reason is that on the one hand, some medium and high carbon die steels such as AISI420 mainly rely on interstitial solid solution strengthening of C atoms, resulting in poor plasticity and poor resistance to fatigue crack initiation and propagation; on the other hand, the high C content leads to A certain amount of retained austenite is produced, and its distribution shape often affects plasticity and toughness

Method used

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  • Ferritic stainless steel and preparation method and application thereof
  • Ferritic stainless steel and preparation method and application thereof
  • Ferritic stainless steel and preparation method and application thereof

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preparation example Construction

[0037] The present invention also provides the preparation method of the above-mentioned ferritic stainless steel, and the method comprises the following steps:

[0038] 1) Prepare spherical alloy powder with fine-grained martensite structure according to the chemical composition ratio;

[0039] 2) Using the powder-spreading additive manufacturing method, the spherical alloy powder in step 1) is printed and formed;

[0040] 3) Heat treatment to obtain ferritic stainless steel.

[0041] In step 1), the particle size of the spherical alloy powder is 5-85 μm, which is normally distributed.

[0042] In step 2), during the powder-laying additive manufacturing process, the laser power is 120-350W, the scanning rate is 0.2-1.2m / s, the powder-laying layer thickness is 42-110 μm, and the scanning path between layers is at an angle of 65-70° .

[0043] In step 3), the heat treatment process is: tempering at 250-300°C for 2-6h, then air-cooled, and then repeating tempering and air-coo...

Embodiment 1

[0048] print + temper

[0049] Composition: Fe-0.19C-0.82Mn-0.49Si-0.56Ni-13.45Cr-0.22V-0.14Mo(wt%)

[0050] Process: milling + printing (laser power 320W, scanning rate 0.96m / s, layer thickness 100μm) + tempering at 250°C for 2h×2 times.

[0051] Print Quality: Porosity 0.14%, Density 99.59%.

[0052] Microstructure: tempered martensitic cell-like grains + columnar grains interspersed layered structure.

[0053] Mechanical properties: Rockwell hardness 44.3±0.5HRC, V-notch impact energy at room temperature 58.7±5.1J.

Embodiment 2

[0055] Printing + Solution Treatment + Tempering

[0056] Composition: Fe-0.19C-0.82Mn-0.49Si-0.56Ni-13.45Cr-0.22V-0.14Mo(wt%)

[0057] Process: milling + printing (laser power 320W, scanning rate 0.96m / s, layer thickness 100μm) + solution treatment at 1030°C for 0.5h + tempering at 250°C for 2h×2 times.

[0058] Print Quality: Porosity 0.14%, Density 99.59%.

[0059] Microstructure: tempered martensite equiaxed grain structure.

[0060] Mechanical properties: Rockwell hardness 46.6±0.5HRC, V-notch impact energy at room temperature 21.7±3.1J.

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Abstract

The invention relates to ferritic stainless steel and a preparation method and application thereof, and the ferritic stainless steel comprises the following chemical components in percentage by weight: 0.10%-0.25% of C, 0.38%-0.8% of Ni, 12.2%-13.8% of Cr, 0-0.50% of V, 0.50%-1.00% of Mn, 0.20%-0.60% of Si, 0.10%-0.50% of Mo, 0-0.10% of Nb, less than 0.015% of P, less than 0.010% of S and the balance of Fe and inevitable impurities. Compared with the prior art, the chemical components of the ferritic stainless steel for the injection mold are optimized, the corresponding additive manufacturing method is defined, and particularly a cryogenic method in the subsequent heat treatment process is provided, so that the impact toughness of the additive manufacturing mold steel can be greatly improved, and the risk of fatigue cracking is reduced; and meanwhile, the polishing performance and the machining performance are improved, and technical support is provided for stable manufacturing and large-scale application of the additive manufacturing mold.

Description

technical field [0001] The invention belongs to the technical field of die steel, and relates to a ferritic stainless steel and a preparation method and application thereof. Background technique [0002] Additive manufacturing technology has changed the traditional manufacturing method of die steel smelting + forging, greatly reducing or even avoiding the influence of impurity elements and component segregation. The product surface quality and production efficiency have been improved, and the quality of my country's additive manufacturing die steel has been improved. However, in the specific service process, high-strength die steel tends to crack and lead to premature failure under repeated fatigue loads. The reason is that, on the one hand, some medium and high carbon die steels such as AISI420 mainly rely on the interstitial solid solution strengthening of C atoms, resulting in poor plasticity and poor resistance to fatigue crack initiation and expansion; on the other ha...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/46C22C38/04C22C38/02C22C38/44C22C38/48C22C33/02B22F10/28B22F10/64B33Y10/00B33Y70/00C21D6/00C21D6/04C21D1/18
CPCC22C38/46C22C38/04C22C38/02C22C38/44C22C38/48C22C33/0285B22F10/28B22F10/64B33Y10/00B33Y70/00C21D6/004C21D6/005C21D6/008C21D6/04C21D1/18C21D2211/008C21D2211/001Y02P10/25
Inventor 刘庆冬于一笑刘妍洁林钢张静顾剑锋
Owner SHANGHAI JIAO TONG UNIV