Low-temperature anti-corrosion gas nitriding method for metal workpiece and metal workpiece

A metal workpiece, gas nitriding technology, applied in the field of chemistry, can solve the problem of unsolved problems such as harmful application defects, and achieve the effects of shortening the nitriding cycle period, reducing the nitriding temperature, and improving the corrosion resistance.

Active Publication Date: 2015-09-16
SHANDONG UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The above-mentioned patent activates the surface of the workpiece or changes the nitriding atmosphere through pretreatment to promote the nitriding process, so that it can achieve the nitriding effect at a lower temperature, but its corrosion resistance mechanism is still to form a dense nitride layer, which does not solve its brittleness. Hazards and application flaws

Method used

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  • Low-temperature anti-corrosion gas nitriding method for metal workpiece and metal workpiece
  • Low-temperature anti-corrosion gas nitriding method for metal workpiece and metal workpiece
  • Low-temperature anti-corrosion gas nitriding method for metal workpiece and metal workpiece

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Effect test

Embodiment 1

[0025] The metal workpiece in this embodiment is industrial pure iron, 300 DEG C * 9H low-temperature corrosion-resistant nitriding. The chemical composition (mass fraction, %) of the industrial pure iron is: C≤0.003, P≤0.01, S≤0.006, Si≤0.01, Mn≤0.10.

[0026] The industrial pure iron sample was processed into a block sample of 15×10×5mm by wire cutting, annealed at 1033K for 2 hours, and then the surface of the sample was ground from coarse to fine with metallographic sandpaper. Then put it into the electrolyte for electrodeposition pretreatment. The electrodeposition pretreatment uses a two-way adjustable AC power supply, with a pure iron sample as the cathode and an inert electrode as the anode. The electrodeposition pretreatment pretreatment parameters are shown in Table 1 .

[0027] Table 1 Bidirectional adjustable AC power electrodeposition pretreatment parameters

[0028]

[0029] After the pure iron sample pretreated by electrodeposition was ultrasonically cleane...

Embodiment 2

[0031] The metal workpiece in this embodiment is No. 45 steel, 400 ℃ * 6H low-temperature corrosion-resistant nitriding, and this No. 45 steel chemical composition (mass fraction, %) is: C 0.46, Si 0.25, Mn 0.68%, P≤0.04, S≤0.04, Cr≤0.25, Ni≤0.2, after quenching and tempering treatment (quenching at 1123K, tempering at 873K), process No. 45 steel into a 10×8×5mm block sample by wire cutting, annealing at 1033K for 2 hours, In this way, use 0#, 2#, 4#, 6# metallographic sandpaper to polish and smooth it. Rinse with tap water, then degrease and derust with acetone and 5% HCl, rinse and dry with distilled water and alcohol after treatment. Afterwards, the No. 45 steel sample was put into the electrolyte for electrodeposition pretreatment. The electrodeposition pretreatment used a two-way adjustable AC power supply, with the No. 45 steel sample as the cathode and the inert electrode as the anode. The electrodeposition pretreatment The processing pre-parameters are listed in Table...

Embodiment 3

[0036] The metal workpiece in this embodiment is 38CrMoAl steel, 450 ℃ * 6H low-temperature corrosion-resistant nitriding. The chemical composition (mass fraction, %) of the 38CrMoAl steel is shown in Table 3 below.

[0037] Table 3 Chemical composition of 38CrMoAl steel (mass fraction, %)

[0038] Grade

C

Si

mn

Cr

Mo

Al

38CrMoAl

0.35～0.42

0.20～0.45

0.30～0.60

1.35～1.65

0.15～0.25

0.70～1.10

[0039] After the 38CrMoAl steel sample has been quenched and tempered, the sample is processed into a 10×8×5mm block sample by wire cutting, annealed at 1033K for 2 hours, and 0#, 2#, 4#, 6# gold Smooth with sandpaper. Rinse with tap water, then degrease and rust with acetone and 10% HCl, rinse and dry with distilled water and alcohol after treatment. Then put the 38CrMoAl steel sample into the electrolyte for electrodeposition pretreatment. The electrodeposition pretreatment uses a two-way adjustable pulse power supp...

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Abstract

The invention relates to a low-temperature anti-corrosion gas nitriding method for a metal workpiece and the metal workpiece. According to the method, the metal workpiece is put in configured electrolyte, a common electro-deposition is utilized for carrying out pulse or alternating current treatment on the surface of the metal workpiece to form a micro-nano structural layer containing Ni<2+> and Cr<3+> on the surface of the metal workpiece under the effect of an electric field, grains on the surface of the workpiece are refined, and the activation energy is enhanced; by virtue of introduced Ni<2+> and Cr<3+>, nitriding can be promoted, the low-temperature nitriding is realized, and the corrosion resistance of the workpiece is improved; without recourse to a dense nitride layer (white bright layer), the danger caused by brittleness is solved, and the corrosion resistance of the workpiece is improved. In conclusion, by virtue of electro-deposition pretreatment provided by virtue of the method, the metal workpiece is not deformed, meanwhile, the nitriding temperature can be effectively decreased, the nitriding period can be shortened, the electro-deposition pretreatment is applicable to parts with complex shapes and precise parts, and the energy is saved.

Description

【Technical field】 [0001] The invention belongs to the field of chemistry, and relates to a low-temperature corrosion-resistant gas nitriding method for a metal workpiece and a product thereof. 【Background technique】 [0002] Gas nitriding technology is widely used in the industrial field because of its simple equipment and easy-to-operate process technology. According to the performance requirements of nitriding workpieces, gas nitriding can be divided into enhanced nitriding and corrosion-resistant nitriding. The current research focus is on strengthening the nitriding process, mainly to solve the defects of relatively high gas nitriding temperature and long processing time. The corrosion resistance of nitriding is mainly reflected in the dense nitride layer (white layer) formed by nitriding, but the brittleness of the white layer limits its application range. [0003] The existing disclosed technologies are mainly low-temperature gas nitriding technology and low-temperatu...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C23C8/24C23C8/02C25D3/02
Inventor 张国松崔洪芝张洪云温敬
Owner SHANDONG UNIV OF SCI & TECH
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