Low-temperature corrosion-resistant gas nitriding method for metal workpieces and products thereof

A metal workpiece, gas nitriding technology, applied in the chemical field, can solve problems such as unresolved harmful application defects, achieve the effects of shortening the nitriding cycle, improving corrosion resistance, and saving energy

Active Publication Date: 2017-11-24
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 corrosion-resistant gas nitriding method for metal workpieces and products thereof
  • Low-temperature corrosion-resistant gas nitriding method for metal workpieces and products thereof
  • Low-temperature corrosion-resistant gas nitriding method for metal workpieces and products thereof

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Experimental program
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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 supply, with th...

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Abstract

A low-temperature corrosion-resistant gas nitriding method for metal workpieces and its products, by placing the metal workpiece in a prepared electrolyte, using a common electrodeposition device to treat the surface of the metal workpiece with pulse or alternating current, and under the action of an electric field, the metal Ni 2+ 、Cr 3+ The micro-nano structure layer, the grain refinement on the surface of the workpiece, the activation energy increase, and the introduced Ni 2+ 、Cr 3+ It can also promote the progress of nitriding and ensure the realization of low-temperature nitriding. At the same time, the introduced Ni 2+ 、Cr 3+ Improve the corrosion resistance of metal workpieces. The method provided by the invention does not rely on the dense nitride layer (white layer), solves the harm caused by its brittleness, and improves the corrosion resistance of metal workpieces. In summary, the electrodeposition pretreatment provided by the method of the present invention will not deform the metal workpiece, and can effectively reduce the nitriding temperature and shorten the nitriding cycle, which is suitable for complex shapes and precision parts, and saves energy.

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 Patents(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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