Preparation method adopting low-temperature boronizing for wear-resistant surface of nodular cast iron

A technology of nodular cast iron and boronizing, which is applied in the direction of coating, metal material coating process, solid-state diffusion coating, etc., can solve the problems of restricting the application of nodular cast iron and the increase of thermal deformation of parts, and achieve high hardness and good wear resistance Sexuality and easy operation

Active Publication Date: 2020-11-24
XIAN UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the traditional boronizing process is carried out in a high temperature (above 950°C) environment, and the thermal deformation of the parts increases, which greatly limits the application of nodular cast iron in precision moving parts

Method used

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  • Preparation method adopting low-temperature boronizing for wear-resistant surface of nodular cast iron
  • Preparation method adopting low-temperature boronizing for wear-resistant surface of nodular cast iron
  • Preparation method adopting low-temperature boronizing for wear-resistant surface of nodular cast iron

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0057] 1. Use 600#, 800#, 1000# and 1200# sandpaper to polish the nodular cast iron sample in sequence to remove the surface oxide layer. Clean them in an ultrasonic cleaner for 10 minutes with absolute ethanol and acetone in turn, then dry them and store them for later use.

[0058] 2. Put the sample into the phosphating solution for phosphating treatment, the phosphating solution: 4% phosphoric acid, 5% nitrate, 3% zinc oxide, 2% citric acid, 1% stabilizer and the remaining amount of water; the time of the phosphating treatment is 5 minutes, and the temperature is normal temperature. After phosphating, the samples were washed with water and dried.

[0059] 3. The composition of boronizing agent is: 6% boron carbide (B 4 C), 10% potassium fluoroborate (KBF 4 ), 83% silicon carbide (SiC), 1% lanthanum oxide (La 2 o 3 ). Weigh the boronizing agent according to the distribution ratio of each component, and refine the boronizing agent by ball milling. The ball milling time ...

Embodiment 2

[0067] 1. Use 600#, 800#, 1000# and 1200# sandpaper to polish the nodular cast iron sample in sequence to remove the surface oxide layer. Clean them in an ultrasonic cleaner for 10 minutes with absolute ethanol and acetone in turn, then dry them and store them for later use.

[0068] 2. Put the sample into the phosphating solution for phosphating treatment, the phosphating solution: 3% phosphoric acid, 5% nitrate, 4% zinc oxide, 2% citric acid, 2% stabilizer and the remaining amount of water; the time of the phosphating treatment is 5 minutes, and the temperature is normal temperature. After phosphating, the samples were washed with water and dried.

[0069] 3. The composition of boronizing agent is: 5% boron carbide (B 4 C), 10% potassium fluoroborate (KBF 4 ), 83% silicon carbide (SiC), 2% cerium oxide (CeO 2 ). Weigh the boronizing agent according to the distribution ratio of each component, and refine the boronizing agent by ball milling. The ball milling time is 6 ho...

Embodiment 3

[0077] A method for preparing a low-temperature boronized ductile iron wear-resistant surface of the present invention is specifically implemented according to the following steps:

[0078] Step 1, ductile iron pretreatment;

[0079] Preprocessing in step 1 includes:

[0080] Step 1.1, use metallographic sandpaper of 600#, 800#, 1000# and 1200# to polish the ductile iron successively, and remove the surface oxide layer;

[0081] Step 1.2, performing ultrasonic cleaning twice on the ductile iron with the surface oxide layer removed in step 1.1, finally removing surface lipids and organic matter;

[0082] Step 1.3, performing surface activation treatment on the nodular cast iron cleaned in step 1.2 with a phosphating solution to obtain an activated surface that is easy to diffuse boron atoms.

[0083] In step 1.2, the first ultrasonic cleaning was performed with deionized water for 5 minutes, and the second ultrasonic cleaning was performed with absolute ethanol as a solvent f...

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Abstract

The invention discloses a preparation method adopting low-temperature boronizing for a wear-resistant surface of nodular cast iron. The preparation method comprises the following steps: firstly, pretreating the nodular cast iron, then preparing a powder boronizing agent and a sealing material, then carrying out boronizing treatment, and finally, carrying out boronizing aftertreatment, so that thehigh-hardness boronized surface is obtained, wherein the step of carrying out boronizing treatment comprises the following substeps: carrying out pre-boronizing treatment on an iron container so thatthe iron container can serve as a boronizing tank, namely, filling the iron container with the boronizing agent, carrying out compacting, carrying out sealing, carrying out heating to 950 DEG C, keeping the temperature for 6 hours, and carrying out cooling; filling the boronizing tank subjected to pre-boronizing treatment with the uniformly mixed boronizing agent, burying the pretreated nodular cast iron sample in the boronizing agent, filling the whole tank with the boronizing agent, compacting the boronizing agent, and finally, sealing the box with the prepared sealing material; and heatingthe sealed container to 200-400 DEG C and keeping the temperature for 1-2 h, wherein the boronizing time is controlled to be 1-24 h. While the boronizing temperature is reduced, a boronized layer which is large in thickness and is uniform can be obtained, and then the microhardness and wear resistance of the nodular cast iron are effectively improved.

Description

technical field [0001] The invention belongs to the technical field of nodular cast iron surface treatment, and in particular relates to a method for preparing a low-temperature boronized nodular cast iron wear-resistant surface. Background technique [0002] Ductile iron is rich in graphite, which forms a transfer film during the friction process and has a good anti-friction effect. It is widely used in key precision moving parts such as automobile drive shafts and machine tool guide rails. However, the hardness of ductile iron is low, and when subjected to high loads, the matrix undergoes severe plastic deformation, resulting in severe adhesive wear. Therefore, there is an urgent need for a surface strengthening process to improve the wear resistance of ductile iron. [0003] Boronizing is a common heat treatment method, and the hardness, corrosion resistance and wear resistance of the boronized surface are far from those of ordinary hardened surfaces. Fe is formed on th...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C23C8/70C23C8/02C23C22/17
CPCC23C8/70C23C8/02C23C22/17
Inventor 张东亚孙喜洲高峰李艳孔令飞税琳棋
Owner XIAN UNIV OF TECH
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