阅读说明：本技术 一种高镍铸铁工件表面处理工艺 (Surface treatment process for high-nickel cast iron workpiece ) 是由 乔琛 张炼 于 2020-11-19 设计创作，主要内容包括：本发明提出了一种高镍铸铁工件表面处理工艺,包括配置渗剂、工件与渗剂混合密封,加热炉内真空保温处理后,加热至680-850℃进行表面处理,从而得到表面处理的高镍铸铁工件,渗剂包括B-4C、BFe、TiFe、V-2O-5、Al、Al-2O-3、催化剂和活化剂,催化剂和活化剂具体包括含Y稀土、NH-4Cl、NH-4F、AlF-3、NaF、NH-4Br、NH-4I、KBF-4中的一种或几种的混合物。本发明的处理工艺,能够在较低的温度下对高镍铸铁工件进行表面处理,处理后的渗层较厚,渗层的结构和外观更好,具有良好的物理性质。(The invention provides a surface treatment process for a high-nickel cast iron workpiece, which comprises the steps of preparing a penetrating agent, mixing and sealing the workpiece and the penetrating agent, heating to 680-850 ℃ for surface treatment after vacuum heat preservation treatment in a heating furnace so as to obtain the high-nickel cast iron workpiece with the surface treated, wherein the penetrating agent comprises B 4 C、BFe、TiFe、V 2 O 5 、Al、Al 2 O 3 Catalysts and activators including, in particular, rare earth containing Y, NH 4 Cl、NH 4 F、AlF 3 、NaF、NH 4 Br、NH 4 I、KBF 4 One or a mixture of several of them. The treatment process can be used for carrying out surface treatment on the high-nickel cast iron workpiece at a lower temperature, and the treated infiltration layer is thicker, has better structure and appearance and has good physical properties.)

1. A surface treatment process for a high-nickel cast iron workpiece is characterized by comprising the following steps:

step one, preparing a penetrating agent, filling the penetrating agent into a heat-resistant sealing tank, putting a high-nickel cast iron workpiece to be treated into the heat-resistant sealing tank, coating the surface of the high-nickel cast iron workpiece with the penetrating agent, and sealing the heat-resistant sealing tank;

secondly, hoisting the heat-resistant sealed tank subjected to sealing treatment into a heating furnace, and sealing the heating furnace;

step three, carrying out vacuum pumping treatment on the heating furnace, introducing inert gas to replace the gas in the heating furnace, and keeping the pressure in the heating furnace at 101.325 x 1.5-101.325 x 2 kPa; step four, heating the heating furnace to 400-;

and step five, after the treatment is finished, heating the heating furnace to 680-850 ℃, and preserving heat for 8-12 hours to obtain the high-nickel cast iron workpiece with the surface treated.

2. The surface treatment process for high-nickel cast iron workpieces according to claim 1, wherein the impregnation agent comprises B₄C、BFe、TiFe、V₂O₅、Al、Al₂O₃A catalyst and an activator.

3. The surface treatment process for a high-nickel cast iron workpiece according to claim 2, wherein the impregnation agent comprises 10 to 20% by mass of B, based on 100% by mass₄C、25-35％BFe、6-10％TiFe、2-8％V₂O₅、8-16％Al、20-30％Al₂O₃3-5% of catalyst and 1-2% of activating agent.

4. The surface treatment process for a high-nickel cast iron workpiece according to claim 2, wherein the catalyst is an ammonium halide.

5. The surface treatment process for a high-nickel cast iron workpiece according to claim 4, wherein the catalyst is NH₄F、NH₄Cl、NH₄Br and NH₄And (I) one or a mixture of more than one of the components.

6. The high-nickel cast iron workpiece surface treatment process of claim 2, wherein the activator comprises Y-containing rare earth.

7. The high-nickel cast iron workpiece surface treatment process of claim 6, wherein the activator further comprises NH₄Cl、AlF₃、NaF、KBF₄One or a mixture of several of them.

8. The surface treatment process for the high-nickel cast iron workpiece according to claim 6, wherein the Y-containing rare earth is cerium carbonate and/or lanthanum carbonate.

9. The surface treatment process of the high-nickel cast iron workpiece according to claim 1, wherein the first step further comprises adding carbon powder into the sealing tank, and the mass ratio of the carbon powder to the penetrating agent is 2-7: 100.

10. the use of the surface treatment process of the high-nickel cast iron workpiece according to claim 1 in the surface treatment of oil extraction pump impellers and fittings thereof.

Technical Field

The invention relates to the technical field of metal workpiece processing, in particular to a surface treatment process for a high-nickel cast iron workpiece.

Background

In oil exploitation, a pump body of an oil pipeline is used as an important exploitation element and needs to adapt to various severe exploitation environments, so that the material consumption is particularly high, the pump body pipeline, an impeller and various accessories are mostly cast by high-nickel cast iron alloy, in order to enable a workpiece to better meet the use requirement, the surface hardening process adopted in the prior art is to carry out element infiltration on the surface of the high-nickel cast iron, however, the infiltration layer component of the conventional treatment process is too single, the hardness layer of the material is difficult to reach the standard, the infiltration layer thickness cannot meet the requirement due to the infiltration process, the corrosion resistance is poor, the surface infiltration layer is easy to peel off in the use process, and the service life is short.

In order to achieve better surface treatment effect, more modifying elements are often needed to be infiltrated, so as to improve the surface performance of the metal as a whole, however, the infiltration of multiple elements has higher requirements on the surface treatment process, such as higher infiltration treatment temperature and longer treatment time, which may bring negative effects, such as: the metal parts are easy to crack and even peel off due to improper element proportion, and deform at high temperature, so that the qualification rate is reduced; the thickness of the multi-component co-permeation layer at low temperature is not easy to reach the standard, and the permeation effect of elements is poor. Therefore, the difficulty of the multi-component co-permeation technology is high.

Disclosure of Invention

In view of the above, the present invention provides a surface treatment process for a high-nickel cast iron workpiece, which can be performed at a low temperature.

The technical scheme of the invention is realized as follows: the invention provides a surface treatment process of a high-nickel cast iron workpiece, which comprises the following steps:

step one, preparing a penetrating agent, filling the penetrating agent into a heat-resistant sealing tank, putting a high-nickel cast iron workpiece to be treated into the heat-resistant sealing tank, coating the surface of the high-nickel cast iron workpiece with the penetrating agent, and sealing the heat-resistant sealing tank;

secondly, hoisting the heat-resistant sealed tank subjected to sealing treatment into a heating furnace, and sealing the heating furnace;

step three, carrying out vacuum pumping treatment on the heating furnace, introducing inert gas to replace the gas in the heating furnace, and keeping the pressure in the heating furnace at 101.325 x 1.5-101.325 x 2 kPa;

step four, heating the heating furnace to 400-;

and step five, after the treatment is finished, heating the heating furnace to 680-850 ℃, and preserving heat for 8-12 hours to obtain the high-nickel cast iron workpiece with the surface treated.

On the basis of the above technical scheme, preferably, the penetrating agent comprises B₄C、BFe、TiFe、V₂O₅、Al、Al₂O₃A catalyst and an activator.

The comprehensive performance of the cast iron workpiece and the surface of the boron, titanium, vanadium and aluminum co-infiltrated alloy structure is enhanced, and the diffusion layer has a special metallurgical needle-shaped junctionUnder the condition of single B-penetration, the penetration layer is made of FeB and Fe₂B composition in a concentration of V₂O₅Under the action of high temperature, the superfine Al powder and Y-containing catalyst have diffusion layer except FeB and Fe₂B, besides (Fe, V, Ti) B, (Fe, V, Ti)₂B,(Fe,V,Ti)₃C,(Fe,V,Ti)₇C₃And the like, and an irregular FeBTiVAl + C alpha solid solution layer is formed within the concentration range of 8-16% of Al; VTi particles are uniformly distributed in Fe after V infiltration of parts₂B or (Fe)₂V)₂On B, the infiltration layer is continuous, compact and has no gap; particularly, after Ti is infiltrated into the part, titanium carbide is formed on the surface of the part, the hardness and the wear resistance of the part are superior to those of V infiltration and B infiltration, the Ti infiltration layer has higher corrosion resistance, and the anti-corrosion capability of the part is superior to that of other metal layers; the boron titanium vanadium infiltration layer has stable aluminum alloying infiltration layer structure and good infiltration layer thickness elasticity; comprehensive performance after infiltration: the thickness of the infiltrated layer is more than 40 mu m, and the highest hardness can reach HV 0.21900.

On the basis of the technical scheme, preferably, the penetrating agent comprises 10-20% of B by mass percent of 100%₄C、25-35％BFe、6-10％TiFe、2-8％V₂O₅、8-16％Al、20-30％Al₂O₃3-5% of catalyst and 1-2% of activating agent.

In the actual work of chemical heat treatment, the Ti, V and Al infiltration temperature is greater than 900 ℃ in principle, the low-temperature co-infiltration by using elements such as Ti, V, Al and the like is difficult to realize, and the invention researches prove that a certain proportion of activator such as NH₄Cl、AlF₃、NaF、KBF₄Y-containing rare earth, etc. may be heated to contain Al and V₂O₅The medium of the penetrating agent is decomposed to form an active gas-phase compound, the active gas-phase compound plays an obvious activating role in the thermal reaction of the penetrating agent, the energy change of a crystal boundary is caused by the interaction of elements, the penetration parts, FeB and FeTi materials can be seriously decarburized at high temperature, the chemical properties of the materials are changed by decarburization, the atmosphere in the environment of high-temperature catalytic infiltration has the process of supplementing carbon to the materials, the surface layer structure of the materials is rearranged and combined, the atmosphere of catalyst decomposition not only accelerates the chemical heat treatment process of powder in the gas-phase medium, but also can greatly reduce the penetrationThe temperature range of the covering reaction is 680-850 ℃, the deformation of parts is reduced, and the added activating agent can greatly improve the activation of Ti, V and Al in the metal penetrating agent and improve the penetrating speed. The high-temperature multicomponent co-permeation of boron, titanium, vanadium and aluminum is mainly boronizing, the contradiction of boron, titanium and vanadium atoms generation and boron, titanium, vanadium and aluminum atom consumption by oxidation exists in a plurality of elements under a high-temperature environment, and the contradiction can be overcome by correctly adjusting the proportion of various raw materials according to the characteristic of certain oxidizability of the permeation agent. The process is characterized in that excessive Al is added in the process, the excessive Al serving as a reducing agent participates in the infiltration of materials, and a small amount of oxygen atoms generated in the reaction can be consumed to generate Al₂O₃And gives off heat, thus further enhancing the material impregnation reaction. Preferably, the ratio of boron, titanium, vanadium and aluminum penetration agents is (8-12): (2-4): (1-3): (3-7).

The reaction formula at high temperature of the invention comprises:

on the basis of the above technical scheme, preferably, the catalyst is ammonium halide.

Even more preferably, the catalyst is NH₄F、NH₄Cl、NH₄Br and NH₄And (I) one or a mixture of more than one of the components.

Based on the above technical solution, preferably, the activator includes Y-containing rare earth.

In the above technical solutionsPreferably, the activator further comprises NH₄Cl、AlF₃、NaF、KBF₄One or a mixture of several of them.

On the basis of the above technical scheme, preferably, the Y-containing rare earth is cerium carbonate and/or lanthanum carbonate.

On the basis of the technical scheme, preferably, the first step further comprises adding carbon powder into the sealing tank, wherein the mass ratio of the carbon powder to the penetrating agent is 2-7: 100.

on the basis of the technical scheme, preferably, the high-nickel cast iron workpiece is an oil extraction pump impeller and accessories thereof.

Compared with the prior art, the surface treatment process for the high-nickel cast iron workpiece has the following beneficial effects:

(1) the invention utilizes the interaction of the permeation agent containing vanadium, titanium and aluminum and the catalyst containing Y under the condition of boronizing the surface of the workpiece, and leads the permeation layer to have (Fe, V, Ti) B, (Fe, V, Ti) at a certain temperature₂B、(Fe,V,Ti)₃C and (Fe, V, Ti)₇C₃The FeBTiVAl + C infiltrated layer is continuous and compact, has no gap, has good wear resistance and corrosion resistance, and is stable in structure, thick in infiltrated layer, good in elasticity and not easy to break and fall off when being compared with the boron-titanium-vanadium infiltrated layer and the aluminum alloy;

(2) the conventional coating temperature is high, and the structural shape of a workpiece is easy to damage, so that a specific active agent component is adopted, an active gas-phase compound is formed after heating, an activation effect is achieved in the thermal reaction of the coating agent, the temperature of the coating agent is raised through the replacement exothermic reaction of element interaction, the energy change of a crystal boundary is caused, the chemical heat treatment process of powder in a gas-phase medium is accelerated by the atmosphere generated by the decomposition of the active agent component, the temperature range of the coating reaction is greatly reduced, and the deformation of parts is reduced.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.

Example 1

Respectively weighing 10 parts of B₄C. 35 parts of BFe, 10 parts of TiFe and 5 parts of V₂O₅8 parts of Al, 25 parts of Al₂O₃3 parts of NH₄F. 2 parts of KBF₄And 2 parts of cerium carbonate powder, and uniformly mixing to obtain the penetrant.

Filling 100 parts of penetrating agent powder into a heat-resistant sealed tank, placing a petroleum pump impeller cast by high-nickel cast iron to be treated into the heat-resistant sealed tank, coating the surface of the petroleum pump impeller by the penetrating agent, sealing the heat-resistant sealed tank, hoisting the sealed heat-resistant sealed tank into a heating furnace, sealing the heating furnace, vacuumizing the heating furnace, injecting argon to replace air in the heating furnace, keeping the pressure in the heating furnace at 101.325 x 1.5kPa, heating the heating furnace to 400 ℃, carrying out heat preservation treatment for 3 hours, then heating to 680 ℃, carrying out heat preservation treatment for 12 hours, cooling to room temperature, taking out the sealed tank from the heating furnace, and taking the petroleum pump impeller cast by the high-nickel cast iron out of the sealed tank.

Example 2

Respectively weighing 20 parts of B₄C. 25 parts of BFe, 6 parts of TiFe and 8 parts of V₂O₅16 parts of Al, 20 parts of Al₂O₃3 parts of NH₄Cl, 0.5 part of lanthanum carbonate and 1 part of KBF₄And 0.5 part of AlF₃The penetrating agent is obtained by uniformly mixing the powder.

100 parts of penetrating agent powder and 2 parts of carbon powder are uniformly mixed and filled in a heat-resistant sealing tank, a petroleum pump impeller cast by high-nickel cast iron to be treated is placed in the heat-resistant sealing tank, the penetrating agent and the carbon powder coat the surface of the petroleum pump impeller, the heat-resistant sealing tank is subjected to sealing treatment, the sealed heat-resistant sealing tank is hung in a heating furnace, the heating furnace is sealed, the heating furnace is subjected to vacuum pumping treatment, then argon is injected to replace air in the heating furnace, the pressure in the heating furnace is kept at 101.325 & lt2 & gt kPa, then the heating furnace is heated until the temperature in the furnace is 450 ℃, the heat preservation treatment is carried out for 2 hours, then the temperature is raised to 700 ℃, the heat preservation treatment is carried out for 11 hours, after the treatment is finished, the temperature is reduced to room temperature, the sealing tank is taken out from the heating furnace, and the petroleum pump impeller cast by.

Example 3

Respectively weighing 13 parts of B₄C. 32 parts of BFe, 7 parts of TiFe and 6 parts of V₂O₅10 parts of Al, 26 parts of Al₂O₃4 parts of NH₄Br, 0.5 part of cerium carbonate, 1 part of KBF₄And 0.5 part of lanthanum carbonate powder, and uniformly mixing to obtain the penetrant.

100 parts of penetrating agent powder and 4 parts of carbon powder are uniformly mixed and filled in a heat-resistant sealed tank, a petroleum pump impeller cast by high-nickel cast iron to be treated is placed in the heat-resistant sealed tank, the penetrating agent and the carbon powder coat the surface of the petroleum pump impeller, the heat-resistant sealed tank is subjected to sealing treatment, the sealed heat-resistant sealed tank is hung in a heating furnace, the heating furnace is sealed, the heating furnace is subjected to vacuum pumping treatment, then argon is injected to replace air in the heating furnace, the pressure in the heating furnace is kept at 101.325 & lt1.5 kPa, then the heating furnace is heated until the temperature in the furnace is 500 ℃, the heat preservation treatment is carried out for 2 hours, then the temperature is raised to 750 ℃, the heat preservation treatment is carried out for 10 hours, after the treatment is finished, the sealed tank is taken out of the heating furnace after the temperature is reduced to room temperature, and the petroleum pump impeller cast by the high.

Example 4

Respectively weighing 18 parts of B₄C. 27 parts of BFe, 9 parts of TiFe and 5 parts of V₂O₅12 parts of Al, 22 parts of Al₂O₃5 parts of NH₄I. 1 part of cerium carbonate and 0.5 part of NH₄Cl and 0.5 part of NaF powder are uniformly mixed to obtain the penetrant.

100 parts of penetrating agent powder and 6 parts of carbon powder are uniformly mixed and then filled in a heat-resistant sealing tank, a petroleum pump impeller cast by high-nickel cast iron to be treated is placed in the heat-resistant sealing tank, the penetrating agent and the carbon powder coat the surface of the petroleum pump impeller, the heat-resistant sealing tank is subjected to sealing treatment, the sealed heat-resistant sealing tank is hung in a heating furnace, the heating furnace is sealed, the heating furnace is subjected to vacuum pumping treatment, then argon is injected to replace air in the heating furnace, the pressure in the heating furnace is kept at 101.325 x 2kPa, then the heating furnace is heated until the temperature in the furnace is 550 ℃, heat preservation treatment is carried out for 2 hours, then the temperature is raised to 800 ℃, heat preservation treatment is carried out for 9 hours, after the treatment is finished, the temperature is reduced to room temperature, the sealing tank is taken out of the heating furnace, and the petroleum pump impeller cast by the high-nickel cast.

Example 5

Weighing 15 parts of B respectively₄C. 30 parts of BFe, 8 parts of TiFe and 4 parts of V₂O₅13 parts of Al, 25 parts of Al₂O₃2 part of NH₄F. 2 parts of NH₄I. 0.5 part lanthanum carbonate and 0.5 part KBF₄And (5) uniformly mixing the powder to obtain the penetrant.

Filling 100 parts of penetrating agent powder and 7 parts of carbon powder in a heat-resistant sealed tank, placing a petroleum pump impeller cast by high-nickel cast iron to be treated in the heat-resistant sealed tank, coating the surface of the petroleum pump impeller by the penetrating agent and the carbon powder, sealing the heat-resistant sealed tank, hoisting the sealed heat-resistant sealed tank into a heating furnace, sealing the heating furnace, vacuumizing the heating furnace, injecting inert gas to replace air in the heating furnace, keeping the pressure in the heating furnace at 101.325 & lt1.5 kPa, heating the heating furnace until the temperature in the furnace is 600 ℃, carrying out heat preservation treatment for 1 hour, then heating to 850 ℃, carrying out heat preservation treatment for 8 hours, cooling to room temperature after the treatment is finished, taking the sealed tank out of the heating furnace, and taking the petroleum pump impeller cast by the high-nickel cast iron out of the sealed tank.

Comparative example 1

Respectively weighing 25 parts of B₄C. 35 parts of BFe, 5 parts of TiFe, 6 parts of Al and 25 parts of Al₂O₃2 part of NH₄F. 2 parts of NH₄And Cl powder is uniformly mixed to obtain the penetrant.

Filling a penetrating agent into a heat-resistant sealed tank, placing a petroleum pump impeller cast by high-nickel cast iron to be treated into the heat-resistant sealed tank, coating the surface of the petroleum pump impeller by the penetrating agent and carbon powder, sealing the heat-resistant sealed tank, hoisting the sealed heat-resistant sealed tank into a heating furnace, sealing the heating furnace, vacuumizing the heating furnace, injecting inert gas to replace air in the heating furnace, keeping the pressure in the heating furnace at 101.325 x 1.5kPa, heating the heating furnace until the temperature in the furnace is 600 ℃, carrying out heat preservation treatment for 1h, then heating to 850 ℃, carrying out heat preservation treatment for 8h, cooling to room temperature, taking the sealed tank out of the heating furnace, and taking the petroleum pump impeller cast by the high-nickel cast iron out of the sealed tank.

Comparative example 2

Respectively weighing 35 parts of B₄C. 25 parts of BFe and 5 parts of V₂O₅5 parts of Al, 25 parts of Al₂O₃3 parts of NH₄F. 2 parts of NH₄And I, uniformly mixing the powder I and the powder I to obtain the penetrant.

Filling a penetrating agent into a heat-resistant sealed tank, placing a petroleum pump impeller cast by high-nickel cast iron to be treated into the heat-resistant sealed tank, coating the surface of the petroleum pump impeller by the penetrating agent and carbon powder, sealing the heat-resistant sealed tank, hoisting the sealed heat-resistant sealed tank into a heating furnace, sealing the heating furnace, vacuumizing the heating furnace, injecting inert gas to replace air in the heating furnace, keeping the pressure in the heating furnace at 101.325 x 1.5kPa, heating the heating furnace until the temperature in the furnace is 600 ℃, carrying out heat preservation treatment for 1h, then heating to 950 ℃, carrying out heat preservation treatment for 8h, cooling to room temperature, taking the sealed tank out of the heating furnace, and taking the petroleum pump impeller cast by the high-nickel cast iron out of the sealed tank.

The appearance, the surface infiltrated layer morphology, the thickness and the hardness of the infiltrated layer of the impellers of examples 1 to 5 and the comparative example were respectively detected, and the detection results are as follows:

the results show that the treatment process can effectively reduce the temperature in the treatment process by matching with the specific penetrating agent, thereby avoiding the performance influence on the workpiece at high temperature, and simultaneously the high-nickel cast iron workpiece treated at low temperature has good performance.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.