CN117684181A - Titanium alloy casting surface pickling solution and preparation method thereof - Google Patents
Titanium alloy casting surface pickling solution and preparation method thereof Download PDFInfo
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- CN117684181A CN117684181A CN202311628619.2A CN202311628619A CN117684181A CN 117684181 A CN117684181 A CN 117684181A CN 202311628619 A CN202311628619 A CN 202311628619A CN 117684181 A CN117684181 A CN 117684181A
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- pickling solution
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- 238000005554 pickling Methods 0.000 title claims abstract description 82
- 238000005266 casting Methods 0.000 title claims abstract description 40
- 229910001069 Ti alloy Inorganic materials 0.000 title claims abstract description 32
- 238000002360 preparation method Methods 0.000 title abstract description 14
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 11
- 239000002994 raw material Substances 0.000 claims abstract description 6
- 238000003756 stirring Methods 0.000 claims description 11
- 238000000034 method Methods 0.000 claims description 9
- 239000000203 mixture Substances 0.000 claims description 4
- 239000007787 solid Substances 0.000 claims description 4
- 238000004519 manufacturing process Methods 0.000 claims 1
- 230000008901 benefit Effects 0.000 abstract description 4
- 230000000694 effects Effects 0.000 abstract description 4
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 abstract description 2
- 238000010924 continuous production Methods 0.000 abstract description 2
- 239000007769 metal material Substances 0.000 abstract description 2
- 238000004381 surface treatment Methods 0.000 abstract description 2
- 239000010936 titanium Substances 0.000 abstract description 2
- 229910052719 titanium Inorganic materials 0.000 abstract description 2
- 239000000243 solution Substances 0.000 description 25
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 15
- 229910052739 hydrogen Inorganic materials 0.000 description 15
- 239000001257 hydrogen Substances 0.000 description 15
- 230000007797 corrosion Effects 0.000 description 12
- 238000005260 corrosion Methods 0.000 description 12
- 238000010521 absorption reaction Methods 0.000 description 10
- 239000002253 acid Substances 0.000 description 9
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 8
- 230000007547 defect Effects 0.000 description 7
- 238000012360 testing method Methods 0.000 description 7
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 description 6
- 239000011159 matrix material Substances 0.000 description 6
- 229910045601 alloy Inorganic materials 0.000 description 4
- 239000000956 alloy Substances 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 4
- 230000003746 surface roughness Effects 0.000 description 4
- 229910010413 TiO 2 Inorganic materials 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 238000007689 inspection Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000005498 polishing Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 238000005406 washing Methods 0.000 description 2
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- 150000007513 acids Chemical class 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 239000000428 dust Substances 0.000 description 1
- 239000013461 intermediate chemical Substances 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000011259 mixed solution Substances 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
Landscapes
- Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)
Abstract
The invention relates to the technical field of metal material surface treatment, in particular to a titanium alloy casting surface pickling solution and a preparation method thereof. The pickling solution is prepared from the following raw materials: NH (NH) 4 HF 2 250‑300g/L、NaNO 3 150-200g/L, HCl-500-550 ml/L, and the balance being water. The pickling solution prepared by the invention has the advantages of high efficiency, low cost, simple preparation method and good effect of removing the surface pollution layer of the titanium casting when used for pickling the surface of the titanium alloy, realizes the industrialized continuous production of the surface pickling of the workpiece by special pickling equipment, and generates certain economic benefit.
Description
Technical Field
The invention relates to the technical field of metal material surface treatment, in particular to a titanium alloy casting surface pickling solution and a preparation method thereof.
Background
The titanium alloy has the characteristics of high specific strength, high and low temperature resistance, good corrosion resistance, good biocompatibility and the like, and is widely applied to the tip fields of aerospace, military industry, medical treatment and the like. However, it is cast intoAfter forming, an oxide layer (alpha layer) with a certain thickness is easily generated on the surface, and the main components are TiO and TiO 2 As shown in figure 1, the titanium alloy casting has high hardness, obvious brittleness, easy cracking under stress and serious influence on the mechanical properties of the titanium alloy casting.
The current method for removing the oxide layer on the surface of the titanium alloy casting is mainly mechanical polishing and chemical corrosion.
The mechanical polishing is to remove a certain thickness on the surface by adopting physical modes such as cutting, friction and the like through a specific tool, and the method has low working efficiency, is easy to generate dust pollution, has difficult control on thickness uniformity and surface roughness, and is not suitable for parts with large specification and complex shape.
The chemical corrosion is to utilize alkaline or acid solution to chemically react with the surface of the titanium alloy so as to achieve the aim of rapidly and uniformly removing the surface oxide layer, and at present, the most application is to use hydrofluoric acid and hydrochloric acid or mixed solution of hydrofluoric acid and nitric acid for pickling, wherein the former has high corrosion speed, but is easy to cause intergranular corrosion, and the surface of the part absorbs more hydrogen so as to cause hydrogen embrittlement; the latter has less hydrogen absorption, but has low corrosion speed and low efficiency, and the main components of the two are liquid, and the acid liquor has stronger corrosiveness, so that the transportation and preparation processes have larger potential safety hazards. Therefore, a safe, efficient, low-cost and low-hydrogen-absorption pickling solution for the surface of the titanium alloy casting needs to be developed.
Disclosure of Invention
The invention aims to provide the pickling solution for the surface of the titanium alloy casting, which is efficient, safe, low in cost and small in hydrogen absorption amount, and the preparation method thereof, and the pickling solution can be used for rapidly and uniformly removing the oxide layer on the surface of the titanium alloy casting, so that the surface quality and the mechanical property of the product are improved.
In order to achieve the above object, the technical scheme of the present invention is as follows:
the invention provides a pickling solution for the surface of a titanium alloy casting, which is prepared from the following raw materials: NH (NH) 4 HF 2 250-300g/L、NaNO 3 150-200g/L, HCl-500-550 ml/L, and the balance being water.
Further, the NH 4 HF 2 The purity of (2) is more than or equal to 98 percent。
Further, the NaNO 3 The purity of (2) is more than or equal to 99 percent.
Further, the mass concentration of the HCl is 36-38%.
The invention also provides a preparation method of the pickling solution for the surface of the titanium alloy casting, which comprises the following steps:
(1) NH is added to 4 HF 2 、NaNO 3 Pouring the mixture into a container according to a certain proportion, adding water, and stirring until the solid is completely dissolved;
(2) And pouring HCl into a container according to a certain proportion, adding water after stirring, and standing to obtain the pickling solution.
Further, in the step (2), the first stirring time is 1-2min, the second stirring time is 2-3min, and the standing time is 30min.
The principle of the invention is as follows:
the composition of the pickling solution is determined according to the corrosion speed and the hydrogen absorption speed (shown in fig. 2) when the acid solution reacts with the oxide layer: HF+HCl+HNO 3 The chemical reaction in the pickling process is as follows:
4HF+TiO＝TiF 4 +2H 2 O (1)
6HF+TiO 2 ＝H 2 TiF 6 +2H 2 O (2)
4HNO 3 +12HF+3Ti＝3TiF 4 +8H 2 O+4NO↑ (3)
the beneficial effects of the invention are as follows:
the invention considers the safety of the pickling solution preparation process, selects solid raw materials for preparation, and generates a target product through intermediate chemical reaction, thereby reducing the risks in the transportation and preparation processes.
The pickling solution prepared by the invention has the advantages of high efficiency, low cost, simple preparation method and good effect of removing the surface pollution layer of the titanium casting when used for pickling the surface of the titanium alloy, realizes the industrialized continuous production of the surface pickling of the workpiece by special pickling equipment, and generates certain economic benefit.
Drawings
FIG. 1 is a schematic diagram of the structure of an oxide layer on the surface of a casting;
FIG. 2 is a graph showing the corrosion and hydrogen absorption effects of different acids on a titanium alloy after addition of hydrofluoric acid;
FIG. 3 is a photograph showing metallographic structure of a sample of the 5# casting in example 1 before pickling;
FIG. 4 is a photograph showing metallographic structures of a 5# casting sample in example 1 after pickling;
FIG. 5 is a photograph of metallographic structure of a 3' # cast specimen of comparative example 1 before pickling;
FIG. 6 is a photograph showing the metallographic structure of a 3' # cast specimen of example 1 after pickling.
Detailed Description
The following examples will enable those of ordinary skill in the art to more fully understand the invention and are not intended to limit the invention in any way.
Example 1
A pickling solution for the surface of a titanium alloy casting is prepared from the following raw materials: NH (NH) 4 HF 2 250-300g/L、NaNO 3 150-200g/L, HCl-500-550 ml/L, and water in balance; wherein NH is 4 HF 2 The purity of (C) is more than or equal to 98 percent, naNO 3 The purity of (2) is more than or equal to 99 percent, and the mass concentration of HCl is 36-38 percent.
The preparation method of the pickling solution comprises the following steps:
(1) NH is added to 4 HF 2 、NaNO 3 Pouring the mixture into a container according to a certain proportion, adding water, and stirring until the solid is completely dissolved;
(2) Pouring HCl into a container according to a certain proportion, stirring for 1-2min, adding water, stirring for 2-3min, and standing for 30min to obtain pickling solution.
The pickling solution is used for carrying out a surface pickling test on a titanium alloy casting sample, the pickling temperature is less than or equal to 40 ℃, and the result is as follows:
(1) selecting casting samples, respectively marking the samples as 0# -5#, and testing the change of H content in different pickling times:
table 10 # -5# casting sample pickling test results
The oxide layer on the surface of the titanium alloy casting is basically removed after 25min of pickling, the hydrogen absorption speed of the sample in the pickling process is low, and the total hydrogen absorption amount is 0.0023 percent, so that the method has no influence on components basically.
(2) Surface quality variation:
surface quality inspection of the 5# casting sample pickled for 25min found that:
the original surface roughness Ra of the sample before pickling is more than 12.8 mu m, the surface of the sample after pickling is smooth and silvery white without obvious defects, and the surface roughness Ra of the casting is 3.2-6.3 mu m and is obviously improved by comparison with a casting surface roughness test block;
the original surface of the sample before pickling has defects such as microcracks, air holes and the like, and the surface defects are basically removed through fluorescence penetration detection after pickling.
(3) Metallographic structure change:
the metallographic structure photographs before and after pickling of the No. 5 casting sample are shown in fig. 3 and 4. The thickness of the oxide layer on the surface before pickling is 289.6 mu m, and the surface of the casting after pickling for 25min has no obvious oxide layer and has good removal effect.
(4) Mechanical property change:
the pickling solution is used for carrying out a surface pickling test on a titanium alloy casting sample, wherein the sample number is 6# -7#, the pickling temperature is less than or equal to 40 ℃, the mechanical properties are tested after pickling for 25 minutes, and the change of the mechanical property indexes is shown in tables 2-3:
TABLE 2 comparison of tensile Properties at room temperature
Table 3 hardness comparison
The tensile property index of the titanium alloy casting after 25min acid washing is improved, wherein the elongation after fracture and the area shrinkage of the sample after tensile fracture are improved by 40-60%, the surface hardness is reduced by 10% -18%, and the plasticity of the titanium alloy casting is obviously improved.
Comparative example 1
The preparation method of the pickling solution is similar to that of the example 1, except that the pickling solution is prepared from the following raw materials: NH (NH) 4 HF 2 300g/L、NaNO 3 200g/L, HCl ml/L, the balance being water.
The pickling solution is used for carrying out a surface pickling test on a titanium alloy casting sample, the pickling temperature is less than or equal to 40 ℃, and the result is as follows:
(1) casting samples are selected and respectively marked as 0 '#5' #, and the change of H content in different pickling times is tested:
table 40 '# -5' # pickling test results for cast samples
The oxide layer on the surface of the titanium alloy casting is basically removed after 15min of pickling, the hydrogen absorption speed of the sample in the pickling process is high, and compared with the sample before pickling, the hydrogen content is increased by 0.0147%.
The removal amount of the surface of the titanium alloy casting after pickling for 25min reaches 504 mu m, the pickling solution continuously reacts with the sample because the oxide layer on the surface of the sample is completely removed within the period of 15-25min to corrode the matrix structure of the sample, and the removal amount of the matrix after pickling for 10min is 221 mu m, so that uneven corrosion phenomenon occurs because the reaction rate and the reaction degree of various alloy elements in the matrix and the pickling solution are different, uneven distribution hole defects are formed on the surface, the hydrogen absorption speed is accelerated at the stage, and the hydrogen content is increased by 0.0551 percent compared with that before pickling.
(2) Surface quality variation:
surface quality inspection of 3'-5' # cast samples found:
3' # sample: a small amount of dispersed micro holes (diameter and depth are smaller than 0.2mm and can be ignored) are formed on the surface of the sample after pickling for 15min, and the micro holes are caused by the preliminary corrosion of alloy elements in a matrix by acid liquor;
4' # sample: along with the extension of the pickling time, the corrosion degree of alloy elements in the sample matrix after pickling for 20min is increased, more micro holes are formed, and the diameters of the holes are increased (the depth and the diameter are 0.2-0.3 mm);
5' # sample: after pickling for 25min, the alloy elements in the matrix are severely corroded, and lamellar holes (the holes are connected into flakes and have the depth and the diameter of 0.3-2.0 mm) appear on the surface of the sample.
(3) Metallographic structure change
The metallographic photographs of the 3' # cast samples before and after pickling are shown in fig. 5 and 6. The thickness of the surface oxide layer before pickling is 279.6 mu m, the removal amount of the surface oxide layer after pickling is 283 mu m after 15min, the surface oxide layer is basically removed, and the acid liquor starts to corrode the substrate, so that surface defects are caused.
(4) Casting samples are selected and respectively marked as 6'# -7' #, the pickling temperature is less than or equal to 40 ℃, the mechanical properties are tested after pickling for 15min, and the change of the mechanical property indexes is shown in tables 5-6:
TABLE 5 comparison of tensile Properties at room temperature
Table 6 hardness comparison
The tensile property index of the sample after 15min acid washing is improved, the area shrinkage rate and the elongation rate after fracture of the sample after tensile fracture are improved by 8-25%, and the surface hardness is reduced by 5-13%.
In summary, the pickling time of the pickling solution with the ratio is less than 15min, so that surface defects can be avoided, but the sample has serious hydrogen absorption, the hydrogen content exceeds the requirement of titanium alloy components, and the surface oxide layer can not be thoroughly removed; the pickling time is more than or equal to 15min, so that an oxide layer can be thoroughly removed, excessive corrosion of a sample can be caused, the hydrogen content is increased rapidly, and the surface defect of the sample is serious. Therefore, the acid solution with the concentration higher than the above ratio is not preferable.
The above examples are only preferred embodiments of the present invention and are not limiting of the implementation. The protection scope of the present invention shall be subject to the scope defined by the claims. Other variations or modifications may be made in the various forms based on the above description. Obvious variations or modifications of the embodiments are within the scope of the invention.
Claims (6)
1. A pickling solution for the surface of a titanium alloy casting is characterized in that: the pickling solution is prepared from the following raw materials: NH (NH) 4 HF 2 250-300g/L、NaNO 3 150-200g/L, HCl-500-550 ml/L, and the balance being water.
2. The titanium alloy casting surface pickling solution according to claim 1, wherein: the NH is 4 HF 2 The purity of the product is more than or equal to 98 percent.
3. The titanium alloy casting surface pickling solution according to claim 1, wherein: the NaNO 3 The purity of (2) is more than or equal to 99 percent.
4. The titanium alloy casting surface pickling solution according to claim 1, wherein: the mass concentration of the HCl is 36-38%.
5. The method for preparing the pickling solution for the surface of the titanium alloy casting, according to any one of claims 1 to 4, wherein the method comprises the following steps: the method comprises the following steps:
(1) NH is added to 4 HF 2 、NaNO 3 Pouring the mixture into a container according to a certain proportion, adding water, and stirring until the solid is completely dissolved;
(2) And pouring HCl into a container according to a certain proportion, adding water after stirring, and standing to obtain the pickling solution.
6. The method of manufacturing according to claim 1, characterized in that: in the step (2), the first stirring time is 1-2min, the second stirring time is 2-3min, and the standing time is 30min.
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| CN202311628619.2A CN117684181A (en) | 2023-11-29 | 2023-11-29 | Titanium alloy casting surface pickling solution and preparation method thereof |
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| CN202311628619.2A CN117684181A (en) | 2023-11-29 | 2023-11-29 | Titanium alloy casting surface pickling solution and preparation method thereof |
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