阅读说明：本技术 一种镀铬方法 (Chromium plating method ) 是由 鲁贤高 陈林 陈越伟 胥超 于 2020-12-04 设计创作，主要内容包括：本发明涉及电镀技术领域,公开了一种镀铬方法,包括以下步骤：将身管做前处理；将身管大端朝下装夹,垂直放入镀铬槽中,进行第一次镀铬；完成第一次镀铬后,取出身管,将身管大端朝上装夹,进行第二次镀铬；内膛抛光；检验身管。使用本发明提供的方法得到两端尺寸公差均可控制在0.02mm以内,且镀出的身管合格率可达60%以上,特别适用于高精度身管镀铬。(The invention relates to the technical field of electroplating, and discloses a chromium plating method, which comprises the following steps: pretreating a barrel; clamping the large end of the barrel downwards, vertically placing the barrel into a chromium plating groove, and carrying out primary chromium plating; after the first chromium plating is finished, taking out the barrel, clamping the barrel with the large end facing upwards, and carrying out second chromium plating; polishing the inner bore; and (4) inspecting the barrel. The dimensional tolerance of the two ends obtained by the method provided by the invention can be controlled within 0.02mm, the qualification rate of the plated barrel can reach more than 60 percent, and the method is particularly suitable for high-precision barrel chromium plating.)

1. A method of chromium plating comprising the steps of:

firstly, preprocessing a barrel;

secondly, clamping the large end of the body pipe downwards, vertically placing the body pipe into a chromium plating groove, and carrying out primary chromium plating;

step three, after the first chromium plating is finished, taking out the barrel, clamping the barrel with the large end facing upwards, and carrying out second chromium plating;

step four, polishing the inner chamber;

and step five, inspecting the quality of the coating.

2. A chromium plating process according to claim 1, characterized in that: the pretreatment of the step one comprises oil removal, lead removal, acid cleaning, wiping and washing.

3. The process for chromium plating according to claim 1, wherein said first chromium plating in said second step comprises: the body tube is used as a cathode, a chromium plating anode is placed in the body tube, the temperature of a plating solution is controlled to be 58-66 ℃, the current density is controlled to be 36-42A/dm 2 during first chromium plating, and the chromium plating time is 40-90 min.

4. The process for chromium plating according to claim 1, wherein said three second chromium platings of step (a) comprise: the barrel is used as a cathode, the electroplating electrode is used as an anode, the temperature of the plating solution is controlled to be 58-66 ℃, the current density is controlled to be 36-42A/dm 2 during the second chromium plating, and the chromium plating time is 40-90 min.

5. The process for chromium plating according to claim 1, wherein said bath components of said first and second chromium plating comprise: chromic anhydride: 160-220 g/L; cr (chromium) component³⁺：2～5g/L；Fe³⁺＜5 g/L；SO4^2-：1.6～2.8 g/L。

6. A chromium plating process according to claim 1, characterized in that: the chrome-plated anode is a copper alloy anode base material, and is directly plated with lead after oil removal and acid washing.

7. The process for chromium plating according to claim 6, wherein said copper alloy anode substrate has a diameter of 3.5mm and a diameter of 4mm to 5.1mm after lead plating.

Technical Field

The invention relates to the technical field of electroplating, in particular to a chromium plating method.

Background

In the existing light weapon manufacturing industry, a chromic anhydride and sulfuric acid system is mainly adopted for barrel chromium plating solution, certain trivalent chromium is needed in the chromium plating solution, chromium deposition is facilitated, and barrel taper is eliminated. The metal impurities are generally dissolved in the chromium plating solution when the matrix metal is reversed, and are usually expressed by iron ions.

The trivalent chromium content in the chromium plating solution is high, and the purpose of reducing the trivalent chromium can be achieved by hanging a large anode lead plate and a small cathode to oxidize the chromium plating solution. And the iron ion content is high, and the iron ion content is reduced by adopting a method of diluting and supplementing the chromium plating solution.

Therefore, in the common barrel chromium plating process, the content of trivalent chromium is generally controlled to be 1-10 g/L, and the content of iron ions is generally controlled to be less than or equal to 5-7 g/L. In general, the influence of the factors such as technical means, low requirement on the service life of a barrel and the like is limited in the past, the content of trivalent chromium and metal impurity iron ions is determined to be high, and the crystallization compactness of a chromium coating is directly influenced.

The anode base material is generally selected from low-carbon steel wires plated with copper and lead (or lead-tin alloy) and the like, and supports the anode tension strength. The temperature of the plating solution is generally higher than that of the common hard chromium plating. Because the low-carbon steel wire is plated with copper, the uniformity of the plating layer, the thickness of the copper layer, the skin tendency of current and other factors influence the coaxiality of the chromium plating tool clamp and the barrel, the uniformity of the thickness of the plating layer at the two ends of the barrel is poor, the precision of the barrel is influenced, and the service life of the barrel is also influenced.

When the barrel is electroplated, the small end is generally downward, and the large end is clamped on the chromium plating frame and vertically placed in the chromium plating groove. The small end of the plated steel tube is small in size, the large end of the plated steel tube is large in size, and the taper of the two ends of the plated steel tube reaches 0.03-0.05 mm.

Disclosure of Invention

In order to overcome the problems and disadvantages of the prior art described above, the present invention is directed to a chromium plating method.

The technical scheme of the invention is as follows:

a method of chromium plating comprising the steps of:

firstly, preprocessing a barrel;

secondly, clamping the large end of the body tube downwards, vertically placing the body tube into a chromium plating groove, and carrying out primary chromium plating;

step three, after the first chromium plating is finished, taking out the barrel, clamping the barrel with the large end facing upwards, and carrying out second chromium plating;

step four, polishing the inner chamber;

and step five, inspecting the quality of the coating.

Preferably, the pretreatment of the step one comprises degreasing, lead removal, acid washing, wiping and washing.

Preferably, the first chrome plating in the second step includes: the body tube is used as a cathode, a chromium plating anode is placed in the body tube, the temperature of a plating solution is controlled to be 58-66 ℃, the current density is controlled to be 36-42A/dm 2 during first chromium plating, and the chromium plating time is 40-90 min.

Preferably, the second chromium plating in the third step comprises: the barrel is used as a cathode, the electroplating electrode is used as an anode, the temperature of the plating solution is controlled to be 58-66 ℃, the current density is controlled to be 36-42A/dm 2 during the second chromium plating, and the chromium plating time is 40-90 min.

Preferably, the plating solution components in the first chromium plating and the second chromium plating comprise: chromic anhydride: 160-220 g/L; cr (chromium) component³⁺：2～5g/L；Fe³⁺＜3 g/L；SO4^2-：1.6～2.4 g/L。

Preferably, the chrome-plated anode is a copper alloy anode base material, and is directly plated with lead after oil removal and acid washing.

Preferably, the diameter of the copper alloy anode base material is phi 3.5mm, and the diameter after lead plating is phi 4 mm-phi 5.1 mm.

Compared with the prior art, the technical scheme of the invention has the following beneficial effects:

according to the method for plating the chromium on the barrel, the tolerance of the sizes of the two ends of the barrel is generally controlled to be 0.04-0.05 mm in the prior technical scheme, the qualified rate of the plated barrel can be controlled to be more than 60%, and the method is particularly suitable for plating the chromium on the high-precision barrel, wherein the tolerance of the sizes of the two ends of the barrel is generally controlled to be within 0.02mm, and the qualified rate of the plated barrel is low (between 30% and 50%).

Detailed Description

The technical solutions for achieving the objects of the present invention are further illustrated by the following specific examples, and it should be noted that the technical solutions claimed in the present invention include, but are not limited to, the following examples.

Example 1

As a specific embodiment of the invention, a chromium plating method is disclosed, comprising the steps of:

firstly, preprocessing a barrel;

secondly, clamping the large end of the body tube downwards, vertically placing the body tube into a chromium plating groove, and carrying out primary chromium plating;

step three, after the first chromium plating is finished, taking out the barrel, clamping the barrel with the large end facing upwards, and carrying out second chromium plating;

step four, polishing the inner chamber;

and step five, inspecting the quality of the coating.

Example 2

As a specific embodiment of the invention, a chromium plating method is disclosed, comprising the steps of:

firstly, pretreating a barrel, wherein the pretreatment comprises oil removal, lead removal, acid pickling, wiping and washing;

secondly, clamping the large end of the body pipe downwards, respectively installing a chromium plating cap, then wearing a chromium plating anode, keeping the state of the tensed chromium plating anode by using a tension device after tensioning, downwards installing the large end of the body pipe with the upper cap, the lower cap and the tensioned chromium plating anode, clamping the large end of the body pipe on a chromium plating frame, taking the chromium plating frame as a cathode, connecting an anode current to the anode from the upper end, performing first-stage chromium plating, controlling the temperature of a plating solution to be 58-66 ℃, controlling the current density to be 36-42A/dm 2, and controlling the chromium plating time to be 40-90 min;

step three, after primary chromium plating is completed, taking out the barrel, respectively installing chromium plating caps when the large end of the barrel is upwards clamped, then putting on chromium plating anodes, after tensioning, keeping the tension state of the chromium plating anodes by using a tensioning device, upwards installing the large end of the barrel with the upper caps, the lower caps and the tensioned chromium plating anodes, clamping the barrel on a chromium plating frame, using the chromium plating frame as a cathode, connecting an anode current on the anode from the upper end, performing secondary chromium plating, controlling the temperature of a plating solution to be 58-66 ℃, controlling the current density to be 36-42A/dm 2, and controlling the chromium plating time to be 40-90 min;

step four, polishing the inner chamber;

and step five, inspecting the quality of the coating.

Example 3

As a specific embodiment of the invention, a chromium plating method is disclosed, comprising the steps of:

the method comprises the following steps of firstly, performing pretreatment, wherein the pretreatment comprises oil removal, lead removal, acid cleaning, wiping and washing;

step two, when the large end of the body pipe is clamped downwards, the body pipe is respectively provided with a chromium plating cap, then a chromium plating anode is worn, after tensioning, the tensioning device is used for keeping the tension state of the chromium plating anode, the large end of the body pipe provided with the upper cap, the lower cap and the tensioned chromium plating anode is downwards, the body pipe is clamped on a chromium plating frame, the chromium plating frame is used as a cathode, the anode current is connected to the anode from the upper end, the first-stage chromium plating is implemented, the temperature of a plating solution is controlled to be 58-66 ℃, the current density is controlled to be 36-42A/dm 2, the chromium plating time is 40-90 min, and: chromic anhydride: 160-220 g/L; cr (chromium) component³⁺：2～5g/L；Fe³⁺＜5 g/L；SO4^2-：1.6～2.8 g/L；

Step three, after the first chromium plating is completed, taking out the barrel, respectively installing chromium plating caps when the large end of the barrel is upwards clamped, then wearing chromium plating anodes, after tensioning, keeping the tension state of the chromium plating anodes by using a tensioning device, installing the large end of the barrel with the upper caps, the lower caps and the tensioned chromium plating anodes upwards, clamping the barrel on a chromium plating frame, using the chromium plating frame as a cathode, connecting an anode current on the anode from the upper end, performing second chromium plating, controlling the temperature of a plating solution to be 58-66 ℃, controlling the current density to be 36-412A/dm 2, and controlling the chromium plating time to be 40-90 min, wherein the plating solution comprises the following components: chromic anhydride: 160-220 g/L; cr (chromium) component³⁺：2～5g/L；Fe³⁺＜5 g/L；SO4^2-：1.6～2.8 g/L；

Step four, polishing the inner chamber;

and step five, inspecting the quality of the coating.

Preferably, the chrome-plated anode is a copper alloy anode base material, and is directly plated with lead after oil removal and acid washing.

Preferably, the diameter of the copper alloy anode base material is phi 3.5mm, and the diameter after lead plating is phi 4 mm-phi 5.1 mm.

According to the method for plating the chromium on the barrel, the tolerance of the sizes of the two ends of the barrel is generally controlled to be 0.04-0.06 mm in the prior technical scheme, the qualified rate of the plated barrel can be controlled to be more than 60%, and the method is particularly suitable for plating the chromium on the high-precision barrel, wherein the tolerance of the sizes of the two ends of the barrel is generally controlled to be within 0.04-0.06 mm, and the qualified rate of the plated barrel is low (between 30% and 50%).

The above-mentioned embodiments are further described in detail for the purpose of illustrating the invention, the technical solutions and the advantages, it should be understood that the above-mentioned embodiments are only exemplary of the invention, and are not intended to limit the invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the invention should be included in the protection scope of the invention.