GT-FH802 steel blackening agent developed by our company has the advantages of stable solution, short blackening time, suitable color, simple use process, sufficient raw materials and low cost, especially the adhesion and corrosion resistance of blackening film are obviously better than the original product. It has the characteristics of no pollution, energy saving and no steel grade selectivity. It opens up a new way to solve the long-standing problems of high pollution, high energy consumption and hardness selection in alkaline high-temperature blackening, and provides an ideal advanced technology for blackening steel products of various manufacturers. This product is widely used for surface blackening decoration and protective treatment of steel parts in mechanical parts, standard parts, craft products, springs and other industrial departments.
Changsha guterui new material technology co., ltd
Main features: (black, good adhesion, high corrosion resistance, short working time)
1, saving energy. Blackening does not require electricity at all, saving electricity 100% compared with alkaline high-temperature blackening.
2. Improve work efficiency. Alkaline blackening takes 40-80 minutes, while this blackening agent only takes 1-5 minutes.
3, the blackening cost is low. The equipment is simple, only plastic and ceramic pots and pans are needed, and the operation is easy.
4. Strong process adaptability. There is no choice in rigidity. Steel parts with different carbon content and different surface addition States can obtain the same overall surface color effect, and blackened workpieces can be sealed with dehydrated oil. It can also be sealed by soaking in hot oil.
5. The adhesion is firm, the corrosion resistance is strong, the surface of the workpiece is stable after blackening, and the indoor environment can be effectively rusted for 2 years.
6. The size of the workpiece will not be affected, and the thickness of the black film is only 1.3 micron to 3 micron. There is no need for external processing, which saves the time and cost of round-trip transportation and cargo loading and unloading, otherwise the workpiece will be damaged and the time will be unnecessarily delayed.
Changsha guterui new material technology co., ltd
Mechanism of blackening and film formation:
There is no unified opinion on the mechanism of blackening at room temperature. Because the blackened film is very thin (usually less than 3μm), observed by X-ray diffractometer and scanning electron microscope, the composition of blackened film at room temperature is not like Fe3O4 of alkaline blackened film, but a composite film, so it is difficult to make an accurate judgment.
Main technical indicators: the blackening agent is blue liquid, without mechanical impurities, tasteless, nonflammable, non-explosive, non-corrosive and safe to transport. PH value: 2-2.5 Density: 1.04 Water insoluble matter:
Performance index: According to the standard WJ535-82 "Technical Conditions for Alkaline Chemical Oxidation of Iron and Steel Parts" issued by Ordnance Industry Department, the test result of blackened parts is 1, and the experiment is conducted with 3% copper sulfate, and the discoloration time (15-20℃) is not less than 32 seconds.
2. It meets the standard after soaking in 3% neutral sodium oxide solution for 2 hours. The results show that the properties of the workpiece treated with this blackening agent meet the requirements of the ministerial standard.
Usage: 1, framing → degreasing (5- 10 min) → washing (1 min) → rinsing (0.5 min) → derusting (1-5 min) → washing (1 min) → Stabilize (0.5- 1 min) → Soak GT-FX238 dehydrated antirust oil (3-5min) /GT-FB806 water-based sealing agent (1 min) → Dry or dry at room temperature (80-90℃10-20min.
1. Pretreatment process includes degreasing and derusting activation, which is the key to the success of blackening at room temperature. The general requirement is that the parts to be treated must be thoroughly degreased and derusted to obtain a good blackening film.
The following technological processes are recommended:
Process 1: degreasing at medium temperature → water washing → water washing → derusting and activation at normal temperature (slightly corroded machined parts can be washed with hydrochloric acid (the ratio of industrial hydrochloric acid to water is 1: 1) 1-5 minutes; Parts with thick oxide scale will rust in 180-250g/L hot sulfuric acid. ) → water washing → water washing →GT-FH802 blackens at room temperature.
(This process is suitable for parts with little oil stain and no thick oxide scale. The processing time of each process is in place, the quality is stable and the cost is low. )
Process 2: sandblasting → water washing →GT-FH802 blackening at room temperature.
This process is suitable for parts with thick oxide scale, thick oil stain and difficult acid activation, such as high silicon steel, high manganese steel and high chromium steel. Sandblasting machine can be sealed or water-based sandblasting machine to protect the environment and realize clean production. At present, sandblasting machine manufacturers have introduced various types of products, and their performance has considered the requirements of clean production. )
Process 3: ultrasonic degreasing → water washing → derusting activation → water washing →GT-FH802 blackening at room temperature (suitable for parts with deep holes, blind holes and complex shapes.
Blackening process:
Preparation of bath solution for blackening at room temperature: the finished product GT-FH802 is a concentrated solution, which is diluted with 4 times of water (well water is not allowed) to become a working solution. For loose parts such as cast iron, cast steel and powder metallurgy, 5 times of water should be added to the working fluid, and 4 times of water should be added to other steels. The working fluid should be light but not thick, and less water is not good. Soak the cleaned parts without oil stains and rust spots in the blackening working solution quickly, pull them up and down for 2-3 times, soak them for 1-3 minutes and then take them out (the initial concentration of the solution is preferably around 1 minute), and the black film will be grayish black. After the blackened part is taken out of the tank, it stays in the air for 1-2 minutes, and then it is cleaned. Rinse with tap water.
Post-treatment process: choose one of three different treatment methods: (1) GT-FX238 dehydrated antirust oil for hole sealing: immerse the washed and rinsed blackened part in GT-FX238 dehydrated antirust oil for 3-5 minutes, and lift it up and down for 3-5 times; (2) Hot soaking oil: soak in boiling water solution for 5 minutes, and then hot soaking engine oil or various antirust oils can improve corrosion resistance (soaking dehydrated antirust oil is better). (3) Soak GT-FB806 sealant: For high-grade parts (such as photographic equipment, optical instruments, etc.) with high wear resistance and good gloss, you can dehydrate them with boiling water and then soak GT-FB806 sealant. (such as acrylic paint, polyurethane paint, etc. Solution maintenance: When the efficiency of blackening agent decreases, the blue-green color of the solution gradually fades, and the PH value rises to about 2.8, resulting in white precipitate, indicating that the blackening agent is aging. At this time, it can be filtered and clarified, and the precipitate can be separated, and then the blackening agent stock solution (measured by precision test paper with pH of 0.5-5) can be added, and it can be used continuously when the pH is restored to 2-2.5. It is best to use two tanks, one for work and the other for cleaning deposits.
Common defects, causes and elimination methods of blackening;
1. Reasons for uneven blackening film 1, incomplete degreasing of workpieces 2, incomplete cleaning 3, elimination method of overlapping workpieces 1, strengthening degreasing and increasing water washing. 2. Wash with hot water after degreasing, and then rinse with cold water. 3. Shake the workpiece and consider it from the fixture.
Second, the surface of the parts is loose and the binding force is not firm. The reason is 1, the blackening time is too long or too short. 2. Removal method of surface residue of parts 1, strict technology and appropriate control time 2. Strengthen the pretreatment of blackening.
Third, the reason why the blackened film is light in color 1, and the blackening time is too short. Second, the elimination method of insufficient components is 1, and the blackening time is prolonged. Second, the solution is adjusted or replaced.
4. Poor gloss, resulting in rust spots 1 and excessive water in dehydrated oil. The dehydration time of parts is short. Remove method 1. Remove water, check dehydrated oil or replace dehydrated oil 2. Extend the dehydration time.
5. Reasons for the blue difference of firmness and alkalinity:1; Blackening has not yet fully acted; 2. The oxide layer of the parts has not been completely removed.
Exclusion method: 1 Leave it for one day after blackening. 2. Strengthen the treatment before blackening.
6. The spotted and oil-free workpiece can be washed with water and reissued for 0.5- 1 min.
Seven unqualified products can be repaired with 10% dilute nitric acid to remove the blackened film and then blackened.
Other remarks: 1. The film adhesion of blackened parts increases with the increase of storage time, and the longer the storage time, the better the adhesion. After the blackened part is sealed with dehydrated antirust oil, it is best to store it for one day before use. 2. This product is concentrated solution, and each kilogram of concentrated solution can blacken steel 30- 100 kg (surface area is about 3-4 square meters). 3. This blackening agent is not only suitable for soaking blackening of parts, but also suitable for painting blackening of large parts. 4. In the process of blackening, this solvent will produce a small amount of precipitation, which will not affect the blackening quality. (Note: When the working fluid is not used, the sediment needs to be removed. ) 5, 25 kg PE plastic barrel packaging solution should be protected from light, light, high temperature and freezing for no more than one year. Room temperature blackening agent for iron and steel
Changsha guterui new material technology co., ltd