金属表面处理工艺(Metalsurfacetreatmentprocess)

1、金属表面处理工艺(Metal surface treatment process)Surface blackening treatment processSurface blackening of steel parts processing, also known as barffing Black treatment now commonly used methods have the traditional alkaline heating and blackening of the late appearance of two kinds of room temperature But

2、 the blackening process at room temperature is not very good for low carbon stee1. A3 steel is slightly better by alkaline blackening Alkaline black fractionize comes out, have again black and two black distinction. The main components of the black liquor are sodium hydroxide and sodium nitrite When

3、 you re black, you need a good tolerance of temperature You can get a nice surface between 135 and 155 degrees Celsius, but it takes only a little time. In the actual operation, the need to pay attention to is the workpiece before blackening and rust removing oil quality, and blackening after passiv

4、ation of immersion. Blackening quality is often due to these processes and changeBlue liquid metalUsing alkaline oxidation or acid oxi da tion; to form a layer of oxide film on metal surface to prevent metal surface corrosion, this process is called blueThe black metal surface by the blue treatment

5、after the formation of the oxide film, the outer layer is mainly magnetite, the inner layer is feoA blue, alkaline oxidation liquid1. formula: 50100 grams of sodium hydroxide and sodiumnit rate from 600 to 700 grams of sodium nitrate 100200 grams1000 grams of water2. system method: according to the

6、formula after measuring, in the mixing cond itio ns, in turn each mat erial to add, dissolve, mix evenly.3. instruetions:(1) the metal surface must be cleaned and dried before the basket can be processed.(2) metal devices blue to deal with the relevant condition and the metal carbon amount, and the

7、solution temperature and the metal component can refer to the following table in the processing time.The carbon content of metals, % operating temperature (DEG C), and processing time (minutes) begin to terminate0.7135 137143 10-300.5-0.7135 140、150 30-500.4142 145153 40-60Alloy steel 142/145153/155

8、 60-90(3) analyze the content of sodium nitrate, sodium nitrite and sodium hydroxide in the solution regularly every other week, so as to supplement the ingredients in time. Generally use six months later, you should replace all the solution.(4) and metal processing, preferably with hot soapy water

9、and rinse for several minutes, then rinse with cold water Then rinse it with hot water and blow it dry.Two, the acid oxidation of blue liquor1. formula: 310 grams of calcium phosphate 80100 gramsto 15 grams of manganese peroxide 10 water 1000 grams2. method: according to the formula of measurement,

10、under the condition of continuously stirring, in order to phosphoric acid, manganese peroxide and calcium nitrate added, dissolving, mixing3. instruetions:(1) the first metal device washed and dried before processing blue.(2) the protective film is black, and its main component is composed of calciu

11、m phosphate and iron oxide. Its corrosion resistance and mechanical strength are all over the protective film obtained by alkaline oxidation process4. blue working temperature is 100 DEG C, the processing timefor 4045 minutes When dealing with carbon steel, the contentof phosphoric acid in the solut

12、ion is controlled at 3 5 grams / liter. When dealing with alloy steel or cast st eel, the content of phosphoric acid is controlled at 5 10 grams / liter. Attention should be paid to the regular analysis of the content of phosphoric acidThe same method for cleaning metal device 5. blue aftertreatment

13、.Knowledge of galvanizing1 Hot-dip galvanizing has been developed from an older method of hot plating It has been one hundred and forty years since France applied hot-dip galvanizing to industry in 1836 However, the hot-dip galvanizing industry has developed rapidly in the past thirty years with the

14、 rapid development of cold rolled strip stee1.The production process of hot-dip galvanized sheet mainly includes: plate preparation, plating pretrestment, hot-dip galvanizing, plating treatment, finished product inspection, etc According to the habit, often according to the method before platingDiff

15、erent hot-dip galvanizing process can be divided into two categories, that is, outside annealing and line annealing:Wet process (sheet steel hot-dip galvanizing)Hot dip galvanizing of sheet steel by outside annealingHot dip galvanized wheeling (Wheeling) method (hot dip galvanizing method)Improved a

16、nnealing method of wire annealing (Sendzimir) method (protective gas method)UEC (Japan Kawasaki)Silas (Selas) lawSharon (Sharon) law1. line annealing is hot or cold rolled steel plate into the hot galvanizing line before the first pumping hearth annealing furnace annealing furnace recrystallization

17、annealing, galvanizing line there is the annealing process A clean pure iron active surface without oxides and other impurities must be maintained prior to hot-dip galvanizing This method is the first method to remove surface oxide by pickling iron annealing, then coated by a layer of zinc chloride

18、or a mixture of ammonium chloride and zinc chloride solvent protection, so as to prevent the steel plate by oxidation.(1) wet galvanizing： the solvent on the surface of the steel plate does not dry (i e. , the surface is still wet) and enters the zinc liquid which is covered with molten solvent on t

19、he surface and is hot-dip galvanized. The disadvantage of this method is that:A. can only be galvanized in lead free condition, and the alloy coating is very thick and bad adhesion.B genera ted zinc accumulated not deposi ted to the bottom of the pot at the interface of liquid zinc and lead liquid (

20、because the zinc slag is greater than the proportion of liquid zinc is less than the lead liquid), so that the steel plate through the zinc layer surface pollution. Therefore, the method has been basically eliminatedThe difference between http：/wwwtpdao. com/readphp and Dacromet galvanized tid二345?(

21、2) sheet steel: this method is generally used hot rolling laminated plate as raw material, first of all, the annealed steel plate into the pickling workshop, with sulfuric acid or hydrochloric acid to remove the surface of the steel sheet oxygen hot galvanized iron sheet After pickling, the steel pl

22、ate immediately enters the tank and is soaked for galvanizing, thus preventing the steel plate from re oxidation. After pickling, cleaning, drying, drying, into the pot (the temperature has remained at 445 - 465 degrees Celsius) hot galvanizing, and then oiled and chromium treatment The hotdip galva

23、nized sheet produced by this method has significantly improved the quality of wet galvanized products, and is only of certain value for small-scale production.Hui Lin (3): the method of hot continuous galvanizing production line including a series of pre-treatment process of alkali degreasing, hydro

24、chloric acid, water washing, coating solve nt, drying, and the original plate into before galvanizing galvanizing line for annealing furnace The production process is complex, the production cost is high, and more importantly, the products produced by this method often have solvent defects, which af

25、fect the corrosion resistance of the coating And the zinc pot AL often the solvent and the steel surface function to generate aluminum chloride consume, deterioration of the adhesion of the coating Although this method has been published for nearly thirty years, it has not been developed in the worl

26、d hot galvanizing industry.2. in line annealing: the cold rolling or hot rolling mill is directly supplied with the coil as the original plate of hot galvanizing, and the gas protection, recrystallization and annealing are carried out in the hot galvanizing line Including the hot galvanizing method

27、belongs to the class of the industry： the Sendzimir met hod, modified Sendzimer method, UEC (Japan Kawasaki Nori); Silas method; Sharon methodSen Jimmy Apha: it is a combination of annealing process and hot galvanizing process. The annealing in line mainly cons is ts of two parts: the oxidation furn

28、ace and the reduction furnace In the oxidation furnace, the gas flame is heated directly to about 450 degrees The remaining rolling oil on the strip is burned and the surface is purified The strip is then heated to 700800 degrees to complete recrystallization annealing, controlled by the cooling sec

29、tion into the zinc pot temperature at abo ut 480 degrees, and finally in the case does not cont act the air into the galvanized zinc pot, therefore, high yield, good quality galvanized Sendzimer met hod, this method has been widely appliedUnited States Steel Union Law: it is a variant of Sen Jimmy A

30、pha, it is only using an alkaline electrolytic degreasing tank instead of oxidation furnace degreasing function, and the rest of the process and Sen Jimmy Apha basically the same After the original plate enters the operation line, the electrolytic degreasing is carried out first, then the water is w

31、ashed and dried, and then the recrystallization annealing is carried out through a reducing furnace with protective gas Finally, the zinc is dipped into the zinc pot to be hot-dip galvanized under the seal condition.Because the st rip is not hea ted by the oxi da tion furnace, the surface oxide film

32、 is thinner, and the hydrogen cont ent of the protective gas in the reducing furnace can be appropriately reduced. In this way, it is beneficial to furnace safety and production cos t reduc tion. However, as the st rip can not be pre heated, it enters the reduction furnace, which undoubtedly improve

33、s the heat load of the reduction furnace and affects the service life of the furnace Therefore, this method has not been widely appliedSilas Law: also known as direct flame heating method; first strip by alkali cleaning, then use hydrochloric acid to remove surface oxide, and after washing and dryin

34、g before ent ering the vertical lines directly heated by the gas flame annealing furnace, through strict control of the furnace gas and the air of the flame burning ratio, which were not completely the gas flame in excess and lack of oxygen under the condition of burning, so that the furnace caused

35、by reducing atmosphere It can be heated rapidly to achieve recrystallization temperature and cool the strip steel under low hydrogen protection atmosphere Finally, the zinc liquid is dipped into the zinc bath under closed condition to do hot galvanizing The method has the advantages of compact equip

36、ment, low investment cost and high output (up to 50/ hours) But the complexity of theproduction process, especially when the unit stops running, in order to avoid burning off the strip, the stove sliding away from the st rip met hod, so a lot of opera tio nal problems, so the galvanizing industry using this method rarely.the United States Sharon company put into galvanizing unit, so it is also called method is the injection of hydrogen annealing furnace to strip and the stripSharon Law: in 1939, operation a new hot Sharon met