Classifications

• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
  • C23G1/00—Cleaning or pickling metallic material with solutions or molten salts
  • C23G1/02—Cleaning or pickling metallic material with solutions or molten salts with acid solutions
  • C23G1/04—Cleaning or pickling metallic material with solutions or molten salts with acid solutions using inhibitors
  • C23G1/06—Cleaning or pickling metallic material with solutions or molten salts with acid solutions using inhibitors organic inhibitors
  • C23G1/061—Cleaning or pickling metallic material with solutions or molten salts with acid solutions using inhibitors organic inhibitors nitrogen-containing compounds

Definitions

• the present invention relates to pickling methods and compositions and to corrosion and rust inhibiting materials and processes.
• a dark coating of iron oxide forms on the surface of iron and steel during certain processing steps such as hot rolling and forging. This oxide film must be removed before the metal can be cold rolled, galvanized, tinned, electroplated, etc.
• mill scale is usually eliminated by pickling the iron or steel sheets, plates, bars, etc., in a suitable acid solution.
• the acid pickling bath should be capable of casting oif or dissolving the scale without unduly attacking the surface of the metal itself.
• An additional object of the present invention is to provide pickling compositions and pickling methods which substantially eliminate flash rusting or sulling.
• a further object is to provide improved pickling compositions and pickling methods capable of removing oxide film without causing the evolution of harmful amounts of fumes from the pickling bath.
• Another object of the present invention is to provide an improved iron and steel rinsing composition and method of rinsing iron and steel which substantially prevents immediate rusting.
• a further object of the present invention is to pro- 3,033,796 Patented May 8, 1962 ICC vide a method of pickling iron and steel which prolongs the life of the acid bath.
• the present invention comprises the discovery that conventional pickling, scrubbing, and rinse baths can be greatly improved by adding to said baths a member taken from the group having the following general formula:
• the inhibitors of the present invention can be prepared by reacting a fatty material such as an epoxy, halogenated or halohydroxylated fatty acid, ester, amide, or alcohol having an alkyl chain length of from 10 to 22 carbon atoms with a primary or secondary alkylamine or alkylolamine.
• a fatty material such as an epoxy, halogenated or halohydroxylated fatty acid, ester, amide, or alcohol having an alkyl chain length of from 10 to 22 carbon atoms
• Examples of compounds formed in the above reactions are: hydroxy alkylamino fatty acids and their esters and amides; hydroxy alkylolamino fatty acids and their esters and amides; alkylamino fatty acids and their esters and amides; and alkylolamino fatty acids and their esters and amides.
• alkylolamino fatty acids and their esters and amides are described in United States Patent No. 2,277,016. Hydroxy alkylamino fatty acids can be made as indicated in United States Patent No. 2,445,892. Methods of preparing hydroxy alkylolamino fatty acids and their esters and amides and hydroxy alkylolamino fatty alcohols are shown in copending United States Patent application Serial No. 629,235, filed December 19, 1956, and now US. Patent No. 2,993,919, under the name of New Compositions of Matter.”
• Example I A pickling bath comparable to that used in the steel industry to remove mill scale was prepared by heating a 20 percent sulfuric acid solution to 95 C. Another bath was prepared in the same manner except that one (1) percent by weight of 9,l(10,9)diethanolaminohydroxystearic acid diethanolamide formed by condensing chlorohydroxystearic acid and diethanolamine was dissolved in the solution. Steel coupons cut from a steel sheet covered with mill scale were degreased and Weighed and were then immersed in the pickling baths for 30 seconds, minutes, and 30 minutes. The coupons were then rinsed in a water bath, allowed to air dry, and were again weighed. The following results were obtained:
• Control 30 secondsLoss in weight 1% CHSADEA 30 seconds-Loss in weight:
• Weight losses in the above chart and in the examples to follow are expressed in grams per square meter of coupon surface.
• each of the control samples reacted vigorously with the acid, causing the evolution of considerable hydrogen gas.
• coupons immersed in the baths containing the inhibitor reacted significantly less with the acid and very little hydrogen was given off.
• the control coupons On being removed from the rinse bath and air dried, the control coupons rusted severely during drying, whereas the treated coupons remained shiny.
• Example 11 Two pickling baths containing 20 percent H 80 were heated to 95 C. To one of the baths was added one (1) percent by weight of the reaction product of diethanolamine methyldichloro stearate, which is principally bis[N,N-bis (fi-hydroxyethyl) amino] stearic acid diethanolamide. Steel coupons were pickled in each of the baths for 30 seconds, 5 minutes, and 30 minutes. The results of the treatment were as follows:
• the weight losses of the coupons were as follows:
• Example IV Coupons were pickled in a bath, prepared as shown in Example I, which contained one (1) percent by weight of the diethanolamine condensate of alpha-bromostearic acid, which is principally a-[N,N-blS (,B-hydroxyethyl) amino] stearic acid diethanolamide.
• the weight losses of the coupons were as follows:
• Example V One (1) percent by weight of the diethanolamine condensate of alpha-bromomyristic acid, which is principally a-[N,N-bis (fl-hydroxyethyl) amino] myristic acid diethanolamide, was added to a pickling bath as shown in Example I. After 30 minutes of treatment, a steel coupon was found to have lost 57.8 g./m. No fumes were given off from the bath and the coupon, after rinsing and air-drying was rust-free.
• Example VI Pickling baths containing the additives listed below were prepared as shown in Example I. Steel coupons immersed in the various baths did not evidence any sulling after the rinsing and drying steps. Each of the inhibitors effectively controlled metal corrosion and sup pressed the evolution of acid fumes from the bath. The inhibitors, their concentrations, and pickling times were as follows:
• Example VII Ten (10) grams of ll-bromoundecylic acid was mixed with twenty (20) grams of dibutylamine and the mixture was refluxed for five hours. The product was not completely soluble in acid, an insoluble oil being present. The soluble portion of the reaction mixture, principally 1l-dibutylaminoundecanoic acid, was an effective corrosion inhibitor and anti-sulling agent for pickling of steel in 20 percent H at C.
• Example VIII Twenty (20) grams of alpha-bromomyristic acid was mixed with 35 grams of dibutylamine and the mixture was refluxed for 5 hours. The product was not completely soluble in acid, an insoluble oil being present. The soluble portion of the reaction mixture was an efof the particular material to the water rinse bath. Concentration levels of from .01 percent to about percent by weight of the inhibitor, for example, are satisfactory to prevent rinsed coupons from flash rusting.
• compositions and methods described in the present invention those that contain or make use of hydroxyalkylolamino compounds are especially effective.
• the unexpected success of these materials in particular probably is due at least in part to their unusual solubility characteristics.
• An essential feature of the inhibitors of the present compositions is that they have either a primary or a secondary amine group substituted along an alkyl chain of a fatty acid or fatty acid derivative.
• Such derivatives include fatty esters, fatty amides, and fatty alcohols.
• W and X is selected from the group consisting of [-NRRH]+[AN]-, and -NR'R"; where W is selected from the group consisting of [--NR'RH]+[An]-, and -NRR" when X is selected from the group consisting of H and OH; and where W is selected from the group consisting of [--NR'R"H]+[An]-, NR'R", H and OH when X is selected from the group consisting of and R'R"; and where R is selected from the group consisting of alkyl and alkylol, R" is selected from the group consisting of H, alkyl and alkylol, where Z is selected from the group consisting of CH OH
• An acid bath for pickling ferrous metals containing about 2-25% acid and a small amount sufiicient to inhibit fumes of 9,10(l0,9) butyl-ethanolaminohydroxy-stearic acid butylethanolamide.
• An acid bath for pickling ferrous metals containing about 2-25% acid and a. small amount sufiicient to inhibit fumes of 9,10(10,9)-diisopropanolaminohydroxystearic acid diisopropanolamide.
• An acid bath for pickling ferrous metals containing about 225% acid and a small amount sufficient to inhibit fumes of a-[N,N-bis(/8-hydroxyethyl)amino] myristic acid diethanolamide.
• a method of treating ferrous metals which comprises: immersing said metals in an aqueous bath containing a small amount sutficient to inhibit sulling of a composition having the formula:

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)
• Preventing Corrosion Or Incrustation Of Metals (AREA)

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Citations (16)

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• 0
  • BE BE558157D patent/BE558157A/xx unknown
• 1957
  • 1957-01-23 US US635585A patent/US3033796A/en not_active Expired - Lifetime
  • 1957-05-03 GB GB14202/57A patent/GB858233A/en not_active Expired
  • 1957-05-17 FR FR1175370D patent/FR1175370A/fr not_active Expired
  • 1957-06-01 DE DES53745A patent/DE1104286B/de active Pending

Patent Citations (16)

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