MD192Y - Process for thermochemical treatment of steel articles - Google Patents
Process for thermochemical treatment of steel articles Download PDFInfo
- Publication number
- MD192Y MD192Y MDS20090103A MDS20090103A MD192Y MD 192 Y MD192 Y MD 192Y MD S20090103 A MDS20090103 A MD S20090103A MD S20090103 A MDS20090103 A MD S20090103A MD 192 Y MD192 Y MD 192Y
- Authority
- MD
- Moldova
- Prior art keywords
- steel
- hcl
- electrolyte
- solution
- thermochemical treatment
- Prior art date
Links
- 238000000034 method Methods 0.000 title claims abstract description 19
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 16
- 239000010959 steel Substances 0.000 title claims abstract description 16
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims abstract description 33
- 239000003792 electrolyte Substances 0.000 claims abstract description 15
- NLXLAEXVIDQMFP-UHFFFAOYSA-N Ammonia chloride Chemical compound [NH4+].[Cl-] NLXLAEXVIDQMFP-UHFFFAOYSA-N 0.000 claims abstract description 10
- 235000019270 ammonium chloride Nutrition 0.000 claims abstract description 9
- AVXURJPOCDRRFD-UHFFFAOYSA-N Hydroxylamine Chemical compound ON AVXURJPOCDRRFD-UHFFFAOYSA-N 0.000 claims abstract description 5
- 229910017912 NH2OH Inorganic materials 0.000 claims abstract description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 5
- 239000007864 aqueous solution Substances 0.000 claims abstract description 4
- 238000010438 heat treatment Methods 0.000 claims abstract description 4
- 239000000243 solution Substances 0.000 description 18
- 238000005260 corrosion Methods 0.000 description 12
- 230000007797 corrosion Effects 0.000 description 11
- 238000005261 decarburization Methods 0.000 description 9
- 230000003647 oxidation Effects 0.000 description 9
- 238000007254 oxidation reaction Methods 0.000 description 9
- 239000002344 surface layer Substances 0.000 description 6
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 5
- 229910052799 carbon Inorganic materials 0.000 description 5
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- 230000007423 decrease Effects 0.000 description 4
- 238000005121 nitriding Methods 0.000 description 4
- 239000007832 Na2SO4 Substances 0.000 description 2
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 2
- PMZURENOXWZQFD-UHFFFAOYSA-L Sodium Sulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=O PMZURENOXWZQFD-UHFFFAOYSA-L 0.000 description 2
- 238000005275 alloying Methods 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 238000004090 dissolution Methods 0.000 description 2
- 239000008151 electrolyte solution Substances 0.000 description 2
- 239000010410 layer Substances 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 229910017464 nitrogen compound Inorganic materials 0.000 description 2
- 150000002830 nitrogen compounds Chemical class 0.000 description 2
- 238000010791 quenching Methods 0.000 description 2
- 230000000171 quenching effect Effects 0.000 description 2
- VWDWKYIASSYTQR-UHFFFAOYSA-N sodium nitrate Chemical compound [Na+].[O-][N+]([O-])=O VWDWKYIASSYTQR-UHFFFAOYSA-N 0.000 description 2
- 229910052938 sodium sulfate Inorganic materials 0.000 description 2
- 235000011152 sodium sulphate Nutrition 0.000 description 2
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 1
- 229910000976 Electrical steel Inorganic materials 0.000 description 1
- 235000011114 ammonium hydroxide Nutrition 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 230000003628 erosive effect Effects 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 150000004767 nitrides Chemical class 0.000 description 1
- 235000017550 sodium carbonate Nutrition 0.000 description 1
- 229910000029 sodium carbonate Inorganic materials 0.000 description 1
- 235000010344 sodium nitrate Nutrition 0.000 description 1
Landscapes
- Resistance Heating (AREA)
- Heat Treatment Of Strip Materials And Filament Materials (AREA)
Abstract
Inventia se refera la procedeele de tratare a otelului, in special la un procedeu de tratare termochimica a pieselor din otel. Procedeul, conform inventiei, include incalzirea anodica a piesei pana la temperatura de 400…950°C, timp de 3…5 minute, intr-un electrolit ce contine, g/L: NH4Cl 40…60, NH2OH·HCl 0,05…0,10, N2H4·HCl 0,1…1,0, apa — restul, la o tensiune a curentului de 100…220 V si o densitate de 1,0…2,5 A/cm2, dupa care piesa se caleste intr-o solutie apoasa ce contine 50…100 g/L de hidroxid de sodiu.The invention relates to the steel treatment processes, in particular to a thermochemical treatment process of steel parts. The process according to the invention includes anodic heating of the part to a temperature of 400 ... 950 ° C, for 3 ... 5 minutes, in an electrolyte containing, g / L: NH4Cl 40 ... 60, NH2OH · HCl 0.05 ... 0.10, N2H4 · HCl 0.1… 1.0, water - the rest, at a current voltage of 100… 220 V and a density of 1.0… 2.5 A / cm2, after which the part is heated in - an aqueous solution containing 50 ... 100 g / L of sodium hydroxide.
Description
Invenţia se referă la procedeele de tratare a oţelului, în special la un procedeu de tratare termochimică a pieselor din oţel. The invention relates to steel treatment processes, in particular to a process for thermochemical treatment of steel parts.
Este cunoscut un procedeu de prelucrare a oţelului electrotehnic, care include prelucrarea fierbinte a piesei din oţel şi decarburarea suprafeţei acesteia cu un curent electric continuu, în soluţie de Na2CO3 (de 15%) la o tensiune de 175 V, o densitate de 3…5 A/cm2, la o temperatură de 700 ± 20°C sau 885 ± 15°C timp de 180 s. Decarburarea stratului superficial al oţelului înlătură centrele active şi sporeşte rezistenţa metalului la coroziune [1]. A process for processing electrical steel is known, which includes hot processing of the steel part and decarburization of its surface with a direct electric current, in Na2CO3 solution (15%) at a voltage of 175 V, a density of 3…5 A/cm2, at a temperature of 700 ± 20°C or 885 ± 15°C for 180 s. Decarburization of the surface layer of the steel removes active centers and increases the metal's resistance to corrosion [1].
Dezavantajul acestui procedeu constă în numărul mare de etape de prelucrare şi decarburarea insuficientă a oţelului. The disadvantage of this process is the large number of processing steps and insufficient decarburization of the steel.
Este de asemenea cunoscut un procedeu de decarburare a oţelului şi un electrolit pentru realizarea acestuia, care include prelucrarea pieselor din oţel în soluţie de electrolit ce conţine suplimentar 4…6% clorură de amoniu, la o tensiune a curentului de 180 V, o densitate de 1 A/cm2 şi o temperatură a piesei de 650°C. În urma decarburării, conţinutul carbonului din stratul superficial scade la o adâncime de până la 0,2 mm, de la 62 până la 28%. Piesele pot fi răcite cu electrolit, sau la aer. Concomitent cu decarburarea stratului superficial al piesei are loc nitrurarea lui şi oxidarea suprafeţei piesei la temperaturi înalte în vaporii soluţiei apoase a electrolitului [2]. Dezavantajul procedeului constă în decarburarea şi nitrurarea insuficientă a suprafeţei pieselor, ce conduce la eroziune şi arsuri, ce au loc în urma procesului, adică la o coroziune locală, iar pe alocuri se observă extinderea corodării punctiforme.A steel decarburization process and an electrolyte for its production are also known, which include processing steel parts in an electrolyte solution containing an additional 4…6% ammonium chloride, at a current voltage of 180 V, a density of 1 A/cm2 and a temperature of the part of 650°C. As a result of decarburization, the carbon content in the surface layer decreases to a depth of up to 0.2 mm, from 62 to 28%. The parts can be cooled with electrolyte or in air. Simultaneously with the decarburization of the surface layer of the part, its nitriding and oxidation of the surface of the part at high temperatures in the vapors of the aqueous electrolyte solution take place [2]. The disadvantage of the process is the insufficient decarburization and nitriding of the surface of the parts, which leads to erosion and burns that occur as a result of the process, i.e. local corrosion, and in some places the extension of pitting corrosion is observed.
Cea mai apropiată soluţie este un procedeu de mărire a rezistenţei oţelului la coroziune, care include alierea piesei cu timpul specific de aliere de 1 min/cm2, cu o energie a descărcării electrice de 0,3…4,0 J, tratarea termochimică prin încălzirea anodică a piesei timp de 30 s, într-un electrolit ce conţine NH4Cl şi NH4OH, NH4Cl şi NaNO3, la o temperatură de 750°C, o tensiune dintre electrozi de 150…220 V, o densitate a curentului electric de 1…15 A/cm2 şi răcirea ulterioară a piesei la aer [3]. The closest solution is a process for increasing the corrosion resistance of steel, which includes alloying the part with a specific alloying time of 1 min/cm2, with an electric discharge energy of 0.3…4.0 J, thermochemical treatment by anodic heating of the part for 30 s, in an electrolyte containing NH4Cl and NH4OH, NH4Cl and NaNO3, at a temperature of 750°C, a voltage between the electrodes of 150…220 V, an electric current density of 1…15 A/cm2 and subsequent cooling of the part in air [3].
Dezavantajul procedeului constă în nitrurarea şi decarburarea insuficientă, ceea ce asigură o protecţie redusa a suprafeţei piesei din oţel. The disadvantage of the process is insufficient nitriding and decarburization, which provides reduced protection of the surface of the steel part.
Problema pe care o rezolvă invenţia constă în sporirea rezistenţei pieselor prelucrate la coroziune, ca rezultat al intensificării decarburării, cât şi a oxidării suplimentare. The problem solved by the invention consists in increasing the corrosion resistance of machined parts, as a result of the intensification of decarburization, as well as of additional oxidation.
Procedeul, conform invenţiei, include încălzirea anodică a piesei până la temperatura de 400…950°C, timp de 3…5 min, într-un electrolit ce conţine, g/L: NH4Cl 40…60, NH2OH·HCl 0,05…0,10, N2H4·HCl 0,1…1,0, apă - restul, la o tensiune a curentului de 100…220 V şi o densitate de 1,0…2,5 A/cm2, după care piesa se căleşte într-o soluţie apoasă ce conţine 50…100 g/L de hidroxid de sodiu. The process, according to the invention, includes anodic heating of the part to a temperature of 400…950°C, for 3…5 min, in an electrolyte containing, g/L: NH4Cl 40…60, NH2OH·HCl 0.05…0.10, N2H4·HCl 0.1…1.0, water - the rest, at a current voltage of 100…220 V and a density of 1.0…2.5 A/cm2, after which the part is quenched in an aqueous solution containing 50…100 g/L of sodium hydroxide.
Rezultatul invenţiei constă în micşorarea conţinutului de carbon în stratul superficial al piesei şi saturarea suplimentară cu azot prin formarea nitrurilor. Datorită călirii suplimentare în soluţia de hidroxizi alcalini, grosimea peliculei de oxizi se măreşte de 2…3 ori, ceea ce conduce la sporirea semnificativă a proprietăţilor anticorosive ale piesei prelucrate. The result of the invention is the reduction of the carbon content in the surface layer of the part and its additional saturation with nitrogen through the formation of nitrides. Due to the additional quenching in the alkaline hydroxide solution, the thickness of the oxide film increases by 2…3 times, which leads to a significant increase in the anti-corrosion properties of the machined part.
Tratamentul se realizează în modul următor. Piesa supusă prelucrării, care serveşte totodată şi în calitate de anod, se introduce într-un electrolizor cu o soluţie apoasă a compuşilor de azot. La o tensiune de 100…200 V şi o densitate a curentului de 1,0…2,5 A/cm2 electrolitul din preajma anodului începe să fiarbă. În aceste condiţii, datorită vaporilor, de pe suprafaţa piesei se îndepărtează pelicula de oxizi, iar temperatura anodului poate fi reglată în limitele de 400…950°C. În conformitate cu gradientul de concentraţie, carbonul din straturile de adâncime difundează parţial spre suprafaţa materialului, apoi în pelicula de vapori şi gaze, iar prezenţa compuşilor de azot în soluţie conduce la crearea unei concentraţii necesare de azot în peliculă. Prezenţa în pelicula de oxizi a vaporilor de apă permite la temperaturi înalte oxidarea suprafeţei oţelului şi creşterea peliculei menţionate. După deconectarea piesei de la sursa de curent electric şi extragerea din electrolit, aceasta se căleşte în soluţie de hidroxid de sodiu unde concomitent are loc şi oxidarea suplimentară. The treatment is carried out as follows. The workpiece, which also serves as an anode, is placed in an electrolyzer with an aqueous solution of nitrogen compounds. At a voltage of 100…200 V and a current density of 1.0…2.5 A/cm2, the electrolyte near the anode begins to boil. Under these conditions, due to the vapors, the oxide film is removed from the surface of the workpiece, and the anode temperature can be adjusted within the limits of 400…950°C. In accordance with the concentration gradient, carbon from the deep layers partially diffuses to the surface of the material, then into the vapor and gas film, and the presence of nitrogen compounds in the solution leads to the creation of a necessary concentration of nitrogen in the film. The presence of water vapor in the oxide film allows the oxidation of the steel surface and the growth of the aforementioned film at high temperatures. After disconnecting the part from the electrical power source and extracting it from the electrolyte, it is quenched in sodium hydroxide solution where additional oxidation also takes place.
Exemplu de realizare a procedeului Example of the process
Au fost supuse tratării termochimice nişte piese confecţionate din oţel de marca 45 cu un diametru de 30 mm, înălţimea de 25 mm şi compoziţia, % masă: C - 0,42…0,5; Cr - 0,25; Ni - 0,25; Mn - 0,5…0,8; Si - 0,17…0,37; P - 0,035. Tratarea a fost efectuată într-un electrolit de control, ce conţine doar NH4Cl cu concentraţia 50 g/L şi totodată în electrolitul revendicat, ce conţine, g/L: NH4Cl - 50; NH2OH·HCl - 0,1 şi N2H4·HCl - 1,0, apă - restul. Prelucrarea piesei-anod a fost efectuată la o tensiune a curentului de 150…220V, o densitate de 1,0…2,5 A/cm2, timp de 3…5 min. După prelucrare piesa a fost deconectată de la curent, scoasă din baie şi introdusă în soluţia de hidroxid de sodiu până la răcirea ei. Parts made of steel grade 45 with a diameter of 30 mm, a height of 25 mm and a composition, % mass: C - 0.42…0.5; Cr - 0.25; Ni - 0.25; Mn - 0.5…0.8; Si - 0.17…0.37; P - 0.035 were subjected to thermochemical treatment. The treatment was carried out in a control electrolyte, containing only NH4Cl with a concentration of 50 g/L and at the same time in the claimed electrolyte, containing, g/L: NH4Cl - 50; NH2OH·HCl - 0.1 and N2H4·HCl - 1.0, water - the rest. The processing of the anode part was carried out at a current voltage of 150…220V, a density of 1.0…2.5 A/cm2, for 3…5 min. After processing, the piece was disconnected from the power supply, removed from the bath and placed in the sodium hydroxide solution until it cooled.
Rezistenţa pieselor prelucrate la coroziune a fost testată într-o soluţie de Na2SO4 (0,05 M). Rezultatele prezentate în tabelele 1 şi 2 demonstrează că tratamentul termochimic a pieselor din oţel într-un electrolit ce conţine NH4Cl, NH2OH·HCl, N2H ·HCl şi călirea lor suplimentară în soluţie de hidroxid de sodiu la o concentraţie de 75 g/L micşorează de 2,1 şi respectiv de 3,3…8 ori valoarea curentului dizolvării anodice în comparaţie cu soluţia cea mai apropiată la un potenţial φ = - 0,1 V, iar la un potenţial de φ = 0,1 V - de 6,2 şi, respectiv, de 13,5…25,9 ori. Totodată, conţinutul carbonului în stratul superficial se micşorează de două ori, iar microduritatea creşte de la 5600 până la 5900…5990 MPa. Ultima confirmă nitrurarea stratului superficial. Viteza coroziunii se micşorează de 1,4…2,5 ori la testarea timp de 8 ore, de 1,4…2,0 ori la testarea timp de 24 de ore şi de 1,8…2,4 ori timp de 72 ore. Evident este că micşorarea maximă a vitezei de coroziune are loc în cazul oxidării în soluţia de hidroxid de sodiu cu o concentraţie mai mare. Cu toate acestea, utilizarea unei soluţii cu concentraţia mai mică de 50 g/L nu permite obţinerea rezultatelor dorite, iar la o concentraţie mai mare de 100 g/L se modifică însuşi mecanismul oxidării, ceea ce este destul de riscant din punct de vedere ecologic. The corrosion resistance of the machined parts was tested in a solution of Na2SO4 (0.05 M). The results presented in Tables 1 and 2 demonstrate that the thermochemical treatment of steel parts in an electrolyte containing NH4Cl, NH2OH·HCl, N2H ·HCl and their additional quenching in sodium hydroxide solution at a concentration of 75 g/L reduces the value of the anodic dissolution current by 2.1 and 3.3…8 times, respectively, compared with the closest solution at a potential of φ = - 0.1 V, and at a potential of φ = 0.1 V - by 6.2 and, respectively, 13.5…25.9 times. At the same time, the carbon content in the surface layer decreases by two times, and the microhardness increases from 5600 to 5900…5990 MPa. The latter confirms the nitriding of the surface layer. The corrosion rate decreases by 1.4…2.5 times when tested for 8 hours, by 1.4…2.0 times when tested for 24 hours and by 1.8…2.4 times when tested for 72 hours. It is obvious that the maximum decrease in the corrosion rate occurs in the case of oxidation in a sodium hydroxide solution with a higher concentration. However, the use of a solution with a concentration of less than 50 g/L does not allow obtaining the desired results, and at a concentration of more than 100 g/L the oxidation mechanism itself changes, which is quite risky from an ecological point of view.
Tabelul 1 Table 1
Influenţa modului de tratament asupra curenţilor dizolvării anodice în soluţia de Na2SO4 (0,05 M) Influence of treatment mode on anodic dissolution currents in Na2SO4 solution (0.05 M)
Varianta Ia, A/m2 la φ = - 0,1 V Ia, A/m2 la φ = - 0,1 V Piesa neprelucrată 168 308 Soluţia cea mai apropiată 65,2 290 Electrolitul revendicat 31,4 46,7 Oxidare suplimentară în soluţie de NaOH, 50 g/L 19,8 21,5 Oxidare suplimentară în soluţie de NaOH, 75 g/L 9,7 14,9 Oxidare suplimentară în soluţie de NaOH, 100 g/L 8,1 11,2Variant Ia, A/m2 at φ = - 0.1 V Ia, A/m2 at φ = - 0.1 V Raw part 168 308 Closest solution 65.2 290 Claimed electrolyte 31.4 46.7 Additional oxidation in NaOH solution, 50 g/L 19.8 21.5 Additional oxidation in NaOH solution, 75 g/L 9.7 14.9 Additional oxidation in NaOH solution, 100 g/L 8.1 11.2
Tabelul 2 Table 2
Influenţa modului şi a duratei de tratament asupra conţinutului de carbon în stratul superficial, a microdurităţii suprafeţei şi a vitezei de coroziune a probelor Influence of treatment method and duration on the carbon content in the superficial layer, surface microhardness and corrosion rate of the samples
Electrolit Modul de răcire Microduritatea, Hµ, MPa Conţinutul de C, % Viteza coroziunii, kg/m2 8 ore 24 ore 72 ore Soluţia cea mai apropiată În electrolit 5600 0,28 25,4 8,3 5,8 Procedeul revendicat În electrolit 5900 0,14 18,1 5,8 3,2 În soluţia de hidroxid de sodiu, 75 g/L 5900 - 10.3 4,1 2,4Electrolyte Cooling mode Microhardness, Hµ, MPa C content, % Corrosion rate, kg/m2 8 hours 24 hours 72 hours Closest solution In electrolyte 5600 0.28 25.4 8.3 5.8 Claimed process In electrolyte 5900 0.14 18.1 5.8 3.2 In sodium hydroxide solution, 75 g/L 5900 - 10.3 4.1 2.4
Aşadar, procedeul revendicat permite de a mări considerabil rezistenţa pieselor metalice, a sculelor şi a echipamentului tehnologic la coroziune, şi ca rezultat mărirea duratei lor de exploatare. Therefore, the claimed process allows to considerably increase the resistance of metal parts, tools and technological equipment to corrosion, and as a result to increase their service life.
1. SU 502963 A1 1976.02.15 1. SU 502963 A1 1976.02.15
2. SU 969761A1 1982.10.30 2. SU 969761A1 1982.10.30
3. MD 3708 G2 2008.09.30 3. MD 3708 G2 2008.09.30
Claims (1)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| MDS20090103A MD192Z (en) | 2009-06-04 | 2009-06-04 | Process for thermochemical treatment of steel articles |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| MDS20090103A MD192Z (en) | 2009-06-04 | 2009-06-04 | Process for thermochemical treatment of steel articles |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| MD192Y true MD192Y (en) | 2010-04-30 |
| MD192Z MD192Z (en) | 2010-11-30 |
Family
ID=43569609
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| MDS20090103A MD192Z (en) | 2009-06-04 | 2009-06-04 | Process for thermochemical treatment of steel articles |
Country Status (1)
| Country | Link |
|---|---|
| MD (1) | MD192Z (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| MD336Z (en) * | 2010-03-03 | 2011-09-30 | Институт Прикладной Физики Академии Наук Молдовы | Process for thermochemical machining of metal articles |
| MD614Z (en) * | 2012-07-03 | 2013-10-31 | Институт Прикладной Физики Академии Наук Молдовы | Process for chemicothermal treatment of steel products |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| MD561Z (en) * | 2012-02-08 | 2013-06-30 | Институт Прикладной Физики Академии Наук Молдовы | Process for anticorrosion machining of steel |
Family Cites Families (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SU502963A1 (en) * | 1974-06-24 | 1976-02-15 | Новолипецкий Металлургический Завод | The method of processing electrical steel |
| SU969761A1 (en) * | 1980-02-20 | 1982-10-30 | Институт Прикладной Физики Ан Мсср | Method and electrolyte for decarburizing steel |
| MD783G2 (en) * | 1996-12-09 | 1998-05-31 | Mihail Zaguralschi | Steel pickling solution |
| RU2242543C2 (en) * | 2003-02-11 | 2004-12-20 | Воронежский государственный технический университет | Method for electrochemical etching of steel band |
| MD3077C2 (en) * | 2004-06-29 | 2007-01-31 | Институт Прикладной Физики Академии Наук Молдовы | Electrolyte for steel dimensional electrochemical treatment |
| MD2959C2 (en) * | 2004-06-29 | 2006-08-31 | Институт Прикладной Физики Академии Наук Молдовы | Process for steel article working for anticorrosive superficial layer obtaining |
| MD3122C2 (en) * | 2005-04-13 | 2007-05-31 | Институт Прикладной Физики Академии Наук Молдовы | Electrolyte for steel dimensional electrochemical treatment |
| MD3288C2 (en) * | 2005-06-03 | 2007-11-30 | Институт Прикладной Физики Академии Наук Молдовы | Electrolyte for dimensional electrochemical working of hard tungsten-cobalt alloys |
| MD3289C2 (en) * | 2005-07-05 | 2007-11-30 | Институт Прикладной Физики Академии Наук Молдовы | Electrolyte for steel dimensional electrochemical working |
| MD3082G2 (en) * | 2005-08-08 | 2007-01-31 | КОСОВ Вилгельм | Process for metal electrochemical protection from corrosion |
| MD3316C2 (en) * | 2005-12-06 | 2007-12-31 | Институт Прикладной Физики Академии Наук Молдовы | Electrolyte for electrochemical pickling of tungsten |
| MD3481G2 (en) * | 2006-06-19 | 2008-10-31 | Институт Прикладной Физики Академии Наук Молдовы | Process for metal electrochemical working |
| MD3917C2 (en) * | 2006-09-20 | 2009-12-31 | Dinano Ecotechnology Llc | Process for thermochemical processing of carboniferous raw material |
| MD3457G2 (en) * | 2007-03-19 | 2008-07-31 | Институт Прикладной Физики Академии Наук Молдовы | Process for electrochemical activation of tungsten-free hard alloy surface for low-temperature brazing |
| MD3708G2 (en) * | 2007-05-23 | 2009-04-30 | Институт Прикладной Физики Академии Наук Молдовы | Process for enhancing the corrosion resistance of steel |
-
2009
- 2009-06-04 MD MDS20090103A patent/MD192Z/en not_active IP Right Cessation
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| MD336Z (en) * | 2010-03-03 | 2011-09-30 | Институт Прикладной Физики Академии Наук Молдовы | Process for thermochemical machining of metal articles |
| MD614Z (en) * | 2012-07-03 | 2013-10-31 | Институт Прикладной Физики Академии Наук Молдовы | Process for chemicothermal treatment of steel products |
Also Published As
| Publication number | Publication date |
|---|---|
| MD192Z (en) | 2010-11-30 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Li et al. | Porous nanocrystalline Ti (CxN1− x) thick films by plasma electrolytic carbonitriding | |
| CN103088384A (en) | valve metal plasma electrolytic oxidation surface treatment method | |
| Tavakoli et al. | Electrochemical and physical characteristics of the steel treated by plasma-electrolysis boronizing | |
| CN101580941B (en) | Method for preparing WC-Co hard coating | |
| MD192Y (en) | Process for thermochemical treatment of steel articles | |
| Belkin | Anode electrochemical thermal modification of metals and alloys | |
| Kartal et al. | Influence of process duration on structure and chemistry of borided low carbon steel | |
| CN105543773B (en) | Rare earth formula salt for deep layer QPQ technologies and preparation method thereof | |
| CN101423971A (en) | Treating fluid in electrochemical corrosion of low-voltage anode aluminum foil | |
| Galedari et al. | Effect of pulse frequency on microstructure and surface properties of Ck45 steel treated by plasma electrolysis method | |
| RU2562185C1 (en) | Modification method of surface of items from titanium alloys in vacuum | |
| CN112725855B (en) | Preparation method of high-bonding-force high-corrosion-resistance coating on surface of neodymium iron boron magnet | |
| MD3708G2 (en) | Process for enhancing the corrosion resistance of steel | |
| CN109267002A (en) | A kind of new and effective rush boronizing technology of steel | |
| CN105238935B (en) | A kind of electroslag remelting slag system | |
| Skakov et al. | Influence of regimes electrolytic plasma cementation on the mechanical properties of steel 12Cr18Ni10Ti | |
| CN212316227U (en) | QPQ low temperature direct current electric field nitriding device | |
| CN104195571A (en) | Treatment technique capable of enhancing wear resistance of bearing | |
| RU2558320C1 (en) | Surface hardening of titanium alloys in vacuum | |
| CN201634747U (en) | Hot galvanizing stabilizer roller | |
| RU2562187C1 (en) | Method of modification of surface of products from titanic alloys in glow discharge | |
| CN101660180A (en) | Formula for high-temperature electroforming of molybdenum by refractory metal molten salt and special process method thereof | |
| CN105256350A (en) | Electroplating pretreatment method for high alloy steel | |
| Salve et al. | Carburizing of Plane Carbon Steels by Electrolyte Plasma | |
| SU1761812A1 (en) | Method for heat treatment of steel alloyed with chromium and/or aluminium and oxidizing medium for realization thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MK4Y | Short term patent expired |