CS266263B1

CS266263B1 - The method of production of vinegar powder from chips resulting from chip machining of rolled semi-finished products

Info

Publication number: CS266263B1
Application number: CS878328A
Authority: CS
Inventors: Andrej Ing Csc Salak
Original assignee: Salak Andrej
Priority date: 1987-11-19
Filing date: 1987-11-19
Publication date: 1989-12-13
Also published as: CS832887A1

Abstract

Spósob výroby ocelového prášku z triesok, vznikajúcich pri trieskovom obrábění válcovaných polovýrobkov z liatych ocelí, ktoré majú koncentráciu uhlíka v rozsahu 0,3 až 1,5 %, umožňuje vyrobit prášok nízkej koncentrácie kyslíka a uhlíka, a to obvykle niže 0,15 resp. 0,1 % hmot. Jeho podstata spočívá v tom, že kúskové a odmaštěné triesky sa indukčně vysokou frekvenciou rýchlo ohrejú nad obvyklú kaliacu teplotu príslušnej ocele a zakalia sa do vody. Po osušení triesky sa melú a vyrobený prášok výhodnéj frakcie, ku ktorému sa přidá práškový oxid železnatý, sa dvojstupňovo žíhá pri teplotách 700 až 1 100 °C, a to v prvom stupni v inertnej atmosféře a v druhom stupni v redukčněj atmosféře. Tieto podmienky spracovania umožňujú nezávisle od východiskovéj koncentrácie uhlíka a kyslíka v prášku dosiahnuť nízké koncentrá cie týchto prvkov, ako je hoře uvedené. Tým sa dosiahnu vysoké technologické vlastnosti prášku.The method of producing steel powder from chips resulting from chip machining of rolled semi-finished products from cast steels, which have a carbon concentration in the range of 0.3 to 1.5%, allows the production of powder with a low concentration of oxygen and carbon, usually below 0.15 or 0.1% by weight. Its essence lies in the fact that the piecemeal and degreased chips are rapidly heated by induction at high frequency above the usual quenching temperature of the respective steel and quenched in water. After drying the chips, they are ground and the produced powder of the preferred fraction, to which powdered iron oxide is added, is annealed in two stages at temperatures of 700 to 1,100 °C, in the first stage in an inert atmosphere and in the second stage in a reducing atmosphere. These processing conditions allow, independently of the initial concentration of carbon and oxygen in the powder, to achieve low concentrations of these elements, as mentioned above. This will achieve high technological properties of the powder.

Description

Vynález sa týká spósobu výroby ocelového prášku z triesok, vznikajúcich pri trieskovom obrábaní válcovaných polovýrobkov z liatych ocelí, ktorý sa s výhodou použije na výrobu súčiastok postupmi práškovej metalurgie.The invention relates to a process for the production of steel powder from chips resulting from the machining of rolled cast steel semi-finished products, which is preferably used for the production of components by powder metallurgy processes.

Jo známých viacej sposobov výroby ocelového prášku'pre prášková motalurgiu z triesok, ktoré vzniká já pri trieskovom obrábaní ocelí, a to v závislosti od koncentrácie uhlíka. Tt ít-iky - ·»<·<|f k< >ικ -·ηΙ I š<-i < tílilfk.i .i-;i dti (i,4 v, hmot. možno mlioť na ptášok napr. v kryoqonných mlynoch, v ktorých působením kvapalnóho dusíka skrehnuté triesky sa lahko rozdrobia, Iný spósob je rozdrobovanie takýchto triesok vo vířivých nárazových mlynoch s výhodou po predbežnom oduhličení, aby sa zvýšila ich plasticita a aby tak došlo k ich deformačnému spevneniu počas mletia ako podmienky vzniku častíc prášku. Triesky z ocelí vyššej koncentrácie uhlíka asi ako 0,4 % hmot, možno rozdrobovat aj pri okolněj teplote v příslušných mlynoch, ale proces trvá dlho. Na skrátenie doby rozdrobovania možno takéto triesky zakalit: do vody po predchádzajúcom ohřeve pri teplote 800 až 950 °C. Vo všetkých prípadoch takto vzniklý prášok sa musí redukčně žíhat: s cielom znížiť koncentráciu kyslíka a uhlíka aspoň 0,20 % hmot*, aby sa dosiahia dostatočná lisovateínost a spekavosť prášku, základnou podmienkou akéhokolvek spósobu výroby prášku z triesok je, aby triesky boli z jedného druhu ocele.There are several known methods of producing steel powder for powder metallurgy from chips, which arise during chip machining of steels, depending on the carbon concentration. Tt ít-iky - · »<· <| fk <> ικ - · ηΙ I š <-i <tílilfk.i .i-; i dti (i, 4 v, wt. Another way is to crush such chips in vortex impact mills, preferably after pre-decarburization, in order to increase their plasticity and thus to deform them during grinding as a condition for the formation of powder particles. from steels with a higher carbon concentration of about 0.4% by weight, can also be crushed at ambient temperature in the respective mills, but the process takes a long time. In all cases, the powder thus formed must be reductively annealed: in order to reduce the oxygen and carbon concentration to at least 0.20% by weight * in order to achieve sufficient compressibility and sintering of the powder, the basic condition for any method of producing powder from chips is that the chips are from onetype of steel.

Nevýhodou doterajších sposobov je, že bud vyžadujú napr. Špeciálne mlyny, alebo mletie dlho trvá a preto sú tieto postupy energeticky náročné. Nevýhodou sposobu využívajúceho známy sposob kalenia triesok je, že počas ohřevu i v endotermickej atmosféře, ktorý kvóli dosiahnutiu rovnoměrného prehrevu triesok trvá asi 30 minut, dochádza k oxidácii povrchu častíc triesok, ale i po hraniciach metalografických zrn. Takéto oxidy, najmá v oceliach legovaných mangánom a chrómom, číže prvkami vysokej afinity ku kyslíku, pri bežne používaných teplotách žíhania asi dn 1 100 °C, aby sa vyléčilo spečenie prášku, nie sú odstranitelné ani vo vysokoredukčných atmosférách. Spoločnou nevýhodou známých sposobov je, že pri nevyhnutnom žíhaní takéhoto prášku v redukčných atmosférách nedaří sa odstránit súčasne kyslík na hodnotu níže 0,2 % a uhlík koncentrácie niže 0,1 % hmot. Takéto prášky majú potom v porovnaní s bežne používanými železnými práškami zhoršenu lisovatelnost a spekavost. Vyššie koncentrácie kyslíka sa prejavia potom v spekaných a kovaných výrobkoch, vyrobených z taktýchto práškov, ako nežiadúce vtrúseniny. Přitom jednotlivé částice prášku sú v závislosti od velkosti rózne oduhličené, čo je taktiež nežiadúce.The disadvantage of the existing methods is that they either require e.g. Special mills or grinding take a long time and therefore these procedures are energy intensive. The disadvantage of the method using the known method of chip hardening is that during heating even in the endothermic atmosphere, which takes about 30 minutes to achieve uniform heating of the chips, the surface of the chip particles is oxidized, but also along the boundaries of metallographic grains. Such oxides, especially in steels alloyed with manganese and chromium, which have elements of high affinity for oxygen, at commonly used annealing temperatures of about 100 DEG C. in order to cure sintering of the powder, are not removable even in highly reducing atmospheres. A common disadvantage of the known methods is that with the necessary annealing of such a powder in reducing atmospheres, it is not possible to simultaneously remove oxygen to a value lower than 0.2% and carbon concentration lower than 0.1% by weight. Such powders then have poorer compressibility and sintering compared to commonly used iron powders. Higher oxygen concentrations are then reflected in sintered and forged products made from such powders as undesirable inclusions. In this case, the individual powder particles are strongly decarburized depending on the size, which is also undesirable.

Uvedené nedostatky sú odstraněné spósobom podlá vynálezu, ktorého podstata spočívá v tom, že triesky, vznikajúce pri trieskovom obrábaní válcovaných ocelových polovýrobkov z liatych ocelí, ktoré majú s výhodou koncentráciu uhlíka 0,3 až 1,5 % hmot., rozdrobené na kúsky velkosti niže asi 10 mm a odmaštěné, podrobia sa kvóli zvýšeniu ich křehkosti pre zlepšenie mechanického rozdrobovania tepelnému spracovaniu, ktoré sa skládá z indukčného ohřevu frckvenciou 100 až 500 kHz na teplotu 900 až 1 200 °C a kalenia do vody z tejto teploty. Takto zakalené triesky sa osušia a rozdrobia v mlynoch na prášok velkosti častíc po preosiati niže 0/3 mm. K takémuto prášku sa primieša práškový oxid železnatý v množstve, aby sa v takto vzniklej práškovej zmesi dosiahol poměr kyslíka a uhlíka 1,5 aá 3. Táto prášková zmes sa potom dvojstupňovo žíhá pri teplote v rozsahu 700 až 1 100 °C. Přitom prvý stupeň žíhania sa vykoná počas 1 až 4 h v inertnej atmosféře s prídavkom vodnej páry, aby sa dosiahol rosný bod atmosféry 0 až +30 °C. Druhý stupeň žihania prášku sa vykoná počas 15 až 20 min v redukčnej atmosféře. Potom sa čiastočne spečený prášok opatovne rozdrobí a preoseje na žiadané frakcie.Said drawbacks are eliminated by the process according to the invention, the essence of which consists in the fact that the chips formed during machining of rolled steel cast steel blanks, which preferably have a carbon concentration of 0.3 to 1.5% by weight, are broken up into pieces of size below. about 10 mm and degreased, subjected to increasing their brittleness to improve the mechanical comminution by a heat treatment consisting of induction heating at a frequency of 100 to 500 kHz to a temperature of 900 to 1200 ° C and quenching in water from this temperature. The turbid chips thus dried are dried and ground in powder mills to a particle size of less than 0/3 mm after sieving. To such a powder, iron oxide powder is mixed in an amount so as to obtain an oxygen-to-carbon ratio of 1.5 to 3 in the thus obtained powder mixture. This powder mixture is then annealed in two stages at a temperature in the range of 700 to 1100 ° C. The first annealing step is carried out for 1 to 4 hours in an inert atmosphere with the addition of steam to achieve an atmospheric dew point of 0 to + 30 [deg.] C. The second step of annealing the powder is performed for 15 to 20 minutes in a reducing atmosphere. The partially sintered powder is then again crushed and sieved to the desired fractions.

Výhodou sposobu podlá vynálezu je, že možno ním přepracovat na prášok triesky širokej koncentrácie uhlíka, pretože kalením napr. z teploty 1 200 °C sa dosiahne tvrdost 58 HRC i pri koncentrácii uhlíka 0,4 %. To umožňuje rýchly vysokofrekvenčný ohřev na vysoké teploty a zakalenie do vody. Ďalšou výhodou tohto procesu sposobu je, že v dósledku vysokej rýchlosti a tým krátkej doby ohřevu, vylučuje oxidáciu najmS. po hraniciach metalografických zrn častíc triesok. Ďalšou a rozhodojúcou výhodou sposobu je, že prídavkom oxidu železnatého k prášku, ktorý má vysoká koncentráciu kyslíka, vytvárajú sa podmienky na sučasnú redukciu kyslíka a na oduhličenie, ktoré sa vykoná dvojstupňovým žíháním. To zabezpečuje dosiahnutie z technic i -.,¹ An advantage of the process according to the invention is that it can be used to process chips of a wide concentration of carbon into a powder, since hardening e.g. from a temperature of 1200 ° C, a hardness of 58 HRC is achieved even at a carbon concentration of 0.4%. This allows fast high-frequency heating to high temperatures and turbidity in water. Another advantage of this process is that, due to the high rate and thus the short heating time, it eliminates the oxidation in particular. along the boundaries of the metallographic grains of the particle particles. Another and decisive advantage of the process is that the addition of iron oxide to a powder having a high oxygen concentration creates the conditions for the simultaneous reduction of oxygen and for decarburization, which is carried out by two-stage annealing. This ensures the achievement of the techniques i -., ¹

CS 266 263 Bl kého híadiska velmi nízku koncentráciu kyslíka a uhlíka v takto vyrobenom prášku , a to kyslíka níže 0,15 % a uhlíka 0,1 % hmot. Tým sa vytvárajú podmienky na dosiahnutie vysokých technologických vlastností ocelového prášku vyrobeného z triesok podlá vynálezu. Hlavnou výhodou spósobu podfa vynálezu je, žo takými, o propracováním dotora j š i oho odpadu sa vyrobí lačnější prášok, ako obvyklými postupmi.In view, the very low concentration of oxygen and carbon in the powder thus produced, namely oxygen below 0.15% and carbon 0.1% by weight. This creates the conditions for achieving high technological properties of the steel powder produced from the chips according to the invention. The main advantage of the process according to the invention is that, by processing the waste, a hunger powder is produced than by conventional methods.

P r í k l a dExample

Na kúsky velkosti niže 10 mm rozdrobené a odmaštěné triesky z ocele koncentrácie uhlíka 1,0 %, mangánu 0,3 %, křemíku, 0,3 % a chrómu 1,5 % hmotnostných, boli indukčně ohriate pri frekvencii 400 kHz na teplotu 1 000 °C počas 30 s a z tejto teploty boli priamo zakalené do vody. Po vyhřátí z vody zakalené triesky boli osušené teplým vzduchom a mleté pri okolnej teplote. K vyosiatej frakcii prášku velkosti častíc niže 0,315 mm, ktorý mal koncentráciu kyslíka 1,5 %, bol přidaný práškový oxid železnatý velkosti častíc niže 0,04 mm v množstvo 2,5 % hmot. Tým sa zvýšila koncentrácia kyslíka v prášku na 2,23 %, čím sa dosiahol poměr kyslíka k uhlíku v práškovej zmesi 2,23 a tým bóla splněná podmienka vynálezu. Táto prášková zmes bola napřed žíhaná v dusíku pri teplote 950 °C počas 2 h a potom v druhom stupni pri teplote 1 100 °C počas 1 h vo vodíku. Po rozdrobení a preosiati prášok mal koncentráciu kyslíka 0,16 l a uhlíka iba 0,02 % hmot. Prášok žíhaný doteraz obvyklým spósobom pri teplote 1 100 °C počas 2 h v redukčnej atmosféře, v štiepenom čpavku, ale bez přídavku oxidu železnatého, mal koncentráciu kyslíka 0,57 % a uhlíka 0,17 % hmot. Tým boli preukázané výhody spósobu podlá vynálezu.Shredded and degreased steel chips with a carbon concentration of 1.0%, manganese 0.3%, silicon, 0.3% and chromium 1.5% by weight, broken into pieces of less than 10 mm, were inductively heated at a frequency of 400 kHz to a temperature of 1,000. ° C for 30 hours at this temperature were directly turbid in water. After heating from the water, the cloudy chips were dried with warm air and ground at ambient temperature. To the sieved fraction of the particle size powder of less than 0.315 mm, which had an oxygen concentration of 1.5%, iron oxide powder of a particle size of less than 0.04 mm was added in an amount of 2.5% by weight. This increased the oxygen concentration in the powder to 2.23%, thus achieving an oxygen to carbon ratio in the powder mixture of 2.23, and thus the condition of the invention was fulfilled. This powder mixture was first calcined in nitrogen at 950 ° C for 2 h and then in a second step at 1100 ° C for 1 h in hydrogen. After comminution and sieving, the powder had an oxygen concentration of 0.16 l and a carbon concentration of only 0.02% by weight. The powder, annealed in the usual manner at 1,100 ° C for 2 hours in a reducing atmosphere, in split ammonia, but without the addition of iron oxide, had an oxygen concentration of 0.57% and a carbon concentration of 0.17% by weight. This has demonstrated the advantages of the process according to the invention.

Spósob podlá vynálezu možno úspěšně využit jednak priamo v práškovej metalurgii, jednak v strojařských podnikoch, v ktorých vznikajú triesky z jedného druhu ocele. Takýmito miestami sú napr. podniky na výrobu ložísk, ktoré používajú iba jeden základný druh ocele koncentrácie uhlíka 1,0 a chrómu 1,5 7, hmot., preto u nich nedochádza k zrniešaniu róznych triesok. 7Ό vytvara podmienky na vysoko efektívne využitie odpadu a na zavedenie bezodpadovej technologie, čo je dalšou výhodou spósobu podlá vynálezu.The process according to the invention can be successfully used both directly in powder metallurgy and in engineering companies in which chips from one type of steel are formed. Such places are e.g. bearing production companies which use only one basic type of steel with a carbon concentration of 1.0 and chromium 1.5 7, by weight, therefore they do not grain the various chips. 7Ό creates conditions for highly efficient use of waste and for the introduction of waste-free technology, which is a further advantage of the method according to the invention.

Claims

In view of this, a very low concentration of oxygen and carbon in the thus produced powder t and the oxygen is lower than 0.15% and carbon 0.1%, respectively. This creates the conditions for achieving high technological properties of the steel powder made from the chips of the invention. The main advantage of the present invention is that such by extrusion of waste to produce a more processable powder than by conventional processes. P roducts Crumbled and degreased steel chips of carbon concentration of 1.0%, manganese 0.3%, silicon, 0.3% and chromium 1.5% by weight have been inductively heated at frequency! 400 khz at 1000 ° C for 30 s and from this temperature were directly quenched in water. After removing the turbid chips from the water, they were dried with warm air and ground at ambient temperature. To the sieved fraction of particle size below 0.315 mm having an oxygen concentration of 1.5 L, iron oxide powder having a particle size of less than 0.04 mm was added in an amount of 2.5% by weight. This increased the oxygen concentration of the powder to 2.23%, thereby achieving a carbon dioxide ratio in the powder mixture of 2.23 and thus the condition of the invention. This powder mixture was first calcined in nitrogen at 950 ° C for 2 h and then in a second step at 100 ° C for 1 h in hydrogen. After crushing and sieving, the powder had an oxygen concentration of 0.16% and a carbon and even 0.02% by weight. The bristle annealed to the usual way at 1100 ° C for 2 hours in a reducing atmosphere, in a cleaved ammonia but without the addition of iron oxide, had an oxygen concentration of 0.57% and a carbon of 0.17% by weight. Thus, the advantages of the present invention have been demonstrated. The method according to the invention can be used successfully either directly in powder metallurgy or in mechanical engineering companies where chips from one type of steel are produced. Such sites, for example, for the manufacture of castings which use only one basic type of carbon 1.0 < -1 > and a chromium of 1.5 ' This creates conditions for highly efficient waste utilization and for the introduction of waste-free technology, which is another advantage of the method of the invention. BACKGROUND OF THE INVENTION A method for producing steel chips from chips produced by chip machining of rolled steel products having a carbon concentration of preferably 0.3 to 1.5%, characterized in that the chips are broken into pieces less than 10 mm in size and degreased, it is usually processed, which is stored from induction heating at 100 to 500 kHz temperature of 900 to 1200 ° C and water quenching, then the turbid chips are dried and milled at ambient temperature to the powder, the particle sizes preferably less than 0.3 mm iron powder is then added to the powder in order to obtain oxygen to carbon 1.5 to 3 in the powder mixture thus formed, then the powder mixture is annealed at a temperature range of 700 to 1100 ° C, with the first step being carried out for 1 to 4 hours in an inert atmosphere by the addition of aqueous vapor in order to obtain an atmospheric dew point of 0 to +30 ° C; a heavy, follow-up step is carried out for 15 to 120 minutes in a reducing atmosphere, and then the partially baked powder is crushed and screened to the desired fraction.