FR2507209A1 - AQUEOUS TEMPERING MEDIUM FOR FERROUS METALS AND ALLOYS - Google Patents

Abstract

THE INVENTION CONCERNS ADDITIVES FOR AQUEOUS QUENCHING MEDIA FOR METALS AND FERROUS ALLOYS. THE QUENCHING MEDIUM CONTAINS 0.1 TO 30 BY WEIGHT OF POLYALKYLENE GLYCOL ETHER WITH A MOLECULAR MASS COMPRISED BETWEEN 4000 AND 30,000, AND FROM 0.5 TO 15 OF AN ANTICORROSIVE ADDITIVE CHOSEN FROM OXO ACID SALTS OF 7 HAS 13 CARBON ATOMS OF AN ALKANOLAMINE, THE REST IS WATER. THIS QUENCHING MEDIUM ALLOWS TO SHORTEN THE WARMING PHASE, TO HAVE THE MAXIMUM COOLING SPEED AT THE BEGINNING OF THE NUCLEATED BOILING PHASE, AND TO OBTAIN A VERY RAPID REDISSOLUTION OF THE POLYALKYMENE GLYCOL DEPOSITED ON THE METAL QUENCH.

Description

AQUEOUS TEMPERING MEDIUM FOR FERROUS METALS AND ALLOYS

  The present invention relates to an aqueous quench medium for ferrous metals and alloys and, more particularly, to carbon steels and alloy steels. It is known that the optimal mechanical properties of steels are obtained only after heating at high temperature followed by quenching. The speed and the cooling conditions of the steel, during quenching, have a decisive influence on the mechanical properties Si these conditions are not respected, it may result in deformations and even

hardened parts.

  Quenching is usually carried out in a liquid or fluid medium.

  The liquid medium, depending on the desired cooling rate,

  can be of the aqueous, oily or igneous type (molten salt).

  The theory and practice of quenching steels are exposed by

  example, in the chapter "Quenching of steel", pages 15 to 36 of the

  me 2 of the "Metals Handbook", 8 th edition, edited by American Society

of Metals.

  The present invention relates to the field of quenching in a medium

aqueous.

  When a steel part, previously heated to high temperature,

  for example 8500 C, is soaked in water, the cooling of

  in three distinct stages: The first stage, which corresponds to the temperature range of 8500 C to about 5000 C, corresponds to the "calefaction" The piece is

  surrounded by a sheath of steam that isolates it from liquid water and

the cooling.

  The second stage, which corresponds approximately to the interval

  from about 5000 ° C. to about 1500 ° C., corresponds to the boiling point

  nucleation, that is, the appearance of vapor bubbles on

  a lot of points in the room.

  finally, the third stage corresponds to a cooling by

  duction and convection, thanks to direct contact between liquid water -2-

and the room.

  The quality of a given tempering medium can be appreciated by a

  test consisting in taking a standard test specimen of good metal

  heat conductor (silver, preferably) in which a temperature sensor has been arranged, to carry it at a high temperature in a controlled oven and thermostats (for example 8500 C in the case of quenching for steel), immerse it immediately at the exit of the furnace in the quenching medium and record the evolution

  its temperature as a function of time The dimensions of the test

  for example: diameter 8 mm, length 24 mm, or

diameter 16 mm, length 48 mm.

  Thus, for each quench medium, and at initial temperature, it is possible to draw series of temperature / time curves which allow

  to objectively evaluate the qualities and defects of the said

  places (curves called "drasticity").

  It is known, moreover, to add to the water used as quenching medium, various additives to regulate the action and to

  move in the desired direction, and as far as possible, the

  between calefaction and nucleate boiling.

  In 1960, in a commercial notice, the company WYANDOTTE CHEMICAL CI recommended the use of polyoxyalkylenes glycols as an additive to quenching media The product designated by the trademark PLURACOL

  V 10 had a molecular weight of 25,000 to 35,000.

  In the aforementioned "fletals Handbook" it is pointed out that the addi-

  0.01% of polyvinyl alcohol in the quenching water increases

  the cooling rate during the cooling phase

  faction. In the French patent FR 1 525 603 in the name of B A S F, A G,

  recommends the addition of a water-soluble polymer, containing groups

  pes (-CO-NH-) at a content of between 0.1 and 1% by weight.

  In the German patent application Li E 2,349,225, an application is made

  From 0.4 to 10% by weight of a polyacrylic acid salt in water. In French patent FR 2 316 336 (US 4,087,290) in the name of HOUGHTON & CO, the additive is also a water-soluble salt of polyacrylic acid.

  To obtain quench liquids based on the use of so-

  aqueous solutions of polyglycols and, in particular, polyoxyalkylene glycols, we have added to these solutions an anticorrosive additive

  of the oxo chain amine salt type of 7 to 13 and, preferably

of 9 carbon atoms.

  Unexpectedly, we found that the behavior

  Such a quenching medium presented very large differences

  behavior with previously known quenching media, from the moment the anticorrosive

  which was strictly necessary to produce the only anti-

  corrosive, which requires about 0.1 to 0.2% of this product

in water.

  The present invention therefore relates to aqueous quenching media based on water-soluble organic polymer, for heat treatment

  ferrous metals and alloys, and in particular for carbon steels

  bone and alloy steel, allowing both to shorten the duration

  of the chelation phase, to increase the cooling speed

  during the drying phases and to progressively decrease

  the rate of cooling during the nucleate boiling phase, its maximum value being at the beginning of this phase, and

  avoid the precipitation of the organic polymer on the tremors

  these quenching media comprising from 0.1 to 30 parts by weight of polyoxyalkylene glycol ether, with a molecular mass of between 4,000 and 30,000 and preferably between 10,000 and 12,000 or between 20,000 and 25,000 and with 0, 5 to 76 and preferably 1 to 5% by weight of an anticorrosive additive selected from oxo acid salts of 7 to 13 carbon atoms of an alkanolamine and cinnamates

  alkanolamines, the rest being water.

  Preferably, the quench medium contains from 2 to 15 "of polyoxy-

-4-

  alkylene glycol and from 1 to 15% of amine salt.

  The polyoxyalkylene glycol ether may be a product of moderate mass

  the lecular of the order of 11000 and ratio ethylene oxide / propylene oxide substantially equal to 3. The polyoxyalkylene glycol ether may also be a product of

  a molecular mass of around 22,000 and a ratio of

  ethylene oxide / propylene oxide substantially equal to 3.

  The amine salt can be obtained from oxo acid from 7 to 13 atoms.

  carbon monoxide and an alkanolamine, selected from ethanolamine, propanolamine, isopropanolamine and preferably from acid

  oxo with 9 carbon atoms and a mixture of mono-mono, di and tri-ethanol

ethanolamine.

  Preferably, the polyoxyalkylene glycol ether is constituted by

  a mixed ether of ethylene oxide and propylene oxide, for example

  ple, one of the products sold under the trademark EMKAROX by the

  UGINE Chemicals Company KUHLMANN, such as BB 31-

  19500, with a molecular mass of around 11000 and the FC 31-45000 of mas-

  molecular weight of the order of 20000 These products are characterized

  by an ethylene oxide / propylene oxide ratio of 3.

  The anticorrosive additive, which gives the quenching medium its

  new and unexpected summers is a salt from the reaction

  of an organic acid of the "oxo" type with a chain of 7 to 13 carbon atoms.

  and, more particularly, from 9 to 10 carbon atoms and an amine of the alkanolamine type such as mono, di, tri, ethanolamine,

  butanolamines, and more particularly, mono, di, triiso-

propanolamine and their mixture.

  For example, the product I P 9, supplied by the Company Products

  Chemicals UGINE KUHLMANN, is an oxo acid salt with 9 carbon atoms

  bone, mixed isopropanolamine (mixture of mono, di and triamine).

  As other salts with the same advantages, we retain the

triisopropanolamine cinnanate.

-5-

  Figures 1 to 8 show the curves of drasticity for

  tempering media according to the prior art and according to the invention.

  They were all established on silver specimens of 16 mg in diameter and 48 mm in length. In all the figures, solid curves (1) indicate the temperature as a function of time (scale A, in seconds) and the

  dashed lines (B) indicate the cooling rate.

  depending on the temperature, (scale B, in OC / second).

  FIG. 1, which refers to the prior art, shows the curves of drasticity for an oil quench. It is noted that the speed of

  cooling remains relatively low until around 6000 (approx.

  300 C / s), increases progressively and goes through a maximum towards 50 UOC (approx. 100 OC / s) and gradually decreases to around 2000 C (where it tends to OOC / s). The cauld / boil transition is around 6001 C This curve is reproducible and corresponds to good

quenching conditions.

  In FIG. 2, which refers to a quenching with ordinary water according to the prior art, three successive tests were carried out under identical conditions: the very important dispersion is noted, which excludes any reproducibility of such quenching in the water. In addition, the cooling rate in low temperatures is

  high, which favors deformations and cracks.

  Figures 3, 4 and 5 relate to the implementation of the invention

  they represent the average of a series of tests which gave an excellent reproducibility and correspond respectively to the addition to ordinary water (urban distribution network) of 5% (Figure 3), 12 'O ( FIG. 4) and 20 'é (FIG. 5) by weight of an additive having the following composition by weight EMKAROX FC 31, as previously defined 25% IP 9, as previously defined 10% Water 65 GB which corresponds, in the quenching medium, at respective concentrations of FC 31 'of 1, 2 3 5% o by weight and IPI 9 of

25072-09

-6-

0.5 1.2% by weight.

These curves show that

  1 the cooling rate in the calefaction phase (850-

  5001 C) is increased to about 500 C / s. 2 the length of the calefaction phase is decreased In fact, it extends to about 4500 C with 5% of additive (Figure 3),

  500 with 12% additive (FIG. 4), 5500 C with 20 t of additive (FIG.

  5) So, in this way, it can be fixed in a certain

  measure, depending on the grades of steel being treated.

  the cooling rate is maximum at the beginning of the phase

  nucleate boiling, then gradually decreases.

  This favorable effect is also accentuated when the proportion of

  The curve B of FIG. 5, for example (5 X FC 31 + 2% I P_ 9) shows that the heating phase has been reduced to

  approximately 5501 ° C and that the cooling rate passes through a

  very clear at the beginning of the nucleate boiling phase, then decreases

naked gradually.

  We thus find the same type of curve as in the-quenching at the oil-

the (Figure 1).

  Quite comparable results have been obtained with another quenching medium according to the invention obtained by addition to ordinary water, respectively of 5, 12 '0' and 20 'by weight of an additive having the following composition by weight: EMKARUX BB 31, molecular weight 11000 40%

I.P 9 10

Water 50 "O

  which corresponds in the quenching medium to

  BB targets 31: 2 4.8 8% by weight

I.P 9 0.5 1.2 2% by weight.

  The curves in Figures 6, 7 and 8 are given for purposes of comparison

  reason to show the favorable influence of the association of a poly-

  mother such as the FC 31 with the additive I P 9 Indeed, these curves have

  have been established for a tempering medium containing only poly-

  Water soluble FC 31, with respective concentrations of 2,

4% and 12% by weight.

  In contrast to the quenching medium according to the invention, the quenching medium comprising only FC 31 polymer lengthens the calefaction range well below 5000 C and even up to 4001 C and decreases the cooling rates in this area.

  it is observed that the calefaction is unstable.

  In the nucleate boiling range, the cooling rate is decreasing, but the maximum is in temperatures that are too low (250 to 3000 C). This results in the formation of constituents.

  in treated steels and a danger of deformatins and

tapes.

  These new quench liquids, objects of the invention, therefore have, in summary, the following advantages:

  Very high reproducibility of the cooling curve (tem-

  time / temperature), whereas the only quenching with water gives a very great dispersion, in particular with regard to the phase of caulking which can spread between 850 and 3000 C, and that a simple addition of polyoxyalkylène glycol still leads to an increase in the temperature of ca. 4000 C.

  Significant increase and stability of cooling speed

  during the calefaction, up to around 500 C per minute.

  Maximum cooling rate at the beginning of the phase of

nucleated bullition.

  In total, with the quenching medium according to the invention,

  curves of drasticity which are close to those

  held with good quenching oils.

  Finally, and unexpectedly, we found that the salts

  amines used as additives in the present invention, increase

  In fact, when quenching with aqueous solutions of polyalkylene glycols without amine salts, it is necessary to solubilize the ethers of polyoxyalkylene glycols in water.

  It is noted that at the end of the quenching

  -8 holes are covered with a relatively thick film of polyalkylenes

  glycols which has become attached to the metal at the time of quenching.

  the amine salts confer the advantage of considerably increasing

  the rate of redissolution of the polyalkylene layer which is deposited during the quenching, which makes it possible to leave the bath of

  quenching the parts substantially free of polyalkylene glycols.

  It can also be noted that the quenching media, objects of the invention

  vention, do not foam, do not foul the material and

are inexpensive to use.

-9

Claims (4)

  1 / Aqueous quenching medium, based on organic hydrosoluble polymer   for the heat treatment of ferrous metals and alloys, and in particular for carbon steels and alloy steels, for shortening the duration of the heating phase, for increasing the cooling rate during the heating phase, gradually decrease during the nucleate boiling phase, the maximum velocity being at the beginning of this phase, and to avoid the   precipitation of the organic polymer on the quenched pieces,   characterized in that it comprises from 0.1 to 30% by weight of polyoxyalkylene glycol ether, with a molecular mass of between 4000 and 30000, and preferably between 10000 and 12000 or between 20000 and 25000 and with 0, 5 to 15% by weight of an anticorrosive additive chosen from the oxo acid salts of 7 to 13 carbon atoms of an alkanolamine and the cinnamates of alkanolamines, the balance being water. 2 / quenching medium according to claim 1, characterized in that it preferably contains from 2 to 15% of polyoxyalkylene glycol and from 1 to 15% of amine salt.   3 / quenching medium according to claim 1 or 2, characterized in that the polyoxyalkylene glycol ether is a product having a molecular weight of about 11000 and ethylene oxide / oxide ratio   of propylene substantially equal to 5.   4 / quenching medium according to claim 1, characterized in that the polyoxyalkylene glycol ether is a product having a molecular weight of about 22,000 and an ethylene oxide /   propylene oxide substantially equal to 3.   Quenching medium according to claim 1 or 2, characterized in that the amine salt results from the reaction of oxo acid from 7 to 13   carbon atoms and an alkanolamine chosen from ethanol   lamine, propanolamine, isopropanolamine.   6 / quenching medium according to claim 1 or 2, characterized in that   that the amine salt is obtained from oxo acid having 9 carbon atoms. -10-   bone and a mixture of mono, di and tri ethanolamine.