EP0020792B1 - High-strength freely machinable steel capable of sustaining dynamic forces - Google Patents
High-strength freely machinable steel capable of sustaining dynamic forces Download PDFInfo
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- EP0020792B1 EP0020792B1 EP79101820A EP79101820A EP0020792B1 EP 0020792 B1 EP0020792 B1 EP 0020792B1 EP 79101820 A EP79101820 A EP 79101820A EP 79101820 A EP79101820 A EP 79101820A EP 0020792 B1 EP0020792 B1 EP 0020792B1
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- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 48
- 239000010959 steel Substances 0.000 title claims abstract description 48
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 20
- 238000003754 machining Methods 0.000 claims abstract description 14
- 238000004519 manufacturing process Methods 0.000 claims abstract description 14
- 238000010791 quenching Methods 0.000 claims abstract description 14
- 230000000171 quenching effect Effects 0.000 claims abstract description 14
- 238000005520 cutting process Methods 0.000 claims abstract description 13
- 229910052742 iron Inorganic materials 0.000 claims abstract description 10
- 229910052717 sulfur Inorganic materials 0.000 claims abstract description 6
- 229910052797 bismuth Inorganic materials 0.000 claims abstract description 4
- 229910052684 Cerium Inorganic materials 0.000 claims abstract 3
- 229910052748 manganese Inorganic materials 0.000 claims abstract 3
- 229910052720 vanadium Inorganic materials 0.000 claims abstract 3
- 238000000034 method Methods 0.000 claims description 2
- 230000008569 process Effects 0.000 claims description 2
- 239000000463 material Substances 0.000 description 35
- 229910000915 Free machining steel Inorganic materials 0.000 description 13
- 239000000203 mixture Substances 0.000 description 5
- 230000009467 reduction Effects 0.000 description 4
- 238000005096 rolling process Methods 0.000 description 4
- 238000005496 tempering Methods 0.000 description 4
- 229910045601 alloy Inorganic materials 0.000 description 3
- 239000000956 alloy Substances 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 238000012360 testing method Methods 0.000 description 3
- 238000011282 treatment Methods 0.000 description 3
- 229910000997 High-speed steel Inorganic materials 0.000 description 2
- 238000005299 abrasion Methods 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 238000005266 casting Methods 0.000 description 2
- 230000002349 favourable effect Effects 0.000 description 2
- 238000013467 fragmentation Methods 0.000 description 2
- 238000006062 fragmentation reaction Methods 0.000 description 2
- 238000009434 installation Methods 0.000 description 2
- 239000011572 manganese Substances 0.000 description 2
- 230000000704 physical effect Effects 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 238000007514 turning Methods 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 229910000975 Carbon steel Inorganic materials 0.000 description 1
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 238000005275 alloying Methods 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 239000004568 cement Substances 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000009749 continuous casting Methods 0.000 description 1
- 239000002826 coolant Substances 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000000945 filler Substances 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 239000012634 fragment Substances 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 238000011419 induction treatment Methods 0.000 description 1
- 230000001050 lubricating effect Effects 0.000 description 1
- 238000005461 lubrication Methods 0.000 description 1
- WPBNNNQJVZRUHP-UHFFFAOYSA-L manganese(2+);methyl n-[[2-(methoxycarbonylcarbamothioylamino)phenyl]carbamothioyl]carbamate;n-[2-(sulfidocarbothioylamino)ethyl]carbamodithioate Chemical compound [Mn+2].[S-]C(=S)NCCNC([S-])=S.COC(=O)NC(=S)NC1=CC=CC=C1NC(=S)NC(=O)OC WPBNNNQJVZRUHP-UHFFFAOYSA-L 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 239000011574 phosphorus Substances 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 239000011593 sulfur Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/60—Ferrous alloys, e.g. steel alloys containing lead, selenium, tellurium, or antimony, or more than 0.04% by weight of sulfur
Definitions
- the present invention relates to a free-cutting steel, capable of withstanding dynamic stresses and having a high resistance, even without quenching, as well as an excellent capacity for machining by removing material, which is intended for manufacturing, on machines. machines working by removing chips, machine elements with high resistance and intended to be highly stressed.
- alloyed chipbreaker and surface lubricator elements in fact constitute impurities in the steel, they determine to some extent the parameters of the mechanical properties of free-cutting steels, and in particular their resistance to dynamic stresses , but even sometimes their mechanical resistance.
- good machinability by removing material and with chips of a good shape constitutes, for a steel capable of withstanding great stresses, even without hardening, such an economic advantage, not only for automatic machines but also for any mode of machining by chip removal, that the time and money devoted to the production of the final product represent, under favorable conditions, only a fraction of the current expenditure in time and money.
- the steels of the first group cannot be subjected to a heat treatment, those of the second group can undergo hardening during their use, and finally those of the third group are able to undergo a quenching treatment or quenching followed by tempering.
- the following steels can be mentioned, which belong to the three groups:
- These steels generally contain 0.07 to 0.65% (by weight) of C, maximum 0.40% (by weight) of Si, 0.30 to 1.10% (by weight) of Mn, 0.15 at 0.40% (by weight) of S, at most 0.10% (by weight) of P; in addition, some shades also contain at least 0.15% (by weight) of Pb, 0.80 to 1.50% (by weight) of Cr, 0.15 to 0.50% (by weight) of Mo and 0.05% (by weight) of Se.
- the parameters of non-heat treated steels served as a basis for comparison.
- the tensile strength of these steels is without cold deformation between 290 and 900 N / mm 2 and in the cold drawn state it is between 370 and 1100 N / mm 2 ( 2 ), values to which a limit corresponds of apparent elasticity between 24 and 66 (da N / mm 2 ) and an elongation between 5 and 10%.
- a group of currently known free-cutting steels therefore has a relatively good mechanical resistance, which can be adjusted to the desired values by a quenching or tempering treatment, but the plasticity of these steels and their resistance to dynamic stresses no longer satisfy the current requirements.
- French Patent No. 2,246,650 describes elongated castings made of steel with added lead.
- the basic combination for ordinary carbon steels can be the following range: and that for alloyed steels, the basic composition may optionally contain 1 or more of the following alloying cements:
- the practical embodiments of this document do not describe any steel containing elements other than the five elements mentioned above in addition to iron.
- the object of the present invention is to develop such a high strength free-cutting steel, having an excellent ability to be machined by removing material and intended for the manufacture of machine elements subjected to high stresses, steel which does not only presents, without quenching, a high resistance to dynamic stresses, but which can, moreover, be machined with a formation of chips suitable for automatic machines.
- the steel produced according to the present invention contains, in addition to iron, 0.20 to 0.70% (by weight) of C, 1.20 to 3.00% (by weight) of Mn, maximum 1.00% (by weight) of Si, maximum 0.04% (by weight) of P, 0.05 to 0.11% (by weight) of S, at least 0.10% (by weight) of Pb, 0.001 to 0.03% (by weight) of Ca, 0.001 to 0.005% (by weight) of B, 0.007 to 0.035% (by weight) of N, 0.03 to 0.20% (by weight) of Nb and / or V, maximum 0.25% (by weight) of Zr and / or Ce, maximum 0.20% (by weight) of Be and / or Bi and at most 1.00% (by weight) of Mo and / or Ni.
- composition more particularly preferred according to the invention comprises, in addition to iron and usual residual elements, the elements in the following proportions:
- alloyed elements ensure that the steel, when in the relationship according to the present invention, and without quenching, has sufficient mechanical strength, while retaining the necessary plasticity; other alloyed elements ensure that the chips have an appropriate ability to fragment, without causing a reduction in the resistance of the steel to dynamic stresses, and said steel according to the present invention also contains alloyed elements which contribute to the increase in power lubricating metal surfaces in contact with each other, and, therefore, the excellent suitability of this steel for machining by removing material.
- the steel according to the present invention Due to its chemical composition, the steel according to the present invention has a relatively high mechanical resistance, even in the rolled state, so that a single calibration train is sufficient to achieve the section necessary for the automatic removal of chips. and that the reduction in section which had to be carried out so far in order to provide the free cutting steel with an appropriate mechanical strength which required a lot of work can be omitted.
- the steel according to the present invention has an excellent ability to be machined by removing material, and the ratio of the alloyed elements according to the present invention allows - with parameters suitable for removing material - to obtain sufficiently small chips, even without chipbreakers, as well as good lubrication and very good surface quality, which makes it possible to significantly increase the material removal parameters used.
- the steel according to the present invention can be quenched or treated by quenching followed by tempering, both by normal heat treatment and by induction treatment, the surface hardness can therefore, if necessary, be established and regulated by simple way and on a wide range.
- the steel according to the present invention combines the high resistance to dynamic stresses of mechanical steels, unalloyed or weakly alloyed, with the excellent machinability by removal of material presented by free-cutting steels, and this in addition to a mechanical resistance obtained without quenching and which meet the needs of most modern machine elements.
- the manufacturing process for these steels consists in developing in a furnace a charge comprising, in addition to the iron and the elements indicated above, then refining in metallurgical equipment equipped with pockets, then casting, rolling and on cooling.
- Loads 1 and 3 were produced in a 70 t arc furnace and poured into 6.4 t shells with a square profile.
- the ingots were produced by rolling without surface cleaning, under normal conditions, in the form of square ingots having an edge length of 210 mm, then then transformed by rolling into steel rounds with a diameter of 16 mm, that have been air-cooled on coolers.
- Load 2 was produced by melting in a 60 t arc furnace, then refined in a metallurgical installation equipped with pockets. The molten metal was poured into a four-die continuous casting installation with a square profile, the edge length of the billets being 240 mm.
- the billets were transformed, by rolling, into steel rods with a diameter of 20 mm, which were then air-cooled on coolers.
- the results of the tests carried out are shown in the following tables: 1.3. Suitability for machining by removing material.
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- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Heat Treatment Of Steel (AREA)
- Treatment Of Steel In Its Molten State (AREA)
Abstract
Description
La présente invention concerne un acier de décolletage, capable de supporter les sollicitations dynamiques et présentant une haute résistance, même sans trempe, ainsi qu'une excellente aptitude à l'usinage par enlèvement de matière, qui est destiné à la fabrication, sur des machines automatiques travaillant par enlèvement de copeaux, d'éléments de machine à haute résistance et destinés à être fortement sollicités.The present invention relates to a free-cutting steel, capable of withstanding dynamic stresses and having a high resistance, even without quenching, as well as an excellent capacity for machining by removing material, which is intended for manufacturing, on machines. machines working by removing chips, machine elements with high resistance and intended to be highly stressed.
En technique de transformation, les machines automatiques travaillant par enlèvement de matière et les chaînes constituées par ces machines sont des moyens modernes et efficaces qui permettent de réduire les opérations et les frais, en particulier pour la fabrication en grande série. Mais l'utilisation de ces machines automatiques travaillant par enlèvement de matière n'est rentable pour l'usinage des aciers que lorsqu'il n'est pas nécessaire d'exercer une surveillance continue et que les copeaux découpés peuvent être enlevés de la pièce ou de la machine sans intervention manuelle. Les matériaux utilisés pour la fabrication de produits par enlèvement de copeaux doivent donc satisfaire à une importante exigence, c'est-à-dire présenter une bonne aptitude à l'usinage par enlèvement de matière et donner des copeaux d'une forme appropriée pour les machines automatiques ou décolleteuses.In processing technology, the automatic machines working by removing material and the chains formed by these machines are modern and efficient means which make it possible to reduce operations and costs, in particular for mass production. But the use of these automatic machines working by removal of material is profitable for the machining of steels only when it is not necessary to exert a continuous monitoring and that the cut chips can be removed from the part or machine without manual intervention. The materials used for the manufacture of products by removal of chips must therefore meet an important requirement, that is to say have good machinability by removal of material and give chips of a shape suitable for the automatic machines or bar turning machines.
L'aptitude à l'usinage par enlèvement de matière est une propriété physique des matériaux, au même titre que la résistance mécanique ou la densité, et est donc caractéristique de chaque matériau; elle résulte de propriétés physiques complexes, telles que:
- - l'aptitude du matériau à l'enlèvement de copeaux,
- - une propriété du matériau garantissant une bonne qualité des surfaces travaillées par enlèvement de copeaux,
- - l'effet d'abrasion que le matériau exerce sur l'outil.
- - the suitability of the material for removing chips,
- - a property of the material guaranteeing good quality of the surfaces worked by removing chips,
- - the abrasion effect that the material exerts on the tool.
L'aptitude à l'usinage par enlèvement de matière résume par conséquent, en fonction des objectifs de la fabrication, les paramètres caractéristiques suivants:
- - la force ou résistance de coupe,
- - la forme des copeaux,
- - la qualité de la surface travaillée par enlèvement de copeaux,
- - la durée de coupe de l'outil coupant,
ou les paramètres correspondant à ces notions combinées.The ability to machine by removal of material therefore summarizes, according to the objectives of the manufacturing, the following characteristic parameters:
- - cutting force or resistance,
- - the shape of the chips,
- - the quality of the surface worked by chip removal,
- - the cutting time of the cutting tool,
or the parameters corresponding to these concepts combined.
Il est généralement admis que les matériaux présentant une aptitude optimale à l'usinage par enlèvement de matière sont ceux dont une quantité maximale peut être découpée, dans un temps minimum, par enlèvement de copeaux, entre deux affûtages de l'outil, et ceci avec une qualité de surface appropriée. On obtient ainsi le rendement en copeaux, conformément aux processus intervenant pendant l'enlèvement de copeaux, à partir de deux facteurs différents l'un de l'autre:
- - les propriétés du matériau, et
- - les conditions caractéristiques de l'enlèvement de copeaux.
- - the properties of the material, and
- - the characteristic conditions for chip removal.
En relation avec ce qui vient d'être dit, on a mis au point des aciers appelés de décolletage, à alliage spécial, et dont seule l'aptitude à l'usinage par enlèvement de matière a été prise en considération.In connection with what has just been said, we have developed steels called free-cutting, with a special alloy, and only the aptitude for machining by removing material has been taken into consideration.
L'exigence la plus importante à laquelle doivent satisfaire les aciers de décolletage est que leur usinage par enlèvement de matière doit donner des copeaux d'une taille appropriée et pouvant être automatiquement enlevés de la machine par le liquide de refroidissement, sans intervention extérieure. Pour garantir aux copeaux de bonnes caractéristiques de fragmentation, il a fallu utiliser, pour l'élaboration de l'acier de décolletage, des éléments alliés qui ne se mettent pas en solution dans le fer, ou bien seulement en faible quantité, ce qui permet de bien bénéficier, pendant la fragmentation des copeaux, de leur action favorable à la formation des inclusions, et ce qui réduit le frottement entre les surfaces métalliques.The most important requirement that free-cutting steels must meet is that their machining by removing material must give chips of an appropriate size and which can be automatically removed from the machine by the coolant, without external intervention. To guarantee the chips good fragmentation characteristics, it was necessary to use, for the production of free-cutting steel, alloyed elements which do not dissolve in iron, or only in small quantities, which allows to benefit well, during the fragmentation of the chips, from their action favorable to the formation of inclusions, and which reduces the friction between the metal surfaces.
Etant donné que les éléments alliés brise-copeaux et lubrificateurs de surfaces constituent en fait des impuretés de l'acier, ils déterminent dans une certaine mesure les paramètres des propriétés mécaniques des aciers de décolletage, et notamment la résistance de ceux-ci aux sollicitations dynamiques, mais même aussi parfois leur résistance mécanique.Since the alloyed chipbreaker and surface lubricator elements in fact constitute impurities in the steel, they determine to some extent the parameters of the mechanical properties of free-cutting steels, and in particular their resistance to dynamic stresses , but even sometimes their mechanical resistance.
L'amélioration de l'aptitude à l'usinage par enlèvement de matière a donc entraîné une diminution ou limitation sensible des propriétes utiles des aciers. C'est pourquoi l'on ne peut pas utiliser ces machines économiques que sont les automates travaillant par enlèvement de matière pour la production d'éléments de machine qui sont destinés à subir des sollicitations excédant les aptitudes des aciers de décolletage connus. Ces aciers ne sont donc plus en mesure de répondre aux exigences actuelles relatives à l'aptitude à l'usinage par enlèvement de matière et aux sollicitations et ils ne peuvent plus être usinés sur des machines automatiques rentables.The improvement in the machinability by removal of material has therefore resulted in a substantial reduction or limitation of the useful properties of the steels. This is why it is not possible to use these economical machines that are the machines working by removing material for the production of machine elements which are intended to undergo stresses exceeding the capabilities of known free-cutting steels. These steels are therefore no longer able to meet the current requirements relating to the ability to machine by removal of material and stresses and they can no longer be machined on profitable automatic machines.
Cependant, une bonne aptitude à l'usinage par enlèvement de matière et avec des copeaux d'une bonne forme constitue, pour un acier capable de supporter de grandes sollicitations, même sans trempe, un avantage économique tel, non seulement pour les machines automatiques mais aussi pour tout mode d'usinage par enlèvement de copeaux, que le temps et l'argent consacrés à la production du produit final ne représentent, dans des conditions favorables, qu'une fraction des dépenses actuelles en temps et en argent.However, good machinability by removing material and with chips of a good shape constitutes, for a steel capable of withstanding great stresses, even without hardening, such an economic advantage, not only for automatic machines but also for any mode of machining by chip removal, that the time and money devoted to the production of the final product represent, under favorable conditions, only a fraction of the current expenditure in time and money.
Il est donc devenu indispensable d'élaborer un nouvel acier de décolletage dont la résistance mécanique, obtenue sans trempe, satisfasse aux besoins précédemment mentionnés des éléments de machine, dont la résistance aux sollicitations dynamiques soit suffisante et corresponde aux exigences actuelles, et qui présente une bonne aptitude à l'usinage par enlèvement de matière, avec des copeaux d'une forme appropriée pour les machines automatiques.It has therefore become essential to develop a new free-cutting steel whose mechanical resistance, obtained without quenching, satisfies the previously mentioned needs of machine elements, whose resistance to dynamic stresses is sufficient and corresponds to current requirements, and which has a good machinability by material removal, with shavings of a shape suitable for automatic machines.
On peut diviser en trois groupes les aciers de décolletage actuellement connus qui présentent une bonne aptitude à l'usinage par enlèvement de matière: les aciers du premier groupe ne peuvent pas être soumis à un traitement thermique, ceux du second groupe peuvent subir une trempe pendant leur utilisation, et enfin ceux du troisième groupe sont en mesure de subir un traitement de trempe ou de trempe suivie de revenu. A titre d'exemple, on peut mentionner les aciers suivants, qui appartiennent aux trois groupes:
Ces aciers contiennent généralement 0,07 à 0,65% (en poids) de C, au maximum 0,40% (en poids) de Si, 0,30 à 1,10% (en poids) de Mn, 0,15 à 0,40% (en poids) de S, au maximum 0,10% (en poids) de P; en outre, quelques nuances contiennent, de plus, au minimum 0,15% (en poids) de Pb, 0,80 à 1,50% (en poids) de Cr, 0,15 à 0,50% (en poids) de Mo et 0,05% (en poids) de Se.These steels generally contain 0.07 to 0.65% (by weight) of C, maximum 0.40% (by weight) of Si, 0.30 to 1.10% (by weight) of Mn, 0.15 at 0.40% (by weight) of S, at most 0.10% (by weight) of P; in addition, some shades also contain at least 0.15% (by weight) of Pb, 0.80 to 1.50% (by weight) of Cr, 0.15 to 0.50% (by weight) of Mo and 0.05% (by weight) of Se.
Les propriétés mécaniques de ces aciers varient en fonction des groupes de traitement thermique appliqués.The mechanical properties of these steels vary depending on the heat treatment groups applied.
Les paramètres des aciers n'ayant pas subi de traitement thermique ont servi de base de comparaison. La résistance à la traction de ces aciers est sans déformation à froid comprise entre 290 et 900 N/mm2 et à l'état étiré à froid elle est comprise entre 370 et 1100 N/mm2 (2), valeurs auxquelles correspondent une limite d'élasticité apparente comprise entre 24 et 66 (da N/mm2) et un allongement compris entre 5 et 10%.The parameters of non-heat treated steels served as a basis for comparison. The tensile strength of these steels is without cold deformation between 290 and 900 N / mm 2 and in the cold drawn state it is between 370 and 1100 N / mm 2 ( 2 ), values to which a limit corresponds of apparent elasticity between 24 and 66 (da N / mm 2 ) and an elongation between 5 and 10%.
Ces aciers présentent l'inconvénient d'avoir une résistance aux sollicitations dynamiques ou une tendance à la fragilité qui ne sont pas satisfaisantes, par suite de la nature et de la quantité des matières d'addition destinées à améliorer l'aptitude à l'usinage par enlèvement de matière, ce qui limite à l'extrême leur utilisation. Les différents éléments alliés que l'on ajoute pour améliorer l'aptitude à l'usinage par enlèvement de matière provoquent une si forte réduction de quelques-unes des propriétés utiles de ces a aciers de décolletage connus que leur utilisation en tant qu'aciers de construction mécanique s'en trouve considérablement limitée, en fonction des sollicitations que doivent subir les éléments de machine en exploitation.These steels have the disadvantage of having a resistance to dynamic stresses or a tendency to brittleness which are not satisfactory, owing to the nature and the quantity of additives intended to improve the machinability. by removing material, which limits their use to the extreme. The various alloyed elements which are added to improve the workability by removal of material cause such a great reduction in some of the useful properties of these known free-cutting steels that their use as steels of mechanical construction is considerably limited, depending on the stresses which the machine elements in operation must undergo.
Un groupe des aciers de décolletage actuellement connus présente donc une résistance mécanique relativement bonne, que l'on peut régler aux valeurs souhaitées par un traitement de trempe ou de revenu, mais la plasticité de ces aciers et leur résistance aux sollicitations dynamiques ne satisfont plus aux exigences actuelles.A group of currently known free-cutting steels therefore has a relatively good mechanical resistance, which can be adjusted to the desired values by a quenching or tempering treatment, but the plasticity of these steels and their resistance to dynamic stresses no longer satisfy the current requirements.
Le brevet français N° 2 246 650 décrit des pièces de coulée allongées en acier additionné de plomb.French Patent No. 2,246,650 describes elongated castings made of steel with added lead.
Ce document signale que la combinaison de base pour des aciers au carbone ordinaire peut être la plage suivante:
Par ailleurs, il n'est pas mentionné dans ce document les propriétés et l'utilisation comme acier de décolletage.Furthermore, the properties and the use as free-cutting steel are not mentioned in this document.
La présente invention a pour objet de mettre au point un tel acier de décolletage à haute résistance, présentant une excellente aptitude à l'usinage par enlèvement de matière et destiné à la fabrication d'éléments de machine soumis à de grandes sollicitations, acier qui non seulement présente, sans trempe, une haute résistance aux sollicitations dynamiques, mais qui puisse, de plus, être usiné avec une formation de copeaux appropriés pour les machines automatiques.The object of the present invention is to develop such a high strength free-cutting steel, having an excellent ability to be machined by removing material and intended for the manufacture of machine elements subjected to high stresses, steel which does not only presents, without quenching, a high resistance to dynamic stresses, but which can, moreover, be machined with a formation of chips suitable for automatic machines.
La présente invention permet d'atteindre cet objectif par le fait que l'acier élaboré selon la présente invention contient, outre le fer, 0,20 à 0,70% (en poids) de C, 1,20 à 3,00% (en poids) de Mn, au maximum 1,00% (en poids) de Si, au maximum 0,04% (en poids) de P, 0,05 à 0,11% (en poids) de S, au minimum 0,10% (en poids) de Pb, 0,001 à 0,03% (en poids) de Ca, 0,001 à 0,005% (en poids) de B, 0,007 à 0,035% (en poids) de N, 0,03 à 0,20% (en poids) de Nb et/ou de V, au maximum 0,25% (en poids) de Zr et/ou de Ce, au maximum 0,20% (en poids) de Be et/ou de Bi et au maximum 1,00% (en poids) de Mo et/ou de Ni.The present invention achieves this objective by the fact that the steel produced according to the present invention contains, in addition to iron, 0.20 to 0.70% (by weight) of C, 1.20 to 3.00% (by weight) of Mn, maximum 1.00% (by weight) of Si, maximum 0.04% (by weight) of P, 0.05 to 0.11% (by weight) of S, at least 0.10% (by weight) of Pb, 0.001 to 0.03% (by weight) of Ca, 0.001 to 0.005% (by weight) of B, 0.007 to 0.035% (by weight) of N, 0.03 to 0.20% (by weight) of Nb and / or V, maximum 0.25% (by weight) of Zr and / or Ce, maximum 0.20% (by weight) of Be and / or Bi and at most 1.00% (by weight) of Mo and / or Ni.
Une autre composition plus particulièrement préférée selon l'invention comprend en plus du fer et des éléments résiduels habituels les éléments dans les proportions suivantes:
Quelques-uns des éléments alliés assurent à l'acier, lorsqu'ils sont dans le rapport selon la présente invention, et sans trempe, une résistance mécanique suffisante, tout en lui conservant la plasticité nécessaire; d'autres éléments alliés assurent aux copeaux une aptitude appropriée à la fragmentation, sans entraîner une réduction de la résistance de l'acier aux sollicitations dynamiques, et ledit acier selon la présente invention contient aussi des éléments alliés qui contribuent à l'augmentation du pouvoir lubrifiant des surfaces métalliques en contact les unes avec les autres, et, de ce fait, à l'excellente aptitude de cet acier à l'usinage par enlèvement de matière.Some of the alloyed elements ensure that the steel, when in the relationship according to the present invention, and without quenching, has sufficient mechanical strength, while retaining the necessary plasticity; other alloyed elements ensure that the chips have an appropriate ability to fragment, without causing a reduction in the resistance of the steel to dynamic stresses, and said steel according to the present invention also contains alloyed elements which contribute to the increase in power lubricating metal surfaces in contact with each other, and, therefore, the excellent suitability of this steel for machining by removing material.
En raison de sa composition chimique, l'acier selon la présente invention présente une résistance mécanique relativement élevée, même à l'état laminé, de sorte qu'un seul train de calibrage suffit pour réaliser la section nécessaire à l'enlèvement automatique des copeaux et que l'on peut supprimer la réduction de section qui devait être effectuée jusqu'à présent en vue d'assurer à l'acier de décolletage une résistance mécanique appropriée et qui demandait beaucoup de travail.Due to its chemical composition, the steel according to the present invention has a relatively high mechanical resistance, even in the rolled state, so that a single calibration train is sufficient to achieve the section necessary for the automatic removal of chips. and that the reduction in section which had to be carried out so far in order to provide the free cutting steel with an appropriate mechanical strength which required a lot of work can be omitted.
En dépit de sa haute résistance, l'acier selon la présente invention présente une excellente aptitude à l'usinage par enlèvement de matière, et le rapport des éléments alliés selon la présente invention permet-avec des paramètres convenables pour l'enlèvement de matière-d'obtenir des copeaux suffisamment petits, même sans brise-copeaux, ainsi qu'une bonne lubrification et une très bonne qualité de surface, ce qui permet d'augmenter sensiblement les paramètres d'enlèvement de matière utilisés.Despite its high strength, the steel according to the present invention has an excellent ability to be machined by removing material, and the ratio of the alloyed elements according to the present invention allows - with parameters suitable for removing material - to obtain sufficiently small chips, even without chipbreakers, as well as good lubrication and very good surface quality, which makes it possible to significantly increase the material removal parameters used.
L'acier selon la présente invention peut être trempé ou traité par trempe suivie de revenu, à la fois par un traitement thermique normal et par un traitement par induction, la dureté de surface pouvant donc, en cas de besoin, être établie et réglée de manière simple et sur une large gamme.The steel according to the present invention can be quenched or treated by quenching followed by tempering, both by normal heat treatment and by induction treatment, the surface hardness can therefore, if necessary, be established and regulated by simple way and on a wide range.
L'acier selon la présente invention unit la haute résistance aux sollicitations dynamiques des aciers de construction mécanique, non alliés ou faiblement alliés, à l'excellente aptitude à l'usinage par enlèvement de matière que présentent les aciers de décolletage, et ceci outre une résistance mécanique obtenue sans trempe et qui satisfont aux besoins de la plupart des éléments de machine modernes.The steel according to the present invention combines the high resistance to dynamic stresses of mechanical steels, unalloyed or weakly alloyed, with the excellent machinability by removal of material presented by free-cutting steels, and this in addition to a mechanical resistance obtained without quenching and which meet the needs of most modern machine elements.
Le procédé de fabrication de ces aciers consiste à élaborer dans un four une charge comprenant outre le fer et les éléments indiqués ci-dessus, à procéder ensuite à l'affinage dans un équipement métallurgique équipé de poches, puis à la coulée, au laminage et au refroidissement.The manufacturing process for these steels consists in developing in a furnace a charge comprising, in addition to the iron and the elements indicated above, then refining in metallurgical equipment equipped with pockets, then casting, rolling and on cooling.
La présente invention et les propriétés de l'acier ainsi élaboré seront mieux comprises à l'aide de la description détaillée de plusieurs modes de réalisation pris comme exemples non limitatifs.The present invention and the properties of the steel thus produced will be better understood with the aid of the detailed description of several embodiments taken as nonlimiting examples.
A titre d'exemple, trois charges constituées par de l'acier selon la présente invention sont ici présentées. Les charges 1 et 3 ont été élaborées dans un four à arc de 70 t et coulées dans des coquilles de 6,4 t à profil carré. Les lingots ont été réalisés par laminage sans nettoyage de surface, dans des conditions normales, sous forme de lingots carrés ayant une longueur d'arête de 210 mm, puis ensuite transformés par laminage en ronds d'acier d'un diamètre de 16 mm, que l'on a refroidis à l'air sur des refroidisseurs.By way of example, three fillers constituted by steel according to the present invention are presented here. Loads 1 and 3 were produced in a 70 t arc furnace and poured into 6.4 t shells with a square profile. The ingots were produced by rolling without surface cleaning, under normal conditions, in the form of square ingots having an edge length of 210 mm, then then transformed by rolling into steel rounds with a diameter of 16 mm, that have been air-cooled on coolers.
La charge 2 a été réalisée par fusion dans un four à arc de 60 t, puis affiné dans une installation métallurgique équipée de poches. Le métal fondu a été coulé dans une installation de coulée continue à quatre filières, de profil carré, la longueur d'arête des billettes étant de 240 mm.Load 2 was produced by melting in a 60 t arc furnace, then refined in a metallurgical installation equipped with pockets. The molten metal was poured into a four-die continuous casting installation with a square profile, the edge length of the billets being 240 mm.
Les billettes ont été transformées, par laminage, en ronds d'acier d'un diamètre de 20 mm, que l'on a ensuite refroidis à l'air sur des refroidisseurs. Les résultats des essais effectués figurent sur les tableaux suivants:
Les contrôles de l'aptitude à l'usinage par enlèvement de matière ont été réalisés à l'aide de mesures de l'usure cratère, dont on a déterminé la valeur critique à K crit.=0,05 mm. Le contrôle a été effectué, pendant le tournage extérieur, à l'aide d'un outil à arête unique, à l'aide de plaques coupantes en acier rapide et en alliage dur, à serrage mécanique. L'enlèvement des copeaux a été effectué et contrôlé sur les éprouvettes de la charge 1 de l'acier selon la présente invention, qui avaient préalablement subi un traitement de détensionnement à 400°C, et sur les éprouvettes, traitées par trempe et revenu, d'un acier servant de base de comparaison. La composition chimique de cet acier servant de base de comparaison figure sur le tableau 3, et ses propriétés mécaniques sur le tableau 4.
Le résultat du contrôle de l'aptitude à l'usinage par enlèvement de matière, effectué à l'aide de l'outil en acier rapide, est résumé sur le tableau 5.
Le résultat du contrôle de l'aptitude à l'usinage par enlèvement de matière, effectué à l'aide de l'outil en alliage dur, est résumé sur le tableau 6.
(voir tableau 6 page 8).
(see table 6 on page 8).
Claims (3)
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AT79101820T ATE10652T1 (en) | 1979-06-08 | 1979-06-08 | HIGH STRENGTH AUTOMATIC STEEL RESISTANT TO DYNAMIC STRESSES. |
| EP79101820A EP0020792B1 (en) | 1979-06-08 | 1979-06-08 | High-strength freely machinable steel capable of sustaining dynamic forces |
| DE7979101820T DE2967319D1 (en) | 1979-06-08 | 1979-06-08 | High-strength freely machinable steel capable of sustaining dynamic forces |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP79101820A EP0020792B1 (en) | 1979-06-08 | 1979-06-08 | High-strength freely machinable steel capable of sustaining dynamic forces |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP0020792A1 EP0020792A1 (en) | 1981-01-07 |
| EP0020792B1 true EP0020792B1 (en) | 1984-12-05 |
Family
ID=8186134
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP79101820A Expired EP0020792B1 (en) | 1979-06-08 | 1979-06-08 | High-strength freely machinable steel capable of sustaining dynamic forces |
Country Status (3)
| Country | Link |
|---|---|
| EP (1) | EP0020792B1 (en) |
| AT (1) | ATE10652T1 (en) |
| DE (1) | DE2967319D1 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA1301489C (en) * | 1986-06-10 | 1992-05-26 | St. Marie, Thomas A. | Cold drawn free-machining resulfurized and rephosphorized steel bars having controlled mechanical properties and controlled machinability |
| DE202011003983U1 (en) | 2011-03-15 | 2011-05-12 | Bürkert Werke GmbH | Optical fiber coupling |
| CN114875322A (en) * | 2022-05-18 | 2022-08-09 | 湖南华菱涟钢特种新材料有限公司 | Steel material and method for producing same |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AT337746B (en) * | 1973-10-03 | 1977-07-11 | Inland Steel Co | LONG LEAD-TREATED STEEL CASTINGS |
| US4115111A (en) * | 1973-11-13 | 1978-09-19 | Daido Tokushuko Kabushiki Kaisha | Free-cutting structural steel for machines |
| ZA75241B (en) * | 1974-08-14 | 1976-01-28 | Inland Steel Co | Leaded steel bar |
| FR2338995A1 (en) * | 1976-01-23 | 1977-08-19 | Marrel Freres | Fine grained steel contg. aluminium - where calcium, barium, sulphur and selenium are added to improve machinability |
| FR2395323A1 (en) * | 1977-06-24 | 1979-01-19 | Pompey Acieries | FINE GRAIN CONSTRUCTION STEEL, IMPROVED MACHINABILITY |
-
1979
- 1979-06-08 AT AT79101820T patent/ATE10652T1/en not_active IP Right Cessation
- 1979-06-08 EP EP79101820A patent/EP0020792B1/en not_active Expired
- 1979-06-08 DE DE7979101820T patent/DE2967319D1/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| DE2967319D1 (en) | 1985-01-17 |
| EP0020792A1 (en) | 1981-01-07 |
| ATE10652T1 (en) | 1984-12-15 |
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