FI118738B - Globe Granite Cast Iron and Method of Manufacturing Globe Granite Cast Iron for Machine Construction Parts that Require Strength and Toughness - Google Patents

Description

118738

Ductile iron ductile iron and method for the manufacture of ductile iron ductile iron for mechanical components requiring strength and toughness 5

The invention relates to a spheroidal cast iron according to the preamble of claim 1.

The invention also relates to a method according to the preamble of claim 7.

Typical prior art metallic raw materials for ductile iron are by-products of non-machine-formable cutting, i.e. steel scrap, and by-products of thin-sheet packaging, packaged in sheet metal. In addition, pig iron produced in other iron making processes is used. In order to carry out the casting in the mold, it is necessary to have casting channels and feeds, which have been removed from the body and used as circulation scrap. Raaka- • ^ a •. ·. the substances are generally melted in dome or induction melting furnaces. The exact exact composition of the composition. To blend into the melt, alloying agents such as carbonaceous and various ferric

··· S

. ***. rose branches.

«· A · ·. · * · These feature typical applications of the prior art (e.g., cast iron,

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: *** · Casting steels, MET: Raw Material Handler II) The chemical compositions for high-strength logs * ··; · * 25 for EN-GJS 600-900 (standard EN 1563) are • · «• aa • • ·

Carbon 3.8-3.2% • · ·

Pii 1.8-2.8% • ·

Manganese 0.1-0.8% 30 Magnesium 0.040-0.065% 2 118738

The essential melt treatment of ductile iron is the so-called molten iron. spheronization, which modifies the conditions of the carbon precipitation process to form iron-sputtered graphite, either by ladle treatment or inside a mold using magnesium and / or cerium-containing ferro-silicon or nickel magnesium.

Magnesium reacts with sulfur and other impurities, which promotes the growth of graphite spherically instead of finnish.

Another molten treatment of ductile iron is the seeding, in which granular ferro-alloy is typically added to the molten to add crystallization cores. The aim of inoculation is to make the casting structure finer.

Internal stresses occur in the ductile iron casting structure due to uneven solidification and cooling. Machine parts for demanding applications are generally subjected to stress relieving annealing at temperatures above 600 ° C. If the internal microstructure differences of the material are to be smoothed, a perlite treatment is carried out in which the piece temperature is raised to 880-940 ° C and the furnace is cooled to the desired perliteration temperature between 750-860 ° C, whereupon the piece is cooled to room temperature.

• 20 The paper machine components currently use common structural materials such as EN-GJL 150-350 feldspar iron, EN-GJS 370-900 ductile iron • * ii: (EN 1563), EN- GJS 800-1400 (EN-1564) as well as structural steels and tapping steel. The same materials are used in other similar mechanical engineering applications.

25 • e ·. · J The most significant deficiencies of the current materials are: • · ·: - Sufficient strength and toughness properties (strengths less than 350 kN / mm2 and elongation approx. 1%) are not achieved with finnish graphite irons. - Standard-sized ductile iron bars have to be sufficiently large to provide • rigidity of 30 pitches and size; · Heavy components and not by standards • «·. · ··· 3 118738 sufficient fatigue strength. No values are specified for elongation at break for strength classes above 60 mm. In addition, the values of mechanical properties given in the standard do not apply to the interior of thick-walled pieces.

5 - Forging steel parts have to be manufactured by forging, which results in high mold and forging costs and your extensive machining will further increase the cost of manufacturing. Strength and elongation at break are at the desired level, but the lack of design freedom and the less sensitive notch to ductile iron diminish the true fatigue strength of practice.

- in die casting steels, the difficulty of achieving internal tightness increases the risk of internal faults, which must be taken into account when designing components for greater certainty, thus increasing costs, 15 - special ball graphite cast iron ADI (typically), EN-GJS-800-8 (EN-1564) molded drawbar, but its machining is very difficult due to hardness, and manufacturing ADIs in excess of 1000kg and ··· 200mm wall pieces is technically and economically difficult. Standard mechanical values are defined separately • · ·:: with molded test rod.

···; : - heat from the fabrication process of steel for lapping and ADI: the treatments typically use either oil or salt baths: ***, the emissions and wastes of which produce an adverse effect on the environment. ·: * * *: Paper machine parts are subjected to very heavy mechanical and fatigue stress. The speeds of both paper machines and paper finishing • · ... have doubled and tripled over the last decades. For pre-S · 7 30, the paper web speeds of post-production machines have risen from 600 • ·; m / min to levels above 2000 m / min and development has not stopped.

• * · • · • · ··· 4 118738

Machine parts such as bearing housings, bearing brackets, axle pins, and bracket levers require increased tensile strength, yield strength and elongation, and fatigue strength. The properties of the material in the walls of different thickness throughout the piece must be as uniform as possible.

5

All this should be achieved with a material whose manufacturing process gives full freedom of design to minimize moving masses and which has relatively good machinability by conventional methods. The tools used to make the blank, such as molds and molds, are made as simple and quick as possible to achieve short project lead times. Forging forgings often take months to produce, and in free and mold forging, the design freedom is in practice more limited than casting. Significantly shorter times are needed to make the wooden, plastic or similar model equipment needed for sand casting.

15

It is not known in the prior art to provide such material and the object of the present invention is to provide a material that substantially meets the above characteristics and curves, where the disadvantages of prior art materials are: · · • ... · demanding machine parts such as paper or board machines 2 3 · 20 eliminated or at least minimized.

The object of the invention is to create a new type of cast iron cast iron having new * »·, · | exceptional combinations of material properties.

It is also an object of the invention to provide a manufacturing process for the aforesaid! (! properties for ductile iron are achievable.

• · · • · • ««

In order to achieve the foregoing and further objects, the spheroidal graphite iron according to the invention is essentially characterized by what is stated in the characterizing part of claim 1.

• · • · • ♦ · ··· · · · · 2 • · 3 5 118738

The method according to the invention, in turn, is essentially characterized by what is stated in the characterizing part of claim 7.

According to the invention there is provided a new type of ductile iron cast iron for use in parts of a paper or board machine, for example, which have exceptional mechanical properties and can be manufactured more economically and in an environmentally friendly manner compared to other materials having equivalent strength properties.

According to the invention, there is provided a very good grade of ductile iron for parts of a paper or board machine, which is technically and economically most advantageous in the form of sand mold casting, which has: - good castability, free mold design and tensile strength, tensile strength, is the • ♦ level of the tempering steels and the mechanical values of the thick-walled piece • • ··. the cut test pieces give at least the same values as the individually wound test pieces with ADI-spherical graphite and • · * ··· ·: 20 - economic machinability does not pose a problem with current technology. - the machining is technically and economically good, since hardness is generally less than 300 HB,. - any necessary heat treatment is carried out without oil or · "* · salt bath with controlled air, water, or water.]] 25 casings plus the desired environmentally friendly additives, • ··, ···. , - environmental friendliness is good, because recyclable • * * * "can also be used. * Material to be scrapped.

* · • ·

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The blank made from a spheroidal cast iron cast iron according to the invention is more dimensionally free forging than machining, thus achieving cost savings. With a new combination of exceptionally advantageous properties, the spherical graphite iron achieves the best mechanical properties in a more economical and environmentally friendly way than alternative machine building materials.

5

In combination with the mechanical properties of a spheroidal cast iron cast iron cast iron according to the invention: - the yield limit is adjustable through a wall of a thick-walled part (over ISO mm) from 500 N / mm2 to 750 N / mm2 by varying the casting process and heat treatment From 4% to 8% and * - tensile strength is adjustable up to 1000 N / mm - at the same time the fatigue limit on twisting bend is adjustable from 15 300 to 420 kN / mm2

the hardness of the piece through the piece is generally 260-300 HB

- SharpV rod according to impact resistance standard 4-9 J / mm2 -20 ° C

The type of spheroidal cast iron according to the invention is a fine grain ductile (FGDI) which is different from the present spheroidal iron (FGDI): •:: .:: - The metal matrix consists of a fine-lamellar perlite and a fine-grained perlite-ferritic or bainite-ferritic structure with a perlite-bainite lamella gap of less than Ι, Ομιη (typically less than 0). , 4pm), as well as ferrite, which is in the perlite course at the grain boundaries as desired zones and in the bainitic structure as a needle-like ..... or comb-like structure near the grain boundaries and bainite. ***. • • ♦ ··, 30 - carbides are not present in the structure by more than 1%, • · e • · · ***. '- residual austenite is not generally present in the structure itself, •. · 11 · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · and the alloying provides a composition in which the first prerequisite for the formation of a fine-grained microstructure is created, the main alloying and trace elements being Si, 10 Mn, S, Cu, Ni, Mo, Mg, TijaCe.

in addition, Nb, La, Bi, Sn and B are advantageously affected by the fine grain.

- melt treatments, i.e. spheronization of spheroidal graphite and crystallization nucleation seed, create a high sphere density and a small, traditional molded austenitic grain size, which provides another basis for the granularity.

- in the case of heat treatment, a slow increase in temperature (50 ° C / h) is traditionally carried out in order to avoid tension and tension. The austenitization is carried out in an atmosphere oven at a temperature of 880-960 ° C.

20 - after austering, the piece is brought to a temperature range of 840- • ·] ··· * 760 ° C, whereby the temperature of the piece decreases, contributing to rapid quenching while maintaining excellent toughness and • · '* • • ferrite around the perlite and baie rivet needed to achieve fatigue strength.

25 - the subsequent quenching is carried out in a controlled manner according to the composition at such a rate that a sufficiently fine perlite structure is achieved in the perlite and ferrite · * ··· * perlite quality *: **: (temperature range 800-600 ° C for example 3 to 15 minutes in total:] **: Depending on the core, particle size, wall thickness and desired properties (for example, strength) and bainite structure, dense ferritic needles and secretions are achieved in the phenolic structure. # * · 8 118738 Full fine bainite structure (less than 5 minutes). Fast cooling is advantageous for the properties of fine-grained ductile iron.

- the choice and control of the proper austenitic decomposition temperature and retention time (bainization) is the fourth element in achieving a fine-grained matrix. The perlite structure develops mainly at lower temperatures in the perlite region. Structure of the bainite species entirely within the bainite range. Typically 290-550 ° C, but depending on the composition may be 100-600 ° C. The decay of austenite at low temperatures is slower than at higher temperatures, resulting in 10 fine-grained matrices.

- the complete decomposition of the austenite and the absence of tension and good machinability of the structure are ensured by the release to which the body is slowly heated from bainitization or perlitation temperature to an access temperature of 520-720 ° C depending on composition and particle thickness and desired strength.

- at the end of the heat treatment, the piece is cooled to room temperature in a controlled manner (preferably e.g. 50 ° C / h) to room temperature.

• · ·

In the manufacture of the type of ductile iron cast iron according to the invention, the controlled thermal process of * * *, *: 20 * as described in FI patent application 20011954 is preferably used.

In accordance with the present invention, there is provided a type of spheroidal cast iron which has the following characteristics: ((the quantities can be varied in a controlled manner by adjusting the composition and the manufacturing process and the heat treatment).

The material designation of the fine-grained spheroidal graphite cast iron (FGDI) according to the invention is, inter alia, according to the tensile strength according to EN-1563: GJS-FGDI-P-850 / 500-5C-HB280-H, a perlite species · 30 GJS-FGDI-BF-850 / 600-5C-HB280-H, a bainite-perlite species · GJS-FGDI-BF-750 / 600-7C -HB250-H, which is a bainite-phenite species, 9 118738 GJS-FGDI-PF-850 / 500-7C-HB280-H which is a perlite spherite species and GJS-FGDI-P-900/550 -4C-HB290-H, which is a fully perlite species.

S properties achieved by a finely divided ball graphite cast iron (FGDI) according to the invention in a piece having a wall thickness of e.g. 30 ... 300 mm

Rm (Tensile strength) of 450 to 1000 N / mm2 of tensile bar Rp0.2 (Tensile limit) of 300 to 750 N / mm2 of tensile bar A3 (Fracture elongation) 10 to 4% of tensile bar of 10 δ (Fatigue strength) 300 ... 420 N / mm2 from the drawbar pull Hardness 250 ... 320 Nb from the drawbar pull

The hardness of the spheroidal cast iron type according to the invention is in the range of 250-320 HB and there is no significant hard phase, whereby good machinability is achieved throughout the object.

The fatigue strength of a spheroidal graphite cast iron type according to the invention is defined as rotational bending fatigue strength. A positive consideration in this comparison is the following: a> <: slight delamination when stretched into fine-grain spheroidal cast iron (FGDI) steels according to the invention *: * ·: 20.

ti * • t • · • t »: With the fine-grained ultrafine cast iron (FGDI) according to the invention, due to the uniform microstructure of post-casting and the further smoothing of the heat treatment ··· ·" *: the structure is similar throughout the article or, if desired, · 25 processes can be used to create a functional structure, ie different surface and internal parts •; *: (if necessary, the microstructure can also be controlled).

Ml ·; ***; the placement of the irons and the control of mold filling • · · «places the best features and least risks in the most demanding areas of the section.

· · • M M M M M M M *

III

«* • ·

III

10 118738 This is preferably verified by computer-assisted simulation of pre-filling and solidification of casting, which can be used to pre-verify the success of the manufacturing process, thereby achieving time and material savings.

According to a preferred embodiment of the invention, the control of the casting process is designed by computer-assisted simulation, in which the filling of the mold with the melt and the solidification and cooling of the melt can be ensured. This prevents internal porosity and slag inclusions in the casting to weaken the properties of the material and cause surface defects that would serve as a starting point for fracture.

10 Computer Assisted Simulation Revision of a heat treatment program whereby heat treatment simulation ensures correct heat treatment; verifying the suitability of heat treatment for quality risks especially in small series and single production.

The process for producing spheroidal iron according to the invention differs in several respects from the normal processes for producing spheroidal iron. The following are the major differences described.

Generally, the preferred metal smelting material is ductile iron; "1: ingots sold for manufacture. In the manufacture of the invention, it is used as wax as possible, since the most common commercial grades are by-products of titanium oxide, a white pigment pigment. · · |; 2: high levels of harmful metals such as titanium, chromium, vanadium, molybdenum and phospho ··· · · ri In addition, the invention utilizes the purest grades of steel ··· · .3 · and the purest alloys. - * 1 e 25 more work-friendly and inexpensive, and essential elements include trace elements outside the general precision of the foundry analyzer, such as niobium, bismuth, lanthanum, etc.

• · ·

In the process of the invention, the thawing temperature is kept at a temperature below 1520 ° C, and the batching is carried out in such a way that the thawing time is as low as possible. · 11 118738 short. To prevent oxidation during melting, it is advantageous to use a shielding gas or vacuum treatment in the shielding gas to eliminate any casting defects.

The magnesium treatment may be carried out in the form of: S 1 2 3 mangle treatment with a magnesium-containing treatment agent with or without a shielding gas - with pure magnesium in a converter - with a magnesium alloy in a chamber treatment, - in a mold treatment.

In order to obtain a fine-grained microstructure, before or during casting, addition of solidification cores, i.e. seeding with a ferro-silicon alloy, is carried out. The recommended grain size of the structure, represented by graphite spherical density, is typically 400 ... ISO balls / mm2. The ball density is also increased by the addition of metal molded parts of high thermal conductivity, known as chamomiles, which accelerate the cooling and solidification of the mold casting surface.

The chemical composition of the material according to the invention depends on the desired combination of '1': femininity and wall thickness, and typically is as follows: • · · ...: 20; "1 · typically preferred • · ·: Carbon by weight 3.60- 2.80 3.40-2.90 ··· 1: .1 Silicon by weight 1.30-2.60 1.30-1.90 ·· 1. Magnesium by weight 0.065-0.025 0.055- 0,035 25 Manganese by weight 0,80-0,10 0,40-0,20; ·. Copper by weight 0,10-1,60 0,60-1,20. ···, Nickel by weight % 0.20-2.00 0.40-0.80 • · • .Phosphorus Weight% 0.030-0.005 0.001-0.005

Sulfur by weight% 0.003-0,010 0.005-0,008 • · • · _ _ ··· 30 • · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · «12

Chromium (Cr), Titanium (Ti), Vanadium (V), Wolfiam (W), Molybdenum (Mo), Cobalt (Co), Lead (Pb), Tin (Sn), Cerium (Ce) and Bismuth (Bi) extent.

In the process of the invention, in the heat treatment, the material is first austenitized at 880-960 ° C for at least 1 hour + 1 hour / 25 mm per wall thickness. The aim is to dissolve all carbides and other non-matrix phases in austenite. Next, controlled and controlled temperature reduction in the atmospheric furnace and leveling to 800-850 ° C is performed, followed by rapid controlled cooling to 650-100 ° C, where after 2 to 4 hours lam-10 temperature leveling, the temperature of the piece is maintained at the selected temperature. , if the discharge is at the same temperature as the extinction, or is raised to the discharge temperature of 550 ... 750 ° C, depending on the composition. The pieces are kept at the outlet temperature for 2 to 8 hours, after which they are cooled to room temperature. Preferably, shielding gas is used throughout the heat treatment.

15

Depending on the choice of heat treatment, the microstructure of the spheroidal cast iron iron according to the invention provides three basic structures: - a fine-pearl fully perlite microstructure of graphite spheres;

• M

neen (Multiphase Intermediate Quenching) *** * 20 - needle-like ferrite and fine lamellar bainite with graphite spheres · ♦ * · · ... · neen (Fast Quenching Media) ) The microstructure is controlled by composition and heat treatment in a controlled manner, whereby the desired combination of mechanical properties can be achieved for each body.

«• ·. In accordance with certain preferred features of the invention, the pieces made of the material according to the invention are simulated for mold filling, molten solidification, graphite spherical density and possible carbide phases and hardness. 118738 by a computer assisted simulation program in which the material values are programmed. The software required for mechanical properties is pre-checked by computer-assisted simulation. The purpose of using simulation is to pre-empt defective products S in order to achieve material, cost savings and scheduled production schedules. These advantages are emphasized in single and small series production. After casting, the tightness of the casting is checked by ultrasound or X-ray. Hardness is measured with a pressure gauge. The chemical composition is checked by casting on a piece-by-piece basis. For each piece, the pre-cast 10 test pieces for tensile tests as well as a batch-by-piece reference piece representing the actual casting are also silenced and from which the test results are also determined. This specimen is similarly simulated to ensure representativity of the specimen. In accordance with further preferred features of the process, both the casting event and the mechanical properties of the material hall are modeled and computer simulated before the final casting process is completed.

The cast iron material of sufficiently fine mechanical properties according to the invention can be manufactured from FGDI cast iron, which allows the shape and dimension of the machine part to be freely selected according to its purpose and not to be dependent on, for example, forging or machining methods. Precise dimensioning allows for optimized material utilization, which is important for minimizing energy consumption during the manufacture, transport, and operation of the machine. At the same time models and · «· e. · '. the dimensioning of the tools can also be used to manufacture components of lighter loads ·· 0 25 using the lowest values of the strength of the material according to the invention and the highest values of the material of the invention for the most demanding applications. Components and machines made of stronger, tougher, more fatigue resistant and easily machinable material have smaller dimensions, eg heavy duty bearing housings have a diameter of SOOmm when • · ***** 30 bearing housings are made of the material of the invention, if it were standard | and with a spherical iron it would be 650mm. For a heavily loaded roll with a shark size of 14 118738, 500mm, a bearing body weight of 500kg according to the invention is fine-grained ball graphite cast iron (FGDI), if standard cast iron weight is 800-900kg.

Thanks to the casting process used in the method according to the invention, it is possible to get very close to the final dimension, which reduces the need for machining compared to forging. At the same time, material and energy consumption is minimized.

The fine grit ball ball graphite (FGDI) according to the invention has an exceptional combination of properties, i.e. high strength and high yield strength supplemented with 10 good elongation and fatigue strength while still having good machinability. Generally, in ductile iron, strength is achieved by doping and heat treatment that impairs toughness and machinability. The fine grit spheroidal graphite cast iron (FGDI) of the invention has good fatigue strength in a sample taken from a thick body. This is the result of the process of manufacturing fine-grained granular spheroidal cast iron (FGDI) according to the invention, whereby conditions are created for the structure not to have weakening phases and defect areas. In the casting process, solidification conditions are created such that the casting structure is dense, uniform and non-oriented.

All the variations in the strength properties of the paUgraphite cast iron according to the invention in terms of wall thickness and from one piece to another are substantially standard; smaller, so that the structural dimensioning factor M · · • ** j can be lowered.

«ΦΦ I

The thermal concept preferably used in connection with the process of the invention:. The peculiarity of the lyprocess is that with rapid cooling, the final micro- »·« ·. ***. the structure is fine-grained and contains weakening phases or areas of error • φφ *. lessly. Depending on the desired properties, the selected firing rate, release temperature, and holding time adjust the final microstructure and corresponding ominaisuudet · ***** 30 material properties. Generally, precise heat treatment processes that require rapid cooling require the use of an oil or salt bath. In the context of the invention, a controlled and controlled special lamp processing process is preferably used which provides sufficiently controlled controlled cooling rates of the air and the medium added thereto. As the coolant is preferably air and water added with natural particles, no release into the environment occurs, there is a bottom water risk from oil use and further treatment of the salts in the salt bath creates a potential environmental hazard. The quenching and heating steps of the heat treatment are short and the temperature differences are reasonable and the piece is not cooled to room temperature, but much of the heat content remains in the piece throughout the heat treatment process. Except for possible water vapor, the heat treatment does not transfer to the environment.

Compared to other materials suitable for the same purpose, the raw material base of the pdlograph cast iron according to the invention is mainly recycled materials, the melting temperatures are lower than those of steels, the energy required is less than forging and the piece is cast very close to final dimensions. As a casting material, the material according to the invention is completely recyclable: within the foundry, casting slurry is immediately utilized in the melting and use of the following castings: parts of the inventive material to be removed from the hen are purchased by the foundry 20 as secondary raw material. Casting intermediates such as pouring channels are used .1 2 3 · 1. again, the mold material is recycled, the machining chips are thawed again and • · a • · 1. the end product is recyclable iron material.

··· · • • • • t • »i • · 1 ·. 1 1 1. The following Tables 1 to 6 present some of the results obtained with the spheroidal graphite iron ore according to the invention.

• • • • • 1 · · · · 1 · aa • 1 • • • a · • 1 • aa • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • · ·· 16 118738

Table 1 Casting 600 kg

Drawbars on the side of the casting from table A, s = 5 150mm for that point

Atmospheric Extinction

Part number Tensile strength Tensile strength Fracture elongation Rm Re A

_ | MPa_ | MPa__

TABLE

K671 [842 [492 [5/7

K672 858 5Ö8 M

K673 847 EATED H

K691 [827 [480 [5/7 K692 "852 496 ~ 6.1

K623 „842,492 M

TABLE B

· · ·

·: ··· STAND. SFS-ΕΝ 1563 + A1 TEST BARS

; ···· Ks51 873 51Ö 7 · ** _____________ ϊ Ks 56 873 512 7 * · ·: 'X Ks58 855 5ΪΪ el • · ·

Ks6Ö 86! "496“ Tfi • ·

Ks 62,873,520 6.5. . Ks 64 863 5Ö8 7 ^ »· · *;: / Ks67 859 506 Ifi · ... · Ks 69 877 ϋ 6l • -------- * · · 11! Table B shows the standard castings for the castings of the various sections; 10 values for test rods (SFS-ΕΝ 1563 + A1).

··· · ·· «• s • · ... 1 a · 17

Table 2 118738

Heavy block weight about 1700 kg

The test pieces detached from the sides of the different pieces were located at s = 100 and 5 s = 300mm from the side of the wall area.

air Extinguishing

Item ID Wall mm Tensile strength Tensile strength Fracture elongation

Rm Re A

___ MPa__MPa __% __

TABLE A

The table shows a small dispersion between different test rods G041 Γ300 Γ84Ϊ [494 [6 G042 3ÖÖ 842 498 6 ^ 3 GÖ43 300 842 "494 5/7 G044 IÖÖ 835" 497 4 ~ 6 G045 WÖ 838 494 5Ä G046 Ϊ05 841 497 6Ä. · *. G071 Γ500 Γ838 | ~ 5Ö3 I ~ 63. !!!: G072 3ÖÖ 842 "494 6fi • · '' __ ___. ···, G073 300 841 487 6.3." I G074 IÖÖ 835 497 4 £ • · ·.

! * Υ G076 IÖÖ 844 194 ^ 6 • · · • «· -» 'I ·· 1 1 I' ··· · ·· *: ···: K091 [3Ö0 fm [499 T6j K092 3ÖÖ 836 "486 5 / 7 ί .: *: K093 3ÖÖ 836 "492" 63 C !: K094 NIGHT 841 ”492 6Ä K095 NIGHT 834 498 6Ä • · _____________ _ __ K096 100 834 498 5.9 • · _____________ ** t • · _______: cough [300 Π542 [499 T ^ ö «* · ________ __ ________ *. · • · ··· 18 118738 K052 T1ÖÖ 842 | ~ 5Ö5 Γμ K053 300 842 5Ö5 43 K054 3ÖÖ 837 493 53 K05S hit 838 487 63 K056 hit 829 486 53 TABLE B Standard Drawbar Results (SFS-ΕΝ 1563 + A1)

For the values of standard test rods fixed in connection with the same paragraphs, see 04 [834 [496 [6

See 07 812 501 5

See 13,858 5Ö4 6

See 10,833,500 53

YA02A 300 [864 PsTÖ [M

YA02B 3ÖÖ 863 502 63 YA02C 3ÖÖ 85Ϊ 503 53 YA02D [1ÖÖ [873 [5T7 [6/7 YA02E 3ÖÖ 864 503 73 * ·· ________________ YA02F 300 870 515 6,4 • .... 1 II _____ I -___ • · • 1 2 3 · • · • ·

• • I

• 1 • • • • • · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 1 • · * # · • · 1 • · 1 * · • · «• · 1 * · · · · ·. Φ · 2 • · 3 19

Table 3 118738

Chemical casting mass 600 kg.

Rapid cooling of the medium (water quenching).

5 Piece bars cut from the side of the piece wall.

Body / Rod Wall Tensile Strength Stress Limit Elongation

thickness s Rm Re A

__MPa_ MPa% _ G9411 200 812 624 5,1 G9412 2ÖÖ 893 6Ö1 ΉΪ G 9413 2ÖÖ 793 6Ϊ7 "HÖ G9512 [2ÖÖ [877 | ~ 591 [Hl G7911 200 806 656 4Ä G7912 2ÖÖ 87Ö 637 5Ä G7913 ~ 2ÖÖ 825 663 ~ 4] / 7 G8812 T2ÖÖ Γ882 [59Ö | ~ 6 G9012 2ÖÖ 852 "~ 592 5 G7911 2ÖÖ 8Ö6 656 4Ä • · · * * ···) G7912 2ÖÖ 87Ö 637 5Ä G7913 2ÖÖ 825 663 4/7 aaa___ __

G8912 200 ~ 87Ö 637 M

I .; ': G872 2ÖÖ 863 596 5 ^: G921 2ÖÖ 857 633 5 # a a a a 7 • · a' 1 1 '1 • · • · aaa:. *. YJ301 flÖO 876 [623 [T, l • aa. "• V YJ302 2ÖÖ 843 64Ϊ 4/7 • a • aa - 111 1" "Il II - i —- 1 'aa • a • aa • aaa • aa aaaaaaaaaaaaaaaaaaa · a

Table 4a 20 118738

Chemical casting mass 700 kg.

Rapid extinguishing (water medium).

S Test pieces cut inside the piece.

Item / Rod Wall Location Tensile Strength Stress Limit Elongation

thickness s Rm Re A

____ MPa__MPa __% _ YJ30A [8Ö outer surface Γ879 [6Ϊ2 [87 YJ30B 8Ö outer surface 878 618 67 YJ30C 80 central surface 917 592 57 YJ30 D 80 boiling surface 888 608 5.3 YJ30F 80 boiling surface 878 612 4.6 YK06 CAI [1Ö 589 outer surface [57 YK06 CA3 80 Central Surface 847 602 4.7 YK06CB1 80 Outer Surface 842 589 4.6 YK06 CD1 80 Outer Surface 873 587 67 YK06 CD2 80 Central Surface 855 596 5.0 • · · · · 1 · · • • • • • • M • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • · • · • «« · • 1 ·.

«1 • • • • • • • • 1 '· · 1 · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · ·

Table 4b 21 118738

Chemical casting mass 700 kg.

Rapid extinguishing (water medium).

S Test pieces cut inside the piece.

Item / Rod Wall Location Tensile Strength Stress Limit Elongation

thickness Rm Re A

__mm ___ MPa__MPa __% _ YJ30A 170 outer surface 935 614 7.3

YJ30B 170 Biscuit Surface 942 6Ϊ4 5J

YJ30 C 170 thread surface 844 606 3.0 YK03A2 Πτ0 outer surface [935 Γ617 p79 YK03A4 170 outer surface 907 598 4 ^ 6 YKLA1 170 outer surface 864 591 [7/7 YKLA2 170 center surface 929 611 6.9 YKLA3 17Ö center surface 903 598 4 ^ 3 YKLA4__ 890__611__4j6_

The table shows the mechanical properties of the various parts of the part.

aaa • 1 I 1 • · a • a ··· • a • · a # aa · • · aaa M1 1 • • • • • • · · · · · · · · · · · · · · · · · · · · · · · · · · · 1 · a • · · ··· t ··· aaaa ··· • aa # a · • a »i · • · • la •« «« • »a · a • aaaa 1«

Table 5 22 118738

Heavy casting Cut inside mass 1300 kg 5 Quick quench (medium as water).

Section Wall Tensile strength Tensile strength Fracture elongation

mm Rm Re A

___ MPa__MPa __% _ GV9ES 300 / Page [883 [656 [Ed

GV9GS 300 / page 869 701 5J

GV9A2 90 Surface [873 [627 Hfi GV9A5 160 Surface 851 59Ö 4/7 GV9A7 90 Middle 917 6ÖI 5fi GV9A12 90 Surface 847 614 5 ^ 4 GV9B1 120 Surface 883 705 1 ^ 9 GV9B2 120 Inside 841 60S 4/7 YV03A7 90 In [ 823 [64Ϊ [Tl

YV03A9 90 indoor 9ÖÖ 596 4J

... YV01A10 90 Inside 9Ö6 608 £ l: ··· '1 YV03B4 120 Inner 856 629 *: 1 i YV03S1 300 Surface 825 630:] ”i YV03S2 300 Surface 844 611 5Ö • · • · · · j1 V Same features properties at different wall strengths. Features • · · '!!. I do dispersion relatively small.

•••••••••••••••••••••••••

• • I

• • • • • tl · ·

* m • M

Table 6 23 118738

Rotary fatigue test (test pieces cut from different parts of a piece)

Test Stick Diameter Total Tension

Makeup mm_ (reading) Mpa

Outside 1 6,740 144104627 323 6 6,740 183 306 743 333 10 6,740 46368754 357 14 6,740 76 338 376 357 18 6,740 259344245 333 22 6,740 2 427656 352 26 6,740 1 481978 357 30 6,740 97530904 357_

Keema Side 5 6,740 44323 676 333 9 6,740 493 647 333 13 6,740 19,047 785 333 17 6,740 20 493 782 333 21 6,740 16667 061 333 25 6,740 326 086 333 29_6,740_7 585 424 333 S The invention will now be described in more detail in the accompanying drawings, the details of which, however, are not intended to be. · · ·. in no way narrowly constrained.

n · n 9 • n · · · • ·, ···. Figure 1 is a schematic block diagram of a prior art cast iron 9 9: 10 GJS800.

Figure 2 is a schematic block diagram of the preparation of a fine-grained ball graphite iron (FGD1) according to the invention.

Figure 3 is a diagrammatic representation of the step heat treatment of a fine lattice ball (FGDI) iron according to the invention.

• · t · · * ...: Figure 4 is a schematic block diagram of a heat treatment simulation •: 1: Process diagram for a manifold.

··· · · 2 • · 3 24 118738

Figures 5A and 5B show the rate of cooling of the body at different points of the different body in connection with the simulation of the heat treatment of the body.

Figure 6 shows a typical microstructure view of a spherical-5 graphite cast iron type according to the invention at 100x magnification.

Figure 7 shows a magnification of 6,400 times that of Figure 6.

Figure 8 shows a 700x magnification similar to Figure 6.

10

Figure 9 is a typical microstructure view of prior art cast iron material at 100x magnification.

Figure 10 shows a magnification of 700 times that of Figure 9.

15

Figure 1 is a schematic block diagram of a prior art material, GJS-800. As can be seen in Figure 1, the prior art processes use steel scrap, pig iron, ferrous materials, ferro-silicon and alloys as raw materials and, if necessary, carry out *! 20 Elemental Analysis. The melting is effected by induction melting 11, after which, in the melting treatment, the sputtering step 12 is added to the melt. This is followed by • · j followed by inoculation 13, where the inoculum is added to the melt, after which the molten lie ·! The casting is then disassembled at the disassembly step 15, followed by the subsequent finishing 16: surface cleaning, casting removal and cleaning grinding.

2; 1 2: This is followed by a quality check by ultrasonic examination 17 and a ··· ·: 3: possible tensile test 18.

· »· ·

Figure 2 is a schematic block diagram representation of a process for making a 2 3 3 3 ductile iron cast iron according to the invention. • · 1 ♦!.! ! such as iron, pig iron, scrap, carbonates, ferro-silicon and alloys, followed by Elemental Analysis if necessary. The melting is carried out by induction melting 21 and during the melt treatment step, the ballast 22 is added with a ballast. Following sputtering 22, seeding addition and seeding 23 are followed, Elemental analysis and casting temperature are performed, followed by melt casting at casting stage 24. Subsequently, casting at casting stage 25 followed by casting post-treatment 26: surface cleaning, casting and cleaning. The quality check is performed by ultrasound check 27. This is followed by a heat treatment as a step heat treatment 28 and a quality check by a tensile test 29, followed by machining and surface cracking (magna flux).

Figure 3 is a diagrammatic representation of a preferred embodiment of the spherical cast iron-Jin phase heat treatment of the invention. In the heat treatment, the temperature of the piece is first heated to about 900 ° C, whereby the pieces are held for 15 specific periods, then the temperature is lowered to about 800 ° C, where the temperature is shortened for a short period, followed by rapid cooling to 400 ° C, the temperature at which the pieces are held for a period of time, after which the piece is reheated to about 580 ° C, • e * ··· 'the temperature at which the pieces are held for a period of time after which the cap ····· 20 pieces are cooled to the desired cooling rate. Stage heat treatment is described in greater detail in, inter alia, FI patent application 20011954.

Fig. 4 is a schematic diagram of a heat treatment simulation process for multiform bodies. Based on the material properties 31, the desired microstructure 32 (temperature curves) and the thermal properties 33 of the materials are determined, which data is input for the heat treatment simulation 30. In addition, the information on the desired material properties 34 and the geometry of the part are entered; for heat treatment simulation 30. Based on this, a target is defined. ***. and a basis for determining furnace control parameters

• M

. *. 30 39 for both the target heat treatment program 38 and the furnace parameters 40 pe- * s s ♦ · · · · · · · · 26 118738. The furnace parameters 40 also determine the heat transfer to the environment 36, which is taken into account in the heat treatment simulation 30.

Figure SA-3B shows a simulation of the heat treatment of a piece and the cooling rate of a piece S at different points of a different piece. Fig. 5A shows the temperatures T as a function of time t, in which the heat treatment curves at the position indicated by the reference S indicate the doped perlite and bainite regions which are dependent on the material additives. The reference designations Pi and P2 refer to the points Pi and P2 in the example body of Figure 5B, which are influenced by the thermal currents 10 on different sides of the body, depending on the shape of the body.

Figures 4, 5A and SB show that by simulating the cooling rate of an object, the microstructure obtained by heat treatment in different parts of the object can be calculated in advance. In the method, the heat treatment curve can be determined beforehand for 15 pieces according to the desired properties. The heat treatment simulation can be carried out, for example, with commercial FEM (finite element methods) software. Heat treatment simulation is also possible with suitably modified loop simulation software.

Fig. 6 shows a typical microstructure view of a spheroidal cast iron cast iron according to the invention. The image is magnified 100x. The figure shows graphite spheres of microstructure on a perlite base and according to the invention there is a question: fine granular rite. The image also shows ferrite at the grain boundaries, which increases the toughness of the material.

··· 25; Figure 7 is a 400x magnification of Figure 6 of a fine-grained • • 9 9: ***: epallographite cast iron (FGDJ). The figure shows graphite spheres with perlite base 2 and ferrite with grain boundaries marked with reference numeral 1.

99 • 99 9 9 • 9 999 • • 9 9 9 9 9 9 9 999 9 999 • 9 9 9 999 27 118738

Fig. 8 is a 700-fold magnification of the fine-grained spheroidal graphite (FGDI) iron according to the invention, showing a fine-grained lamellar structure with a lamellar slope <0.4 µm. The grain size is 10-20 pm.

Figure 9 shows a typical microstructure image of prior art material showing graphite spheres on a perlite base and about 1-2% carbides designated as reference A and graphite spheres marked as reference B. This structure typically does not contain ferrite.

Fig. 10 shows a 700-fold magnification of prior art material showing a typical perlite structure of good quality material. The grain size is typically 50 to 100 µm.

The invention has been described above with reference only to some advantageous embodiments thereof, the details of which, however, are not intended to be limited in any way.

· • 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 i i i i i i i i · • 1 • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • «F • · · · · • • 1« ·

Claims (10)

1. Nodular cast iron for machine structural parts requiring pour strength and toughness, characterized therein, a nodular cast iron is a fine-grained nodular cast iron (FGDI), the fine-grained nodular cast iron (FGDI) comprises as weight percent: C 3.6-2. 8, Si 1.3-2.6, Mg 0.065-0.025, Mn 0.8-0.1 and Cu 0.1-1.6, Ni 0.2-2.0, P 0.03-0.005 and S 0.003-0.01, that the graphite nodule density of the fine-grained nodular cast iron is 150-400 nodules / mm 2, that the fine-grained nodular cast iron (FGDI) comprises a combination of mechanical properties: yield strength through the wall of a piece of thick wall 500 N / mm2 - 750 N / mm2, elongation 4-8%, tensile break strength -1000 N / mm2, fatigue limit at torsion bending 300-420 kN / mm2, hardness preferably 260-300 HB and impact resistance Sharp V 4-9 J / mm2 (-20 ° C) and that the slab spacing of the perlite and bainite of the fine-grained nodular cast iron (FGDI) is below 1.0 µm. 15 2. Nodular cast iron according to claim 1 or 2, characterized in that the metal structure of the fine-grained nodular cast iron (FGDI) consists of fine lamellar pearl. * · *. as well as fine perlite ferrite or bainite ferrite structure and ferrite. · * · · • * · ··· · • 20 3. Nodular cast iron according to claim 1 or 2, characterized in that the ferrite ·· »·: * * * j is present at the grain boundaries as zones in the perlite-ferrite structure. Nodular cast iron according to claim 1 or 2, characterized in that the ferrite ··· ϊ, ϊ exists as web-shaped or comb-shaped structure in the vicinity of the grain boundaries and between the bainite in the bainite-ferrite structure. «A * 5. Nodular cast iron according to any of claims 1-4, characterized in that: · · · ♦ ·· *. · · ·. the degree of spheroidization of graphite nodules is over 85%. • · ··· 31 118738 Nodular cast iron according to any of claims 1-5, characterized in that the fine-grained nodular cast iron (FGDI) further comprises as alloying and blocking agents Mo, Ti, Ce, Cu, Ni, Mg, Nb and Bi. 5 7. Method of manufacturing nodular cast iron for machine structural parts requiring pour strength and toughness, in which process the raw materials are melted by induction melting (21), in steps of treating the melt, spheroidized (22), seeded (23) and cast (24) melt. , and after a step (25) for unloading the ingot, steps (26) for finishing the ingot are performed, characterized in that the pieces are heat treated in stage heat treatment (28) to produce a fine-grained nodular cast iron (FGDI) and the material in the stage heat treatment first austenitized, followed by a controlled lowering and equalization of the temperature, followed by a rapid controlled cooling, followed by a step of equalizing the temperature, in which the temperature of the piece is poured at a selected temperature, after which an annealing is carried out, and the piece is cooled to room, ···, temperature. «1 ♦ · 2 t • · .1 ··, 8. A method according to claim 7, characterized in that the heat treatment. is carried out in protective gas, for example air or water mist. a ·· S ϊ. ·. 20 • · 2 ··· · .3. 9. A method according to claim 7, characterized in that the heat treatment is carried out in the quenching water or in some other rapidly cooling medium. • 1 · • · · «M: 3: Process according to any one of claims 7-9, characterized in that in step 1 \ for treating the melt in the process: the spheroidisation of the fine grain is created. nig nodular cast iron and at the grafting that produces crystallization a ··· 9, \ high nodular density and a small customary grain size of the austenite in cast state. • · · • · «··· a ·· • 1 2 *» 3 Miles