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Steel & Color

Technology tools and: The free-form modeling air pressure, as applied to art

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Technology Tools

Microstructure of the steel

Alloy steel

Without treatment is malleable iron steel The individual grades behave differently. So the soft rivet pin -steel is so flexible that it is up to 8 mm rivet diameter can handle even cold yet. Tool steel on the other hand is also in the glowing state of his still significant resistance against deformation. The reason for this different behavior lies in the different composition of the steels.

As a result of kneading in forging the steel structure is refined and compacted

Steel contains, in addition to the existing iron always predominantly carbon. Next there are some other substances present in small percentages applying, such as silicon, manganese, phosphorus, sulfur, etc.

Carbon strongly affects the properties of the steel.

With increasing content of steel is much stronger, harder and more brittle . The blacksmith and weldability decrease. Depending on the intended use is to steel a carbon content of 0.05 ... 1.7 ° / o. In no case, however, he loses through the addition - of carbon, and so its metal properties.

Steel is an alloy consisting essentially of iron and carbon

and their properties is of the type and quantity of the alloy components are determined.

Of the alloy steel is the pure iron (ferrum, iron) to distinguish that an Fe content of 99.90 ... Was 99.98 ° / o. It is silvery white and so soft and stretchy, it will be used only in a few special cases, for technical purposes, such as for certain magnetic properties.

8th Structural components of steel

In operation, the material is often judged by the structural break in terms of composition and treatment errors, and observed to form jagged or whether the fracture pattern grained, lighter or darker, matte or gloss appears.

However, since the circumstances of how the break was brought about, the lighting and other conditions affect the appearance of the fracture surface you still have to be careful with the verdict.

Microstructure of the steel

Flawless reveals contrast micrograph of an etched steel surface under the microscope the structure of the steel.

It is a steel whose carbon content to the right end increases from 0 to 1.7 ° / o.

It can be seen at the beginning of light fields, which give way to the middle of a dark mass, the right to enter a heightened extent bright veins. The dark mass bears because of their pearl effect reminiscent of the name of perlite. The bright cores are a chemical compound of iron and carbon, the iron carbide (iron-carbon) is called as a structural component (secondary) cementite. It consists of three iron atoms and one carbon atom (Fe3C). A comparison with the micrograph can be registered under the carbon content indicate that up to 0.9% occurs, an increase of perlite with a corresponding decrease of ferrite. With a carbon content above 0.9% perlite is increasingly replaced by cementite, ferrite is no longer available.

Kohlenstoffdiagramm

--->%£- Content

The curve is the function of the carbon content highest attainable hardness values

Micrograph with increasing carbon content.

a) ferrite (200 times

b) pearlite (600 times)

c) cementite network

(150x) i

Schliffbild

0 %

0,9 °/o

1,7 %

As structural components of natural hard steel will be ferrite, pearlite and cementite. Carbon is represented here in the form of a chemical compound that the chemist is called iron carbide and the metal expert cementite. To find castings and pig iron are other structural components.

Iron: fourth most common element in the Earth's crust (chemical symbol Fe, atomic weight 55.9, atomic number 26, relative density 7.8, melting point 1535 ° C). In its pure form is a silvery gray iron, ductile, malleable, magnetic metal. Chemically, iron, most metals such as a good reducing agent, which means it dissolves oxygen from chemical compounds. The element has four stable isotopes. Because of the high frequency of its occurrence (5 weight percent of the Earth's crust) and its excellent properties, it has become the main metal of our industrial age. Especially in the production of steel, cast iron and wrought iron and basic materials for the paint industry, it is used.

Alloy: a mixture or compound produced by melting a metal with another substance, which can be metallic or nonmetallic. Most metals that we use today are alloys. Produce by combining materials in the correct proportions, scientists alloys with specific physical properties that are used for scientific or industrial purposes, examples of this are the many varieties of steel, brass and bronze. The properties of an alloy are different in nature from those of the metals contained in it, so is for example the melting point of silver at 960 ° C to that of copper at 1083 ° C, while alloys of silver and copper melting points between 770 ° and 1069 ° C possess. When cooled alloys form various types of crystals, and the properties of an alloy are determined largely by the prevailing crystal. Metallurgists have found that the behavior of an alloy depends strongly on their composition and cooling rate. If rapid cooling, the so-called "quenching" can be no large crystals, using this method, therefore, to produce hard alloys. By alloys of magnesium, aluminum and titanium, which are characterized by high hardness and low weight, it has achieved in aircraft and rocket great progress. Under â â,¬ "â-º steel refers to many iron alloys with various proportions of manganese, tungsten or other metals.

Metals: Large group (71 out of 92) of naturally occurring elements that are certain physical and chemical properties in common (â â,¬ "> Periodic System). These similar properties are due to her similarities in the atomic structure of these elements, yet they are in their appearance, their frequency of occurrence and some very different characteristics. Metal atoms have a maximum of four electrons in its outermost shell and thereby achieve a stable chemical compounds in the form that they give off electrons from the shell. The reactivity of a metal depends on the number of outer electrons. These electrons can move relatively freely within the metal crystal atom by atom to hold the crystal together, by responding with the positively charged atomic nuclei bonds. From the presence of these free electrons are in general both the typical ability of metals to conduct electricity and emit electrons, as well as explain their ductility and malleability.

Metals are not only good conductors of electricity - Silver is actually the best conductor, but also have relatively high densities and high boiling and melting points, not least they are good conductors of heat, and turn silver is the best. Metals are composed entirely of crystals of certain structures. When heating or radiation they emit electrons. Except for mercury, they are solid, ductile (copper is characterized herein in particular), malleable (gold is best) and malleable. All metals have the chemical property of reacting with oxygen to form oxides, and these metal oxides are -> bases.

Non-metals: Group of elements that are different in an appropriate but arbitrary manner of the â â,¬ "> Metals (-> Periodic System). Nonmetals are poor conductors of electricity and difficult to deform and exhibit high ionization potential. They are generally oxidizing agents, and the less their metallic properties, the greater is their Oxydationsfähigkeit. Nonmetal oxides form acids with water. Some elements, namely, tin, antimony and tellurium, are neither metallic nor clearly non-metallic, but exhibit characteristics of both groups of elements, therefore they are called metalloids.

Nickel: Chemical element with the symbol Ni, atomic weight 58.71, order number 28, the specific gravity of 8.9, the melting point 1453 ° C and the boiling point 2800 ° C. Pure nickel is ferromagnetic, ductile and polish very capable, resistant to air, water and alkalis, but soluble in acids, which are salts of a greenish tint bildet.Gediegen nickel is found only in meteoric iron, otherwise than in most copper-nickel and cobalt compounds gloss, nickel and nickel bloom gravel. Nickel ores are promoted, particularly in Canada, the Soviet Union, Cuba and New Caledonia. Nickel is used primarily for nickel plating, and plating of iron and steel and in alloys: nickel steel (very hard and not stainless), nickel silver, Nickeline (copper-nickel-tin alloy for heat conductors, etc.), monel, chromel, constantan, etc. Alfenide . In the electrical industry, nickel is used as a catalyst.

Oxidation: the addition of oxygen to an element or chemical compound. The rate of oxidation varies greatly. With a slow oxidation, as, for example, in the rusting of iron, only a small amount of heat released. In contrast, rapid oxidation, such as during combustion of a fuel, produces a lot of heat and light, and very rapid oxidation can be explosive. Each reaction, in which an electron transition takes place is usually a re-duction-oxidation reaction (redox) reaction. This is the one starting material, loses electrons is oxidized, however, that which absorbs the electrons, is reduced. The number of emitted electrons equals the number of electrons taken up. Also -> rust.

Melting points of some substances

Material	Melting point
Oxygen	-282 ° C
Mercury	-39 ° C
Ice	0 ° C
Gold	1062 ° C
Iron	1535 ° C
Platinum	1773 ° C
Diamond	3500 ° C or higher

Spark sample, spark picture elements

Spark forms

spikes

branching explosion

Teardrop

floral explosion

Spearheads

Cone shape

C content
W content
Si-content
Mon-content
	Mn, Cr, Ni, V and Co alloying elements of steel have as little or no effect on the radio images.

Material Alloy in%
Use of steel C 15; 0,15 C, 0.25 Si, 0.37 Mn Smooth beam, little C-explosions Influence of C
Steel C 45, 0.45 C, 0.25 Si, 0.65 Mn Many stacheifï¿ige C-explosions Influence of C
Tool steel C 100, 1, OC, <0.25 Si, <0.25 Mn Many C-explosions, highly branched Influence of C
Leg. Tool steel 60 Si 4 Mn, 0.6 C, 1.0 Si, 1.0 Mn Many C explosions are preceded by bright swellings Influence of C and Si
Leg. Tool steel 105 Cr 6 W, 1.05 C, 0.25 Si, 1, OMN, 1, OCR, 1.2 W Thin beams with tongue-shaped ends Influence of W
Hot work steel 45 Cr V 7 W, 0.45 C, 1, OSi, 0.3 Mn, 1.1 Cr, 0.2 V, 2, OW Few C-lobe explosions followed by bright Influence of W and Si
Cold work tool steel X 210 Cr W 12, 2.1 C, 0.3 Si, 0.3 Mn; 12Cr, 0.7 W Short Garbe, as hardened many C-explosions Influence of wound C
Speed work steel S 18 - ° -1, O, 75C, 18W; 1.1 V, 4.2 Cr Interrupted jet only few C-explosions Influence of W and C

Steel - glow color - colors occasion

Steel annealing colors - colors occasion applied upon abstract work of art steel horse

Annealing temperatures and annealing colors for tools

Tempering Purpose: Implementation:

-Increasing tensile strength and increase in toughness.

Steels are hardened and then tempered at a temperature between 450 and 700 ° C.

Process in the material:

Carbides are excreted fine and uniformly distributed in the structure. By the refinement of the structure increases the hardness.

Note:

Well suited for this treatment are the hot tempered steels according to TGL 6547th

Ferrous materials

Steel without post-treatment in hot or cold for malleable iron material with a carbon content up to 2.06%

Malleable cast steel,

Encapsulated in steel forms

Of pig iron, scrap melted and cast-metal scrap and in forms encapsulated iron material with a carbon content above 2.06%

unalloyed

low-alloyed

alloyed

High-alloy

Carbon steel contains other than 0, 05 to 2, 06% carbon, small amounts of other iron companions (up to 0.5% Si, up 0, 8% Mn, up to 0, 09% to 0.06% P and S). Mass constructional steels, also called general structural steels, are primarily in the steel and mechanical engineering. Its technically most important properties are tensile strength and formability. With increasing tensile strength decreases the formability. Steels are characterized by their minimum tensile strength. Examples: St 33, St 60, ST 70

etwa600-720Mpa

General constructional steels are divided into three groups:

Quality group 1 for general requirements, melted in the Thomas converter.

Examples: St 38, St 42nd

Group 2 for higher quality requirements, melted in the open-hearth furnace,

1) 2)-effervescent or calmed (b) cast.

Examples: St 38 u-2, St42b-2.

1) Move the on cooling of the liquid steel gases released into the steel wall motion. He is restless. Can not escape these gases, they will form in the steel block gas bubbles, which are welded during the rolling of the steel in most cases.

2) Set: one is the molten steel to aluminum, thus preventing the formation of gas. The steel is reassured. Its chemical composition is uniform.

Weldability

The weldability of steels is dependent on the chemical composition of the material, and the melting type potting art (protected, effervescent). For the welding of steels, the guidelines of the Central Institute of Welding.

Fusion welding is better suited for calm and semi-killed steels than for unkilled. The carbon content affects the weldability of structural steels. The upper limit is 0.22% C (hardening by rapid cooling of the welding parts). At higher carbon content, special measures are required (preheating).

For fusion-welding appropriate steel grades:

U-2 St 34 St 38 S St 34-3

Hb-2 St 34 St 38 St 38-3 U-2

St 34 St 38 St B-2 hb-2 42-3

St 38 St b-2 52-3

Resistance butt welding is possible for all steel grades.

Pressure welding is generally possible with a maximum of steel grades with 0.20% C. The ability to take pressure welding with increasing silicon content.

Alloying elements and their influence on the properties of the steel

Alloying element	Influence on strength and technological properties	Other effects
Carbon C	increased tensile strength, yield strength and hardness, reduced strain, blacksmith and welding	Remanence and resistivity increase
Phosphorus P	increased tensile strength, yield strength and machinability, reduces strain and impact strength	makes steel melt low viscosity, increased Kaitbruchgefahr
Sulfur S	increased machinability, reduces strain, malleability and weldability	reduced electrical conductivity, increased fragility of hot, molten steel makes thick
Silicon Si	increased tensile strength, hardness and elasticity, malleability decreases, weldability and machinability	favors the formation of graphite, substantially increased the electrical resistance
Nitrogen N	increased yield strength, hardness and Verschieiï¿·iderstand; reduced. Drawability favors, aging ---> Aging is the change in properties during storage, especially after cold working. The cause is the elimination of dissolved nitrogen in the form of iron nitrides. They prevent the sliding of the crystals. Natural aging: embrittlement takes place after several hundred hours. Artificial aging: heating to 250 ° C embrittlement occurs in about one hour.	increases the corrosion resistance

Manganese Mn	increased tensile strength, elongation, malleability and wear resistance, machinability and cold workability decreases	increased thermal expansion, reduced electrical conductivity
Chromium Cr	increased tensile strength, heat resistance, oxidation resistance and curing, reduced ductility, weldability and machinability	increased remanence and corrosion resistance, reduced thermal conductivity and electrical conductivity
Molybdenum Mo	increased tensile strength, hardness, heat resistance and wear resistance, reduced malleability	increased remanence
Nickel Ni	increased tensile strength, hardness and curing, reduces machinability and drawability	increased remanence and corrosion resistance, reduced electrical conductivity
Tungsten W	increased tensile strength, hardness, edge retention and wear resistance, reduce strain, malleability and machinability	increased remanence (alloy additive for magnetic steel), reduced sensitivity to high temperatures
Vanadium V	increased tensile strength, hardness and heat resistance, machinability and reduced drawability	increased remanence and corrosion resistance, reduced thermal conductivity
Cobalt Co	increased tensile strength and edge, reduced rust process and curing	remanence increases, electrical conductivity and thermal conductivity
Titan Ti	increased tensile strength, hardness and weldability, machinability decreases	gives high resistance to heat, pressure and corrosion

Use and characteristics of some high-alloy steels

Generic name	Steel mark symbol	Features	Use
Speed work steel	X97WMo3.3	for roughing and finishing operations on materials with tensile strength of max.830 MPa	rotary cutting tools, such as milling cutters, circular saws, metal cutting, reamers, drills
	X82WMo6. 5	High speed steel for high performance for machining materials with a tensile strength of 850 MPa	Turning and planing tools, broaches, thread cutter turned behind, routers, Strehler
	X133WCol2.5	Speed work steel with high wear and hot hardness, suitable for work without cooling	Turning and Einstechmeiï¿¥l, dies, reamers, end mills, cutting wheels
Stainless and acid resistant steels	X20Crl3	stainless steel, oil hardening	Plastpreï¿¦ormen for chemically aggressive materials
	X10Crl3	stainless steel, hardened	medical instruments

Heat treatment of unalloyed steels

Through such processes as hardening, annealing and tempering of the structure of the metal structure is changed. In order to change the properties of the steel, such as hardness, toughness, strength and elasticity.

4.1. Change in the lattice structure of pure iron

Pure iron is cooled from the temperature 1600 ° C slowly, then changes in the solid iron of the lattice structure. This heat is released. This is evident by the breakpoints in the cooling curve.

Simplified state diagram of the system iron-carbon

Material property change

General properties of a solid body can be changed or introduction of particulate matter, screening, sorting through repositioning,

with a resulting change in shape does not occur in the nature of the process belongs.

Rearrangement of particles of matter:	It changes the structure or the crystal lattice, or both, such as hardness, surface rolling, tempering, magnetizing.
Separating out particles of matter:	properties of solid bodies are chemical or thermal route changed, such as decarburization during annealing.
Introduction of particulate matter:	properties of solids are altered, such as by carburizing, nitriding.
Heat treatment of steel:	It aims to structural changes in the material with a change in temperature or the temperature process. From these structural changes will result in certain desired properties.
Glow:	It is heating a workpiece in the solid state, with subsequent, usually slow cooling. It consists of: annealing, stress relieving, normalizing. See details in materials science!
Warming:	Is the heat to moderate Behandlungstemperaturen.ErhitzenIst heating to higher temperatures.
Annealing temperature:	is the temperature for heat treatment is heated to or heated.
Soak duration:	Is the time from reaching the desired temperature at the surface of the workpiece biszum reaching the desired temperature in the core or unilateral warming on the back.
Holding time (annealing time):	Is the time, the workpiece after heat soaking at the appropriate temperature is maintained during.
Cooling:	Is the slow or normal lowering the temperature of a heated or heated work piece.
Cooling time:	Is the time from the beginning of cooling until it reaches a certain temperature, usually room temperature.
Quenching:	Is the accelerated cooling of a heated or heated work piece.
Burn:	Are the loss of material due to oxidation of the heated workpiece (burning).
Overheating:	It is caused by too high annealing temperature leads to grain coarsening and a large burn.
Overtime:	Is a large holding period, it leads to grain coarsening and a large burn.

Melting and boiling points

Body	Melting boiling point
Alcohol (ethyl)	-114 ° 78.5 °
Aluminium	658 ° 2500 °
Antimony	630 ° 1635 ·
Petrol	90-100 °
Lead	327 ° 1750 °
Bronze	^ 900 °
Chrome	1800 ° 2330 °
Special brass	^ 1800 ° -
Iron, former purely	1540 ° 2880 °
gray cast iron	^ 1250 ° -
white iron	^ 1175 ° -
Steel	^ 1400 °
Mild steel	^ 1500 °
Rubber	125 °
Cobalt	1450 ° 3180 °
Copper	^ 1083 ° 2560 °
Air	- -193 °
Manganese	1250 ° 2030 ·
Brass	~ 930 ° - -
Molybdenum	2600 ° 4700 °
Nickel	1455 ° 3100 °
Petroleum	- - 150 °
Platinum	1773 ° 3800 °
Mercury	-38.8 ° 357 °
Oxygen	-218 ° -183 °
Nitrogen	-210 ° -196 °
Tantalum	3000 ° insec. 4,100 °
Vanadium	1720 ° insec. 4,100 °
Water	0 ° 100 °
Hydrogen	-259 ° -253 °
Bismuth	1500 ° -271 °
Wolfram	3380 ° 5000 °
Zinc	419 ° 807 °
Tin	232 ° 2430 °
Cylinder oil	.-- Insec. 310 °

Glowcolors of the steel

Color	Heat in degrees C °
in the dark red	475 ° - 550 °
dark red	550 ° - 650 °
dark cherry-red	650 ° - 750 °
cherry	750 ° - 850 °
light cherry red	850 ° - 925 °
orange	925 ° -1000 °
yellow	1000 ° -1100 °
Yellow White	1100 ° -1250 °
incandescent	1250 ° -1400 °
Welding heat	1400 ° -1600 °

Forge

Forging purpose

Forming of metallic materials that can be at room temperature or not is difficult to bring pressure, bending and impact forces in the required form and must therefore be heated. Shaping is the area between yield and ultimate strength when the material is in the state's largest and lowest plasticity of force is required. Simultaneously, a grain refinement and improvement of material properties possible.

Application

For all metals that allow for warming of recrystallization significant change in shape without the material which is destroyed (steel, cast steel, to a limited extent malleable iron, copper, bronze, brass, magnesium alloys and aluminum alloys, particularly the group AlCuMg alloys). The procedure is associated with only minor material losses.

Disadvantages are required for many large forging tolerances.

Comparison of the making of a pin head

formed Machined

Forged

Bolt Forged-verformt.jpg

Considerable material losses,

Grain broken

Production time high, reduced strength

Hardly the loss of material grain structure is maintained,

Production time low

Strength increased

Effect of temperature

In malleable materials (alloys) are strength and ductility temperature. The strength decreases with increasing temperature, the strain of, in steel at temperatures above 400 ° C. The temperature range of 200 to 300 ° C for the forming of steel is very unfavorable, because the material gets here in a state of hardening and embrittlement.

Image 3.2.41. Strength and elongation of St 42 at higher temperatures

Forging temperatures

They should be above the recrystallization temperature. When the material is kept at very heated (superheated) or too long at high temperature (ï¿¥rzeitet), coarse-grained structure is formed with low resistance. The required forging temperatures are dependent on the alloy components, in particular from carbon steel. They are eg

Structural steel 850-1200 ° C, tool steel, 800-1050 ° C, high speed steel 1000-1050 ° C, brass (60% Cu) at 700 ° C,

Aluminum at 500 ° C, AlCuMg alloys at 420 ° C. The manufacturing plants give exact values for the materials.

Heating

Low-carbon steels can be quickly heated up to forging temperature, high-carbon and alloy steel to red heat slowly, then quickly to the forging temperature.

Cool

Workpieces must after forging to cool slowly and evenly to avoid undesirable hardness and tension. /

Combustion

The forging must not be too long to the air blower directly exposed to the heat, otherwise oxidation to Fe304 (scale or iron hammer) and increased material loss (erosion) may occur. At very high temperatures can result in scale formation on the grain boundaries come into the interior of the material, the steel can not forge more, he is .. burned and crumbled (Figure 3.2.42).

If burning tool steel long exposed to the airflow of the fan, the air oxygen burns the carbon of the 'boundary layer, the steel is no longer curable. It must always be coal via the air nozzle to distribute the air flow. Sulfur from coal is at the grain boundaries of the heated steel iron sulphide FeS, the steel is red-hot or brittle. Fresh coal must therefore be placed at the edge of the fire, where the sulfur burns - the coal abflammt.

Gas and electric oven allow atmospheric oxygen and sulfur away from the workpiece.

Forging

Forging

Heated material is forced between two surfaces by linear compression pressure forces from its original form into the desired shape. Material flows in the direction of least resistance. The pressure forces are created dynamically (by hitting) or statically (by pressing).

The transformation depends on

. the temperature of the workpiece

. the kinetic energy of the hammer blow.

Image 3.2.43. Influence of the temperature of the material on its formability

The inertia of the anvil and workpiece mass counteracts the force of the hammer blows.

The material is kneaded in forging, gas bubbles and voids are compressed and welded.

Beside the Free forming air pressure modeling procedure by using compressed air, are standing nor further test series of the pressure modeling procedure for sheet steel hollow bodies segments with steam, water vapour as well as the the high-speed forming of metal sheets through blasting agent at.

---

Skulpture model dinosaur so far cold blow-mould, then gas-tight welded with water filled. Heat for water-vapour pressure through straw fire ---> Extrusion.

The free-form modeling air pressure, as applied to art

Resulting outcome of the pilot project "free-form modeling for air pressure welded together steel hollow body

dolphin model raw body

Steel Dragon the 1 Generation of air pressure and smolder under extruded by individual and by parti essential heat generation with the burner flame is to create artistic expansion modeling.

Steel Dragon the 1 Generation Generation	Steel dragon of the 2nd Generation Generation

After reaching the yield strength material reduces the thickness of 1.24 mm to about 0.16 mm with a factor --> 7. By welding of new plates or by welding of the bodies are which ones burst, gas tightness is restored to the re-modeling.

Benefits of the modeling for the art we see primarily in so far as ground-breaking because the art works are effectively producible economically. Precisely because of the low weight and high body strength, given by the optimum uniform expansion in the air by annealing under pressure to offer our views on the optimum for oversized works of art in turn. ---> ( Colossus of Rhodes ), etc. ....

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