Principle of ultrasonic testing

Ultrasonic testing (UT)

This article provides answers to the following questions, among others: What is the measurement principle behind ultrasonic testing?What is the coupling agent used for?How are ultrasound waves generated and received?What is the...
Cupping test

Cupping test

This article provides answers to the following questions, among others: What is the cupping test (according to Erichsen)?What is cold formability? Sheets for deep-drawing applications must have very good cold formability, i.e. they...
Schematic setup for stress-relaxation test

Stress-relaxation test

This article provides answers to the following questions, among others: How is the stress-relaxation test performed?For which applications is the stress-relaxation test of great importance?What is relaxation strength? In the creep rupture test,...
Determination of the creep diagram from creep curves

Stress rupture test (creep rupture test)

This article provides answers to the following questions, among others: What is a hot yield strength?What is creep?What factors influence the intensity of creep?At what temperatures is a technically relevant creep to...
Fatigue test setup

Fatigue test

The fatigue test provides information about the strength of a material under continuously changing stress (dynamic load). This article provides answers to the following questions, among others: What are the objectives of the...
Test setup for Charpy impact test

Charpy impact test

This article provides answers to the following questions, among others: What are the objectives of the "Charpy impact test"?Why does "notch impact energy" represent a measure of the toughness of a test...
Test setup for flexural test

Bending flexural test

This article provides answers to the following questions, among others: How does the flexural stress distribution in the cross-section of a specimen subjected to bend loading look like?Where does the maximum bending...
Brinell hardness test procedure

Hardness test

This article provides answers to the following questions, among others: How is the hardness of materials defined?On which principles are all hardness testing methods based?Which indenter is used for Brinell hardness testing?What...
Setup for compression test

Compression test

This article provides answers to the following questions, among others: Why are no longish specimens used in the compression test?Why is the true compressive stress lower than the engineering stress?What is the...
Brittle fracture and ductile fracture

Tensile test

The tensile test is used to determine material parameters such as strength (yield point, ultimate tensile strength) and toughness (elongation at break)! More information about the tensile test can be found...
Types of loads

Destructive material testing & non-destructive testing (NDT)

This article provides answers to the following questions, among others: What type of loads do exist?What is dimensioning?What is the primary purpose of destructive testing?In which cases is non-destructive testing preferable? Materials such...
Flame hardening of a surface

Surface hardening (case-hardening)

Surface hardening is used to produce a hard and wear-resistant surface layer on steel workpieces, while the toughness in the core is largely retained. You will find more information on the...
Temperature curve during quenching and tempering

Quenching and tempering

This article provides answers to the following questions, among others: What is the aim of quenching and tempering compared to hardening?In which three process steps can quenching and tempering be divided?Why is...
Normalization of a heterogeneous microstructure

Annealing processes

This article provides answers to the following questions, among others: What are the objectives of annealing processes, such as normalizing, soft annealing, coarse grain annealing, recrystallisation annealing, diffusion annealing, solution annealing and...
Temperature ranges of the heat treatment processes

Overview of heat treatment processes

This article provides answers to the following questions, among others: What is a rolling texture?How should a metal sheet be bent with respect to its rolling direction?What is isotropy or anisotropy?For what...
Micrograph of hypoeutectic cast iron with a carbon content of 3.85 %.

Cast iron

This article provides answers to the following questions, among others: What is the difference in microstructure between steels and cast iron?For which manufacturing processes are steels particularly suitable compared to cast iron?What...
Overview of the microstructure formation of steels

Summary of the phase transformations of steel

In this article we give a short summary of the microstructural processes during solidification and cooling of steel. This article provides answers to the following questions, among others: What microstructural transformations does a...
Comparison of the iron-carbon phase diagram with the phase diagram of a crystal mixture

Comparison of phase transformations

This article provides answers to the following questions, among others: What analogy can be found between the iron-carbon phase diagram and the phase diagram of an alloy whose components are insoluble in...
Determination of the microstructure fractions of a hypoeutectoid steel

Determination of microstructure and phase fractions

This article provides answers to the following questions, among others: How can the microstructure fraction of a steel be determined from the iron-carbon phase diagram?How is the phase fraction of a steel...

Influence of carbon on hardness and strength of steels

This article provides answers to the following questions, among others: Why does the hardness of steel increase with increasing carbon content?How do the cementite lamellae in pearlite increase the strength of steels?Why...
Micrograph of eutectoid steel with a carbon content of 0.8 % (C80)

Phase transformations in solidified state (metastable system)

This article provides answers to the following questions, among others: What is the carbon content of a eutectoid steel?Why is virtually no carbon soluble in ferrite?What phases does pearlite consist of and...
Transformation lines in the iron-carbon phase diagram (steel part)

Microstructure formation during solidification

This article provides answers to the following questions, among others: What is steel made of?What is the difference between steel and cast iron regarding their composition?Why is carbon used as an alloying...
Continuous casting of steel

From steel to semi-finished products

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This article provides answers to the following questions, among others: What are slabs?What are bottom and top pouring?What are the advantages of rimmed steel?Why is only killed steel suitable for continuous casting?What...
Electro-slag remelting process (ESR)

From crude steel to steel

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This article provides answers to the following questions, among others: What is secondary metallurgy?What is rimmed steel, semi-killed steel and killed steel?For what purpose is vacuum treatment carried out?How does the electro-slag remelting...
Ladle transfer car

From pig iron to crude steel

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This article provides answers to the following questions, among others: Why is pig iron brittle?What are red shortness and hot shortness?What ist Linz–Donawitz-steelmaking?Why is scrap added to the oxygen converter process? Introduction Due to...
Shaft furnace for the direct reduced iron process

Direct reduced iron process

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The direct reduced iron process (DRI) is becoming more and more important in the climate change debate about producing steel with as little CO2 as possible. Learn more about this process...
Zones in the blast furnace

Blast furnace process

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This article provides answers to the following questions, among others: Why is carbon used for the blast furnace process?How important is the "Boudouard reaction" for the blast furnace process?What chemical processes distinguish...
Construction of a blast furnace

Ironworks

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This article provides answers to the following questions, among others: What is charge?What is meant by charging a blast furnace?What is the function of the slag in the blast furnace process?What is...
Schematic overview of an ironworks

Iron ore mining and dressing

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This article provides answers to the following questions, among others: What is steel made of?Which two main processes can be distinguished in steel production from iron ore?What is ore smelting?What are iron...
Phase diagram and microstructure diagram of an alloy system with limited solubility of the components

Limited solubility of components in solid state

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This article provides answers to the following questions, among others: How does the phase diagram of an alloy with limited solubility of components look like?What is a (alpha) solid solution or (beta)...
Phase diagram and microstructure diagram of an alloy system with complete insolubility of the components

Complete insolubility of components in solid state

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This article provides answers to the following questions, among others: What is a crystal mixture?How do the cooling curves of an alloy with insoluble components look like?How do you create the phase...
Reading the phase diagram of an alloy system with complete solubility of the components (solid solution)

Complete solubility of components in solid state (solid solution)

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This article provides answers to the following questions, among others: What is a solid solution?What do the cooling curves of solid solution look like?What is a phase?What is a phase diagram?How to...
Classification of alloys

Typs of alloys

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This article provides answers to the following questions, among others: What are alloys and why are they needed?What are binary alloy systems?What characterizes a solid solution alloy?What types of solid solutions can...
Heterogeneous and homogeneous nucleation

Types of nuclei

This article provides answers to the following questions, among others: What is homogeneous and heterogeneous nucleation?How can homogeneous nucleation occur in the melt?Which type of nucleation is more likely during solidification?What measures...
Slip plane and slip direction

Schmid’s law

This article provides answers to the following questions, among others: What is the mathematical relation between an external applied normal stress and the resulting shear stress in the slip system?What statement makes...
Microstructure of polycrystalline iron

Microstructure formation

This article provides answers to the following questions, among others: What is meant by a microstructure?What are grains and grain boundaries?What is a single crystal and a polycrystal?Why is a fine-grained microstructure...
Dendritic crystal growth (nucleus growth)

Crystal growth

This article provides answers to the following questions, among others: What is polygonal crystal growth?What distinguishes a microstructure with polygonal crystal growth?What is dendritic crystal growth?What distinguishes a microstructure with dendritic crystal...
Water droplet on a tablecloth

Heterogeneous nucleation

This article provides answers to the following questions, among others: How can foreign particles promote nucleation?What is the contact angle?What influences the contact angle?What is the connection between heterogeneous and homogeneous nucleation?What...
Critical nucleus radius and activation energy for nucleation

Homogeneous nucleation

This article provides answers to the following questions, among others: How can the Gibbs energy be used to assess whether a process is voluntary or not?How can the different states of matter...
Golf clubs as application of an amorphous metal (metallic glass)

Amorphous metals

This article provides answers to the following questions, among others: What are amorphous metals (metallic glasses)?Why is glass a thermodynamic liquid?What is meant by the term glass transition temperature?What are the technological properties...
Cooling curve of a pure substance

Heat of solidification

This article provides answers to the following questions, among others: Why does the temperature remain constant when pure substances solidify?How can it be explained on a microscopic level that the temperature is...
Conditions for solidification

Conditions of solidification

This article provides answers to the following questions, among others: Which atomic processes take place during solidification?What conditions must be fullfiled for crystallization?What is supercooling?What are nuclei used for in a melt?How...
Stress-strain curve of a single crystal

Deformation process in single crystals

This article provides answers to the following questions, among others: How to explain the stress-strain curve for single crystals?What is meant by Hooke's law?What characterizes easy gliding?Which atomic processes occur in the...
Lattice orientation for single and multiple gliding

Deformation of ideal crystal structures (single crystal)

This article provides answers to the following questions, among others: Why are slip steps preferably characterized by a single crystal at an angle of 45° to the tensile axis?What is meant by...
Illustrated dislocation movement

Deformation process in real crystal structures

This article provides answers to the following questions, among others: What influence do dislocations have on the ductility of metals?What does the Peierls stress describe?What is meant by strengthening?How is an increase...
Influence of the lattice structure on the ductility

Influence of the lattice structure on ductility

This article provides answers to the following questions, among others: What is a lattice plane?What is meant by a slip system?Why should well-deformable lattice structures have as many slip systems as possible?In...
Real crystal with crystallographic defects

Crystallographic defects

This article provides answers to the following questions, among others: Which types of crystallographic defects can be distinguished?What are vacancy defects?What are the differences between substitutional atoms and interstitial atoms with regard to...
Derivation of the packing density of the face-centered cubic lattice structure (fcc)

Derivation of the packing density

This article provides answers to the following questions, among others: What is meant by the packing density (or packing factor)?How is the packing density calculated for the body-centered cubic lattice (bcc)?How is...
Slip planes and slip steps

Fundamentals of deformation

This article provides answers to the following questions, among others: What is the difference between elastic and plastic deformation?What is the atomic process of deformation?In which cases must springback be considered during...
Important lattice structures of metals

Important types of lattice structures

This article provides answers to the following questions, among others: How is a body-centered cubic lattice structured?What is meant by the coordination number?Which statement provides the packing density?How does the hexagonal closest...
Acting forces on the metall ions

Lattice structure of metals

Due to their crystalline structure, metals are highly loadable, but still have high ductility so that they do not break instantly. This article explains how such a regular lattice structure occurs. This...