COURSE PROGRAMME FOR ENGINEERING MATERIALS 2

(full semester course – 15 weeks)

SEMESTER: Fall

HOURS FOND: 5 (full semester block)

academic year:

I week (theoretical course 1)

1. hour 2. hour 3. hour

Diagram of the type Fe–Fe3C. Recapitulation of basic terms from the theory of alloys and solid state diagrams: solid solutions, intermediate compounds, mechanical mixtures. Basic types of diagrams, liquidus, solidus, solvus – lines, phase/structural regions. Diagram of the type Fe–C. Basic terms. Application. Mechanical properties of pure iron. Polymorphism of pure iron, crystal lattices and cooling curves. Properties of carbon, characteristics of the crystal lattice. Two types of diagrams – metastable and stable phase transformation, depending on the cooling rate. Reactions in the solid state between Fe and C: solid solutions (ferrite, austenite, ferrite), intermediate compounds (cementite as the most important), mechanical mixtures – eutectic and eutectoid reactions. Primary and secondary crystallization, liquidus, solidus and solvus lines on the metastable solid state diagram. Classification of alloys, steels and cast irons. Basic phases in the metastable solid state diagram and characteristics.

4. hour 5. hour

Cooling curves, lever rule. Cooling curves for particular alloy types. Lever rule. How to plot the solid state diagram iron–carbon, based on cooling curves, and how the curves appear for a given alloy composition, starting from pure iron through hypo-eutectoid-, eutectoid, hyper-eutectoid alloys, hypo-eutectic-, eutectic and hyper-eutectic alloys. Also, explanation of the lever rule and how to apply it for calculating the phases in given cases.

II week (theoretical course 2)

1. hour 2. hour 3. hour 4. hour 5. hour

Steels. Solid state diagram of the type Fe-C. Cast irons. Steels. Short on technology and fabrication. Killed, semi-killed and non-killed steels. Influence of chemical elements on the structure and properties of steel: carbon, manganese, silicon, phosphorus, sulphur, oxygen, nitrogen and hydrogen. Cast steels. Pre-fabrication for plastic deforming. White cast iron, structure and characteristics. The stable solid state diagram. Basic phases in the stable solid state diagram and their characteristics. Graphitization, primary and secondary. Basic classification of cast irons according to structure: grey, modified, tempered, nodular. Influence of cooling rate on graphitization and iron structure. Conditions that favour a certain eutectic reaction. Special irons. Basic classification of irons according to technology: raw, cast and their sub-classes.

III week (laboratory 1)

1. hour 2. hour 3. hour 4. hour 5. hour

Metallographic tests. Steel designations. Proof and verification of exercises. Taking specimens for metallographic tests. Preparation of metallographic specimens by grinding on paper and polishing. Selection and preparation of etching media. Analysing prepared samples by metallographic microscopy. Photo imaging of characteristic location. Microstructural analysis. Steel designations according to former standards, newer standard systems and examples of particular cases.

IV week (theoretical course 3)

1. hour 2. hour 3. hour 4. hour 5. hour

Heat treatment of steel. Basic terms of heat treatment. Basic types of heat treatments: steels. Basic mechanisms responsible for a heat treatment process of steels: transformation P ® A at heating, transformation A ® P at cooling, transformation A ® M below the temperature of  metastable equilibrium, transformation M ® P, S, T, B at temperatures below A1. Annealing without phase transformation, annealing with phase transformation, full and partial, quenching, tempering. Recrystallization, annealing for stress relieving, diffusive annealing, normalization, high temperature normalization, spheroidization. Quenching, transformation mechanisms, martensitic structure, types. Tempering, transformation mechanisms, types.

V week (theoretical course 4)

1. hour 2. hour

Chemical heat treatment of steel. Basic terms in chemical heat treatment. Basic types of chemical heat treatment and diffusive metallization. Influence of temperature on the diffusion process. Chemical heat treatments: Cementation in the solid, liquid and gas media. Quenching and tempering after cementation. Steels for cementation. Nitration. Steels for nitriding. Nitrating as a final phase of chemical heat treatment. Cyaniding (carbonitriding), high and low temperature. Diffusion metallization: chrome, silicon, aluminium, and zinc -based.

3. hour 4. hour 5. hour

TTT and CC diagrams. Alloyed steels. Understanding diagrams of isothermal decomposition (transformation), and diagrams of continuous cooling; critical cooling rate. Understanding these diagrams in solving practical problems. Isothermal decomposition of austenite. Hardenability. Alloyed steels. Classification. Properties. Influence of alloying elements on the shifting of critical points. Structures of alloyed steels in the equilibrium and normalised state.

VI week (laboratory 2)

1. hour 2. hour 3. hour 4. hour 5. hour

Heat treatment procedures. Heat treatment of aluminium alloys. Proof and verification of exercises. Heat treatment of samples of various steel types by quenching in different media. Hardness measurements after quenching and analysis of results. Hardenability. Testing the hardenability of given steel class. The Jominy test heating up to specific temperature, holding and surface quenching. The specimen is prepared for hardness testing. The results are used for plotting the Jominy curve and analysis of results. Heat treatment of aluminium alloys. Exercises. A specific aluminium alloy is quenched and aged at different temperatures at given time intervals, the hardness is measured, and aging curves are plotted.

VII week (theoretical course 5 + Lab Test 1)

1. hour (or 5. hour)

Lab Test 1. Includes lab exercises from weeks III and VI (lab. 1 and lab. 2)

2. hour 3. hour 4. hour 5. hour

Light metals and alloys. Some non-metallic materials. Light metals and alloys that are most common in mechanical engineering. Wrought and cast aluminium alloys and their characteristics. Heat-treatable aluminium alloys. Aluminium copper alloys. Quenching, aging and over-aging of aluminium alloys. Aluminium silicon alloys. Nickel alloys and their application. Titanium alloys and their applications. Hard alloys. Composite materials. Basic types and characteristics of composites. Bimetals.

VIII week (theoretical course 6 + Test 1)

1. hour (or 5. hour)	Test 1, consists of the theoretical courses from weeks I, II, IV, and V.
2. hour	Introduction to welding. Electrical arc. SMAW procedure. Basic terms in welding and classification depending on the heat source and applied pressure. Basic elements of the welded joint–basic metal, weld metal, heat affected zone, fusion line. Types of joints and grooves. Positions in welding–horizontal, vertical, horizontal–vertical and overhead. Basic terms of the electric arc and influencing parameters on its stability. Electric arc characteristics. Arc welding procedures most frequent in applications. Shielded metal-arc welding.
3. hour 4. hour 5. hour	Welding procedures and technology of SMAW. Initializing the electric arc and problems that might appear. Preparation of the base material, choosing the polarity and current, welding electrodes. Voltage and current influence, welding rate, arc length, electrode slope, current types and polarity influencing the created weld. Electrode coating characteristics.

IX week (theoretical course 7 + optional repeated Lab Test 1)

1. hour (or 5. hour)	Repeated Lab Test 1. Includes lab exercises from weeks III and VI (laboratory 1 and laboratory 2)
2. hour 3. hour	TIG, MIG, MAG and Submerged metal arc welding (SAW). TIG and types of non-melting electrodes in practice. MIG and MAG procedures and automated arc length adjustment depending on power sources for welding. Submerged metal arc welding, pros and cons, compared to other welding techniques.
4. hour 5. hour	Technologies of TIG, MIG, MAG and SAW. Understanding the gas shielding used in particular welding procedures: TIG; MIG; MAG; and how gas shielding influences the shape of the weld. Influence of current type and polarity on the bead shape. Fluxes for submerged metal arc welding and selection based on criteria.

X week (theoretical course 8)

1. hour 2. hour

Oxy-acetylene welding and cutting. Resistance welding. Oxy-acetylene welding–pros and cons compared to other welding techniques. Types of gas mixtures for oxy-acetylene welding. Type of flames. Flame zones. Temperatures in the flame. Primary and secondary combustion of acetylene. Flames and gases for oxyacetylene cutting. Conditions for weld cutting. Diagram of steel combustion and melting depending on the chemical contents of steel. Resistance welding – welding without consumable material. Types of resistance welding: spot, seam, projection, flash welding etc.

3. hour 4. hour 5. hour

Procedures and technologies of oxy-acetylene welding and cutting, and resistance welding. The oxidizing, neutral and carburizing flames and their application. Cylinder-tanks, valves, hoses and torches for welding and cutting. Various torches for welding and cutting. Forward and backward travel motion. Thin plate cutting, applications of gas cutting for grooving and automated gas cutting. Regimes of resistance spot and seam welding. Electrodes for resistance seam and spot welding. Nugget formation in resistance spot welding. Quality control of welds by testing.

XI week (laboratory 3 + Test 2)

1. hour (or 5. hour)	Test 2, consists of the theoretical courses from weeks VII, VIII, IX, and X.
2. hour 3. hour 4. hour 5. hour	Imperfections and flaws in materials. Non-destructive testing (NDT). Weldability. Proof and verification of exercises. Laboratory exercises and particular cases: flaw detection in materials: visual inspection, ultrasonic techniques, radiography, penetrants and magnetic techniques, pros and cons of certain inspection techniques.

XII week (laboratory 4)

1. hour 2. hour 3. hour 4. hour 5. hour

Mechanical tests of welded joints. Preparation of material for welding. The welded plate sample is used for producing specimens for mechanical testing of welded joints. Tests include hardness; ultimate tensile strength of the weld metal; and of the welded joint as a whole; testing the toughness at different temperatures. Technology bending test with a tension zone at the weld face and at the weld root. Students should view the material preparation for welding (grooving, cleaning, fixating etc). Laboratory exercises of electric arc welding procedures, oxy-acetylene gas welding and cutting. Demonstration of creating and maintaining the electric arc in SMAW and other arc welding techniques, TIG, MIG, MAG. Problems that usually occur in practice. Demonstration of flame ignition in oxy-acetylene gas welding and regulating the gas torch for developing particular flames. Torches. Practical movement techniques travelling direction and demonstration of gas cutting. Laboratory exercises in resistance welding. The resistance welding equipment, elements and their purpose, selecting the current for spot welding, types of nuggets. Determining the electrode pressure force and the time and current. Welding several spots by different regimes of current and time. Cleaning metal surfaces before welding procedure. Mechanical testing of welded joint and inspection of the selected welding parameters.

XIII week (Lab Test 2)

1. hour

Lab Test 2. Includes lab exercises from weeks XI and XII (laboratory 3 and laboratory 4)

XIV week (optional repeated Test, only 1 of 2 + optional repeated Lab Test 2 + index signature/stamp from the lab. assistant- evidence of constant class attendance of students and active role in exercises)

1. hour	optional repeated Test, only 1 of 2
2. hour	optional repeated Lab Test 2. Includes lab exercises from weeks XI and XII (laboratory 3 and laboratory 4)
3. hour 4. hour 5. hour	Index signature/stamp from the lab assistant. Consultations–concerning the whole course. It is assumed the student has been regular in class and actively took part in the lab exercises.

XV week (January exams)

Exam - written and oral. (See the calendar for specific dates)