'L2T2 Material Technology (Mtrl) 221_241029_094427

Page 1

  • Ir. Hj. Abdul Wahab Ikhsan, Technical Advisor, TWA (M) Sdn Bhd

  • Topic: Railway Welding Material Technology (T2L2)

  • Date: 22.10.2024

  • Week: 2

Page 2: Introduction to Material Technology

1.1 Material Technology or Material Science

  • Definition: Study of materials, which includes raw materials, processing, and production.

  • Material Types:

    • Metals: Ferrous (contains iron) and Non-Ferrous (does not contain iron).

    • Non-Metallic Materials: Includes Plastics and Ceramics.

  • Key Areas:

    • A. Raw Materials

    • B. Processing of Materials

    • C. Production: Shapes and Forms

    • D. Specific Applications

Page 3: Classification of Materials

  • Metals:

    • Ferrous

    • Non-Ferrous

  • Polymers:

    • Thermoplastic

    • Thermoset

    • Elastomers

  • Ceramics:

    • Glasses

    • Crystalline

  • Composites:

    • Metal, Ceramic, Polymer

Page 4: Materials Science

Material Classification

  • Metallic (Ferrous):

    • Steel:

      • Plain Carbon, Alloy (Chromium, Nickel)

      • Cast Iron (Grey, White, Malleable, Ductile)

    • Non-Ferrous Metals:

      • Aluminum, Copper, Magnesium, Tin, Zinc, Lead, Nickel

  • Non-Metallic:

    • Organic: Wood, Paper, Rubber, Leather, Petroleum Products

    • Inorganic: Plastic, Cement, Glass, Ceramic, Graphite

Page 5: Properties of Materials

1.3 Characteristics of Metals and Non-Metals

  • Metals: Good conductors of heat/electricity, malleable, ductile (most are solids at room temp. except Mercury).

  • Non-Metals: Poor conductors and lack malleability/ductility.

  • Metalloids: Intermediate properties, can conduct electricity under certain conditions (important in electronics).

1.5 Grain & Grain Structure

  • Elements consist of grains/crystal formed from solidification, each with unique structure.

Page 6: Ferrous Metals

i(a) : Ferrous Metals - Steel/Carbon Steel

  • Steel: Made by mixing iron and carbon; made tougher with elements like chromium, nickel.

  • Production Process: Heating iron ore in furnaces to produce molten steel, poured into molds for forming.

  • Applications: Construction, manufacturing; carbon steel used for tools due to hardness.

Types of Ferrous Metals

  • Alloy Steel: Incorporates additional elements for strength/durability (e.g., stainless steel).

  • Iron/Cast Iron: Hard, brittle; used in pipes and engines.

  • Wrought Iron: Low carbon, corrosion-resistant, used for fencing and ornamental items.

Page 7: Non-Ferrous Metals

ii(a): Non-Ferrous Metals Overview

  • Aluminium: Lightweight, easily fabricated, used in aircraft and packaging.

  • Copper: Ductile, high conductivity; used in electrical applications.

  • Lead: Heavy, malleable; used in power cables and batteries.

  • Zinc: Low strength, used for galvanizing iron/steel.

  • Tin: Ductile, used to coat steel for corrosion resistance (tin cans).

Page 8: Metal Hardness

  • Grain structure influences hardness; hardness tested using:

    • Brinell (HB): Tests coarse structures.

    • Rockwell (HRC): Measures depth of indentations from minor/major loads.

    • Vickers (HV): Measures hardness with precision, slower process.

Page 9: Brinell Hardness Test

  • Used for materials with coarse structures.

  • High loads applied with a large indenter; diameter measured to determine hardness.

  • Commonly used for rail materials.

Page 10: Rockwell and Vickers Tests

ii. Rockwell Hardness Test

  • Uses a minor load followed by a major load to determine hardness with quick measurements.

iii. Vickers Hardness Test

  • Uses a diamond tip to determine hardness under varying loads.

Page 11: Hardening Processes

  • Work Hardening: Surface hardening through straining.

  • Solid Solution Strengthening: Add alloy to improve strength.

  • Age Hardening: Initial rapid hardening after casting slows over time.

  • Anodization: Hardens aluminum.

  • Case Hardening: Surface treatment for wear resistance.

  • Tempering: Heat treatment for enhanced properties.

Page 12: Impact Resistance

  • Evaluation of metal's resistance to dynamic loads;

  • Charpy Test frequently used to measure impact strength.

Page 13: Elasticity of Metal

Definitions:

  • Elasticity: ability of materials to return to original shape post-deformation.

  • Young's Modulus (E): Ratio of stress to strain used to predict material responsiveness under loads.

Page 14: Ductile vs. Brittle Materials

Differences

  • Ductile: can undergo substantial plastic deformation.

  • Brittle: exhibit minimal deformation before fracture.

  • Ductility influenced by temperature and internal stresses.

Page 15: Characteristics Comparison

  • Ductile Materials:

    • High elongation, gradual failure, can be formed easily.

  • Brittle Materials:

    • Little elongation, sudden failure, not easily formed.

Page 16: Magnetism

  • Occurs due to electron spin creating a magnetic field.

  • Conductors create magnetic fields in the presence of electric currents.

Page 17: Types of Metals

Magnetic Metals

  • Ferromagnetic metals attract magnets:

    • Iron, Nickel, Cobalt, Steel.

  • Non-Magnetic Metals:

    • Gold, Silver, Copper, Aluminum (non-attractive unless alloyed).

Page 18: Ferrous Metals Characteristics

  • Prone to rust, can be magnetically attracted.

Examples of Ferrous Metals:

  • Mild Steel, Cast Iron, High Carbon Steel.

Page 19: Thank You

Page 20: Atom & Atomic Structure

  • Atoms: Smallest unit of matter with chemical properties.

  • Atomic Structure: Consists of nucleus (with protons and neutrons) and electrons.

  • Periodic Table: Arrangement of elements by atomic number.

Page 21: Mechanical Properties

Overview

  • Mechanical properties: Assess material response to loads.

  • Includes yield strength, ductility, hardness, impact resistance.

Changes Due to Conditions

  • Properties vary with temperature, loading rates, and are subject to variability across specimens.

Page 22: Summary of Properties

  • Metal properties influenced by temperature (strength/durability can decrease)

  • Variability in measured mechanical properties requires multiple testing for accuracy.

Page 23: Metals & Their Uses

Mild Steel

  • Used for construction, rusts easily.

Page 24: Cast Iron

  • Strong under compression, used for brake discs and machinery.

Page 25: High Carbon Steel

  • Very tough, used for tools and springs.

Page 26: High Speed Steel

  • Strong and wear-resistant, used for drill bits.

Page 27: Stainless Steel

  • Corrosion resistant, used for kitchenware and surgical instruments.

Page 28: Non-Ferrous Metals Characteristics

  • Examples: Copper, Aluminum, Tin, Zinc (not magnetic, do not rust like ferrous metals).

Page 29-36: Non-Ferrous Metals Usage

  • Aluminum: Lightweight cooking and structural materials.

  • Copper: Excellent electrical conductor for plumbing and electrical components.

  • Zinc: Mainly used for galvanizing steel.

  • Tin: Corrosion resistant coating for food cans.

  • Lead: Heavy, used in batteries and for radiation shielding.

  • Silver and Gold: High conductivity and resistance to tarnish, used in jewelry and electronics.

  • Magnesium: Lightweight metal for pyrotechnics; ignites easily.

Page 37: Brass and Bronze

  • Brass: Copper and zinc alloy, used in fittings and musical instruments.

  • Bronze: Copper and tin alloy, used in corrosion-resistant applications.

Page 38: Solder

  • Fusible metal alloy for joining metal pieces.

Page 39: Metals in Everyday Use

  • Common metals used in bicycles include steel, aluminum, and brass.